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Zilch's AK Design Collaborative - Econowave Speaker

Zilch said:
Plasterers perforate plastic. ;)
Click to expand...

Spoke to my brother about the plaster on plastic, won't stick apparently.
He also said:

"When plying skills particular to plaster of Paris, audiophiles are poor, but persistent, pretenders. Puréed sand and epoxy is preferable."

I said, "OK."
 
Econo Wave Guides...........

skywave-rider said:
Spoke to my brother about the plaster on plastic, won't stick apparently.
He also said:

"When plying skills particular to plaster of Paris, audiophiles are poor, but persistent, pretenders. Puréed sand and epoxy is preferable."

I said, "OK."
Click to expand...
SWR,
At least you are passionate about prerequisites for perfecting production,
parameters.........Eh!....Cheers, T:thmbsp:
 
Last edited:
Econo Wave Guides...........

skywave-rider said:
Haha.
Thanks.
I like "SWR"
Standing Wave Ratio.
Never thought of it.:thmbsp:

How's ur project going?
Click to expand...

SWR,
Slowly this week, illness in family.....Most of the parts in hand, got template
made for baffles, hope to have some 'extra' time for flinging sawdust soon,
am excited/impatient, still have not decided whether to 'extend' cabs, similar
to what Zilch did, but have extra MDF on hand....Hope to have some photo's
next week.....Take care, T
 
Zilch said:
Earl Geddes's measurements of the the EconoWave polar response are now posted on the GedLee website:
http://140.174.80.168/downloads/Horn VS waveguide.pdf
[With commentary.... ;) ]
Click to expand...

The Geddes results are not honest results. That is a bold claim, but the data support the claim.

All it takes is a comparison of the NON-Eq'd charts with the EQ'd charts to see that Geddes has EQ'd his waveguide to present optimally, while leaving the JBL waveguide to present less than optimally. The end result is an optical illusion that portrays his product to be superior. Let's explore the results.

Geddes game 1: EQ
a. Add 20db EQ to the top end in order to present a flat response, but not mention it.
b. EQ out the bump at 15k, so frequency response appears flat
c. EQ out the bump at 2.2k, so frequency resonse appears flat
d. FAIL to add similar EQ to the EconoWave 1k-1.6k. Off axis repsonse in this region is almost perfectly decreasing for the EconoWave, but the whole level is just low.
e. FAIL to use EQ to fix the bumps that are constant in their off-axis response on the EconoWave. The bumps are 6khz and 12khz are two examples of non-linear frequency response that can be EQ'd out to make the system present best, but Geddes did not EQ them out.

Geddes game 2: Fail to mention the 5db suckout on-axis in his design. Every now and then, people may find themselves on-axis when listening to speakers in the home environment.

Geddes game 3: More EQ. The frequency response from 600hz-1khz has been EQ DOWN on the EconoWave. The unEQ'd response was down ~12db before he added the EQ, but then it was down ~18db after he added the EQ. This makes his waveguide APPEAR to have a lower point of controlled directivity.

I suppose more observations will be made as people study the results, but at this point, my conclusion is the EconoWave/JBL waveguide is almost as good at maintaining directivity control as the Geddes waveguide, yet the EconoWave doesn't suffer from the strange artifact of on-axis suckout. So, all this considered, I don't see a clear performance winner here.
 
skywave-rider said:
Spoke to my brother about the plaster on plastic, won't stick apparently.
He also said:

"When plying skills particular to plaster of Paris, audiophiles are poor, but persistent, pretenders. Puréed sand and epoxy is preferable."

I said, "OK."
Click to expand...

This can be purchased in an easy to use kit form as: Epoxy Tile Grout
I recommend Laticrete SpectraLOCK, cleanup is easy.
But it won't work unless you drill a gazillion holes in the plastic and make sure to key the epoxy to the substrate by pushing back on the inside.

fcc
 
publius said:
I suppose more observations will be made as people study the results, but at this point, my conclusion is the EconoWave/JBL waveguide is almost as good at maintaining directivity control as the Geddes waveguide, yet the EconoWave doesn't suffer from the strange artifact of on-axis suckout. So, all this considered, I don't see a clear performance winner here.
Click to expand...
Thank you for posting your analysis. I went over some of that in the DIYaudio thread, and recognizing that his own viewpoint was perhaps not as unbiased as he may have initially supposed, Earl apologized in writing there for any unfairness in the presentation. That's good enough for me, but I may still write up my own commentary in counterpoint and ask that he publish it along with his:

http://www.diyaudio.com/forums/showthread.php?s=&threadid=123426

As I said from the start, "The data speaks for itself; everything in context," and I believe most everyone understands that context. We all appreciate Dr. Geddes's having taken the time to measure our little project in comparison to his product; I don't believe any of us had any expectation that it would eclipse or outclass his life's work, and certainly not from his perspective.

It's all good, in my view. There's been a lively discussion over there, and we've all learned a lot. The experience has been extraordinary in many respects, and EconoWave has done exceedingly well. Bottom line: it's about knowledge and data, and I look forward to working with GedLee again in the future.... :thmbsp:
 
I was unaware of the discussion on the other site. Thanks for pointing me to it (I read through the whole thing; great stuff). Has anyone put a BMS 4550 on the 338800-001?
 
publius said:
I was unaware of the discussion on the other site. Thanks for pointing me to it (I read through the whole thing; great stuff). Has anyone put a BMS 4550 on the 338800-001?
Click to expand...

Zilch will post best links im sure, he's done a pretty comprehensive/practical study of the 1" BMS drivers on the $9.90 wavendiffractionator for his C36 Viscount frankenspeaker project...doesn't quite fit the "econo-" criteria @~$135 per driver; but still a bargain by almost any performance standard. As I understand, the 4540nd also plays very nice, with less physical mass; the BMS specs suggest the 4550 plays a tad lower.

I don't fiddle too much with my rig; simply enjoying the music that comes out and lurkin' over the banter of here & there.:yes:
yes...Uber-imaging, uber-dynamics

CIMG6092small.jpg

processing
Behringer DEQ2496
Behringer CX3400

amps
Sub:Low -av123
Low:Mids- Behringer 500A
Highs-Trends Audio TA-10.1 (t-amp)

sources
Kenwood KT8300
Slim Devices SqueezeBox 3

xo
3way, CD off - a little too much ear tickle when on
low - 100Hz
high - 1.2kHz, gain cut just a bit

drivers
sub/low - pair of AV123 X-subs
low/mid- John Muska of S.F. bookshelf; 1.3cuft, cabs loaded w/Dayton DC250-8 10" PE classics
high-BMS 4550 comp. drivers mounted on JBL’s famousfrugal waveguides (338800-001)
 
4550 as well

I'm listening to 4550 on JBL waveguide using same active EQ and crossover components as ValvTubeHead. My bottom is 8" EV, and I second his opinion. My system is set up very flat.

Zilch,

I previously missed the point Publius brought up, that there is 20dB boost on top end in Gedlee's system. I assume that's all active EQ. With that much boost applied, should not the performance of the EQ be considered in the analysis? For example, I believe I could digitally EQ an Altec 802 on whatever horn flat to 20kHz, if I were allowed as much boost as I needed, and that doesn't mean it will sound good.

I am aware that Geddes says it measures well, so here's where a listening session is appropriate. If you haven't already, I propose you have a set of his waveguides sent to you.
:D
Following your analysis, I propose you send them to me if I can arrange for them to be set up in a WSDG room.
:D
 
oh boy, the 4550 on the $9.90 wavendiffractionator seems to be what i have been looking for (for a long time). while both have received good reviews as independent components, i was curious to know if there were any peculiarities that made them poor in combination. so far, it seems that you guys are very pleased...thanks for the infos.

re: listening session. hilarious! it kind of brings up a good point though in that once you do enough studying of the liteature on how we make judgments/decisions -> you will develop such a mistrust for your own judgment, you won't be able to form a judgment -> so the only people who will hold confidence in their judgments are the ignoramouses who suffer from all the biases. it's all very weird.
 
skywave-rider said:
I previously missed the point Publius brought up, that there is 20dB boost on top end in Gedlee's system. I assume that's all active EQ. With that much boost applied, should not the performance of the EQ be considered in the analysis? For example, I believe I could digitally EQ an Altec 802 on whatever horn flat to 20kHz, if I were allowed as much boost as I needed, and that doesn't mean it will sound good.
Click to expand...
There's no doubt Dr. Geddes best knows how to optimally EQ his own device. He used the same topology, whatever that was, to EQ EconoWave and bring it into a comparable operating region.

Did he do that as well as you or I might? Possibly not, but I certainly did not expect him to develop a fully refined approach to this aspect of the evauation, either. Clearly, with minimal effort, he was able to get EconoWave performing well within his +/- 2 dB criteria, and in some respects, better than his own design.

We can now debate the relative merits of axisymmetry and on-axis linear distortion, and the desirability of uniform power response outside the design constant directivity control window, and scrutinize the details revealed by cumulative spectral display and cool leading-edge variable-resolution spectrogram techniques, all great and good fun for us curve junkies and speakergeeks.

Fact is, as now independently verified by Gedlee, EconoWave is a worthy performer for minimal cost, at least insofar as the measurements reveal. Is it a "World Class" contender? Let's just say it's better than many, if not most, might suppose, "Better than it deserves to be," as commonly observed, and offers a unique and economical opportunity for technological exploration and sonic enjoyment to AKers desiring to pursue the quest.... :thmbsp:
 
publius said:
oh boy, the 4550 on the $9.90 wavendiffractionator seems to be what i have been looking for (for a long time). while both have received good reviews as independent components, i was curious to know if there were any peculiarities that made them poor in combination. so far, it seems that you guys are very pleased...thanks for the infos.
Click to expand...
"Wavendiffractionator." Heh, heh. :thmbsp:

Consider stepping your BMS purchase up to 4552nd, if you're willing to spend the extra $$$ at this point. AK members did a group buy of those, and all participants seem to have been quite pleased with the results in various applications.... :yes:
 
Received my pair of JBL 2214H's, bought on EBay, yesterday. Have just finished refoaming the first, and working on the second. They will be ready this afternoon for inclusion with the EconoWave HF in a pair of Baronets. Was going to put them into the smaller one, but already have baffles cut for the 1.5X version, so that is probably where they will go.

Still waiting to get the drivers and "wavendiffractionator's" from Geddes. He said on diyAudio some time ago that he had shipped them back, but they still aren't here. I will send him a PM on diyAudio and see how he sent them.

Will be out of town for about two weeks starting next Monday, so will play with the CX-3400 and EconoWaves when I return.

EDIT: The mailman just delivered the package from Geddes, so now we are good to go.
 
Since Dr. Geddes got the drivers and waveguides here, I simply couldn't help at least mounting them to the baffles. The newly foamed 2214H's voice coils seem to be almost exactly the same depth from the back of the baffle as the D220Ti's, if they are where they seem to be. Accidental time alignment?

They will just set in JackLab's office til we get back from our trip. I ordered crossover parts, since they will eventually become part of the system in the library, and won't be bi-amped.

They will provide some lessons in using the CX-3400.

I am really glad that Dr. Earl Geddes measured the JBL waveguides and Selenium drivers for us. He proved that the Econowave concept was pretty much OK, as all of us who had tried it had discovered. I didn't expect he would ever endorse it, since he is trying to make and sell his own "waveguides." He claims the right to define the term waveguide, since he was the first to apply it to audio applications. And only his waveguide fits the description. Fair enough. But I would rather sit on axis instead of having to toe my speakers in at something like 45 degrees. To each his own.

Anyway, thanks Dr Geddes, if you should read this post. We really appreciate your spending the time and energy to do that for us.
 

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Mxlews and I struggled with time alignment in our C38s. Like you, we followed conventional wisdom and found that with the woofers mounted on the rear of the baffle, the physical alignment of the voice coils was nearly perfect. Measurements revealed that the LF lagged the HF, however, thus aiming the axis of time alignment downward toward our ankles.

HUH? We WANT the woofer voice coil ahead of that of the compression driver? The answer (I think) is that the mass of the moving assembly of the woofer has an inherent electro-mechanical delay, much like the response time of a conventional PM DC motor, and mounting it on the front of the baffle made for an improved time alignment.

You can check this out using the equipment you have. Invert the phase of the HF on the CX3400, and then watch the null at crossover on your RTA move up and down as you adjust the LF delay control. I believe you'll find that the maximum depth will occur with the woofer front-mounted, and the delay near zero. With the phase restored to normal, that's the alignment of maximum driver summation.

Another method of verification: with phase inverted and no delay, move the mic up and down to find the height at which the notch is deepest. The angle between there and horizontal to the midpoint between the drivers is the "tilt" of the plane of time alignment. Ideally, that's aimed at listening height with normal phase.... :thmbsp:

http://www.audioroundtable.com/PiSpeakers/messages/11054.html
 
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