Kappa 9 refurb

[nailzgun]

Well as I mentioned in my last thread I got the Kappa 9's home and was a little underwhelmed by the sound. The wood though is virtually mint (just a couple of spots of paint, now removed) and has been treated with a special finish my buddy makes himself. They positively glow.

The electronics is another thing though. I removed all the drivers and the cross-overs. One of the rear emits is cooked. All the other drivers read great on the multi-meter. I was truly surprised to find the woofers had been replaced with (new) factory units from Infinity. Even more surprising was the labels on the woofers. They were control woofers from the IRS series. accelerometer wires were snipped, but suddenly thoughts of servo controlled Kappa 9'ss ran through my head. Very coool:smoke:.

I called the 'man' at Millersound to ask his opinion regarding this idea and he strongly advised against it. He also suggested that I check under the dust caps to see if there was a foam core filling the voice coil space that tremendously inhibits the drivers ability. This was used to stabilize the accelerometer in these drivers. No foam core and no internal wiring so Infinity had already done this. Mr. Miller also mentioned that the crossovers on the 9's were problematic, specifically the inductors used on the woofers and this was likely the place where my sound problems lie.

So now I have these stunning cabinets sans drivers and electronics. The cross-overs I initially thought to do myself but have access to some truly magical electronic technicians locally so I am sending them out. (The Sonic Frontiers gnomes are all local as is Dan Santoni who does my Threshold gear.) All of these guys are electronic artists who will upgrade these things mecilesssly.

I will also take the opportunity to replace the Wonder Wire with something more transparent internally.

Anyway I will keep you all abreast:scratch2: of my progress.

[Iagent]

Sounds to me like you will have a splendid set of Kappas in the end. I love my Kappa 8s, that I just bought but they too need work.

[Augy]

Well as I mentioned in my last thread I got the Kappa 9's home and was a little underwhelmed by the sound. The wood though is virtually mint (just a couple of spots of paint, now removed) and has been treated with a special finish my buddy makes himself. They positively glow.

The electronics is another thing though. I removed all the drivers and the cross-overs. One of the rear emits is cooked. All the other drivers read great on the multi-meter. I was truly surprised to find the woofers had been replaced with (new) factory units from Infinity. Even more surprising was the labels on the woofers. They were control woofers from the IRS series. accelerometer wires were snipped, but suddenly thoughts of servo controlled Kappa 9'ss ran through my head. Very coool:smoke:.

I called the 'man' at Millersound to ask his opinion regarding this idea and he strongly advised against it. He also suggested that I check under the dust caps to see if there was a foam core filling the voice coil space that tremendously inhibits the drivers ability. This was used to stabilize the accelerometer in these drivers. No foam core and no internal wiring so Infinity had already done this. Mr. Miller also mentioned that the crossovers on the 9's were problematic, specifically the inductors used on the woofers and this was likely the place where my sound problems lie.

So now I have these stunning cabinets sans drivers and electronics. The cross-overs I initially thought to do myself but have access to some truly magical electronic technicians locally so I am sending them out. (The Sonic Frontiers gnomes are all local as is Dan Santoni who does my Threshold gear.) All of these guys are electronic artists who will upgrade these things mecilesssly.

I will also take the opportunity to replace the Wonder Wire with something more transparent internally.

Anyway I will keep you all abreast:scratch2: of my progress.

Nailsgun. Please keep me posted on your progress....I am specifically curious as to what these guys are going to charge to check out your crossovers. I also find it hard to believe that an inductor can be problematic (Unless I have it confused with something else) basically all it is is a coil of copper wire. Again I have heard a kappa 9 that was not bi amped and the bass was very thin. Mine are bi amped and plenty of bass. What a difference it made.

[rabbit]

Nailsgun. Please keep me posted on your progress....I am specifically curious as to what these guys are going to charge to check out your crossovers. I also find it hard to believe that an inductor can be problematic (Unless I have it confused with something else) basically all it is is a coil of copper wire. Again I have heard a kappa 9 that was not bi amped and the bass was very thin. Mine are bi amped and plenty of bass. What a difference it made.

I was going to say the same thing. Unless there is a shorted turn what else could go wrong with the inductors ??

Do you have any pictures of your progress ??

[rroobbcc]

I will also once again add my voice to those who advocate bi-amping 9 Kappas. You won't be able to experience them at their best until you do.

[junkaudio]

biamp or die ,btw the rear tweeter has not mutch effect in the overall sound

[nailzgun]

I was going to say the same thing. Unless there is a shorted turn what else could go wrong with the inductors ??

Do you have any pictures of your progress ??

The iron core inductors that Infinity used with these speakers short out causing grief. It was not something I would have looked for that's for sure. Also here are some pics of my Infinity's. My Ren's in the living room, the new 9's and the 7's they will be replacing soon.

[Augy]

The iron core inductors that Infinity used with these speakers short out causing grief. It was not something I would have looked for that's for sure. Also here are some pics of my Infinity's. My Ren's in the living room, the new 9's and the 7's they will be replacing soon.

Hope you getum fixed up I definatly want to hear how the kappa9 compares to the ren 90 ....Only if you power them right though.:music:

[Spasticteapot]

Hmm. Sounds like there's a pretty penny to be made making replacement Infinity crossovers out of proper parts.

Does anyone have links to the schematics?

[nailzgun]

Hmm. Sounds like there's a pretty penny to be made making replacement Infinity crossovers out of proper parts.

Does anyone have links to the schematics?

I don't have to make replacement crossovers just repair them. No different then having to rebuild the power supplies of older amps because the electrolytics get tired and new diodes and capacitors are faster. In the end you have equipment that cost very little comparatively to what a new system costs and sounds unbelievable.

The schematics are at
http://www.infinity-classics.de/infinity/technik/manuals/Kappa_9_technical_sheet.pdf

[rabbit]

I don't have to make replacement crossovers just repair them. No different then having to rebuild the power supplies of older amps because the electrolytics get tired and new diodes and capacitors are faster. In the end you have equipment that cost very little comparatively to what a new system costs and sounds unbelievable.

The schematics are at
http://www.infinity-classics.de/infinity/technik/manuals/Kappa_9_technical_sheet.pdf

You'll find that the large value bipolar electros in the woofer section still measure ok. They seem to be of a good quality construction according to the ones used in my RS4.5's.

[nailzgun]

Well it's going to be a couple of weeks before the crossovers are done. (Parts and assistance). So I have been thinking about all your advice regarding bi-amping these speakers. I do have 2 Threshold S-500's that I can use, the second is currently driving my Ren 90's. My thoughts though tend toward using tubes for the upper end of these speakers.
I would like some ideas regarding necessary wattage for the mids tweeters section and opinions about whether active crossovers are necessary or not. As my pre-amp does not have dual line outs I will have to come up with some kind of alternative. Just splitting the cables doesn't feel right. Maybe some sort of Tube buffer with dual line outs?

Opinions please
Scott

[Augy]

Well it's going to be a couple of weeks before the crossovers are done. (Parts and assistance). So I have been thinking about all your advice regarding bi-amping these speakers. I do have 2 Threshold S-500's that I can use, the second is currently driving my Ren 90's. My thoughts though tend toward using tubes for the upper end of these speakers.
I would like some ideas regarding necessary wattage for the mids tweeters section and opinions about whether active crossovers are necessary or not. As my pre-amp does not have dual line outs I will have to come up with some kind of alternative. Just splitting the cables doesn't feel right. Maybe some sort of Tube buffer with dual line outs?

Opinions please
Scott

I guess the correct way would be to use an active crossover however I do not use one Bi amping mine. I rely on the speakers crossover system for the mids and highs. I also have two identical amps ( Nak PA-7 200wpc @ 8 ohm ) in a vertical bi amp configuration and it sounds beautiful. The highs are great too. Though at times I wish I had bigger amps for these. But the problem with these speakers is you really need about 2-4 k in amps to run a 1k speaker. Unless you use a pro DJ amp like a crown or qsc for woofer duty.

[rabbit]

I guess the correct way would be to use an active crossover however I do not use one Bi amping mine. I rely on the speakers crossover system for the mids and highs. I also have two identical amps ( Nak PA-7 200wpc @ 8 ohm ) in a vertical bi amp configuration and it sounds beautiful. The highs are great too. Though at times I wish I had bigger amps for these. But the problem with these speakers is you really need about 2-4 k in amps to run a 1k speaker. Unless you use a pro DJ amp like a crown or qsc for woofer duty.

This is not always the case. I use a Harman Kardon Signature Series PA2400 power amp to drive my RS4.5's with no problems. This amp is rated at 170 watts per channel into 8 ohms or 4 ohms depending on the impedance selector and has a high current capability of +/- 100 amps. Circuit wise this amp shares a lot of similarities with the classic top of the line Harman Kardon Citation XX and X-1 amps. It is a wide bandwidth low negative feedback design and it has 4 pairs of high speed Toshiba output transistors per channel and a fully cascoded complimentary differential FET input stage. The last one of these amps went on Ebay for about $200 ;) A bargain by any measure and one of Harman Kardon's best kept secrets IMHO ;)

I don't necessarily listen to my music at ear shattering levels but the HK delivers a well defined bass and goes low when the music demands it !! It easily reproduces transients at frightening levels on Mike Oldfield's Amarok and Blood Sweat and Tears with perfect clarity and without any strain !! I run the system for hours on end whilst I'm in another room and it never shuts down ;) Also when I tried selecting between FLAT and CUT mode on the bass EQ switch I didn't find much difference because of the limits of the room size so I leave it on CUT mode which is easier on the amps although the impedance still drops down to two ohms instead of one.

Of course I would not recommend your common or garden variety power amps, integrated amps or receivers to drive the Infinities. They are just not designed for low impedance loads :nono:

Just out of Interest the Yamaha MX1000 power amp which some others have recommended in the past only has 3 pairs of 2SC3280/2SA1301 12 Amp 120 Watt Toshiba transistors in its output stage whereas the HK PA2400 has 4 pairs of 2SC3281/2SA1302 15 Amp 150 Watt transistors in its output stage ;)

[Augy]

This is not always the case. I use a Harman Kardon Signature Series PA2400 power amp to drive my RS4.5's with no problems. This amp is rated at 170 watts per channel into 8 ohms or 4 ohms depending on the impedance selector and has a high current capability of +/- 100 amps. Circuit wise this amp shares a lot of similarities with the classic top of the line Harman Kardon Citation XX and X-1 amps. It is a wide bandwidth low negative feedback design and it has 4 pairs of high speed Toshiba output transistors per channel and a fully cascoded complimentary differential FET input stage. The last one of these amps went on Ebay for about $200 ;) A bargain by any measure and one of Harman Kardon's best kept secrets IMHO ;)

I don't necessarily listen to my music at ear shattering levels but the HK delivers a well defined bass and goes low when the music demands it !! It easily reproduces transients at frightening levels on Mike Oldfield's Amarok and Blood Sweat and Tears with perfect clarity and without any strain !! I run the system for hours on end whilst I'm in another room and it never shuts down ;) Also when I tried selecting between FLAT and CUT mode on the bass EQ switch I didn't find much difference because of the limits of the room size so I leave it on CUT mode which is easier on the amps although the impedance still drops down to two ohms instead of one.

Of course I would not recommend your common or garden variety power amps, integrated amps or receivers to drive the Infinities. They are just not designed for low impedance loads :nono:

Just out of Interest the Yamaha MX1000 power amp which some others have recommended in the past only has 3 pairs of 2SC3280/2SA1301 12 Amp 120 Watt Toshiba transistors in its output stage whereas the HK PA2400 has 4 pairs of 2SC3281/2SA1302 15 Amp 150 Watt transistors in its output stage ;)

Not sure how the 4.5's compare to the Kappa 9 on the impedence curves but I do know the Kappa's dip below 1 ohm on some frequencies.

[VintInfinity]

I run a Yamaha PC2002M up top (basically an M-2 ruggedized and set up for pro use) and a BGW 500D on the woofers.

I just use the 1/4" input/output loops on the Yamaha to send the signal to the BGW. No active crossover for me and it sounds great to my ears.

The PC2002M also worked fine full range.

[nailzgun]

I am thinking of using a SET tube amp for the upper range. There are 50 watt single endeds available that are not two outrageously priced. My Threshold S 500 II would run the woofers. I think that this should be enough for the mids and highs. Any thoughts?

[rabbit]

I am thinking of using a SET tube amp for the upper range. There are 50 watt single endeds available that are not two outrageously priced. My Threshold S 500 II would run the woofers. I think that this should be enough for the mids and highs. Any thoughts?

Those SET amplifiers usually have high output impedance, lots of distortion and hence produce lots of coloration. They are only really good for driving efficient horn speakers. As soon as they are called upon to drive a speaker with a complex impedance they produce lots of coloration and although this may be subjectively more impressive it probably is not doing your music justice ;)

IMHO if I was you I would use the one Threshold amp to drive the whole speaker rather than bi-amping it. Set the bass EQ switch on the speakers to CUT because it won't make a lot of difference to the bottom end but it will represent an easier load for the amplifier ;)

[nailzgun]

Just wondering, I'm sure the answer has been posted before but is there any audible difference to the bass when the switch is changed fro 'Normal' to 'Extended'?

[rabbit]

Just wondering, I'm sure the answer has been posted before but is there any audible difference to the bass when the switch is changed fro 'Normal' to 'Extended'?

Depends on how good your room is and how it reproduces low bass. If it is relatively small then you'd most likely be wasting amplifier power trying to reproduce the deepest bass that these speakers are capable of. In this case it is better to use cut mode which will represent an easier load to the amplifier. Simplest way to find out is to choose some music with lots of bottom end and switch between the two settings and then see if there is much of a difference ;)

[BrocLuno]

I am thinking of using a SET tube amp for the upper range. There are 50 watt single endeds available that are not two outrageously priced. My Threshold S 500 II would run the woofers. I think that this should be enough for the mids and highs. Any thoughts?

Always thought tubes on top were/are where it's at :) Never quite got the loading issue. When I worked in the theater business, we ran BIG RCA mono blocs with hall heaters (not room heaters) and could shake the front row hard, but still convey clean orchestral pieces. Power and distortion can be controlled and have been for years. IMHO, it's about the design and implementation.

[nailzgun]

My crossover guy is still not back from vacation so odd ideas run through my wee brain. I saw today a bunch of Emims on Ebay and wondered to myself if they would make a good replacement for the Polydomes on the Kappa 9s. Has anyone heard of this being done? I think the Emim would be better sounding than the dome and if it was to be done then pre crossover work would be the time so the values for the mids could be adjusted accordingly. Any thoughts here?

[VintInfinity]

You know, I was pondering that very same question last week.

I would like to know as well... but you would need a way to mount it so it can work as intended, open back and all.

[Tedrick]

It would take some serious re-engineering to make them work. Most EMIMs are designed to operate as dipoles; the backs are open for this reason. All Infinity models that use EMIMs, save the Renaissance 80 and 90, are designed to take advantage of this. You would either have to (a) change the cabinet to allow the back-wave to exit the cabinet (but it would probably not be time-aligned with the rear-firing EMIT which would not be optimal), or (b) attenuate the back-wave inside the cabinet. You'll definitely want to read the Infinity Renaissance White Paper (http://www.davidsaudio.com/Infinity_Renaissance_Technical_Summary0001.pdf) to learn a little about how Infinity managed the back-wave (they used a transmission line).

[VintInfinity]

This MUST be achieved!!

:lmao:

[VintInfinity]

How bad would it sound if you added an EMIM to the side of the cabinet? Which is the only thing I could think of that would be relatively easy. But obviously not properly aligned.

[rabbit]

It would take some serious re-engineering to make them work. Most EMIMs are designed to operate as dipoles; the backs are open for this reason. All Infinity models that use EMIMs, save the Renaissance 80 and 90, are designed to take advantage of this.

You forgot to add the IRS Epsilon, Sigma and Omega which have especially designed heavily damped cavities behind the EMIM's.

http://www.infinity-classics.de/infinity/models/IRS-series+Beta+Gamma-Delta-Sigma-Epsilon-1988-95-98/IRS-Epsilon/IRS-Epsilon-24.jpg

[CAK1]

The Renaissance 80's and 90's are dipole for the EMIM, only they addressed it differently with those speakers than they did with the Omega's, Sigma's and Epsilon's.

The EMIMS for the Rens do radiate backwords and are damped with Daron and foam and exit on either side of the rear plate attached by standoffs to the back of the speaker.

[geoff727]

I saw today a bunch of Emims on Ebay and wondered to myself if they would make a good replacement for the Polydomes on the Kappa 9s. Has anyone heard of this being done? I think the Emim would be better sounding than the dome.....

As a fellow audiophile and Infinity lover, I would implore you to allow those of us who truly need replacement EMIM's for our speakers the opportunity to bid on any ebay drivers unfettered. Save, of course, the ones that are in bad shape. If this is truly an experminent you want to pursue, I may have some decent but partially-fatiguing EMIM's that I would consider selling. But for the good ones that come up, for those of us who need them, please let us buy them.

And, it sounds like you're having some crossover work done already, but you can change out things like the series capacitors with some very high-end models. The results can sometimes be just magical; you could be very pleasantly surprised And, it may totally obviate the desire to try a different driver, which would save you a lot of work as well (soldering is easier than cutting up enclosures). Looking at the schematic, it looks like there are 2 capacitor positions, each one totalling 15uf. I'd be willing to bet that if you replaced those with something like 15uf BlackGate AC caps, or a combination of BlackGate's topped with Mundorf Silver/Oil's with a SONICAP in the 7uf shunt position, you'd open up a whole new window into the midrange of these speakers. And much enhance the capacitor longevity at the same time.

Just a few thoughts...
Thanks,
Geoff

[rroobbcc]

I saw today a bunch of Emims on Ebay and wondered to myself if they would make a good replacement for the Polydomes on the Kappa 9s. Has anyone heard of this being done? I think the Emim would be better sounding than the dome and if it was to be done then pre crossover work would be the time so the values for the mids could be adjusted accordingly. Any thoughts here?
I wondered the same after hearing the midrange performance of Tedricks RSIIb's. BTW, the midrange in the Kappa 8 and 9 also acts as a dipole. The cylinder behind the mid is filled with polyester filling (not too tighly packed) and exits through cloth covered grill opening from the back of the speaker. I suspect the most difficult thing would be creating a decent mounting plate in order to avoid mutilating the 9 Kappas cabinet. Maybe I will try this on of these days.

Rob

[Tedrick]

[EAT CROW MODE] Clearly, I've got a lot to learn still, and my previous post was but misinformed. Having never actually SEEN any of the IRS models, I had no idea that the EMIMs on the Epsilon, Omega, or Gamma operated in dipole configuration. Similarly, I was unaware that the Kappa 9 Polydome operated in as a dipole. As far as the Renaissance line, I was going by what the white-paper mentioned, i.e. that Infinity used a transmission line design to control and dampen the back wave from the EMIMs. Please accept my apologies for my mis-guided but well-intentioned post. [EAT CROW MODE/]

After I posted this, I went back to Infinity Classics to look and learn, and found this cool picture inside an IRS Sigma showing the EMIM chamber:

http://www.infinity-classics.de/infinity/models/IRS-series+Beta+Gamma-Delta-Sigma-Epsilon-1988-95-98/IRS-Sigma/IRS-Sigma14.jpg

Damn, learn something new everyday.

[VintInfinity]

Why did they dampen the EMIM on that model? Why not just use it as normal?

[Bemopti123]

As a fellow owner of a pair of mint Kappa 9s, with rotten foams, I read from a outfit that sells redesigned Kappa 9 crossovers. When I asked the man for an explanation of the virtues of his $900+ per pair crossovers, he sent me a write up explaining the procedure he took in order to rebuild and better the stock crossovers. It seems that the Kappa 8s and possibly the Kappa 9s have some components in the crossovers that are designed to extend the output of the woofers into the lower 30 hz territory, which makes amps see the crossovers as a dead short, therefore the call for biamping and also overpowering them. As the manufacturer explained to me in the email, he said that the re engineering ensured that the speaker frequency would never fall below 6 ohms, thus actually allowing the speaker to be ran with a smaller amplifier without the risk of clipping it. Me being someone who lacks a lot of electric expertise, I cannot but wonder what great things $900+ in new components would do to the sound of the Kappas.

Furthermore, how Bill at Millersound stated, the only reason the stock components fail have to do with the crossovers handling large amounts of current or power when being driven (which means MOST used Kappa 9s will need to have their crossovers rebuilt to specs, if one wishes to run them with massive power.)

I would NEVER attempt to run these speakers without at least 1000 watts per channel, for the lack of power will equate to the frying of the delicate Emit tweeters. So, things like receivers need not apply, unless you want to fry these speakers.

[rabbit]

Why did they dampen the EMIM on that model? Why not just use it as normal?

They were trying to minimize the comb effect that you get because of cancellations between the front and back of a dipole.

[rabbit]

I would NEVER attempt to run these speakers without at least 1000 watts per channel, for the lack of power will equate to the frying of the delicate Emit tweeters. So, things like receivers need not apply, unless you want to fry these speakers.

You can't always go by the power rating of the amp. It's the current capability that is more important. A lot of high powered amps use load line limiting protection in order to prevent the output transistors from destroying themselves when driving adverse loads. What this means is that with a difficult to drive speaker you could find a powerful amp limit prematurely and thus be driven into clipping well before its rated output power. You may not even be aware of the protection mechanism but when an amp clips or limits the EMITS can be overheated and destroyed fairly quickly :(

I use a 170 watts per channel Harman Kardon power amp to driver my RS4.5's which has a high current capability of +/- 100 amps. This amp doesn't use load line limiting but has over current protection which switches the amp off instantaneously if an over load condition exists. So far the amp has never shut down once even with music with lots of deep bass content and the top end is crystal clear ;) No need to bi-amp with this amp ;)

[Bemopti123]

I wholesomely agree with you, Rabbit. When I first purchased the Kappa 9s back in 1989, I had a pair of shitty, I mean, godly shitty Carver M 4.0 ts, which did give out about 1 kilowatts per channel bridged mono, but they simply did not have the guts, or the current to do the Kappas justice. I am very lucky that NO components were sacrificed to the Altar of Clipping due to these inferior amplifiers.

The Kappas reside in ATL, in my mom's place and I got an older H20 250S digital ICE amplifier from Henry Ho to prevent the possibility of current running dry. At 1 ohm, Henry estimated that the modules would produce around 50 Amps or almost 5 kilowatts when there was sufficient current available.

:thmbsp:

[rabbit]

I wholesomely agree with you, Rabbit. When I first purchased the Kappa 9s back in 1989, I had a pair of shitty, I mean, godly shitty Carver M 4.0 ts, which did give out about 1 kilowatts per channel bridged mono, but they simply did not have the guts, or the current to do the Kappas justice. I am very lucky that NO components were sacrificed to the Altar of Clipping due to these inferior amplifiers.

The Kappas reside in ATL, in my mom's place and I got an older H20 250S digital ICE amplifier from Henry Ho to prevent the possibility of current running dry. At 1 ohm, Henry estimated that the modules would produce around 50 Amps or almost 5 kilowatts when there was sufficient current available.

:thmbsp:

Are you talking about the B&O ICE power Class D power amp modules ??

You might find that at that current the voice coils will cook themselves ;)

[rroobbcc]

I wholesomely agree with you, Rabbit. When I first purchased the Kappa 9s back in 1989, I had a pair of shitty, I mean, godly shitty Carver M 4.0 ts, which did give out about 1 kilowatts per channel bridged mono, but they simply did not have the guts, or the current to do the Kappas justice.I also started my 9 Kappa odyssey with Carver amps, using an M1.5t on the woofers with a M1.0t on the top end. While these amps can't handle the 9 Kappas in "extended', they can do an OK job in "normal".

It sounds like the real problem you had was that you bridged the M4.0t's. While bridging increases wattage, it reduces the amps ability to drive low impedance loads. Basically what happens with bridging is that each amp channel sees half of the actual speaker impedance. So if you have a speaker like the 9 Kappa which even in "normal" will dip down a little below 3 ohms, each channel of the bridged amp is seeing a little below 1.5 ohms. Those Carver amps just weren't designed to drive those kinds of impedances. You would have been better off bi-amping the 9 Kappas with the two M4.0t's instead.

All of that said, I would still recommend a different amp for the 9 Kappas. I loved my Carver amps when I was into Polk Audio speakers. However, once I bought my 9 Kappas, I quickly regretted not buying Adcom. At the time (89/90) the GFA-555 was comparably priced and sounded better. I let the look of the Carver gear (which I am still drawn to) sway my decision too greatly. I now use an Adcom GFA-5802 on the 9 Kappas and love it. Eventually I will pick up another for biamping, unless of course I find a Krell KSA-300 at the local goodwill for $20 :D. Until then I am happy with the 5802/Kappa 9 combo.

Rob

[VintInfinity]

They were trying to minimize the comb effect that you get because of cancellations between the front and back of a dipole.

Why does it work undamped on models like RS 4.5, Beta, etc?


No need to bi-amp with this amp

There may be no need, but it sounds so much better when you do. I was skeptical until I tried it.

[davidb]

I am waiting the outcome of the tweeter issue because my 9 has the same problem. I am running mine with an Adcom GFA-5500 in normal mode in a small room and it has worked fine so far. I will bi-amp also when I get the tweeter issue worked out.

[Tedrick]

I also started my 9 Kappa odyssey with Carver amps, using an M1.5t on the woofers with a M1.0t on the top end. While these amps can't handle the 9 Kappas in "extended', they can do an OK job in "normal".

It sounds like the real problem you had was that you bridged the M4.0t's. While bridging increases wattage, it reduces the amps ability to drive low impedance loads. Basically what happens with bridging is that each amp channel sees half of the actual speaker impedance. So if you have a speaker like the 9 Kappa which even in "normal" will dip down a little below 3 ohms, each channel of the bridged amp is seeing a little below 1.5 ohms. Those Carver amps just weren't designed to drive those kinds of impedances. You would have been better off bi-amping the 9 Kappas with the two M4.0t's instead.

All of that said, I would still recommend a different amp for the 9 Kappas. I loved my Carver amps when I was into Polk Audio speakers. However, once I bought my 9 Kappas, I quickly regretted not buying Adcom. At the time (89/90) the GFA-555 was comparably priced and sounded better. I let the look of the Carver gear (which I am still drawn to) sway my decision too greatly. I now use an Adcom GFA-5802 on the 9 Kappas and love it. Eventually I will pick up another for biamping, unless of course I find a Krell KSA-300 at the local goodwill for $20 :D. Until then I am happy with the 5802/Kappa 9 combo.

Rob
Similar experience here, too, except I had a TFM-25 (225 wpc) driving RS-IIIb's. That Carver amp sounded fine in the mids and treble, but could just never grab hold of the woofers and take control of them. The result was flabby, muddy bass. On a whim, I tried an Adcom GFA-555II (200 wpc), and the bass came alive: tight, fast, articulate, and extended. Needless to say, the Carver didn't hang around for longer after that. Only much later did I learn the reason why the Adcom was so much better. With vintage Infinity's, current is your friend.

[rabbit]

Why does it work undamped on models like RS 4.5, Beta, etc?

There is still the comb effect with these speakers but you don't really notice it that much because it is minimized to some extent with the felt dampers on the EMIMS. There is also the other aspect of the effect that the room has on the imaging due the reflections of the rear energy. The difference in design philosophy with the later speakers came about after Arnie Nudell left the company and John Christie took over

There may be no need, but it sounds so much better when you do. I was skeptical until I tried it.
You have to be careful when using different amps in bi-amp configuration and make sure that the gains of both amps are equal otherwise one section could be emphasized over the other and thus sound more impressive ;) Also with the RS4.5 there is a different crossover setting for bi-amp mode which would result in a difference in sound.

[bastek]

Why does it work undamped on models like RS 4.5, Beta, etc?




There may be no need, but it sounds so much better when you do. I was skeptical until I tried it.

Undamped (dipole) EMIMs-EMITs require special consideration on positioning and distance from walls, while enclosed semi-dipole Mids and bipolar Emits are more room friendly.

[VintInfinity]

Thank you both for the answers...

As to bi-amping and levels, I guess I got lucky with what amps I happened to end up with, as the PC2002M has level controls on front and I was able to adjust it to my taste.

[nailzgun]

I read from a outfit that sells redesigned Kappa 9 crossovers. When I asked the man for an explanation of the virtues of his $900+ per pair crossovers, he sent me a write up explaining the procedure he took in order to rebuild and better the stock crossovers.


Would it be possible to post this write-up? Millersound explained to me that the necessary upgrade/replacements would be the Solen caps and all of the shunt chokes as these are the ones that cause the problems. Changing out these runs at about $400 give or take. Then I looked at upgrading the caps in the mid-range as most of the critical musical energy is here and this would add another $300. Mid-base would be somewhat similar so I can see $1000 in changes.

I would be interested to have knowledge of someone who has done this and where the cash is best spent and what improvements should be expected. I would assume that the refurbing recommended by Millersound would restore things and possibly smooth out the top end and provide a little more information and speed from the Emit/Semit combo. I also would assume that upgrading the mid-range would be where the greatest sound benefits would come from.

When looking at caps I started with all the best names Mundorf, V-Cap etc. and found that for speaker crossovers Auricap, Dynamicap and Hoviland are the only companies that have the values necessary to not change the slopes.

I am though having fun trying to source a 0.4mH aircore choke and a 6.5mH iron core choke. I can find a 6.5mH air core but it is big and heavy (7 lbs) and would pose a challenge getting on the boards.

We'll see next week.

[rabbit]

Would it be possible to post this write-up? Millersound explained to me that the necessary upgrade/replacements would be the Solen caps and all of the shunt chokes as these are the ones that cause the problems. Changing out these runs at about $400 give or take. Then I looked at upgrading the caps in the mid-range as most of the critical musical energy is here and this would add another $300. Mid-base would be somewhat similar so I can see $1000 in changes.

I would be interested to have knowledge of someone who has done this and where the cash is best spent and what improvements should be expected. I would assume that the refurbing recommended by Millersound would restore things and possibly smooth out the top end and provide a little more information and speed from the Emit/Semit combo. I also would assume that upgrading the mid-range would be where the greatest sound benefits would come from.

Search for Kappa 9 on this page

http://www.dstechlabs.com/sound/photos.htm

[Bemopti123]

Lets hope my Email message comes up:

bill@dstechlabs.com to me
show details Jul 5

Reply

Hello from D+S Tech Labs, Inc.

Thanks for your interest in our EDC(tm) crossovers for the Infinity Kappa 9's.
New EDC(tm) crossovers for Kappa 9's are $899.00 per pair.
Here's an example of a Kappa 9 re-fit:


New EDCTM Crossovers for a pair of Infinity Kappa 9's



Infinity is notorious for burning up their over-engineered and unserviceable crossovers. Another set of Kappa 9's did just that and came to my attention on July 10, 2004. I do not attempt to repair the existing crossovers for several reasons:

Getting at individual parts for testing and replacement is next to impossible without breaking other parts.
Even if you replaced bad parts, other components will probably go bad very soon.
The resulting impedance sweep of a working Infinity crossover is too demanding on amps, some dropping below 2ohms. This alone warrants a new crossover to be designed.
I always choose to scrap the old crossovers and build new ones, however, one should not attempt this without facilities such as an anechoic sound chamber with a high quality, full-range microphone, a computerized SPL response and impedance sweep measurement system and complete loudspeaker/crossover simulation and optimizing software. I use the LinearX LMS and LEAP systems for this. The EDCTM Procedure I use has proven to be consistently accurate over many years. If you are interested in this procedure, visit the company website at www.dssoundlabs.com. Look at the "Quality First" section and checkout the crossover blurb. Click on EDCTM.

When the Kappa's first came in, I hooked them up to have a listen. My amp went into "Protect" mode almost immediately. The Kappa's had nearly a dead short in the XO's. This was not surprising, so off to the chamber they went for impedance sweeps. Both Kappa's were identical in impedance with the follow data:

Original Impedance Sweep
This graph shows severe instability below 70Hz and above 1.5KHz.


Out come the old crossovers:




Next, the driver array was re-wired into a three-way system. All three tweeters were connected in series, the two mids and two woofers also connected in series. Individual leads from the three driver sections were fed through a temporary plate where the old crossover mounted.



I then began the EDCTM process. Separate impedance and SPL measurements were made of each driver section:





Notice that the midranges drastically fall in response above 1.8KHz. This left a gap in response between the mids and tweeters that could not be helped (poor driver choices). Midranges should play loud to at least 4KHz before giving out. And allowing the delicate EMIT ribbons to fill in the gap would burn them up in no time. So I let them play down as low as possible and then used a forth-order filter to protect them.

This measured data was imported into LEAP and the new crossovers were designed. Biamping capabilities were maintained in the design. Parts were assembled and I began building:



The completed crossover was then connected to each driver lead and transfer functions were confirmed:



I used a first-order filter (6db/Oct) for the woofers. The mids used a hybrid filter with a second-order filter (12db/Oct) on the low end and first-order filter for the upper end. The tweeters used a forth-order filter (24db/Oct). Crosspoints came out to be about 900Hz and 5KHz. I also added impedance flattening and phase stabilizing conjugate networks for the woofer and midrange sections.

LMS measured each driver transfer function as follows. Notice the near "text book" rolloffs of each section. This is due to the conjugate networks added to drivers that produce reactance. Ribbons have no voice coils to produce reactance so the tweeter section didn't need extra components.



The end result:
The total impedance sweep is rock solid at a nominal 6ohms. The frequency response is also very flat except for the gap between the mids and ribbons. This gap turned out to be much less audibly noticeable than expected. SPL measurements were made at two(2) meters since the drivers were spaced apart a fair distance.

Final Impedance Sweep


Final SPL Response
- Show quoted text -

There were some pics and graphs, but the write up is pretty good. The last graph shows a great improvement in the way the drivers complement each other, unlike the original graph showing how ragged the drivers complement each other, which is attempted to be made up to sound good by doing some interesting things in the original crossover.

BTW, the cost of the crossovers is around $900. I think it is not a bad proposition especially if the replacement parts as recommended by Bill at Millersound come up to be around $400. :thmbsp:

[Bemopti123]

I also started my 9 Kappa odyssey with Carver amps, using an M1.5t on the woofers with a M1.0t on the top end. While these amps can't handle the 9 Kappas in "extended', they can do an OK job in "normal".

It sounds like the real problem you had was that you bridged the M4.0t's. While bridging increases wattage, it reduces the amps ability to drive low impedance loads. Basically what happens with bridging is that each amp channel sees half of the actual speaker impedance. So if you have a speaker like the 9 Kappa which even in "normal" will dip down a little below 3 ohms, each channel of the bridged amp is seeing a little below 1.5 ohms. Those Carver amps just weren't designed to drive those kinds of impedances. You would have been better off bi-amping the 9 Kappas with the two M4.0t's instead.

All of that said, I would still recommend a different amp for the 9 Kappas. I loved my Carver amps when I was into Polk Audio speakers. However, once I bought my 9 Kappas, I quickly regretted not buying Adcom. At the time (89/90) the GFA-555 was comparably priced and sounded better. I let the look of the Carver gear (which I am still drawn to) sway my decision too greatly. I now use an Adcom GFA-5802 on the 9 Kappas and love it. Eventually I will pick up another for biamping, unless of course I find a Krell KSA-300 at the local goodwill for $20 :D. Until then I am happy with the 5802/Kappa 9 combo.

Rob

If I had known about the biamping, I would have done it in a heartbeat. The fact is that my Sumo Athena only has 1 sets of outputs, so that would not have been possible. I was too newb back then to understand the intricacies of impedance, current etc... The only thing I remember was that the sound of the Kappas hit me like a Deer looking at a looming Magtruck. Well, now I know and I will never torture any amps that are incapable of doing the Kappas justice. I am lucky that I have not damaged any drivers in the process of learning the ropes of audiophile geekdom. :thmbsp:

[nailzgun]

Lets hope my Email message comes up:

There were some pics and graphs, but the write up is pretty good. The last graph shows a great improvement in the way the drivers complement each other, unlike the original graph showing how ragged the drivers complement each other, which is attempted to be made up to sound good by doing some interesting things in the original crossover.
:thmbsp:

I've looked at the photos from his website. Intriguing... my concerns with the approach lies with extending the S-Emit range down to far, the rear Emit being the same as the front and driving the Polydome K to low. I like the idea of a flat 6 ohm load though.

I have emailed Bill to ask him about several things including what the re-crossed speakers sound like. Great that they measure well but is there improvement to the ears as well?

[Augy]

I've looked at the photos from his website. Intriguing... my concerns with the approach lies with extending the S-Emit range down to far, the rear Emit being the same as the front and driving the Polydome K to low. I like the idea of a flat 6 ohm load though.

I have emailed Bill to ask him about several things including what the re-crossed speakers sound like. Great that they measure well but is there improvement to the ears as well?

I think I would rather keep my kappa's as a five way speaker rather than a three with gaps in the frequency response. I don't think Infinity made a poor driver choice as stated, when kept as a five way speaker theare aren't any gaps in the frequency response. I would like the idea of a lesser load but would not be willing to spend a another grand to do it and I don't think they would sound as good as a three way design. The two mids definatly cover different frequencies as do the semit and emits. They were not designed to cover the same frequencies as the new crossover proposes. I also think the crossovers hold up pretty good as long as you have the right power driving the speaker after all they are at least 20 years old by now. Thinks are bound to happen with vintage components after 20 years. But then I am no techno geek with electronics I know what I like to hear and know just enough about it to get into or sometimes stay out of trouble. :music:

[grateful]

$900 !!!! They have to be kidding.

[Augy]

$900 !!!! They have to be kidding.

Hey Grateful What wednesday are you stopping by. I dont want you to be under the wrong impression of these. Augy

[Tedrick]

Dang, $900 could get you a fine second amp to set up a nice bi-amp rig.

[rabbit]

I think I would rather keep my kappa's as a five way speaker rather than a three with gaps in the frequency response. I don't think Infinity made a poor driver choice as stated, when kept as a five way speaker theare aren't any gaps in the frequency response. I would like the idea of a lesser load but would not be willing to spend a another grand to do it and I don't think they would sound as good as a three way design. The two mids definatly cover different frequencies as do the semit and emits. They were not designed to cover the same frequencies as the new crossover proposes. I also think the crossovers hold up pretty good as long as you have the right power driving the speaker after all they are at least 20 years old by now. Thinks are bound to happen with vintage components after 20 years. But then I am no techno geek with electronics I know what I like to hear and know just enough about it to get into or sometimes stay out of trouble. :music:

Also ironing out that low frequency impedance dip is not a good idea. The impedance dip is there in order to extend the bass response of the speakers. At low frequencies the amplifier needs to deliver more current in order to compensate for a falling frequency response. I can't see how you can remove the impedance dip and still maintain the extended bass response. You can't have one without the other unless you are willing to provide external active equalization. But then the speaker is starting to look so far removed from the original design that you may as well buy another speaker !!

May advice is to refurbish the original crossover where appropriate and use the speakers in non extended bass mode which will be an easier load on the amplifier. You are not likely to hear the difference in bass response in a limited room environment anyway ;)

[Negotiableterms]

...I now use an Adcom GFA-5802 on the 9 Kappas and love it. Eventually I will pick up another for biamping...
The 5802 is the best Adcom has ever produced, and handles the K9s low impedances very well. But, if you really wanht to hear these speakers at their best, bi-amping with either tubes or McIntosh autoformers on the top will maximize their performance.

[nailzgun]

But, if you really wanht to hear these speakers at their best, bi-amping with either tubes or McIntosh autoformers on the top will maximize their performance.

Funny how this has come full circle back to tubes. I think ultimately this will be the way I will go. Return the crossovers to spec (maybe a little better) and then improve the signal supplying the speakers. So the first week of Sept. when my house is emptied of children the repair oddesy will begin. Speakers first then rebuild the amp driving the Kappa 9's (another thread in another forum:D). I'll keep you posted with progress.

[nailzgun]

Well I finally got around to pulling the one crossover out that was causing the problems. After much debate and research I removed the 15mH choke that is in the shunt position on the woofers. This appears to be there to roll of the base somewhere in the 30-40 Hz range with -3db effect at 29Hz. This also takes the extended/normal switch out of play. I also checked the self resetting fuses for the S-Emit and front and rear Emits - 2 not working. As I have lots of good clean power to drive the speakers I have just removed these as well.

The results? ... Immediately the speakers output is now balanced. Prior I had a 4-5 db difference between the good speaker and the 'bad' with the bad one restricted. Bass response seems fine although I have yet to really put this to the test. (Wife at work tomorrow daughter at school... yah baby, testing!!) Havin the two tweeters working again sure helps with the imaging. I' really starting to appreciate the sound comparable to the Ren 90s upstairs. Female voices seem a bit curious but I'm sure this is due to the cement wall behind the speakers.

Anyway that's it for now, I am going to pull the choke and fuses from the other speaker as well and then get comfortable with the sound before the next round of soldering work. (I'm thinking of the caps and chokes for the Polydome, faster with more spacial accuracy)

[VintInfinity]

Interesting... I still have yet to do any work on the crossovers of my Kappas.
:lurk:

[rabbit]

Well I finally got around to pulling the one crossover out that was causing the problems. After much debate and research I removed the 15mH choke that is in the shunt position on the woofers. This appears to be there to roll of the base somewhere in the 30-40 Hz range with -3db effect at 29Hz. This also takes the extended/normal switch out of play. I also checked the self resetting fuses for the S-Emit and front and rear Emits - 2 not working. As I have lots of good clean power to drive the speakers I have just removed these as well.


The 15 mH choke reacts with the 2000 uF bipolar capacitor in order to produce low end boost. Without the 15mH choke you will loose bottom end performance :(

[rroobbcc]

After much debate and research I removed the 15mH choke that is in the shunt position on the woofers.There was no need to pull the choke. Setting the switch to "normal" achieves the same result by opening that circuit path. Open means no current, and no current means the choke does not have any effect.

BTW, are your Ren90s in your basement too? It would be unfair to compare the 9 Kappas to the Ren90s if they aren't in the same environment. As I work on my listening room/HT I have had my 9 Kappa's in the basement, with nothing more than a rug on the floor. Reflections off of the concrete is still overwhelming. I turned all of the pots on the back all the way down to keep the highs and mids from shouting at me. This was better, but you will probably find it tough to get a good evaluation with out some treatments to the area. Fortunately it is an unfinished basement and doesn't have look good, so anything absorbtive that you can hang or lean against a wall would help.

Rob

[rabbit]

There was no need to pull the choke. Setting the switch to "normal" achieves the same result by opening that circuit path. Open means no current, and no current means the choke does not have any effect.

Rob

No that isn't correct. The 15 mH inductor is always in the circuit. The switch just shorts out the 1 ohm resistor in extended bass mode.

[nailzgun]

The 15 mH choke reacts with the 2000 uF bipolar capacitor in order to produce low end boost. Without the 15mH choke you will loose bottom end performance :(

Actually I believe this would be quite the opposite. The 2K uF capacitor (actually 4 x 500 uF) combined with the choke would limit low end frequencies with the capacitors acting as a high pass filter somewhere about 25-30 hZ and the 15 mH choke shunting frequencies below 35 -40 hZ.

After a good work-out with some music that has lots of bass energy and initially took the fuses out on my amp, I am noticing an increase of energy in the bass region that is real tight and at max volume no blown fuse!:D:D

[nailzgun]

I will put my frequency generator on the speakers tomorrow to see exactly what the heck is going on.

[rabbit]

Actually I believe this would be quite the opposite. The 2K uF capacitor (actually 4 x 500 uF) combined with the choke would limit low end frequencies with the capacitors acting as a high pass filter somewhere about 25-30 hZ and the 15 mH choke shunting frequencies below 35 -40 hZ.

After a good work-out with some music that has lots of bass energy and initially took the fuses out on my amp, I am noticing an increase of energy in the bass region that is real tight and at max volume no blown fuse!:D:D

Ultimately the bass rolls off below the resonance frequency formed by the LC circuit, but before then the resonance of the LC circuit boosts the voltage across the woofer and peaks at a certain frequency (around 30Hz). You will see this if you measure the voltage across the woofer. This is what provides the low end boost. Without the LC circuit the cutoff frequency of the system would be a lot higher of the order of 60Hz or more. So even though the capacitor acts to limit the low frequency response it reacts with the inductor to extend the bass response by about an octave ;) The downside is that the impedance is very low around this region and the speaker draws more current from the amplifier, so you need to make sure you have and amp with high current capability ;)

[ji4m]

I believe Rabbit has it correct. I have a pair of RS4b with a similar woofer crossover circuit. The LC circuit is tuned to boost the low-end response. I have simulated the circuit and have measured it acoustically. It works as described.

I added a modification (well, still tweaking) to my RS4b similar to the Kappa "bass extension" switch. This was done to improve the low-end impedance dip (at the expense of some bass output). For me, room gain is sufficient to make up for the change. The pipe organ lover may have a different opinion. Although I have Adcom and Classe amps, I still think this is a useful mod.

[nailzgun]

Ultimately the bass rolls off below the resonance frequency formed by the LC circuit, but before then the resonance of the LC circuit boosts the voltage across the woofer and peaks at a certain frequency (around 30Hz). You will see this if you measure the voltage across the woofer. This is what provides the low end boost. Without the LC circuit the cutoff frequency of the system would be a lot higher of the order of 60Hz or more.

I have simulated the circuit and have measured it acoustically. It works as described.

I added a modification (well, still tweaking) to my RS4b similar to the Kappa "bass extension" switch. This was done to improve the low-end impedance dip (at the expense of some bass output).

Ok, I am not seeing how there can be accoustic boost from this circuit. Maybe a voltage gain with the added resistance going from extended to normal but I am baffled to find math to support gain out of this circuit. Maybe I have missunderstood you guys or maybe I'm just simple.:smoke:

[bastek]

In passive crossovers you can't boost low frequencies (sensitivity or efficiency of the woofer). You can only attenuate bass. But if you do that, you lower the the efficiency of the whole speaker, as mid and high freq. drivers have to be attenuated too.

[rroobbcc]

No that isn't correct. The 15 mH inductor is always in the circuit. The switch just shorts out the 1 ohm resistor in extended bass mode.Went back and looked at the schematic... YEP! You are right. That's what I get from trying to work from a deteriorating memory. Sorry.

[rabbit]

Ok, I am not seeing how there can be accoustic boost from this circuit. Maybe a voltage gain with the added resistance going from extended to normal but I am baffled to find math to support gain out of this circuit. Maybe I have missunderstood you guys or maybe I'm just simple.:smoke:

There will be a boost in voltage across the speaker because of the series LC circuit formed by the 2000uF capacitor and the 15 mH inductor. The amount of boost will depend on the total Q of the circuit which is dependent on the resistor value and the speaker load as well. Because the speaker is part of the circuit the maths is probably not that simple. However you can say that series LC network is sort of like a step up transformer with a relatively narrow band of operation ;) These sorts of networks are used in RF design all of the time.

If you don't believe me, try measuring the voltage across the woofer with a sinewave input as you vary the frequency ;)

[rabbit]

In passive crossovers you can't boost low frequencies (sensitivity or efficiency of the woofer). You can only attenuate bass. But if you do that, you lower the the efficiency of the whole speaker, as mid and high freq. drivers have to be attenuated too.

Yes you can :) Infinity have done it with many of their designs using convention single voice coil and dual voice coil Watkins woofers ;) Some other manufacturers have used similar techniques as well !! It doesn't actually increase the efficiency but like any equalization it just compensates for the lack of efficiency.

It has fallen out of vogue in recent years because the downside is that it makes the speaker harder to drive because their is an impedance dip :(

Then there is the other approach of using active equalization as used in the RSIIb's and some others where the output of the amplifier is boosted in the low end before it drives the speaker ;) It achieves a similar effect of ultimately boosting the drive to the woofer but is much easier on the amplifier from a transistor safe operating area consideration ;) The down side if you can call it that is that you need to use an external active EQ box that usually goes between the preamp and power amp or in the tape loop circuit etc.

[rroobbcc]

Soooo... I decided that I finally wanted to figure out how this 9 Kappa crossover works, and spent sometime doing calculations on the circuit, including what effect there would be if L12 alone or both L12 and C19 would be pulled.

Let me just say now that "rabbit" is absolutely dead-on regarding how the circuit functions. I will also say now that my calculations are only a close approximation, as I did not have absolute resistive and inductive values for the woofers' voice coils. I also pulled out some old textbooks to make sure I still properly recalled the relationships between capacitive and inductive reactance (including phase shift), resistance, and impedance.

What is happening is that the addition of C19 and L12 (along with R8) are causing a very large impedance drop for the overall circuit. This drop is due to two factors. The first is the parallel circuit that L12 and R8 create with L11 and the woofers' voice coils. The second is the interaction of the inductive reactance of this parallel circuit with the capacitive reactance of C19 which is in series with it.

At a given output voltage (remember, amplifiers amplify the voltage of the input waveform) the current which flows is a factor of the impedance that the voltage is applied to (i.e. the speaker's impedance), and the power supply's ability to deliver the required current. Current is the key to understanding how the 9 Kappa achieves its extended bass response, because it is current which travels through a speakers voice coil and generates the magnetic fields necessary to move the driver's diaphram or cone. More current means a larger magnetic field is generated in the voice coil, which leads to more movement and thus more acoustic output.

By presenting a very low impedance to the amplifier, the 9 Kappa crossover causes the amplifier to output very high levels of current within a narrow band of bass frequencies to which it is tuned. After passing C19, this current splits between the two parallel paths which comprise the rest of the circuit. The large majority of the current passes through the path of L12 and R8, with the remaining current passing through L11 and the woofers. While it may seem like a bad thing that so much current bypasses the woofers, the amount of current that they do receive is still far beyond that which would otherwise be available using a more traditional crossover. In fact, at 30Hz the woofers are receiving a little over 4 times the current that they would receive if all components were eliminates except L11 serving as a first-order low-pass filter. So the 9 Kappa crossover does work as advertised (and as rabbit explained), but it uses amplifier current VERY inefficiently, with up to 75% of the supplied current bypassing the woofers. You pay a big price in wasted current for each bit of additional current supplied to the woofers, and this is why the 9 Kappa is sooooo difficult to drive really well.

One last note... I also performed the calculations for the effect of pulling L12 from the circuit, thus eliminating the path parallel to L11 and the woofers. This change does wonders for the impedance curve, keeping it up around 6-9ohms(depending on the actual resistive and inductive values of the woofers). It does however result in an altered response curve which is approximately... 20Hz = +1db, 30Hz = -6db, 45Hz = -4db, 60Hz = -2db. These are estimates based on the electrical calculations. Other factors such as the cabinet volume and resonant frequency, among others, also have an effect. So making this modification as "nailzgun" has done, will likely result in somewhat reduced bass response. However, given the improved impedance curve and resulting easier load on the amplifier, the bass may actually be of better quality. Any reduction in bass output could likely be accounted for using an equalizer.

I feel good about my calculations, but am open to someone explaining how I might have messed it up. Otherwise, I hope this helpful.

Rob

[nailzgun]

I feel good about my calculations, but am open to someone explaining how I might have messed it up. Otherwise, I hope this helpful.
Rob

Thanks Rob, this has actually helped clarify what the heck is going on. Now I have to figure what to do with this understanding regarding these speakers.

On a general note I want to thank you all for participating in this thread. It certainly evolved considerably from its roots and I personally have been dramatically increasing my understanding of how these wonderful speakers work.

So I guess I'm back to my original premise of replacing L12 as it has a short in it and while at it upgrade some of the caps on the board. Given the explanation from Rabbit and rroobbcc this component is essential and the short would clearly rob energy from the speaker and reduce bass in the described regions.

Thanks
Scott

[geoff727]

Very interesting explanation of this circuit!

Assuming this was the entire intent behind the design, why would Infinity choose not to incorporate it on some other models, the Kappa 7, for example?

Geoff

[rroobbcc]

Very interesting explanation of this circuit!

Assuming this was the entire intent behind the design, why would Infinity choose not to incorporate it on some other models, the Kappa 7, for example?

Geoff
Geoff, they do use this circuit on the 8 Kappa, and from what others have said it is also used on some of the older RS series (RS3 and/or RS4???). Regarding the Kappa series, I can only guess at why it is not used in all models. Possibilities that come to mind include...

- perhaps the cabinet design of the 8 and 9, effected the bass response in such a way that the circuit was necessary

- it may have been necessary to smoothly tie in the woofers with the Polygraph mid-bass in the 8 and 9.

- they wanted to strengthen the bass response of the 8 and 9 to differentiate it from the less expensive Kappas.

- they eliminated the circuit in the 5, 6, and 7 in order to keep costs down.

- the circuit requires a fairly stout (read "expensive") amplifier. Someone who could afford a $3400 pair of 9 Kappas might not be scared off by that. Someone buying a $1200 (not sure of MSRP) pair of 7 Kappas might be.

Once again, I am just guessing, but I am sure that some combination of technical, manufacturing, and marketing factors played a role.

Rob

[nailzgun]

I have found a distributor here in Toronto of high end polypropelene caps made in China. Might not be Duelunds but they are suppose to be at least as good as Hovlands and are a fraction of the cost. I got replacements for all the caps from the Midrange up as well as the chokes for the bottom end shunts. 15mH and 6.5mH. The choke on the polydome I changed to an aircoil from iron core.

Let me tell you, there is not much room to get 22uF poly caps on the board, but after much deep thought :scratch2::smoke: I got everything inside and back together. Then I moved the speaker back and hooked it up to compare with the original.

On first listen there is no immediate difference. Except all the drivers now work:thmbsp:. The midrange I expected to be a little repressed until the big new caps break in. They are fast and detailed. So I can't wait until they get to full potential after break-in.

Also I am going to be curious if there is much difference between the sound of the Polydomes with the different inductors. I am not expecting much given the position as shunt but who knows. I am also awaiting aircores for the low-pass 12.5mH choke as I think this should improve bass speed.

[nailzgun]

Well, they are now completely refurbed and holy cow do they ever sound amazing. These now blow the doors off my Ren 90's in every way. Installing polypropelene caps in the midrange to replace the NPE's has made a remarkable improvement. Detail, imaging, realism, voices - everything is better. Replacing the old 15 mH chokes in the low pass with quality Erse chokes has really tightened up the bass and has rstored the lowest frequencies that were missing when I had these bi-passed.
I will shortly return to my original K9 thread and do the detailed comparison to the Ren's, likely next week.

Thanks for everyone's input and help. My speakers could not have turned out better.

[cdfac]

if you don't mind, can you post a list of all the parts and perhaps a total cost? sounds like it was very much worth it, and i'm probably not the only one who'd love a template to follow when getting around to tweaking them. thanks and good job!

chris

[rabbit]

I have found a distributor here in Toronto of high end polypropelene caps made in China. Might not be Duelunds but they are suppose to be at least as good as Hovlands and are a fraction of the cost. I got replacements for all the caps from the Midrange up as well as the chokes for the bottom end shunts. 15mH and 6.5mH. The choke on the polydome I changed to an aircoil from iron core.

Personally I wouldn't use Chinese made caps or any other Chinese made electronic components :(

From the feedback I have gotten from people who actually manufacture electronics they have had nothing but trouble with Chinese components of any sort. Best to stick to the name brand even if they are more expensive.

The last thing you want is a series capacitor in a crossover to short out and burn out the tweeter or midrange drivers :(

[nailzgun]

if you don't mind, can you post a list of all the parts and perhaps a total cost? sounds like it was very much worth it, and i'm probably not the only one who'd love a template to follow when getting around to tweaking them. thanks and good job!


Thanks Chris, in total the parts on the crossovers cost me $193.00 plus tax of coarse. This compared to well over $1000 using high end name brand caps and inductors from PartsconneXion here in Canada. (Which, by the way, has the best selection online by a longshot).

I have attached a diagramed spreadsheet with a list of the mods.

So far everything is holding up OK and I have not had them off except for when working on them for several weeks. I use Stereophile's test CD capacitor break-in track at high volume during the day and low volume when my wife is home.

Scott

[rroobbcc]

Well, they are now completely refurbed and holy cow do they ever sound amazing. These now blow the doors off my Ren 90's in every way. Installing polypropelene caps in the midrange to replace the NPE's has made a remarkable improvement. Detail, imaging, realism, voices - everything is better. Replacing the old 15 mH chokes in the low pass with quality Erse chokes has really tightened up the bass and has rstored the lowest frequencies that were missing when I had these bi-passed.
I will shortly return to my original K9 thread and do the detailed comparison to the Ren's, likely next week.

Thanks for everyone's input and help. My speakers could not have turned out better.
I am glad to hear the positive comments about your mods. Now you have me contemplating which improvements I might want to tackle.

Rob

[Kappa6]

Since I own Kappa 6's and have had them in my house since I bought them in 1991, bass has been a concern. The single 10" woofer in a sealed box configuration simply does not move enough air to make the pictures rattle.

However, I am very pleased with the upper bass, and the rest of the audio spectrum. But, the lower end just isn't there.

I thought long and hard about moving to an 8 or 9, but the power-hungry reputation of both those speakers made me hesitate.

What to do? After all all my speakers really lack, in my application, is lower bass.

What I decided to do was to add a high-quality sub woofer, electronically crossed over at 80 Hz. This configuration relieves my amplifier circuitry from trying to move the 10" woofer in high excursions, especially since a sealed cabinet puts a huge mechanical load on the driver as it approaches xmax. As it moves out, it has to create a vacuum and as it moves in, it has to compress the air in the cabinet with no pressure relief.

After much research, I went with a VMPS larger sub and a dedicated 500W sub amplifier. This satisfies (in spades) my fiendish need for accurate, impactful bass and has allowed my main amp plenty of headroom to power the upper bass, the Polydomes and the EMITS.

After all The load the speakers present at lower frequencies are not only electrical, but also the mechanical aspect, especially odious in the "oil can" configuration of a sealed cabinet.

Anyway, the overall solution was in the vicinity of $1000.

Gee, I never really thought about the cost before.... :tears:

[VintInfinity]

:thmbsp:

[VintInfinity]

uploading parts list as html for anyone that doesn't have MS excel. I had a free 30 day trial waiting to be installed I guess, so I saved it as something I can use later.

[Augy]

Well, they are now completely refurbed and holy cow do they ever sound amazing. These now blow the doors off my Ren 90's in every way. Installing polypropelene caps in the midrange to replace the NPE's has made a remarkable improvement. Detail, imaging, realism, voices - everything is better. Replacing the old 15 mH chokes in the low pass with quality Erse chokes has really tightened up the bass and has rstored the lowest frequencies that were missing when I had these bi-passed.
I will shortly return to my original K9 thread and do the detailed comparison to the Ren's, likely next week.

Thanks for everyone's input and help. My speakers could not have turned out better.

Just curious I read your upgrades and am wondering why you would bypass the safety fuses in the crossover for the emits and polydome, They are for protection?? Just curious!!

[nailzgun]

Just curious I read your upgrades and am wondering why you would bypass the safety fuses in the crossover for the emits and polydome, They are for protection?? Just curious!!

When I was checking the crossovers initially I found that the fuses which are self resetting were malfunctioning and a couple were stuck open. I thought about replacing them but after several discussions and a reasoning for the fuses earlier in the thread I decided they were most likely in the design to protect from clipping overload. For the last couple of years, try as I might I have never got my Thresholds to clip. Even today I was airing the speakers out a bit and had a meter on the amp. 70v and peak amps of a little over 20:thmbsp:. Still had some room left on the dial but my ears were starting to bleed!:D Not a hint of a clip.

And boy do these speakers sound unreal!

[Augy]

When I was checking the crossovers initially I found that the fuses which are self resetting were malfunctioning and a couple were stuck open. I thought about replacing them but after several discussions and a reasoning for the fuses earlier in the thread I decided they were most likely in the design to protect from clipping overload. For the last couple of years, try as I might I have never got my Thresholds to clip. Even today I was airing the speakers out a bit and had a meter on the amp. 70v and peak amps of a little over 20:thmbsp:. Still had some room left on the dial but my ears were starting to bleed!:D Not a hint of a clip.

And boy do these speakers sound unreal!

Now I understand....Glad to hear you got the right amplification and as a Kappa 9 owner myself I'm glad you hear the magic. I agree they are beautiful sounding speakers. Enjoy Augy:music:

[automojo]

I have to agree the PA-2400 is one of the best amps I have heard period, and probably one of the best kept secrets. Interesting comparasion to the Yamaha.
I picked mine up on Ebay as well for around $240.00- it would easily be a bargin at twice the price.
My Klipsch KG 5.5's provide a realitively easy load for the H?K, but boy does it make them sing! The detail, low distortion, extension top and bottom is just amazing-effortless sound-amazing.

[chasmo]

Hi,
Just noticed the thread. (Nice work BTW)

Anyway, I was wondering if anyone here knows the specified/actual crossover frequencies of the S-Emit super tweeters,
and the rear-firing Emit-K's ?

Thanks in advance,

-chas

[nailzgun]

Well I finally think that the new capacitors are finally stabilized through burn in period and so I decided to see what the response curves looked like so I got myself spl meter and some earplugs and the Stereophile set of test cd's.

What I've measured seem to confirm earlier discussion in the thread and other information sources. Anomalies exist around the crossover points that can swing 6-7 dBs most notably centering around the 80hz point where there is a drop of 8dB from mean and 10db from max spl in the bass region at 30hz. There also seems to be a peak around 8khz that matches the spl of the 30hz peak.

Bass extension was measured to -3dB to 23 hz dramtically dropping off below that with a 10db drop at 20hz.

Extension in the S-Emit was to about 17khz with no appreciable sound at 20khz measurable. (I don't know if that is the meter or the tweeters, my ears definitely can't hear anything:tears:)

Some interesting room anomalies popped up but could be changed with moving the speakers. Ass to the room it is an untreated basement space with size 30' x 35' with the speakers 10' apart, 4' from the one side wall and 2' from the back wall. Seating is approximately 16' back from the mid point.

I did test maximum spl for the cement heads among us :smoke: (me included) and reached 120+ at the listening position before the fuses on the amp departed. First time since the rebuild! Normally I would not be listening at this level as it was uncomfortable even with ear protection. Cool though as there was no distortion that I could discern. :ntwrthy:


Anyway, I was wondering if anyone here knows the specified/actual crossover frequencies of the S-Emit super tweeters,
and the rear-firing Emit-K's ?

As to the crossover frequencies, rear emits cross at same as the front emits and the S-Emits cross at 10k up.

I am off for more fuses. BTW I have now tried bi-amping with two Threshold S-500s instead of one and really did not experience any appreciable improvement. Admittedly if I wanted to listen above 120dB for extended periods I would have to bi-amp but that is not likely to happen anytime soon. Thanks everyone for you input, I have enjoyed this project tremendously.

[rroobbcc]

Odds are that the microphone in the spl meter is responsible for the lack of measurable output beyond 17KHz.

The sharp drop-off below 23Hz would be due to the high-pass filter which makes up the woofers' crossover circuit.

Also know that without performing your measurements in an anechoic chamber, you were also measuring your room response and the speakers interaction with room based on their placement.

Rob

[rabbit]

I am off for more fuses. BTW I have now tried bi-amping with two Threshold S-500s instead of one and really did not experience any appreciable improvement. Admittedly if I wanted to listen above 120dB for extended periods I would have to bi-amp but that is not likely to happen anytime soon. Thanks everyone for you input, I have enjoyed this project tremendously.

There is no need to be testing at such high SPL's as you risk burning out the drivers and /or amps :(

[rabbit]

I have to agree the PA-2400 is one of the best amps I have heard period, and probably one of the best kept secrets. Interesting comparasion to the Yamaha.
I picked mine up on Ebay as well for around $240.00- it would easily be a bargin at twice the price.
My Klipsch KG 5.5's provide a realitively easy load for the H?K, but boy does it make them sing! The detail, low distortion, extension top and bottom is just amazing-effortless sound-amazing.

I am glad you like it ;) It works wonders with my RS4.5's with plenty of bottom end grunt and crystal clear top end. A great match for the EMIT's and EMIM's. They go cheap on ebay because not many people know about them but I haven't seen many lately so maybe people have cottoned on to them ;)

[nailzgun]

Odds are that the microphone in the spl meter is responsible for the lack of measurable output beyond 17KHz.

The sharp drop-off below 23Hz would be due to the high-pass filter which makes up the woofers' crossover circuit.

Also know that without performing your measurements in an anechoic chamber, you were also measuring your room response and the speakers interaction with room based on their placement.

Rob

Your right on all 3 points here Rob. I was expecting the sharp drop off though to be at 29hz as per spec. I am pleasantly pleased with the bass extension.

As to room placement I took measurements with each speaker independently as well as together. Agreed this is not comparible to anechoic measurements but then again I don't listen in a perfect room and the test started as a means of smoothing out room interactions as much as possible.

Rabbit, I only cranked the speakers after running the tests at a range of 60-70dB.