Small Syns

[Dave Zan]

Originally Posted by bwaslo

Here's the discussion where Wayne describes his technique and effects --

Thanks Bill for the information, I expected that someone must have discussed this but I just hadn't seen it.

Originally Posted by bwaslo

(I don't know the particulars of the other Geddes models, but the Nathan is supposed his bottom of the line).

Yes, as I wrote, not his most expensive.
But his top-of-the-line is essentially similar but scaled up, 15" woofer rather than smaller (10" IIRC), wider horn/waveguide to match, scaled up cabinet volume too.
So the polars should be essentially similar too, just scaled.
Perhaps the top speaker can justify a more sophisticated crossover but I don't think there's too much difference.


My main point was that it is helpful to control the source width in the horizontal plane to control horizontal directivity, so why not do this in the vertical plane too?
So, rather than keep the woofer taps close to the horn vertically, it looks to me that it could be better to move them away some distance.
After all, a wider source is needed to maintain control of a narrower pattern, and that's the vertical in a typical speaker.
I didn't mean that it had to be specifically an "array" of point-like sources, woofer taps or whatever, it's a continuum.

Best wishes
David

[Dave Zan]

Originally Posted by bwaslo

...will lose directivity below about 1330Hz, which is about an octave above the 660Hz crossover point. So above around 660Hz there won't be as much output for interraction to use the array effect?

Originally Posted by bwaslo

Here's the discussion where Wayne describes his technique and effects --
PiSpeakers Forum - Matching directivity in the vertical and the horizontal planes - Wayne Parham, July 08, 2008 at 18:52:13

...It does make for some funny nulls vertically off axis...but that's only around the crossover frequency, not broadband...

I mulled over your first point and did some back-of envelope calculations.
It seems the optimum is to use the horn directivity as much as possible, if we make the horn less tall then the benefit from a closer woofer is more than counter balanced by the loss of directivity from the horn.
But it does make sense to use the woofer + horn width to try to extend the vertical pattern control as much as possible.
Some slot or face-plate, like your Small Syns or the JBLs, may help to minimise|eliminate any "funny nulls".
For that I will need more detailed calculations, does Xsim do this sort of work?
It would be nice to explore initial ideas easily, even if eventually I need ABEC or some other BEM/FEM code.

Best wishes
David

[bwaslo]

No, XSim won't do that. XSim3D was intended to, but never finished. Maybe VituixCAD will do it (if you can get good data on the directivity of the horn).

[audiorasp]

Is the SEOS 15 discontinued?

[soho54]

I have emailed eric multiple times over the last few years about the seos15s and have always been told they are a fews months away.

If anyone has 3 to 8 sitting around I would be happy to take them off your hands.

[Patrick Bateman]

Originally Posted by soho54

I have emailed eric multiple times over the last few years about the seos15s and have always been told they are a fews months away.

If anyone has 3 to 8 sitting around I would be happy to take them off your hands.

If someone can measure the height, width and depth of the SEOS 15, I can upload an STL file that you can print or have printed. It won't be 100% idential, but should be close enough to work with Bill's crossover, IMHO.

[Sabbelbacke]

I don´t know if these are identical, but some measuerements are here:
SEOS-15 – Horns by Auto-Tech

[carlthess40]

If you can make up the stl file I’d like a chance to print is. I just got a new printer that can do large prints