Zilch's AK Design Collaborative - Econowave Speaker

[jackgiff]

I just eMailed him, proposing to also send him your new pair of waveguides which just came in, as well.

If this all works out, they'll be routed to you via Novi, MI.... :thmbsp:

Cool, that will work out good for me.

I received my CX-3400, but don't have cables yet. And I would rather work with a new set of waveguides and drivers than get up and unload my garage speakers.

In the meantime, I have to finish my latest furniture project, a redwood slab based sofa table. Just finished oiling it with Watco Natural Danish oil, and now it needs a few coats of polyurethane varnish. Pics here are before oil and after.

Edit: OK, the Seleniums are on the way. It will be good to see what he thinks of the EconoWave.

 

[ttan98]

Hi,

Some of you chaps are very familar with JBL bass drivers, I have 2 (15")woofers extracted from left-over of a JBL outdoor speakers 2 way speakers. The model is:MR825

The model no of woofer is 2032H, with t/s
qts:0.54
qes=0.6
qms=5.5
fs=57Hz
vas=133l
spl=98dB

will the woofer work well with the SElenium and PT-F95HF horn? I think so but
I suspect the bass would not be that strong, ie go very low.

any comments

 

[GordonW]

You might be able to make it work... with a LC "shelf" filter.

This would, in essence, reduce the sensitivity of the driver in the midrange.

I'd probably go for a frequency of about 150-200 Hz for the transition (ie, pick a resistor to reduce output about 2 dB, and an inductor that would give a low-pass crossover at about 150-200 Hz with THAT value of resistance).

With this, I'd then tune the woofer lower than expected, in a normal alignment... say, about 20% lower in frequency, in a box that's maybe 10-20% bigger than normal tuning.

This should give an effective bass rolloff, quite a bit lower than would be predicted for those woofer parameters. I'd expect to get at least down to around 40 Hz or so, probably...

Regards,
Gordon.

 

[Zilch]

What Gordon said.

They're in the box modeling databases for you to work with.

Tuned low, they'll play low, but you've gotta give up ~10 dB in efficiency to get there.... :yes:

 

[Greyhawk17]

E-Waves........

I'm using JBL 123A-1s. !2".
I have Heresys as well. Mine have K-22"K"s, I think. I don't know if it's useful to you, but I could do a nearfield RTA measurement if you need to look at FR for crossover purposes.

I don't know what polyfil is made of. If it's Dacron, Diskason does a comparison of that material to Fiberglass in his book. I like the concept of keeping glass fibers out of my lungs, but it seems to be the most effective overall in damping standing waves, lowering Q and lowering resonant frequency. We'll see. You saw my 50Hz bump....
:scratch2:

Skywave-rider,
JBL's, cool, thought about that too, but had no 'extra' 12's without taking
appart a set of speakers...Have a pristine pair of 82' K-22"K"'s, but decided
on the EF's because of the deeper bottom end, and the extended top end
to better fit the 'project' parameters.....Poly-fil is spun polyester, works
great, and NO allergic problems as with fiberglass......I decided to initially
stay with the Nova 8B cabs, inspite of the 1.8 cuft, if after testing they
don't 'dig' deep enough, I can cut out the bottom of the cabs, and extend
them, possibly another 6" or so.....On the crossovers, going with the 4/05
/08 post/schematic, using the 1.5, because the K-22EF's are 95.5-98.0....
Appreciate the nearfield offer, I'll see how things progress later this week.
Take Care, T

 

[Greyhawk17]

Great work Jack!...........

Cool, that will work out good for me.

I received my CX-3400, but don't have cables yet. And I would rather work with a new set of waveguides and drivers than get up and unload my garage speakers.

In the meantime, I have to finish my latest furniture project, a redwood slab based sofa table. Just finished oiling it with Watco Natural Danish oil, and now it needs a few coats of polyurethane varnish. Pics here are before oil and after.

Edit: OK, the Seleniums are on the way. It will be good to see what he thinks of the EconoWave.

Howdy Jack,
Your table looks great! I built one out a 6.0' redwood burl some years back,
and this may inspire me to build another this summer......Manzanita is a nice
desert wood to work with, though sometimes tough on blades, Cheers,T:thmbsp:

 

[skywave-rider]

.....Poly-fil is spun polyester.....

Duh! How could I not figure that out.:stupid:
OK, I see it around on-line in 12 oz. bags.
Let me know if you have a bulk supplier.

I like the Klipsch stuff, not the k-77 tweeter, though.
You won't have that issue, however.

 

[Greyhawk17]

E-Waves........

Duh! How could I not figure that out.:stupid:
OK, I see it around on-line in 12 oz. bags.
Let me know if you have a bulk supplier.

I like the Klipsch stuff, not the k-77 tweeter, though.
You won't have that issue, however.

I bought several large bags on sale at Michael's Arts & Crafts supply, and
as I remember it was a 'fraction' of PE's price,....Think Michael's has a web
site, Google it.....As for the Klipsch tweeters, Bob Crites has a good drop in
replacement, Recommended........Take Care, T

 

[ttan98]

It looks like I am the only one from DIYAudio who found that a cheap JBL horn that can give excellent performance is coming to this forum is curious enough to ask more questions here?

Where are the rest? Not interested in cheap but excellent horn?

I am waiting for Gedlee to find out whether it has any limitations eg. off axis response performance.

This horn is too cheap not to try a pair no matter what the outcome of Gedlee's findings are. I am from overseas(Australia) hence I made request to JBL spare parts department to buy a pair, request turned down(This is the truth). Anyone wants/volunteers to send me 1 pair(new or used) of PT-F95HF, I will pay the costs of the parts plus all postages incl. local & USPS International, I prefer to pay you via Paypal.

Also, I found the RCF, H100 horn to be very good too $28 each. I am using it with B&C DE250 without equalizing, it gives me relatively flat response if you are fussy some eq. is reqd. above 9Khz. My X-over is around 1.7KHz.

cheers.

 

[Zilch]

It looks like I am the only one from DIYAudio who found that a cheap JBL horn that can give excellent performance is coming to this forum is curious enough to ask more questions here?

There have been maybe 1000 "extra" views in the last 24 hours. DIY folks are looking.

I am waiting for Gedlee to find out whether it has any limitations eg. off axis response performance.

I am confident that Earl will find the waveguides good, but not as good as his.

Anyone wants/volunteers to send me 1 pair(new or used) of PT-F95HF, I will pay the costs of the parts plus all postages incl. local & USPS International, I prefer to pay you via Paypal.

I will order you a pair tomorrow....

 

[ttan98]

Zilch,

Many thanks...

Tell me the total cost, USPS postage is about $35-$50(costs more than the horns) depending on the weight. I will pay you prior to you posting. Once you are ready to send, you can message me (address from my profile), I will send you details of postal address.

cheers.

 

[Zilch]

Let's hope there's still some stock left. :

Note: The part you posted, PT-F95HF, calls out the 1.5" throat heavy composite version, not the 1" thread-on economy one. Try again locally with the correct part number, if you didn't already, 338800-001.... :yes:

 

[ttan98]

Let's hope there's still some stock left. :

Note: The part you posted, PT-F95HF, calls out the 1.5" throat heavy composite version, not the 1" thread-on economy one. Try again locally with the correct part number, if you didn't already, 338800-001.... :yes:

Maybe I misunderstood, I prefer the 1" throat version.

 

[Jerv]

It looks like I am the only one from DIYAudio who found that a cheap JBL horn that can give excellent performance is coming to this forum is curious enough to ask more questions here?

.....

I am waiting for Gedlee to find out whether it has any limitations eg. off axis response performance.

This horn is too cheap not to try a pair no matter what the outcome of Gedlee's findings are. ......

Not the only one...(though this is my first post here)

I have both the Geddes 10" waveguide and the JBL econowaveguide on order. And a couple of JBL, B&C and Beyma drivers (for starters) to try them with.

 

[ttan98]

Not the only one...(though this is my first post here)

I have both the Geddes 10" waveguide and the JBL econowaveguide on order. And a couple of JBL, B&C and Beyma drivers (for starters) to try them with.

When you have to evaluate the econowaveguide, please give us you opinion, particularly in comparison to Gedlee waveguide, most viewers here would be most interested.

 

[Russellc]

Not the only one...(though this is my first post here)

I have both the Geddes 10" waveguide and the JBL econowaveguide on order. And a couple of JBL, B&C and Beyma drivers (for starters) to try them with.

Would it be possible to post aphoto of the 10" Geddes waveguide? Is there a site that shows them, and pricing?

Russellc

 

[Jerv]

When you have to evaluate the econowaveguide, please give us you opinion, particularly in comparison to Gedlee waveguide, most viewers here would be most interested.

Will do when I get them. :yes:

 

[skywave-rider]

Might be something like this:
http://www.ai-audio.com/products_esp15.html

Look here:
http://www.ai-audio.com/waveguides.html

Can't find a better picture yet:

The foam suggest something in the middle -- it's actually an open cell phase plug, I assume denser in the center. Theory, as read above, to reduce diffraction effects in the horn. Sound bouncing from "side to side" within the horn itself.

Would it be possible to post aphoto of the 10" Geddes waveguide? Is there a site that shows them, and pricing?

Russellc

 

[skywave-rider]

More info on Geddes conical with foam attached.

 

[skywave-rider]

Getting There

Hi,
I have crossovers done, no new baffles yet. Check this RTA. I had a hole around 2 or 2.5 kHz, reversing polarity only moved it down to 1.5 or so, and looked worse, so I kept designed polarity and moved the waveguide. This is the best I got so far, about 2 inches out from front of current baffle. Given that the JBL 123A-1 has a shallow depth, does this seem reasonable? I estimate that the voice coil of the Selenium is now approx. 2 3/4" back from the baffle.

This is somewhat critical because if I am to keep this physical arrangement, I won't mount the waveguides in the new baffles. I'll have to keep them on top.

Ideas, suggestions???
:scratch2:
RTA at 1 meter, on axis:

LF on dummy load:

Waveguide forward of baffle: