Thanks Bill for the information, I expected that someone must have discussed this but I just hadn't seen it.
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
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
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.
I don´t know if these are identical, but some measuerements are here:
SEOS-15 – Horns by Auto-Tech
SEOS-15 – Horns by Auto-Tech
How small can it go?
In my research so far, the P-Audio horns with 2" throat appear to be close to either the Eighteen Sound XT1464 or the Faital Pro LTH142. I'm interested in a quality DIY solution for my home, using the proven B65WBAC25-4 mid/tweeter along with DSP to set crossover from the mid/tweet to 2 woofers around 500-600 hz.
I think as the horn/baffle gets smaller (10" in width) I may lose some of the low-end directivity control that a bigger horns can achieve. Here is one question: I'm thinking two small (4" to 5") Woofers with sealed backs, mounted nearer to the mouth of the horn wall can work for a smaller point-source speaker, compared to mounting the woofers on the baffle - but am fooling myself into thinking that a small-ish 10" horn can control directivity below 500 Hz and provide a point-source experience comparable to a larger horn?
If directivity can't be controlled much below 500, is the point-source experience worth chasing? at what point does it make sense to give up on the Unity/Synergy idea, and place the woofers above and below the horn instead of attaching them to the wall of the horn?
Finally, I am curious to learn what folks think about either of the horns below, mated to the SB Acoustics SB65WBAC25-4 for a tweeter and 2 SB Acoustics SB12PFC25-04 4"woofers.
Thanks! - Six.
PH4528
PH2723
In my research so far, the P-Audio horns with 2" throat appear to be close to either the Eighteen Sound XT1464 or the Faital Pro LTH142. I'm interested in a quality DIY solution for my home, using the proven B65WBAC25-4 mid/tweeter along with DSP to set crossover from the mid/tweet to 2 woofers around 500-600 hz.
I think as the horn/baffle gets smaller (10" in width) I may lose some of the low-end directivity control that a bigger horns can achieve. Here is one question: I'm thinking two small (4" to 5") Woofers with sealed backs, mounted nearer to the mouth of the horn wall can work for a smaller point-source speaker, compared to mounting the woofers on the baffle - but am fooling myself into thinking that a small-ish 10" horn can control directivity below 500 Hz and provide a point-source experience comparable to a larger horn?
If directivity can't be controlled much below 500, is the point-source experience worth chasing? at what point does it make sense to give up on the Unity/Synergy idea, and place the woofers above and below the horn instead of attaching them to the wall of the horn?
Finally, I am curious to learn what folks think about either of the horns below, mated to the SB Acoustics SB65WBAC25-4 for a tweeter and 2 SB Acoustics SB12PFC25-04 4"woofers.
Thanks! - Six.
PH4528
PH2723
Attachments
They are the centers of the drilling locations. The size of the ports isn't critical, by the way, wavelengths where they are used are long. Just don't go out to beyond where the driver gaskets will be. And for best vertical pattern, I wouldn't let the height get any taller than in the drawing, want the centers as close as reasonable to the center of the waveguide. Too narrow height might possibly restrict air flow (though not likely).
That drawing is for 0.5' plywood side panels for minimum size and weight Be careful to make sure the back is well braced, maybe more than shown in the plans. My original ones were actually done with 3/4" ply, and seem quite dead, though.
That drawing is for 0.5' plywood side panels for minimum size and weight Be careful to make sure the back is well braced, maybe more than shown in the plans. My original ones were actually done with 3/4" ply, and seem quite dead, though.
aaand.... as I'm waiting for glue to dry on the new cabinets, I browse over to the TechTalk site and find that the tweeter I'm using is apparently being discontinued! The vendor has it on Clearance (Peerless by Tymphany DFM-2535R00-08 1" Compression Horn Driver 2/4-Bolt 8 Ohm).
Way to kill a design, there, Tymphany. Guess I won't need to do a full build guide on this after all.
Looks like QSC has jumped on the bandwagon:
If I'm not mistaken, this is the first time that QSC has used a compression driver that wasn't made by Celestion or B&C.
bwaslo; I've recently added some BMR "ambience drivers" radiating some energy up the wall and to the sides, fed by a delayed signal of about 15msec, which helps depth illusion significantly and livens up the room sound in the rather damped room.
Hello Bill.
What will happen if we add the "ambience drivers with additional xover" just before the speaker on the same amplifier channel? Will it just change the whole speaker impedance or it will affect whole Small Syns crossover?
Hello Bill.
What will happen if we add the "ambience drivers with additional xover" just before the speaker on the same amplifier channel? Will it just change the whole speaker impedance or it will affect whole Small Syns crossover?
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A stupid question, can the box shape be altered and still use the same x-over/expect same sound? I'm wondering if I could change the box proportions a bit to be (38,5x54,5cm) root3 ratio and enable me to have a cloth grille with flush mounting: all sides are recessed so the grille frame sits flush and diffraction is minimised.
I assume this would not have a major effect due the horn directivity, but I'm asking just to be sure as Troels Gravesen says to all box modifications a firm no.
I assume this would not have a major effect due the horn directivity, but I'm asking just to be sure as Troels Gravesen says to all box modifications a firm no.