Hey guys...we need a little rallying here... - Page 23

Originally Posted by penngray

Does this discussion about roundover assume there is no baffle? I assume the design still has a flange to attach the waveguide flush to a baffle.

Originally Posted by penngray

There is always a risk of splitting hairs to far in the discussion. Also "windows of opportunities" never stay open for ever. The longer the discussion goes on the more the inherent risk of failure increases.

Lets remember someone is ready and waiting. There is no time frame set but I would never risk prolonging the discussion and risk that window closing for unforseen reasons.

Originally Posted by coctostan

I agree with all of that I just believe we are at the point where the differences are so small that no amount of simulation or discussion is going to improve on it.
If you look at the success of the QSC WG, I'm confident this one will also be successful. It is very similar, but improved in a number of ways with no real downside other than higher cost.

Originally Posted by LTD02

i'm with penn whose wisdom comes from business experience, getting it 98% right and getting it done is better than getting it 99% right and never getting it done.

my final thoughts in #638. as for any remaining decisions...the advice is simple, go conservative, i.e. "don't f... it up", but lets end the committee meeting.

who has the ball and what is the next step?

Originally Posted by jzagaja

Minimum required roundover for removing "axial dip" depends on coverage. With 90deg coverage it is 12cm, with 50deg - 3cm and these values were used in SEOS-15-9050-N4. Now if you need vertical height to be 8" we need rV=4.5cm and 60deg coverage. Should I draw and simulate SEOS-15-9060-N3?

Originally Posted by jzagaja

I think it's easy modify an existing driver to any kind of aperture - using conventional lathe remove an existing phase plug then insert rapidly prototyped plastic phase plug like in 476Be but with elliptical aperture.

Originally Posted by penngray

I believe audio can have style to it, no doubt its a little harder with waveguide designs since "wide" is hard to pass off as stylish when thin is in and "Monkey coffins" are not

Originally Posted by penngray

Waveguides do not need a tone of screws, The 18sound waveguides have the best flanges I have seen comercially.

Originally Posted by LBDiver

Updated Mock-ups with all profiles

Originally Posted by Geddes

Just to be clear, I did, but I found that there was no value in it for me. I believe that this is why there aren't any on the market right now. It seems like a simple part, and maybe it is if you have a lot of money for tooling, etc. but in small lots its very expensive and people just don't want to pay a price that is interesting to a manufacturer.

Some time ago there was a long thread about making waveguides. The overwhelming postion at that time was that they would be easy to make and that I was just gouging the market. OK, where are they then? That thread was the reason that I stopped selling them. Simply put the waveguide, foam plug and mounting plate are the key to what I make and sell and represent the greatest value-added by far. I am not willing to give this away without due compensation for this value added.

I don't make stand alone waveguides, they are molded into a custom baffle. It is extra work for me to cut them out. I have, and will, sell the baffles with foam plug and mounting plate. Just contact me on the side because I do not advertise this. But be fore warned, they are not cheap

Originally Posted by jzagaja

BTW: There's also E-JMLC-1000 that expands rapidly horizontally and provides loading vertically. All JMLC horns are standalone, can rival OS, EOS and SEOS.

Originally Posted by Erich H

Penngray, there is suppose to be a flange to attach it flush with the baffle.

I'm not sure if the post from jzagaja has anything to do with that or not though.

There's a chance that I will order one with a flange and one without. I'll have to check on pricing for that. If the back side of the roundover was flat, someone could always attach 1" long screw posts with a female end on them. Drill holes in the baffle that correspond to those posts, and the WG would fit real nice, just put screws in through the back posts to hold it in place. But I'm not sure how easy that will be on this first round. It wouldn't be hard for a DIY guy to rig up those posts if they wanted too.

Honestly, if the back side of the WG was solid material, then it wouldn't be hard to figure a way to put the screws in through the back.

I'll find out.

If there's time later today, I might draw a cut away side view of how this should mount to the baffle. If anyone wants to beat me to that, go for it! But I'll try.

Originally Posted by coctostan

I'm agnostic to flange or no flange. I don't care much about appearance. No flange probably looks better though.

I vote for SEOS-15 90x60 (or50) N-3 rH=12.5cm rV=4.5cm...#4 on LB'd mockups.

I say we put the elliptical phase plug discussion on hold for now, but it would be fun to go back to it once these WGs are in production.

Originally Posted by Erich H

Coctostan, there might be more options than what LBDiver posted though. I'm not sure he covered every option with those 6 mock ups. Let's not zero in on those unless they have covered every option.


It's time for the heavy weights to weigh in here. I need to get all the info to the builders.

I'm aware of that, I just think that the SEOS-15 N3 90x50 or 60 rV=12.5cm and rH=~4.5cm is the sweet spot

Originally Posted by A9X-308

Has a ballpark price been given for these units yet?

Originally Posted by penngray

Is it? Im not interested in XOs at 1200Hz and above that is pushing all these larger woofers to high. I definitely would lean towards 90x60 more then 90x50.

Originally Posted by coctostan

AudioJosh-

My calculations show the lobe being at 30deg down for a 15" woofer on the 8" tall WG and a 1000hz crossover. I'm not sure where you are getting 850hz. IMO, a 1000hz crossover for a 15" woofer makes it pretty much ideal. 1250hz for a 12" is great as well. The nulls are spread apart and directivity should match nicely right around there.

BTW: This is what I'm using for calculations based on Linkwitz's formulas: https://spreadsheets.google.com/ccc?...xVTZQX1E&hl=en

Originally Posted by AudioJosh

I can't access that link right now. However, my numbers do need to be checked. I was calculating the corresponding 1-wavelength length based on the assumed CTC spacing. I had seemed to recall Linkwitz's rule of thumb was 1-wavelenght of seperation equaled 60º vertical lobe. That is what I likely misused.

The axis angle and shape of this lobe between the nulls is a function of the crossover.

Originally Posted by Dennis H

John K suggested a novel way to phase align horn systems. Use a 3rd order crossover down 6dB at Fc. The transfer function is a BW2 plus a BW1. The horn should be 1/4 wavelength behind the woofer at Fc for best alignment. I sim'd it and it worked quite well -- nearly flat with the phase one way and a deep null the other way. I tried it with 5th order (BW4 plus a BW1) and that worked too but the phase had to be the opposite of the 3rd order.

Originally Posted by coctostan

Penn-

I know you aren't interested 1200hz crossovers but by my calculations we should get pattern control down to around 1000hz. If you want to crossover at 800hz I really can't say if a 15" wide WG will hold pattern. We'd have to measure it to really know. I'm pretty sure the 15" width is settled. Nobody else seemed to want something wider.

How does that not match up to your requirements then?

When I say "Sweet spot" I mean that it pleases most people here well enough. None of us know the exact ramifications of small changes from this middle ground. Which N value is best? We are all guessing. Same for roundover.

90x60 matches the QSC waveguide and that allows appropriate CTC spacing if the vertical height is similar. This configuration has proven to be versatile enough IMO. In essence we are designing a SEOS version of the QSC with a better throat match.

Originally Posted by penngray

Any more thought on the throat being round to match the CD??

Originally Posted by coctostan

I believe the throat is circular at the entry and gradually becomes elliptical. It was my understanding this was the design.

I think Geddes is saying that the absolute optimum would be an elliptical CD would be used with an elliptical WG.