That's probably a good way to tackle the issue! After all, our ear/brain is evolved to filter out ground reflections. Not so much ceiling reflections since there are no ceilings in nature.
What wa the reason you abondond the project? It looked promising. I was hoping to copy it.
I didn't fully abandon. I built one fully working prototype, then I bought a Genelec 8350 to compare. I really wanted to prefer my design but the Genelec just sounded better.
Waveguides for the SB29SDAC now on my site: https://www.somasonus.net/sb-acoustics-sb29sdac. 8" coming soon.
Tried my new hybrid contour with the SB26STAC since soft domes seem to do better with it: https://www.somasonus.net/sb-acoustics-sb26stac. 5" elliptical with 1 : .82 aspect ratio. Other sizes will be coming soon.
I have not followed all of this thread recently, but what mechanisms (factors?) at work in the various WG iterations makes the Bliesma look more uniform in its off axis curves north of 2kHz than the SB26 and 29?
This is what happens when you put a SB29SDAC into one of augerpro 's 6" waveguides, and tune the on-axis response to be flat- the off axis responses follow in a consistent manner, and become attenuated by equal amounts between 2.5KHz to about 12KHz.
Fantastic! Compare this to a SB29SDAC tweeter in a 8" x 12" cabinet, which goes all over the place.
@augerpro
Looks like you've cracked the code to WG for soft domes with large surrounds. Very impressive Brandon!
Reference: SB29SDAC in 6" circular WG
Fantastic! Compare this to a SB29SDAC tweeter in a 8" x 12" cabinet, which goes all over the place.
@augerpro
Looks like you've cracked the code to WG for soft domes with large surrounds. Very impressive Brandon!
Reference: SB29SDAC in 6" circular WG
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The cabinet was the same 8" x 12" for the waveguided SB29 as for the stock version?
Sorry, I didn't mean to mislead.
The stock version was measured on a 8"W baffle (x 12"H x 10"D cabinet), with the dome centered on the vertical axis, 3 1/8" down from the top edge. No roundovers to any edge.
The SB29SDAC, as measured by augerpro was on his large quasi-IEC baffle IIRC
However, on a 8"W cabinet, the directivity and diffraction signature is much the same, since the dome is 1" behind the baffle surface, and thus largely 'hidden' from the baffle edge. As you probably know, in conjunction with moving the acoustic center backwards, this largely simplifies crossover design, which is another features of waveguides...
The stock version was measured on a 8"W baffle (x 12"H x 10"D cabinet), with the dome centered on the vertical axis, 3 1/8" down from the top edge. No roundovers to any edge.
The SB29SDAC, as measured by augerpro was on his large quasi-IEC baffle IIRC
However, on a 8"W cabinet, the directivity and diffraction signature is much the same, since the dome is 1" behind the baffle surface, and thus largely 'hidden' from the baffle edge. As you probably know, in conjunction with moving the acoustic center backwards, this largely simplifies crossover design, which is another features of waveguides...
Yes I know the benefits of a waveguide but a large IEC-like baffle behaves differently at high frequencies than a 8" wide baffle. I'm almost sure this 6" shallow waveguide would not show that nice uniform off-axis on the 8" flat baffle as on the large (quasi-IEC) baffle and the off-axis response of the stock dome would look much better on the large baffle than on the 8" baffle.
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I agree. I found that a waveguide tweeter benefits from large radius / bevels, just like a flat faced tweeter.
Metal domes are flatter generally than fabric domes, plus they radiate more like a piston so they integrate with the waveguide better. That's my .02 anyway.
Here's a comparison of the SB26CDC in the 6" waveguide. First in my test baffle (roughly 1m x 1.2m), and the second in my standmount speaker.
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I bet the baffle of your standmount speaker is not much wider than the waveguide or have beveled/rounded side edges.
This is just one test case, but it does demonstrate how poorly a hard-edged baffle can perform with a waveguide, and the improvements that good edge treatment can bring to the table.
It is important to note that if this experiment were repeated with a flat faced tweeter, the hard edged flat panel might look even worse. Waveguides lessen the impact of baffle edge, but the effect is still there, and still must be addressed.
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It is important to note that if this experiment were repeated with a flat faced tweeter, the hard edged flat panel might look even worse. Waveguides lessen the impact of baffle edge, but the effect is still there, and still must be addressed.
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