Hey guys...we need a little rallying here... - Page 6

Im not sure about you coctostan but that is a strong statement to me.

I would love for Duke to chime in here. He is an AVS member. For those who know nothing about Duke, here is his website http://www.audiokinesis.com/product_loudspeakers.html

lol

Yes, Zilch is strong in his words there but I read that as saying those speakers have a specific shortcoming (narrow vert) that eliminates them as viable solutions for him and many other people. With my seating arrangement, the Geddes vertical would be tough as well. It would be like building the greatest speaker of all time yet it won't fit through your door.

I also have a feeling that Geddes (and Duke) would quickly move from circular to elliptical if it were feasible. Geddes has eluded to that. A better vertical response is the only reason why. If not for that, we would probably just stick to the circular.

As long as we are dreaming about making a E-OSWG, might as well extend it to a super-ellipical mouth OSWG, say a Piet Hein's ellipse. You gain the benefit of a larger mouth area while keeping the sharp corners out of it.

Different XOs can mitigate that issue and if you add placement flexibility there is only measurement issue that is debated to no end on forums.


I agree EOS is the best of both worlds but Im still curious to why they have less concern about this?? Why does Paul W have HUGE round waveguides and LOVE his setup?

I think it comes down to the simple fact that HOMs can not be minimized with XOs, placements optimization while the CTC issue can be.

Earl and I are pals.

[I do not aspire to deity, is all.... ]


Let's see the vertical polars!

Geddes has steadfastly refused to post them for his products since I first challenged him to do so two years ago. Initial measurements of Nathan by Markus in diyAudio indicated that there were "issues," which are confirmed by the independently measured Princeton polar map from just weeks ago, despite an apparent crossover frequency down near 1 kHz.

Would you alter your views if Duke came in here and confirmed that Wayne and Zilch's argument has merit?

You need to look closer at Paul W's Raptor design. Despite many listeners liking them, there are problems as also seen in the 18-Sound implementation of similar.

http://www.eighteensound.it/staticCo...ound_kit15.pdf

At heart, apparently, you are a subjectivist, falling back on tired old subjectivist saws.



NOT! Build some, measure them, and know the truth of it....



I recently posted a study documenting the relative contributions of these elements in E-Wave Minis using directivity maps. Bottom lines:

1) Baffle width vs. woofer diameter diffraction signature -- job #1; see NeO Note.
2) Deep baffle recess w/overhanging "lips" -- bad; flush (or nearly) mount the baffle.
3) Flush mount woofer and waveguide -- matters, but not so significantly; woofer first. See Zaph.
4) 3/4" roundover -- measurable, but not all what it's made out to be; constant directivity waveguides do not illuminate the cab edges sufficiently for them to be a significant factor.
5) Crossover frequency -- find what produces the smoothest blend through the woofer/waveguide transition region; varies with each combination:



The sequence (in living color) is presented here:

http://techtalk.parts-express.com/sh...37#post1691137

I built a quasi-cbt with some peerless 2" drivers, use them as surrounds. They have the circular arc, but no power shading, and they work adequately, but are by no means an example of the cbt design.

Coctostan,

I have not figured out where the nulls would be, but i am thinking about a c-c spacing of about 3", and a crossover point of about 2-3 khz.....have not done the math yet......also, cbt's can be horizontally oriented....

JSS

ummm...

http://www.diyaudio.com/forums/multi...uides-142.html

post #4948

Better:


http://www.diyaudio.com/forums/multi...ml#post2348922

#4899

You have to stop quoting Pricenton polar map with the Nathans that we have both seen many times now. Talk ONLY about the Summas because that is the size I care about not anything remotely like the Nathans. Did I post before that I LOVE my Neopro5i ribbons have you seen their vertical response curves? You see its not always about all measurements. Its about application and usage too. There isn't a CD/Horn that sounds as good as those in a nearfield listening environment.

I have emailed Duke for clarification on his designs. I would find it amuzing if he is selling $10K speakers and would consider the CTC to be a huge flaw in his design. Does not really make business sense to me but who knows.

FWIW, I only have the view that many people have differing opinions on its importants. I have no conclusions until the discussion is exhuasted. You have no proved it is remotely important outside of measurements. I fully understand that and I acknowledge their measurement compromise but I already know that nulls can not be heard in room during regular listening. Did you know that 99% of the audio population has a null around 200 or 300HzHz because of speaker placement and the rear wall. They do not hear that either. There is a lot to audio that measurements although very important never tells the whole story. Do the blind tests, listening to common music and I will bet $100 right now you can not pick the speaker with the vertical null unless you test for it.




lmao so since Im not convinced this vertical null issue around 10% off axis or so is more important that HOMs that exist then Im a subjectivist? You know its one of the few times I have been called a subjectivist considering my stance on subjectivity in audio

The problem here is that you can not find a measurement that predicts HOMs, if we could do that then maybe some people would consider those measurements more important?

Its great we all have choices because I will still build my round waveguides and enjoy them because they will sound good and actually look awesome.

Looking good is half the battle, didnt they teach you that somewhere?

Pay UP. I will PM you the mailing address; USPS M/O preferred.

The primary reason we pursued mapping the vertical polars was because Markus could hear the nulls in his Nathans, all documented in diyAudio, and in collaboration on how to measure them easily after Earl asserted it was too difficult to do, we did it an found them. It's all documented in Markus's thread there.

As to Summa, you get Geddes (or anyone else) to measure and post the verticals, and we'll discuss them. I'd say it's not even remotely likely that's going to happen; thus we are relegated to analysis of his other designs built using similar waveguides and approach.



I am a certified hack, and proud to be so. What I do serves to illustrate that, even with minimal skills, no one should be intimidated by the aesthetics of the design itself. They can be built in curbside roadkill finds with zero investment. Dumpster diving works, too.

I am also proud of the work scores of others have done with building EconoWaves in more attractive packages, according to their own tastes and preferences. It's design freedom in play here, and it is intentional....

It seems like we're getting way off the topic, but it's fun reading I guess. I'm not really sure why there can't be a middle ground on all these issues.


Anyway, I stopped by a local shop to get some price ranges. I asked for some very rough figures and knew they were going to be quite high.

If someone made up a CAD drawing, it would take about $900-$1200 to get a prototype made using 3D printing or milling a block of softer material like wood or plastic. If the prototype was tested to be good, and we planned to make under 500 parts or so, then it would make sense to make the cheaper type molds which would run about $500. But I could do that part for a bit less on my own. I'm guessing after that, each one could be made for around $25, depending on the amount of plastic used. The larger the WG, the more material of course.

Now if we figured more than 1000 could be made up, then he recommended injection molding of course. I know that's expensive because I've looked into those before. Rough estimate on the aluminum molds for the machine would be around $15,000. That of course would be after a prototype was made and tested.


The cheaper mold is fine for less parts, but the material to make each part is fairly expensive. On the other hand, the injection molding material is very cheap, but the mold is very expensive. So in the end, the costs come very close if you're only going to make 1000. Obviously as you went over 1000, the price starts coming down as you can average the tooling fees out over more parts. At that point, the injection molding is better.


IF a really good design could be figured out, then it's still something worth looking into.

I'm going to talk to a friend of a friend tonight that runs a mill machine. He might be able to do me a favor. But obviously this is all AFTER a design is figured out.



I realize my thoughts here don't hold a heck of a lot of water for the design portion, but I'll put them out there anyway. I think the size of the waveguide should stay around 15"-18" or less. If someone wants to go bigger, maybe they can do some massive round overs? No doubt some want to go way bigger. That could be better, I won't argue that. But if very few people want something that size, then going through the entire molding process is almost a waste of time simply because it's never going to sell strong enough to pay for the tooling fees.

This project, as with all mass produced items would have to hit a middle ground so that more people could use it. A 30" waveguide using a 2.5" CD may be incredible, but if no one will buy it, then I don't think it can be pursued for this project.

I was only pointing out there are many things to consider in a speaker design and I want everyone to know there are succesfull builds with 12" and 15" round waveguides so they should not be excluded from the discussion just because Zilch does not like them. Sorry if it seems like it was anything else besides some common banter with Zilch.

IMO, in the end there seems to always be interest but never any $$$ put into the project. Eric's posts shows some significant $$$ in doing a brand new EOS waveguide.

Jzagaga (Jack) on DIY PMed me on the costs of doing this too and they are dropping out of the waveguide market soon because its not exactly profitable.

If you guys could come close to agreeing on a great new design that has a very very good chance of working for the masses, then getting the prototype made up really isn't going to be a significant amount of money in the end. I'm very far from rich, but I'd probably put up the money for the prototype to keep this project rolling.

But we're not going to have 5 shots at getting it right. We have to come pretty damn close the first time and get it right the second time. Hopefully nail it on the first run.

We've got plenty of pros in this thread alone. Guys that know how each shape performs, guys that know how to model up the computer file, and someone willing to try and get it made. So there's a good chance to get it done.

Nothing Penn or I say to each other is in even the remotest sense an attack.

[Whovever wins a point buys the next round, is all.... ]

Im trying to get the 15" EOS waveguide 3D model done so that is my vote.

I 100% agree btw, Zilch is winning

Of course LTD02 point was made and lets get a design.

I already assume the QSC stuff is being looked at, correct?

I assume so, as well. I wish I could post a link with SKU, but it's not there yet, alas....

Is there something on the QSC model that could be easily modified to make it even better? Maybe some large roundovers off the front that takes the entire WG up to about 18" wide?

Some have commented on the throat needing modification. If we could match its angle to an exact CD like the DE250 that would make for a very nice combination.

Im not sure how you extend the waveguide out to 18" and if you add just a round over it might be very difficult to mount on a baffle.

I provided a link to the Tech Talk post containing the summary. There are seven stages illustrating the progression in refinements over the course of the two week study linked as horizontal polar maps. You'll have to scroll back for the full detail of what I did.

Each of those maps is 19 measurements plus post-processing, one heck of a task; I don't believe anyone's ever posted anything like that before....

It's the "Living color" link at the bottom of #156, above....

That little sucker is one kickass hotrod; I figured out the porting for it last night. I may redo the baffle and send a pair to Princeton for "evaluation...."


The second woofer is run in "0.5" mode and used for BSC, increased efficiency, and steering, i.e., not conventional MTM.

I'm building the TWW AC26 w/6.5" woofers and the 6" square waveguide in Dayton MTM pre-finished cabs next....