@ScottG Do you have any info about the optimum DI for Bacch filters? Dr. Edgar just says 'as direct at possible'. My hunch is that my ATH horns are somewhat limiting the effect. One of the great features of Bacch is that it doesn't mess up the sound out of the sweet spot. So it would be good to find a compromise between horns for normal listening and full effect sweet spot / head tracking mode. (I don't have the full version yet).
..and they are best with high DI loudspeakers broad-band, and at lower freq.s it’s all about the “null” in relation to the listener. This means that a dipole below the modal region is preferably even though it has a rear lobe.
Ex.
https://6moons.com/audioreview_articles/silent-pound-challenger/
I’m not even sure that “as direct as possible“ is really accurate.
What Bacch is attempting is effectively binaural w/ headphones though instead with loudspeakers in-room.
Pretty-much zero crosstalk between the listener’s ears is the desired result.
For loudspeakers this means that you want a null on the “inside edge” of the speaker so you don’t get spl-“transfer” from the right loudspeaker to the left ear (and vice-versus).
Moreover you want the loudspeakers placed closer together than normal (say more like 6 feet apart), AND you want them as far away from room boundaries as possible to lower the spl of reflections (that also generate cross-talk).
My guess is that 180 degrees DI would be good as long as it was aimed w/ extreme toe-out where the inside null crossed just in front of the listener (where you achieve substantive horizontal pressure-loss).
I think that various absorbers would achieve a lot of what’s required to at least 300 Hz.
Ex. 4” mineral wool panels (free-standing) slightly higher than the loudspeakers and positioned about 8 inches from the inside edge of the loudspeakers and forward of them by about foot. This should reduce a fair bit of direct sound crosstalk laterally above 300Hz depending on how close you listen to the loudspeakers.
For reflections: carpets with padding and ceilings + near walls (from loudspeakers to listener’s head) with sound absorptive panels. Though note that suppressing reflections isn’t nearly as important as direct sound, especially as the point of reflection is further away from the loudspeakers. Practically speaking this means that the floor and ceiling (and the “front” wall if your loudspeakers aren’t well away from it) are more important than the side-walls.
It’s the freq.s below (around 300 Hz) that are “tricky“ in most small room contexts. Modes “swamp” the room so that directive loudspeakers don’t measure directive once you move past them by about a foot. Still, there is a pressure gradient from the speaker at a short distance, and as long as the listener doesn’t have a high pressure “node” between the speaker and the listener (the closer to the listener the worse it is) then the null should be easily heard.
Dipole up to 300Hz tends to provide the best result (despite the rear out-of-phase lobe) as long as the null is positioned correctly relative to the listener. Near-field dipole (along with time/phase integration) is optimum for several reasons, but perhaps not practical.
What Bacch is attempting is effectively binaural w/ headphones though instead with loudspeakers in-room.
Pretty-much zero crosstalk between the listener’s ears is the desired result.
For loudspeakers this means that you want a null on the “inside edge” of the speaker so you don’t get spl-“transfer” from the right loudspeaker to the left ear (and vice-versus).
Moreover you want the loudspeakers placed closer together than normal (say more like 6 feet apart), AND you want them as far away from room boundaries as possible to lower the spl of reflections (that also generate cross-talk).
My guess is that 180 degrees DI would be good as long as it was aimed w/ extreme toe-out where the inside null crossed just in front of the listener (where you achieve substantive horizontal pressure-loss).
I think that various absorbers would achieve a lot of what’s required to at least 300 Hz.
Ex. 4” mineral wool panels (free-standing) slightly higher than the loudspeakers and positioned about 8 inches from the inside edge of the loudspeakers and forward of them by about foot. This should reduce a fair bit of direct sound crosstalk laterally above 300Hz depending on how close you listen to the loudspeakers.
For reflections: carpets with padding and ceilings + near walls (from loudspeakers to listener’s head) with sound absorptive panels. Though note that suppressing reflections isn’t nearly as important as direct sound, especially as the point of reflection is further away from the loudspeakers. Practically speaking this means that the floor and ceiling (and the “front” wall if your loudspeakers aren’t well away from it) are more important than the side-walls.
It’s the freq.s below (around 300 Hz) that are “tricky“ in most small room contexts. Modes “swamp” the room so that directive loudspeakers don’t measure directive once you move past them by about a foot. Still, there is a pressure gradient from the speaker at a short distance, and as long as the listener doesn’t have a high pressure “node” between the speaker and the listener (the closer to the listener the worse it is) then the null should be easily heard.
Dipole up to 300Hz tends to provide the best result (despite the rear out-of-phase lobe) as long as the null is positioned correctly relative to the listener. Near-field dipole (along with time/phase integration) is optimum for several reasons, but perhaps not practical.
Last edited:
About 150USD/pc and seems to be able to be cut low and reasonably smooth at HF.
Unfortunately there is not picture of the driver throat.
https://audioxpress.com/article/test-bench-sb-audience-44cdn-pk-1-peek-diaphragm-compression-driver
Unfortunately there is not picture of the driver throat.
https://audioxpress.com/article/test-bench-sb-audience-44cdn-pk-1-peek-diaphragm-compression-driver
One of few manufacturers that actually write out the throat opening angle https://www.sbaudience.com/index.php/products/compression-drivers/rosso-44cdn-pk/
Faital Pro is another to tell their exit angle too, Click on a driver and then it's the second to last spec on the left column:
https://faitalpro.com/en/products/HF_Drivers/
https://faitalpro.com/en/products/HF_Drivers/
I'm not sure that there is a premade config or stl that will suit that combination ideally. The TD2001 really needs a more loading optimized horn to get down to 800Hz crossover and the ST260 are small to mate with a 15" woofer.
Example measurements to demonstrate only
https://croweaudio.blogspot.com/2019/10/tad-td-2001-on-es-800-biradial-horn.html
Example measurements to demonstrate only
https://croweaudio.blogspot.com/2019/10/tad-td-2001-on-es-800-biradial-horn.html
That's pretty much the same setup that I used in my largest design. I found that it worked quite well with a traditional 18" OS waveguide with 6" radius mouth edges into the baffle. Today, I would use Marcels more gradual flare into the baffle, but I'd change little else. Except maybe the fact that I started out with the same TADs, but ended up with B&C.
I used the DE25, DE250, and DE500 along with the 15TBX100 and later the neo version of that. (Crossover change with each combo AWA updates.) What improved? My bottom line - these drivers we almost 1/10th the cost. Otherwise, both objectively and subjectively (statistically significant blind comparison) there was little to no difference.
If you look at the ST260 E version you can see parameters that are more loading optimized, but that comes with a steeper rising DI. The other thing you can do simply is take the ST260 config and increase the length parameter, that will make it bigger in all directions and at least will go some way towards matching the DI of the woofer at your crossover point.
That is surprising, considering 10x the cost. Thanks for sharing your experience.
Yes, much easier indeed, that was the main intent. Make a donation and I'll add an ATHEX-460-25 to the list, which might be more suitable for a 1" driver crossed around 800 Hz to a 15". The 520-25 is specifically aimed for a bigger driver with a throat-reducing plug (like the 1.4" Faital HF146), so it can be used a little lower - for this purpose the WG is also bigger.
An ATHEX teaser (which I'm currently working on, a big one for Radian 760NeoPB): http://at-horns.eu/ATHEX-520-33.html
- Sorry about the end of Ath development/availability, it's just a very long way from writing some code for myself to making it available and usable to public (all the documentation, etc.). For a year or so it was already a mess and it became so little rewarding for me that I just decided it's time to stop.
An ATHEX teaser (which I'm currently working on, a big one for Radian 760NeoPB): http://at-horns.eu/ATHEX-520-33.html
- Sorry about the end of Ath development/availability, it's just a very long way from writing some code for myself to making it available and usable to public (all the documentation, etc.). For a year or so it was already a mess and it became so little rewarding for me that I just decided it's time to stop.
Last edited: