Zilch's AK Design Collaborative - Econowave Speaker

[Steve O]

Dont know where all this has come from, nothing was wished for here, it was designed and implimented. The Econowave guide , when actually built and equalized works in an excellent fashion.

<snip>

I also am reminded of the old proverb, "better to remain silent and appear slow, than open your mouth and remove all doubt.":yes:

Russellc

Clearly you've taken my comments both personally and not as intended.

As I stated, I've followed the development of the econowaveguide here on AK and recently at the DY audio site. I found it interesting that a recognized subject matter expert took notice of it and even agreed to perform a subjective analysis of it. My interpretation of the measurements and esp the accompanying commentary indicate to me that Dr. Geddes considers the econowaveguide a decent, cost effective performer of relatively conventional design. However, he considers it neither a world beater nor something he would incorporate in his high end designs. Over at DIY he was pretty direct about the whole thing to the consternation of a few. I don't think he disliked the project: it's just that he's been there, done that and moved on. So be it.

My reference to being careful about what one wishes for had to do with the enthusiastic promotion this project was receiving by its creators here at AK and at least one other forum. The comment had nothing to do with technical performance. The sense I was getting was something to the effect that the econowaveguide was so good it would surprise even a pro so let’s get a pro to evaluate it…he can’t not like it. Problem is that a pro should be impartial, unemotional and brutally frank in an objective assessment of something like this. And one possible outcome is that the assessment will not be totally positive as was the case here. Again, my sense was that the project promoters had only considered the possibility of the positive outcome and not the possibility of the not-so-positive outcome, thus my comment about “wishing”.

As regards the equalized econowaveguide, based on Dr. Geddes’ comments at DIY, it would seem that the combo has fundamental issues with resonances and HOM just like any other horn of conventional design. Will equalization correct these issues?

Unfortunately, I don’t foresee myself building up an econowaveguide since I’ve got too many unfinished projects at the moment including an ongoing evaluation of the BMS4550/4552 on conventional horns. Too much time and money already invested to take on another project without cleaning out something else first.

Bottom line on this is that from what I’ve read, the econowaveguide project works better than it has any right to considering the price. It’s also been a great project and learning opportunity. That the essential basis of it doesn’t receive a glowing endorsement from a noted industry expert is secondary. If this was a commercial product things might be different. But it isn’t so its creators have no need to take the non-endorsement personally.

Oh…speaking of personal: don’t you think your last comment is a bit personal?

 

[dnewma04]

Well said, Steve O. I didn't get the impression that Geddes was being anything but completely objective about the project. It's an excellent project, and seems like an very good performer but I don't think it should surprise anyone that it can be beat handily when budgets are taken out of the equation. I did get the impression that some offense had been taken by some, though.

 

[Zilch]

I did get the impression that some offense had been taken by some, though.

None by me, certainly, nope.

We got what we hoped for: expert, independent measurements, and I'm not yet done with the data, or analysis thereof.

The rest is what we expected.... :yes:

 

[Russellc]

Clearly you've taken my comments both personally and not as intended.

As I stated, I've followed the development of the econowaveguide here on AK and recently at the DY audio site. I found it interesting that a recognized subject matter expert took notice of it and even agreed to perform a subjective analysis of it. My interpretation of the measurements and esp the accompanying commentary indicate to me that Dr. Geddes considers the econowaveguide a decent, cost effective performer of relatively conventional design. However, he considers it neither a world beater nor something he would incorporate in his high end designs. Over at DIY he was pretty direct about the whole thing to the consternation of a few. I don't think he disliked the project: it's just that he's been there, done that and moved on. So be it.

My reference to being careful about what one wishes for had to do with the enthusiastic promotion this project was receiving by its creators here at AK and at least one other forum. The comment had nothing to do with technical performance. The sense I was getting was something to the effect that the econowaveguide was so good it would surprise even a pro so let’s get a pro to evaluate it…he can’t not like it. Problem is that a pro should be impartial, unemotional and brutally frank in an objective assessment of something like this. And one possible outcome is that the assessment will not be totally positive as was the case here. Again, my sense was that the project promoters had only considered the possibility of the positive outcome and not the possibility of the not-so-positive outcome, thus my comment about “wishing”.

As regards the equalized econowaveguide, based on Dr. Geddes’ comments at DIY, it would seem that the combo has fundamental issues with resonances and HOM just like any other horn of conventional design. Will equalization correct these issues?

Unfortunately, I don’t foresee myself building up an econowaveguide since I’ve got too many unfinished projects at the moment including an ongoing evaluation of the BMS4550/4552 on conventional horns. Too much time and money already invested to take on another project without cleaning out something else first.

Bottom line on this is that from what I’ve read, the econowaveguide project works better than it has any right to considering the price. It’s also been a great project and learning opportunity. That the essential basis of it doesn’t receive a glowing endorsement from a noted industry expert is secondary. If this was a commercial product things might be different. But it isn’t so its creators have no need to take the non-endorsement personally.

Oh…speaking of personal: don’t you think your last comment is a bit personal?

Point taken on "personal" Otherwise, I'd say you've summed it up nicely, not perfect but sounds better than it has a right to is fair enough. Guess I mis took your original tone. Resonances and all, it still measures within + or - 2.5 db across its high frequency band,(with filter) and regardless of how it measures, happens to sound good in a livingroom. Very good. Better than a lot that passes for "high end" anyway.

I also find myself creating more projects than can be handled, seems to be the nature of the sport. I too share an interest in those BMS drivers, as they will likely figure into my next experiment on another controversial horn, which I will admit is somewhat out dated, or vintage anyway, the 511B.

Post your BMS results.

Russellc

 

[skywave-rider]

diyAudio thread where this is being mulled over:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=123426&perpage=25&pagenumber=1

 

[Steve O]

Point taken on "personal" Otherwise, I'd say you've summed it up nicely, not perfect but sounds better than it has a right to is fair enough. Guess I mis took your original tone. Resonances and all, it still measures within + or - 2.5 db across its high frequency band,(with filter) and regardless of how it measures, happens to sound good in a livingroom. Very good. Better than a lot that passes for "high end" anyway.

I also find myself creating more projects than can be handled, seems to be the nature of the sport. I too share an interest in those BMS drivers, as they will likely figure into my next experiment on another controversial horn, which I will admit is somewhat out dated, or vintage anyway, the 511B.

Post your BMS results.

Russellc

My "work" with the BMS drivers has been with the Altec 811 and 511 horns and the Altec Carmel system. I've been thru a larger number of xover iterations than I dreamed possible when I began the project over a year ago (with the inspiration of Mr. Zilch :thmbsp. I intend to post my findings when I finish but I also want to be sure of them so I taking data and doing a lot of listening (tough crowd around here sometimes, esp the anti-wankers). One conclusion so far that has come to me relatively recently is that there is more to satisfying sound than flat on-axis response. More to come when my ducks are in that proverbial row.

Back to lurk mode for now.

 

[Russellc]

My "work" with the BMS drivers has been with the Altec 811 and 511 horns and the Altec Carmel system. I've been thru a larger number of xover iterations than I dreamed possible when I began the project over a year ago (with the inspiration of Mr. Zilch :thmbsp. I intend to post my findings when I finish but I also want to be sure of them so I taking data and doing a lot of listening (tough crowd around here sometimes, esp the anti-wankers). One conclusion so far that has come to me relatively recently is that there is more to satisfying sound than flat on-axis response. More to come when my ducks are in that proverbial row.

Back to lurk mode for now.

I think someone brought that up in the current thread on DIY. All sorts of things, (tube amps, etc) dont always measure correctly, but still sound wonderful. Sometimes even measurements dont agree with themselves. while problems were found with the inexpensive wave guide, It still measures very flat, and however it measures, sounds great in the home listening environment.

I also have and use 511 B and 811B Altec horns. I hate to think what Mr Geddes thinks of them:thmbsp: I find them to be quite enjoyable, as do many, many others. I was glad Mr Geddes reviewed the horn, only wish he had time to actually listen to it with music in the home. I cant wait to see if there are developments a foot with econowave. Zilch indicated he
intended to use the info from Geddes, not sure what he meant, but I am staying tuned.



Russellc

 

[dnewma04]

My guess is that Geddes wouldn't like the 511s/811s much because they'd be a compromise from his findings as an ideal. I don't think he'd tell anyone they shouldn't like them, just that they are old technology that has been long since improved from a performance standpoint.

 

[Zilch]

... while problems were found with the inexpensive wave guide....

Nope. Everything in context. :yes:

[Nobody has analyzed the data yet.... ]

 

[Russellc]

My guess is that Geddes wouldn't like the 511s/811s much because they'd be a compromise from his findings as an ideal. I don't think he'd tell anyone they shouldn't like them, just that they are old technology that has been long since improved from a performance standpoint.

My point is "improved" is a very subjective thing regardless of how any one person feels. One of the things that has held my interest in the 511B is listening to various "improvements" on them. Like a lot of audio, there are lots of "differences" or lateral changes, not necessarily an improvement for all listeners. Solid state was to be "better" than tubes...are they? Depends on your perspective of "performance standpoint" I guess. CDs a long time improvement over vinyl? Again, depends on the individual's preferences, what one sees as an improvement another might not.

I think we can agree to the fact that some things are seen as improvements and prefered by some, while they are not by others. One thing is for sure, no matter how anyone feels about anything in audio, that opinion regardless of who expresses it, will not change the sound of anything one iota! Despite who thinks what about altec horns for example, does nothing to slow the insane collector market for them both here as well as abroad. Neither my econowaves nor my Altecs sound any different after the findings, and I enjoy them no less.

I am certain Mr Geddes feels the same about his horns, and that shouldn't come as any surprise. Unlike many sentiments expressed, I dont think anyone is angry about the results anymore than some, although not associated with Geddes wave guides, seem to revel in his findings. Most of those here knew what the results would be, but wanted Geddes to put them through the paces. He is certainly up to the task, and his work was appreciated by all here, you can bet further development will be done based on it.

I have been reading the threads at "Vendors Bizzare" at DIY concerning his waveguide. I havent got to the end yet, to find out exactly how it is marketed, as it is under discussion, but I havent got to the end. He was stating it looked like 600 per for the kits, which is certainly reasonable. What I havent got to yet is how low this speaker goes, (just that it needs subs) and how much (if it will be marketed this way) only the horn/faceplate will be by itself, sounds like 200-250 per piece? I need to finish the thread.

while I have several projects deep going on here, I wouldn't mind obtaining a set of his waveguides for a try, sure would like to hear one.

Russellc

 

[Russellc]

Nope. Everything in context. :yes:

[Nobody has analyzed the data yet.... ]

Sorry, I meant the part about his finding resonances "as he had predicted"
and all that. Not that I was agreeing the wave guide is flawed, I've been one of its biggest advocates!


Russellc

 

[Russellc]

Haven't tried a 1" version, but it's on my to do list.

I guess I should buy some larger format drivers. The BMS and B&C have some interesting ones. A guy can go broke with all these projects!

Russellc

 

[Steve O]

Well said, Steve O. I didn't get the impression that Geddes was being anything but completely objective about the project. It's an excellent project, and seems like an very good performer but I don't think it should surprise anyone that it can be beat handily when budgets are taken out of the equation. I did get the impression that some offense had been taken by some, though.

Thanks for using the correct word here. I meant to use "objective" in my post above but somehow "subjective " got typed. Since the original text has been quoted a couple of times, it makes no sense to edit in the correction. But I do know the difference...really...I do...honest...

Back to lurkin...

 

[Wayne Parham]

Vertical directivity

I always assumed that was why horns evolved the way they have -- for most applications, a narrower vertical dispersion is preferred.

I use sound absorbing products on the ceiling in 2 relatively small areas, midway between my listening position and the speakers, even with horn monitors, the imaging and phantom image improve.

I've moved away from dome tweeters in part for this reason. The dispersion pattern of the JBL waveguide seems to work very well in this regard. So I can see how a more tightly controlled vertical pattern is desirable.

I agree, absolutely. The ceiling slap at HF is pretty bad in some rooms. The floor is usually the closest boundary and the MF notch from floor bounce is usually the biggest anomaly seen in measurements. So these are significant reflectors, and their influence is seen in the reverberent field.

When an axisymmetrical horn is used that allows the pattern to be taller than the vertical null angle, then response off-axis has a big dip in the crossover region. The nulls form this dip. In my opinon, avoiding floor and celing reflections of this non-uniform pattern are a high priority. Directivity control should not be limited to the horizontal plane, since floor and ceiling reflections contribute to the reverberent field.

 

[Zilch]

There is a clear bias in Geddes's commentary; he promotes his design philosophy above all others. It's like boilerplate.

We are kindred spirits in many respects, as some may have noticed: measurements rule, we don't do subjective opinion, constant directivity matters, etc., etc.

I am waiting for others to actually look at the data, analyze it, and post what it tells us about EconoWave. I'll do it, eventually, but today, I have to ship Russell's grille cloth and some waveguides for another AK member, build some crossovers for a client, and other stuff.... :

 

[Russellc]

315 posts and over 10,000 views......I'd say the crew is onto something good!:yes:

Russellc

 

[Wayne Parham]

Comparisons

I have the eminence H290 horn that is used in the 4 PI, and was wondering how you think it varies from this 9.90 econowave horn?

The H290 is perfect for the four Pi speaker. Everything comes together, good packaging, good coverage, nice response on and off axis. For this application, I'm not sure there is a better tweeter. But the horn you guys are using looks great too. I'll bet you can get the same kind of performance I'm getting from my four Pi with your speaker project. It's an excellent design approach, in my opinion. Relatively small package, high efficiency and uniform coverage.

As an aside, I'm not sure it makes sense to compare horns without comparing whole loudspeakers. I know Earl Geddes measured polars of the horn you're using, but that's just part of the picture. Comparing your axisymmetrical horn with his symmetrical horn doesn't show what happens when the horn is implemented in a loudspeaker system. When mounted on a baffle above a midwoofer, the pro/con balance sheet changes.

I've had similar discussions with people about round horns over the years. Lots of people like round horns, some because they believe the wavefront is spherical, some because they're easier to produce, some for other reasons. But when you stack drivers on a baffle vertically, asymmetrical horns make more sense to me. There's no point in talking about the polar response of a horn if its implementation causes null lobes to appear withinin its pattern.

 

[Russellc]

The H290 is perfect for the four Pi speaker. Everything comes together, good packaging, good coverage, nice response on and off axis. For this application, I'm not sure there is a better tweeter. But the horn you guys are using looks great too. I'll bet you can get the same kind of performance I'm getting from my four Pi with your speaker project. It's an excellent design approach, in my opinion. Relatively small package, high efficiency and uniform coverage.

As an aside, I'm not sure it makes sense to compare horns without comparing whole loudspeakers. I know Earl Geddes measured polars of the horn you're using, but that's just part of the picture. Comparing your axisymmetrical horn with his symmetrical horn doesn't show what happens when the horn is implemented in a loudspeaker system. When mounted on a baffle above a midwoofer, the pro/con balance sheet changes.

I've had similar discussions with people about round horns over the years. Lots of people like round horns, some because they believe the wavefront is spherical, some because they're easier to produce, some for other reasons. But when you stack drivers on a baffle vertically, asymmetrical horns make more sense to me. There's no point in talking about the polar response of a horn if its implementation causes null lobes to appear withinin its pattern.

Thank you for your answer, it very interesting this asymetrical/symmetrical horn thing and their implimentation affecting performance. very interesting.

thanks again,Russsellc:thmbsp:

 

[dnewma04]

There is a clear bias in Geddes's commentary; he promotes his design philosophy above all others. It's like boilerplate.

Is bias the right word, here? He tested many different contours including all of the most common/well liked variations and found that his oblate spheroid WGs measured the best in the areas that his other studies showed were most displeasing.

We are kindred spirits in many respects, as some may have noticed: measurements rule, we don't do subjective opinion, constant directivity matters, etc., etc.

No doubt, and you can count me and others in that group, as well.

I respect his work more than I respect the way he comes across sometimes. He has done a lot of work to find what are the most significant acoustic problems (generally the room and the speakers enclosure) and has designed around the principals. According to his findings, anything less would be a step in the wrong direction. I can respect that. He's gone a step beyond that "flat response" goal that many seem to go after almost exclusively.

I will be the first to admit that he needs to be less sensitive to criticism, however.

 

[jackgiff]

Playing with new toy!

I received my CX-3400, and love it. Wish it were here when we first did the EconoWave. Oh well. I plan to update the first pair of speakers I built,about 40 years ago, give or take a year or so. They are sealed up, since I never planned to open them again. Wasn't thinking clearly, obviously.

I bought a pair of Goldwood 8" woofers and a pair of Goldwood silk dome tweeters, based solely on their specs and prices. (They were cheap) They are also quite good. Just been listening to them powered by Marantz and Dynaco amps, and my new toy. I am stoked. Looks like the tweet needs to lose about 10 db, and then the HF slope should fall within the limits of Wayne Parham's tweeter compensation technique. Thanks, Wayne, that was one of the best lessons I have had in speaker design. You had a large part in developing the EconoWave, so take a well deserved bow. One question I can't refrain from asking, is how do you compensate for the huge HF drop in the PSD2002? I looked at the 4 Pi specs, and it isn't there, so you must have some kind of magic to make it essentially flat. Boggles my poor mind.

I finally realized I had another pair of Trusonic 80FR's, housed in a pair of EV Baronet clones that I built many years ago. I got them down from the overhead, and this is probably my best pair of 80FR's. They will go bye-bye on E-Bay sometime in late June. The Baronets baffles are 13 inches wide, enough for the JBL waveguide, and are something over 20 inches high. I have pair of JBL 2214H's on the way, and maybe they will become the woofers. Or maybe a pair of 10" woofs will be better. Any opinions? Someone have a pair of LE10's they would like to unload?

Anyway, here are pics of the Baronets which will become the subjects of using the CX-3400 with the EconoWave concept. As soon as I get my D220Tis and waveguides from Geddes, we are off to the races. Can't wait.