View Full Version : The Smaller Advent Loudspeaker


Zilch
07-11-2009, 01:02 AM
Incoming:

http://www.audiokarma.org/forums/attachment.php?attachmentid=158890&stc=1&d=1247288519

http://www.stereophile.com/historical/506advent/index.html

tubed
07-11-2009, 01:07 AM
Nice dust caps. Baby Ewave or ?

vinyldavid
07-11-2009, 01:20 AM
waiting with bated breath for this one, Zilch...

marantzfan
07-11-2009, 01:36 AM
Here is MY challenge...Use the tools availble in 1972 and design a better sounding affordable bookshelf speaker...:yes:

Sir.Byrd
07-11-2009, 01:51 AM
here is my challenge...use the tools availble in 1972 and design a better sounding affordable bookshelf speaker...:yes:

+ 1

Zilch
07-11-2009, 01:55 AM
Nice dust caps. Baby Ewave or ?We have an investigative process here, but they will accept the 6" square waveguides, which easily surpass the original high frequency design performance objectives, yes.

Here is MY challenge...Use the tools availble in 1972 and design a better sounding affordable bookshelf speaker... :yes:Stereophile converted the selling price to $668/pair in 2006 dollars. I'm guessing more like $750 today, which translates to rather high-end on the scale of affordability. Considering the acquisition cost, there is a generous margin for update/upgrade, even at the original early 1970s $139.90/pair price point.

vinyldavid
07-11-2009, 01:57 AM
Here is MY challenge...Use the tools availble in 1972 and design a better sounding affordable bookshelf speaker...:yes:

+2 :yes:

marantzfan
07-11-2009, 01:58 AM
We have an investigative process here, but they will accept the 6" square waveguides, which easily surpass the original design performance objectives, yes.

Stereophile converted the selling price to $688/pair in 2006 dollars. I'm guessing more like $750 today, which translates to rather high-end on the scale of affordability. Considering the acquisition cost, there is considerable margin for update/upgrade, even at the original early 1970's price point.

Well yes and no....You're also limited to driver technolgies that were avaialble then. :D If you're gonna beat Mr. Kloss at his own game, you have to play the same game with the same means....

I'm a stinker ain't I?

Zilch
07-11-2009, 02:19 AM
If you're gonna beat Mr. Kloss at his own game, you have to play the same game with the same means....It's a bit early to tell, but Mr. Kloss himself would appear to have done somewhat better for 1/5 the cost using modern knowledge, materials, and design techniques.... :yes:

marantzfan
07-11-2009, 02:21 AM
It's a bit early to tell, but Mr. Kloss himself would appear to have done somewhat better for 1/5 the cost using modern knowledge, materials, and design techniques.... :yes:

Yes, but then he has to sell them for a profit.......................

Brian
07-11-2009, 04:11 PM
Refoan them and recap and give them a try. I like them better than the original Advent Loudspeaker as the drivers are closer and there is less dip in the crossover region.

I not interested in bringing them back it would be better to resell them as there are many who would appreciate them.

dc270
07-11-2009, 04:44 PM
This is one of my favotite speakers in its size- looking forward to the Zilch version deuce!
DC

BmWr75
07-11-2009, 05:06 PM
Zilch, looks like a couple of meteorites got stuck in the voice coils. :D

BmWr75
07-11-2009, 05:09 PM
Refoan them and recap and give them a try. I like them better than the original Advent Loudspeaker as the drivers are closer and there is less dip in the crossover region.

I not interested in bringing them back it would be better to resell them as there are many who would appreciate them.

You don't know Zilch like I know Zilch.......that request just fell on selectively deaf ears. :thmbsp:

Tiver
07-11-2009, 05:25 PM
Anyone who can suggest the right surrounds for the best price will get things off to a good start. I have two pairs that look just like that (as in rotten surrounds). I have foam for one pair, but would like foam for the other. I can get it locally for a li'l over $20, but I am sure someone reading this thread could cut that cost in half?

I also have a pair that has been refoamed, so I will be able to, with complete subjectivity, compare your creation to the original.

Lead on Zilch :lurk:

Zilch
07-11-2009, 07:43 PM
You don't know Zilch like I know Zilch.......that request just fell on selectively deaf ears. :thmbsp:I DO hear it, of course, but I also hear this:

Some aspects of the Smaller Advent's measured performance were positive. For example, it reminded me of the benefits for bass performance of a well-tuned sealed box, compared with the reflex designs that are now ubiquitous. But despite its relatively even balance through the midrange and low treble, the Advent's tweeter is a total underperformer compared with modern designs, and its cabinet is way too resonant.

http://www.stereophile.com/historical/506advent/index4.html

We'll see what the ZilchLab measurements say, once they are refoamed. There's plenty more to investigate before deciding anything.... :yes:

BmWr75
07-12-2009, 10:14 AM
Zilch, you are like E.F. Hutton to me.......:lurk:

Saint Johnny
07-12-2009, 10:29 AM
Zilch, you are like E.F. Hutton to me.......:lurk:

More like, and I say this with all due respect, and admiration, Columbo!:thmbsp::D

nerdorama
07-12-2009, 11:36 AM
I've used my ewaves with the OLA (took them to the NW AK meet this spring) and some EV SP12's, but I also have a pair of smaller Advents which need repair.

Any advice on a good surround for these?

Thanks,
John

Zilch
07-12-2009, 12:58 PM
More like, and I say this with all due respect, and admiration, Columbo! :thmbsp::DYou've seen the ZilchMobile, apparently.... ;)

budgetaudio6
07-12-2009, 01:40 PM
:lurk:

BmWr75
08-14-2009, 11:16 AM
Zilch,

What's the hold up on these? More projects than time?

BMWR75

barredowl
08-14-2009, 03:02 PM
I am curious to see what happens with these as I have a pair of S.A.s I refoamed that are sitting around doing nuthin'. :)

elseed
08-14-2009, 03:20 PM
I am curious to see what happens with these as I have a pair of S.A.s I refoamed that are sitting around doing nuthin'. :)
Me too! (and the wife's irritated they are stored in her office). I used an E-place source for the foam.

Zilch
08-14-2009, 04:39 PM
O.K., I'll give them priority.

The woofs are refoamed, but the queue is huge.

[Maybe if I put up a poll...? :tongue: ]

Zilch
08-15-2009, 03:46 AM
http://www.audiokarma.org/forums/attachment.php?attachmentid=164968&stc=1&d=1250495956

GordonW
08-15-2009, 08:34 AM
Truthfully, that ain't too damn bad of a response curve. I've seen "high-end" speakers that measured worse! On axis, they're +-3.5dB from 90 Hz and up...

In fact, with a little notch-filter (or crossover tweak) at 1KHz, they'd be remarkably flat.

And they do really measure better with the grille on! I try to tell people...

Regards,
Gordon.

tarior
08-15-2009, 11:23 AM
I, for one, really like the Small Advent the way it is, and better than the OLA.
I don't get the perception that a bright speaker is better.

barredowl
08-15-2009, 01:51 PM
Hole(y) 2K suckout Batman...

Zilch
08-15-2009, 01:56 PM
Hole(y) 2K suckout Batman...Wear protection, folks.... ;)

tarior
08-15-2009, 02:13 PM
Hole(y) 2K suckout Batman...

Built-in Fletcher-Munson curve.;) A fortunate accident perhaps.
Could explain why they are enjoyed by so many folks.:scratch2:

70salesguy
08-15-2009, 02:18 PM
Here is MY challenge...Use the tools availble in 1972 and design a better sounding affordable bookshelf speaker...:yes:

Don't forget, the Advent speakers were "Cash Cows" to fund his R&D for the VideoBeam.

Not a criticism of the speakers, but an explanation for their production.

gkimeng
08-15-2009, 03:22 PM
Wear protection, folks.... ;)
Specifically, one tight layer of 20ct flax linen, about 1/2" in front of the drivers...

Jeff's Class
08-15-2009, 10:40 PM
Maybe a dumb question...but do my Advent/1s count as "smaller Advents"?
Thanks
Jeff

lumpy
08-15-2009, 10:52 PM
The 2k "suckout" is a measurement artifact. It is caused by the crossover between the drivers and the directional pick up of the measuring microphone.

Doug G.
08-15-2009, 11:42 PM
Maybe a dumb question...but do my Advent/1s count as "smaller Advents"?
Thanks
Jeff

Well, they are a smaller Advent and they were meant to replace the original "Smaller Advent" but the lowest octave is hurting with them because the same drivers were used as in the New Advent Loudspeaker only in a smaller box.

The original Smaller Advents have customized woofers so the lowest octave is preserved.

Doug

Zilch
08-17-2009, 03:51 AM
The 2k "suckout" is a measurement artifact. It is caused by the crossover between the drivers and the directional pick up of the measuring microphone.We determined in earlier Large Advent studies that the "fried egg" tweeter interferes with itself and the cabinet recesses and edges producing a conspicuous notch in the response. The grille serves to mitigate the problem, in part, at least, acting as the actual "baffle" at a forward plane. In further substantiation of this thesis, here is the tweeter playing alone without any interference from the woofer:

http://www.audiokarma.org/forums/attachment.php?attachmentid=164967&stc=1&d=1250495458

Compare to Atkinson's measurements of the influence of the grille in the Stereophile review linked at #16, above.

[Measurement mics are omni-directional, BTW.... :yes: ]

Zilch
08-17-2009, 04:10 AM
Inboard Polars:

http://www.audiokarma.org/forums/attachment.php?attachmentid=164970&stc=1&d=1250496249

Outboard here, for comparison:

http://www.audiokarma.org/forums/attachment.php?attachmentid=164968&d=1250495956


The Pair:

http://www.audiokarma.org/forums/attachment.php?attachmentid=164971&stc=1&d=1250496258

Nearfield Bass:

http://www.audiokarma.org/forums/attachment.php?attachmentid=164972&stc=1&d=1250496258

lumpy
08-17-2009, 10:23 AM
Measuring mikes even omnis are not completely omnidirectional.

Zilch
08-17-2009, 01:32 PM
Measuring mikes even omnis are not completely omnidirectional.You are dismissively telling everyone that these measurements are not meaningful, implicitly that the results are not "real," based upon an erroneous thesis. Present a valid one, and we'll discuss that.

In the meantime, perhaps you would enjoy the AudioMojo game:

http://www.audiokarma.org/forums/showthread.php?t=243739

lumpy
08-17-2009, 10:02 PM
No do you have a calibration statement for your measuring microphone documenting on axis and off axis performance?

Zilch
08-18-2009, 12:31 AM
No do you have a calibration statement for your measuring microphone documenting on axis and off axis performance?No, but you're set up to do that, I presume, and will present your findings for this forum's perusal, along with YOUR measurements of Smaller Advents for comparison?

It's a -6 dB hole at 2 kHz, and a -20 dB notch without the grille, even with 1/6 octave smoothing. Not the mic, I guarantee.

There IS a valid thesis, not unrelated to your original observation, and, notwithstanding the fact that these are no longer on the test stand, I'll check it out.

Edit: See below.... :yes:

Zilch
08-18-2009, 01:31 AM
Up:

http://www.audiokarma.org/forums/attachment.php?attachmentid=165134&stc=1&d=1250573342

Down:

http://www.audiokarma.org/forums/attachment.php?attachmentid=165135&stc=1&d=1250573351

devnull
08-18-2009, 06:04 AM
No do you have a calibration statement for your measuring microphone documenting on axis and off axis performance?

For curiosity's sake -- just how many other people on AK have you asked for calibration verification on their gear?

John

lumpy
08-18-2009, 11:11 AM
For anyone doing a scientific investigation into acoustics the test setup must be calibrated and any irregularities must be nulled. As you can see there are significant differences in results based on test mike polarization. At best you can see the Smaller Advent is pretty darn flat across the whole freqency range.

Zilch
08-18-2009, 04:07 PM
For anyone doing a scientific investigation into acoustics the test setup must be calibrated and any irregularities must be nulled. As you can see there are significant differences in results based on test mike polarization. At best you can see the Smaller Advent is pretty darn flat across the whole freqency range.May we see YOUR results on The Smaller Advent for comparison here, please?

You suggest that my measurements are inherently inaccurate, yet they reliably indicate that the Smaller Advent is "pretty darn flat?" Not hardly, with those prominent peaks at 1 kHz and 13.5 kHz, also previously found by others, and the hole at 2.kHz punctuating them, these response anomalies are quite audible.

I have no clue what "test mic polarization" is; you apparently have a recognizable agenda here. If you asked the appropriate questions, I would be pleased to answer them, but thus far, you're not getting it, alas.... :(

marantzfan
08-18-2009, 04:11 PM
Lumpy is a good name for a troll... :D

lumpy
08-18-2009, 09:03 PM
I think you know exactly what I am talking about Zilch. Everyone has an agenda. I never suggested that your measurements are inherently inaccurate by the way. It seems like you did though. I am no troll , I just refuse to drink the punch.

Zilch
08-19-2009, 12:10 AM
Yes, of course.

I've put it in the trebuchet bucket.... :D

RayW
08-19-2009, 01:13 AM
The 2k "suckout" is a measurement artifact. It is caused by the crossover between the drivers and the directional pick up of the measuring microphone.

If it is caused by the crossover and is dependent on microphone position then it is not a measurement artifact, it is part of the speaker's polar pattern.

Measuring mikes even omnis are not completely omnidirectional.

That is a moot point. Zilch is measuring using MLS which is a gated signal and using a mic pointed directly at the speaker. The only signal presented in the charts are direct signal from the speaker so the polar pattern of the mic is irrelavant. If he were trying to measure the diffuse sound field at a certain point in the room then the polar response of the mic would come into question.


As you can see there are significant differences in results based on test mike polarization.

What the heck does that mean? If you're still talking about the mic's polar pattern then, as stated above, it doesn't really matter as long as it is good on axis. Callibration is important, but if it's reasonably flat then you'll get reasonable results.

At best you can see the Smaller Advent is pretty darn flat across the whole freqency range.

Didn't you just try to point out how the mic was skewing the results? If you stand by that reasoning then you can't draw any conclusions from these graphs as they are incorrect.

What I see is +/-4dB or so. I wouldn't call that pretty darn flat.

Ray

lumpy
08-19-2009, 02:30 PM
Actually +- 4db is excellent for a speaker. Especially one that has bass response into the 30 hz range and is so small. It is very flat. The polar pattern of the microphone is significant at the crossover point because the radiator is not a point source at that frequency. The correct way to measure is to measure the individual drivers and splice their curves together.

Zilch
08-19-2009, 03:27 PM
Actually +- 4db is excellent for a speaker. Especially one that has bass response into the 30 hz range and is so small. It is very flat. The polar pattern of the microphone is significant at the crossover point because the radiator is not a point source at that frequency. The correct way to measure is to measure the individual drivers and splice their curves together.Yeah, well, AR used that practice during their "Vintage" years and abandoned it soon thereafter, along with their reverberant chamber; it is so patently deceptive that no manufacturer or scientist does it, since it ignores the interaction of the drivers in the system.

Please study up Dickason and D'Appolito regarding how to measure loudspeakers.

You apparently did not play the AudioMojo game -- all of the contestants measure better than these Smaller Advents.

See also Original Large Advents here:

http://www.audiokarma.org/forums/showthread.php?p=2963942#post2963942

Damage
08-19-2009, 03:44 PM
Originally Posted by John Atkinson in Stereophile
Some aspects of the Smaller Advent's measured performance were positive. For example, it reminded me of the benefits for bass performance of a well-tuned sealed box, compared with the reflex designs that are now ubiquitous. But despite its relatively even balance through the midrange and low treble, the Advent's tweeter is a total underperformer compared with modern designs, and its cabinet is way too resonant.


wtf? I thought the fried egg tweeter was all that and a side of bacon? It's superior to the Jensen dome right?

Zilch
08-19-2009, 03:52 PM
Don't be askin' me how they sound, now.... :nono:

RayW
08-19-2009, 04:50 PM
Actually +- 4db is excellent for a speaker.

The Indignia, designed here on AK, measures out at +/-1.75dB.

The polar pattern of the microphone is significant at the crossover point because the radiator is not a point source at that frequency.

Doesn't matter. The wavefront coming from the driver is still going to be coming at the mic on axis. Whether it's a line source (cyllindrical wavefront), large panel (planar wave front) or a point source (spherical wavefront) has no bearing as long as the mic is pointed at the source. At 1m with a smallish 2-way you're looking at a couple of degrees between the axes of the drivers. Once again, as long as the mic has good on axis response, the polar doesn't really matter.

The correct way to measure is to measure the individual drivers and splice their curves together.

That takes the cabinet and crossover out of the equation. Do you listen to your speakers without the cabinet and crossover?

GordonW
08-19-2009, 05:48 PM
You apparently did not play the AudioMojo game -- all of the contestants measure better than these Smaller Advents.



Yeah, but none of the Mojo test speakers were designed 35 years ago... when there was NO computer test apparatus in existence of the sort that was used to measure the units in that test. Not even to the big boy companies.

And I would say- there's really no way you could say the Unity fullrange speaker in the Mojo test measured as well as the Smaller Advent. That giant hump in the response trumps all the faults in the Advent response.

Also, the Gini speaker really isn't any better, in overall response, from what I see, than the Advent...

I would say that for the price, and the time, that the Smaller Advents were pretty remarkably evenly voiced... probably at least as good as any other small speaker of the day. Other than the mild midrange hump, there's really nothing to annoy, and the speaker is just plain well-balanced through the spectrum...

Regards,
Gordon.

lumpy
08-19-2009, 05:50 PM
The response difference is negligible. Overall power response is also a big part of the sound. I doubt a directional waveguide could match the original sound and reproduce the concert hall balance of the original. The woofer and cabinet are a system and are traditionally measured together. The tweeter is measured separately because interference effects between the cabinet and driver invalidates the measurements. They have no audible consequences

GordonW
08-19-2009, 05:57 PM
The response difference is negligible. Overall power response is also a big part of the sound. I doubt a directional waveguide could match the original sound and reproduce the concert hall balance of the original. The woofer and cabinet are a system and are traditionally measured together. The tweeter is measured separately because interference effects between the cabinet and driver invalidates the measurements. They have no audible consequences

Yes, but the HF driver WILL BE PERMANENTLY MOUNTED in the cabinet. To measure one without the other is a fools errand, IME. And I've measured a lot of them...

How do you know if diffraction interference effects from the cabinet on the HF drivers can be ameliorated by slight changes in baffle positioning or not? Sometimes, you can get 3-4 dB differences in the peaks and dips in the response, just by moving the tweeter around an inch or so sideways on the baffle. Seen it happen lots of times...

Regards,
Gordon.

RayW
08-19-2009, 06:05 PM
Where are you getting all of this "traditional" information? Everyone I know who measures speakers uses a far field measurement of the enclosure, crossover, and all drivers from the high limit (most use 20kHz) down to the frequency where the signal is no longer valid because:
a) the MLS signal reaches it's low limit
b) a gated sine sweep reaches the frequency where the first reflections enter the gate and corrupt the direct sound
c) an anechoic chamber ceases to be anechoic

From that point down a near field woofer measurement is taken and spliced with the far field. If a ported or PR system then the port or PR is measured near field and added to the woofer response and then spliced.

This is pretty much standard practice in the industry.

edit: Gordon types faster than me. Good comments on tweeters and cabs!

lumpy
08-19-2009, 06:07 PM
I don't doubt that diffraction effects can be minimized and that perhaps it is worthwhile if there are no other costs. I just doubt that they can be heard. I think they become even less signficant when you are further away from the system as they are averaged out in the reverberant field.

Zilch
08-19-2009, 06:17 PM
The response difference is negligible. Overall power response is also a big part of the sound. I doubt a directional waveguide could match the original sound and reproduce the concert hall balance of the original.The crashing VHF off axis clearly indicates that the power response is not uniform. This is of little consequence to fans of "concert hall" coloration, which is severely rolled off in the high frequencies. East Coast designers struggled mightily to achieve max dispersion and failed. When Allison finally achieved it, nobody wanted it anymore.

Modern constant directivity waveguides easily accomplish their objective without the concomitant adverse consequences. Omni is dead, and good riddance. The design approach you advocate has long since been repudiated by science, the industry, and the marketplace at large.... :thumbsdn:

And I would say- there's really no way you could say the Unity fullrange speaker in the Mojo test measured as well as the Smaller Advent. That giant hump in the response trumps all the faults in the Advent response.As you certainly know by now, I am not a huge fan of full-rangers, either. :no:

Thank you for looking, BTW.... :thmbsp:

lumpy
08-19-2009, 06:20 PM
Ok If you say it Zilch it must be true. I'm done with this.

Celt
08-19-2009, 06:25 PM
Lumpy, I have to say that despite your statement to the contrary, you are coming off as a bit of a troll. Argument for the sake of argument is not helping to achieve anything. So, let this one go.

RayW
08-19-2009, 06:26 PM
It's not true because Zilch said so. It's true because it's true. He just happened to be the one saying it.

Celt
08-19-2009, 06:28 PM
It's not true because Zilch said so. It's true because it's true. He just happened to be the one saying it.

Exactly.

Zilch
08-19-2009, 06:34 PM
I don't doubt that diffraction effects can be minimized and that perhaps it is worthwhile if there are no other costs. I just doubt that they can be heard. I think they become even less signficant when you are further away from the system as they are averaged out in the reverberant field.The normalizing reverberant field you postulate does not exist in typical home listening spaces. Study up Toole's new book, Sound Reproduction - Loudspeakers and Rooms.

Ok If you say it Zilch it must be true. I'm done with this.I hope, instead, it serves as motivation for you to get set up to measure loudspeakers, learn how to do it and what it means, and experience these correlations with listening for yourself, first hand.... :thmbsp:

KentTeffeteller
08-19-2009, 06:49 PM
Another important thing! These are 4 ohm nominal speakers. Make sure your amplifier or receiver can handle this with aplomb. Henry Kloss forgot more than most loudspeaker designers about good performing bookshelf speakers on a low budget. Many of them are competitive with anything which cost more. After all, he and Edgar Villchur were the fathers of the modern bookshelf speaker system. Otherwise, for full range sound we'd still be using huge cornerhorns.

Brian
08-19-2009, 07:00 PM
I just love discussions like this. Now, I'll go downstairs and turn on my KLH 27 powering my Smaller Advents and forget all about whether the speakers are good or bad based on little curves and simply listen and enjoy the music allowing my ears to appreciate the sound. In the end this is all it is about and matters.

vinyldavid
08-19-2009, 08:38 PM
I just love discussions like this. Now, I'll go downstairs and turn on my KLH 27 powering my Smaller Advents and forget all about whether the speakers are good or bad based on little curves and simply listen and enjoy the music allowing my ears to appreciate the sound. In the end this is all it is about and matters.

....and this is all that truly matters....

Celt
08-19-2009, 10:08 PM
All of you guys who don't care how speakers measure, or understand alignment plots, or how speakers can be improved upon, need to either a.) read up if you are interested in learning, or b.) avoid technical threads altogether.

Zilch
08-19-2009, 10:21 PM
Thank you, Celt.

If nothing else, it should be apparent that I put some effort into acquiring and presenting this data here.... :yes:

lumpy
08-20-2009, 09:11 AM
I acknowledge and respect your efforts Zilch.




Thank you, Celt.

If nothing else, it should be apparent that I put some effort into acquiring and presenting this data here.... :yes:

GordonW
08-20-2009, 10:12 AM
The response difference is negligible. Overall power response is also a big part of the sound. I doubt a directional waveguide could match the original sound and reproduce the concert hall balance of the original.

Had to come back to this a bit.

Why would a directional speaker have any inherent difficulty in maintaining balance? In fact, if it's UNIFORMLY directional (i.e, has uniform balance within it's "cone of dispersion" throughout the frequency range), it should have VERY even power balance throughout the room. Yes, some places in the room will be LOUDER (in a broad-band sense) than others (depending on angle), but the tonal balance (i.e, WRT frequency) should NOT change appreciably.

In fact, the tonal balance from a (uniformly) directional speaker will usually change significantly LESS than with an omnidirectional speaker, in different room locations... because directional speakers don't have NEARLY the problem of wall-reflection cancellations. If you don't spray sound at the wall, floor and ceiling, it won't come back to cause you problems!

In essence... we're starting to find that there is an optimal range of dispersion out there... probably somewhere in the 90 degree range (45 degrees in every direction from center line, maybe skewed a little wider in the horizontal axis and a little narrower on the vertical axis), or thereabouts. This avoids the "painting of the side wall" problems of truly omnidirectional speakers... which pays of GREATLY in better perceived transient response, more uniform power balance distribution in the room with respect to frequency, and even better perceived imaging in many cases.

This is, with the obvious caveat of sometimes having some beaminess in the last octave, one reason why dual-concentric speakers like Tannoys have such good perceived imaging and tonal balance wherever you are in the room... they set themselves up, by having controlled dispersion where it counts, to NOT have so many issues with reflections, cancellations and the like. No speaker design is perfect... but IME, well designed waveguides and dual concentrics seem to have an edge in this department...

Regards,
Gordon.

packrat
08-31-2009, 11:55 AM
Zilch,
Weren't you going to mount the 6x6" waveguide in this? I want to do just that, but the 6x12 won't fit and I don't know where to get the 6x6 I've seen show up in other projects.

Zilch
08-31-2009, 02:52 PM
Zilch,
Weren't you going to mount the 6x6" waveguide in this? I want to do just that, but the 6x12 won't fit and I don't know where to get the 6x6 I've seen show up in other projects.Yes, Part #364914-001, $6 from JBL Pro Parts:

http://www.jblproservice.com/forms/parts_order1.html

Measurements confirm what many here already knew -- these have nearly as good bass as the Large Advents.... :thmbsp:

tarior
08-31-2009, 02:55 PM
Measurements confirm what many here already knew -- these have nearly as good bass as the Large Advents.... :thmbsp:

.....and better mids.:D

packrat
08-31-2009, 06:59 PM
Yes, Part #364914-001, $6 from JBL Pro Parts:

http://www.jblproservice.com/forms/parts_order1.html

Measurements confirm what many here already knew -- these have nearly as good bass as the Large Advents.... :thmbsp:

OK, but I'm not sure JBL pro will deal with me. I'll try a local pro shop, but I expect a $6US part to become a $30CAN part. Is there anything at PE that will work?

Zilch
08-31-2009, 07:17 PM
OK, but I'm not sure JBL pro will deal with me. I'll try a local pro shop, but I expect a $6US part to become a $30CAN part. Is there anything at PE that will work?We used a 7" elliptical from PE for upgrading KLH-17, but the filter had to be tweaked a bit. Same's true for the 6" JBL, but nobody's worked out the detail yet.

You're right that JBL Pro won't ship to Canada, but any of your buds in the US here on AK can reship to you without difficulty as they are diminutive waveguides.... :yes:

saltwater
11-22-2009, 02:16 AM
So did you actually do this? I got a pair coming, just not sure if the tweeters are dead yet.... any pictures of what they look like after the waveguide was installed?

Zilch
11-22-2009, 03:07 AM
So did you actually do this? I got a pair coming, just not sure if the tweeters are dead yet.... any pictures of what they look like after the waveguide was installed?Nothing more as yet, but I may cut in the waveguides tomorrow so y'all can get a look, at least.

They're presently mounted in Boston A60s, but I've pretty much decided to abandon those in favor of these Advents and KLH-6s, using their stock woofers. To make A60s happen, I had to install JBL 116H woofers, the same formula as AR4x, and I have plenty of those around here to work with now, instead.... :yes:

saltwater
11-22-2009, 12:51 PM
so the smaller advent woofer is not up to par with the klh 6's?

Zilch
11-22-2009, 01:25 PM
so the smaller advent woofer is not up to par with the klh 6's?Not saying that, merely that among many available options, I'm concentrating the effort upon trying different combinations retaining the stock woofers rather than repeating the proven approach of gutting down to empty boxes.

Data on an array of vintage acoustic suspension woofers/cabs is here:

http://www.audiokarma.org/forums/showthread.php?t=247274

Brian
11-23-2009, 07:50 AM
The Smaller Advent woofer may be the less desirable for DIY projects as the design criteria was somewhat different than most other woofers. It and the box size were designed to sound like the original Advent but 3 db less efficient. Most woofers do not have this type of design objective. It had to live with a 1 octave reduction in freq response to acheive this. It also had to mate to a specified tweeter whose parameters were set by the tweeter in the larger brother. All in all, The Smaller Advent was a design effort in some interesting ways for the guys and required a more integrated approach from the beginning of the projoct than most designs most likely.

The result was a speaker that sounds like the original and has eliminated the worst of the original's final design.

Zilch
11-23-2009, 12:57 PM
The result was a speaker that sounds like the original and has eliminated the worst of the original's final design.Not, apparently:

http://www.audiokarma.org/forums/showthread.php?p=2872971#post2872971

Don't worry, now, ZilchLab is "resourceful;" there is hope:

http://www.audiokarma.org/forums/attachment.php?attachmentid=180946&d=1258939672

I'm goin' in.... :tongue:

Brian
11-23-2009, 02:04 PM
One problem with the objective system is that not there are things that have not been objectively defined. I believe in the objective measurements as a starting place but not the ending place. The subjective is what is apparent to the ultimate test, what the listeing hears.

Zilch
11-23-2009, 02:32 PM
One problem with the objective system is that not there are things that have not been objectively defined. I believe in the objective measurements as a starting place but not the ending place. The subjective is what is apparent to the ultimate test, what the listeing hears.Let's not presume that objectivists don't also listen.

The Smaller Advents did not rock the world of loudspeaker design, the measurements suggest how they might be improved, and we know how to accomplish what they suggest.... :yes:

Brian
11-23-2009, 02:41 PM
Can they be "improved", possibly but, then do they meet the original design goals of Advent? Probably not. Hence what may be perceived as an improvement may infact not be. You can change anything and deem it an improvement and even have measurements to prove it however, if it moves the final result away from the developer's design goals, then it is only a change and not necessarily a real improvement that should come closer to the original developer's design parameters. It is not an objectivist vs subjectivist argument.

Zilch
11-23-2009, 03:45 PM
Can they be "improved", possibly but, then do they meet the original design goals of Advent? Probably not.Those goals are clear: like many others at the time, the objective was to mate an acoustic suspension woofer having the requisite parameters to play extended bass in a small cabinet with a wide-bandwidth tweeter capable of playing low enough to successfully cross with it in a two-way. That's what the "fried egg" tweeter was about, combining mid and tweeter in a single device, but that approach clearly had issues and compromises.

Fast forward 40 years, and technology has advanced to where it is now possible to economically accomplish those design objectives using a modern compression driver and waveguide such as I have shown above, with the added benefit of constant directivity over a substantially wider dispersion pattern, providing the potential to succeed where Kloss and his contemporaries failed.... :music:

Brian
11-23-2009, 04:32 PM
Incorrect, the stated design goal of the speaker was to make a speaker that sounded the same as the original Advent in a smaller box and had the same output.

To acheive the latter, the result was a speaker 3 db less efficient so the design parameters included it to be a 4 ohm system to utilize the characteristics of a SS amp the within reason will double the output power ending with an spl equiv of the orginal Advent.

The construction parameters you mention are not the same as the design goal.

Zilch
11-23-2009, 04:43 PM
Incorrect, the stated design goal of the speaker was to make a speaker that sounded the same as the original Advent in a smaller box and had the same output.Uhmmm, the fundamental objective is once removed, then, from the lesser one, by that perspective.

We've already "fixed" the original and new large Advents with considerable success; I propose to apply the same principles here.... :yes:

Brian
11-23-2009, 05:39 PM
I'm not sure what you fixed as to the original Advents but, to acheive the orginal goal of The Smaller Advent, you'd need to end up with a pair of The Smaller Advents that were indistunquishable from your "fixed" except for the lowest octave. Assuming your revised original Advent is a better speaker and the cost if put into production met the design goal of Henry as to showing that a very good speaker need not be expensive. Then you'd have acheived success.

I've seen some wonderfully modified cars that take a basic design and turn them into a killer muscle car or road car or whatever by ripping out everything and by investing $10ks to make it into a fantastic car. However, is it better? Not necessarily as the design goal may have been to produce a very basic, simple to repair, low maintenance, affordable, car to be used usually within short disances of the home. By those standards, the modified car is a total failure and not better but far worse.

saltwater
11-23-2009, 05:41 PM
We've already "fixed" the original and new large Advents with considerable success; I propose to apply the same principles here.... :yes:

And i cant wait till to see it, keep up the good work!!

Zilch
11-23-2009, 06:02 PM
I'm not sure what you fixed as to the original Advents but, to acheive the orginal goal of The Smaller Advent, you'd need to end up with a pair of The Smaller Advents that were indistunquishable from your "fixed" except for the lowest octave. Assuming your revised original Advent is a better speaker and the cost if put into production met the design goal of Henry as to showing that a very good speaker need not be expensive. Then you'd have acheived success.You'll find it documented in this forum's largest and most popular thread. :yes:

And i cant wait till to see it, keep up the good work!!At the hand of Wiredguy yesterday, it turned that Bose 301 into something like I've never heard anything Bose ever play before.... :thmbsp:

saltwater
05-18-2010, 08:57 AM
Any update on this?

Zilch
05-18-2010, 01:18 PM
None as yet, alas.

[Ain't as if we been snoozin', tho.... ;) ]

saltwater
05-19-2010, 08:48 PM
Your killing me, these woofers are awesome. But im not feeling the tweeters. To "concert hall" in a way. So im trying to figure out a good sub.

Zilch
05-19-2010, 10:16 PM
Hang on. Maybe this weekend -- working something out.... :yes:

rushfan
05-19-2010, 11:44 PM
I've got a pair of Smaller Advents sitting in a closet, waiting for new foam. I'm getting the urge to do something with them.

Zilch
05-24-2010, 01:34 AM
http://www.audiokarma.org/forums/attachment.php?attachmentid=212113&stc=1&d=1274679258

rushfan
05-24-2010, 04:19 PM
Pretty cool, Zilch!

I confess - I haven't been paying attention. What are we looking at here?

Zilch
05-24-2010, 04:52 PM
EconoWave of Smaller Advent using 6" square waveguide and Selenium D220Ti, left.

The build was documented by member Jonmustang as he did it, and I expect he'll be posting that in this forum.

I haven't worked up a crossover for it yet, but may do that on the PE Tech Talk forum; we did hook it up to a stock one, enough to deem it a "worthy" endeavor.

[Spitball sucker has BASS...! :thmbsp: ]

packrat
05-31-2010, 08:03 AM
That woofer probably has the best fb/Vb of any woofer ever made - I have 5 of them all refoamed and the fb (resonance in the box) for all of them, if I remember correctly, is right around 42Hz. fs is something like 18 to 20Hz! Like the Large Advent woofer the voice coil is wrapped around a copper former so the power handling must be very high. It's also about 84db/w/m so matching it to the 220ti must have taken a bit of padding! I'm interested in seeing what you end up with as I've always felt this was a great woofer in a nice sized (bookshelf sized!) box.

BTW, I don't think the S.A. looses an octave of bass compared to the L.A., I'm pretty sure it matches it with the same fb. Maybe Zilch knows for sure, but the often seen comment that the SA has an octave less bass than the LA seems to be repeated often but with no real proof.

Doug G.
05-31-2010, 08:52 AM
You are correct, packrat.

Those who state the Smaller Advent sacrifices the lower octave are confusing it with the later Advent/1 which does compromise compared to the New Advent Loudspeaker.

The Smaller Advent Loudspeaker was designed to have the same useable frequency response as the original Advent Loudspeaker at a reduced efficiency. It was also designed as a 4 ohm nominal impedence to partly counteract the reduced efficiency.

The "spitwad" woofer of the Smaller Advent was specifically designed for this speaker and the added mass afforded by the "spitwad" allows the lower extension.

The Advent/1 uses the same drivers as the New Advent Loudspeaker in a smaller cabinet. Hence the sacrifice of the lowest octave.

Doug

Zilch
05-31-2010, 12:57 PM
BTW, I don't think the S.A. looses an octave of bass compared to the L.A., I'm pretty sure it matches it with the same fb. Maybe Zilch knows for sure, but the often seen comment that the SA has an octave less bass than the LA seems to be repeated often but with no real proof.Indeed, I compared them and a bunch of other vintage acoustic suspension designs here:

http://www.audiokarma.org/forums/showthread.php?t=247274

Brian
05-31-2010, 01:01 PM
Per the advertised specification and Advent literature, the lowest octave of the original Advent speaker is sacrificed with The Smaller Advent Loudspeaker. The other change was to go from 8 to 4 ohms to compensate for the 3db less efficiency. With the increase in output from most SS amps, the efficiency loss becomes a near non-issue per the literature.

Doug G.
05-31-2010, 05:03 PM
All the Advent liturature I have read indicates that the Smaller Advent has the same response range as the original Advent Loudspeaker.

Could you post the relevant specs. to which you refer?

Doug

ahk26
05-31-2010, 10:15 PM
I am listening to my Smaller Advents right now with a Sansui G-4700 and I am reminded how great these things sound. Clarity and bass are very good. Awesome all around speakers!

Zilch
06-02-2010, 12:07 AM
In process here, now:

http://techtalk.parts-express.com/showthread.php?p=1647899#post1647899