The image will probably be confined to a smaller area around the stereo center. Very compact and solid image, detailed imaging, but what you hear will be presented to you without a sense of size.
Changed the parameters for the horn I simulated in post 14,893 to flatten directivity above 4kHz. It can sort of work down to 3kHz between 20 & 25 degrees. Intuitively, I think something like this should be controlled to 2kHz minimum, so it would need to be a little bigger. Even though it might be too small I may print a waveguide to test effect of entry ports on the higher frequency range I want to keep flat. Config attached in Zip.
0, 10, 20, 30 Power+DI (10 degrees)
Normalized 10 degree line chart. You could sit off center with the far speaker at 10 degrees and the near at 30 with a 5 dB drop level from 4kHz to 10kHz.
Center of polar still isn't smooth so sitting at 0 degrees wouldn't be as nice.
+/-90 Horizontal, Vertical
+/-180 Normalized (Yellow is -6dB)
Horizontal, Vertical. Vertical image should show more white like the Horizontal due to uneven 0 degree axis. It didn't come through in the image.
0, 10, 20, 30 Power+DI (10 degrees)
Normalized 10 degree line chart. You could sit off center with the far speaker at 10 degrees and the near at 30 with a 5 dB drop level from 4kHz to 10kHz.
Center of polar still isn't smooth so sitting at 0 degrees wouldn't be as nice.
+/-90 Horizontal, Vertical
+/-180 Normalized (Yellow is -6dB)
Horizontal, Vertical. Vertical image should show more white like the Horizontal due to uneven 0 degree axis. It didn't come through in the image.
Are there any recommendations on the distance between horn and woofer? I want to use the SB Acoustics SB34NRXL75-8 driver in a sealed spherical enclosure with a 37 liter volume below the A520G2 using an active crossover. Pictured is an early draft of how it could look like.
As close as possible. Ideally within a quarter wavelength at the XO frequency. Getting them that close is unlikely.
dave
Do you mean center horn to center woofer? Since the crossover has to be around 620hz, the distance would only be ~13.75cm which seems difficult to achieve.
Thanks,
David
Hello,
Some years ago i had this with 70 liter enclosures for 12“ bass drivers but the horn was not the best.
Greets Hannes
Attachments
One common recommendation is 1.2 to 1.6 times the crossover frequency wavelength from center of horn to center of woofer. I preferred mine even wider than 1.6 times after listening tests. Everything between 1.2 and 1.6 still sounded good and other people may have preferred something in that range.
and because it is unachievable with a big woofer and horn, this rule can be omitted alltogether.
@DCDK, there was a long discussion over this, started by Vituixcad creator Kimmo Saunisto. He suggested to use a center to center distance of 1.1-1.3 lambda of the crossover frequency. This results in quite a spread. The ratio behind this is the following: below the downward directed vertical null of the two-way system, the lobe again begins to sum positively. Due to this, the dip in the power response that is usually resulting from the two-way crossover is mitigated. From my own experiments, I never was quite sure if I could sense, in some cases, that i.e. bass notes where coming from the woofer and the voices from the horn. In any case, the tallness of the image improved. I suggest that you use simulation data in VCad and build a cheap prototype to confirm whether your design choice actually works perceptually.
It is possible to get quite close. With an MEH it is possible.
The closer you get the better. Fewer issues. Not as limited listening window.
Even less possible with cone+dome barring coax with DSP time delay.
dave
It ist made with fibreclay and was original a plant pot.
Sometimes i will bring this project to an end but first i need a nice horn for it.
Greets Hannes
