Bessel Array

[feds27]

Has anyone on this forum designed or built a bessel array? If so, how did you wire the drivers? How did you design the crossovers? I've found info on what a bessel array is, but haven't found details on how to buid one. As an experiment, I was thinking of making a 5x5 arrangement of tweeters. Any thoughts or advice? Thanks.

[GM]

I've experimented with them, using the info in 'Sound System Engineering'/Don & Carolyn Davis. Since there's no efficiency gain and you must be fairly far away for them to 'jell', they are of extremely limited use IMO.

The 'expanded stereo' variant can make for a nifty horizontal stereo TV speaker array, or in mono layout, a wider 'sweet spot' HT CC with the same tonal balance than the L-R mains if 'fullrange' drivers are used.

GM

[johninCR]

Feds27 is right on with using a bessel array for a center channel. I played with the 7 driver amplitude bessel alignment. The center driver gets a 0 factor so that's where the tweeter went. I didn't like that imaging was nil in a stereo arrangement, just a big wall of sound between the speakers. It did work as far as dispersion and eliminating the line array effect.

My link that showed the wiring config doesn't work any more. Maybe Feds27 could post it for us. I'd like to give it another shot as a center channel.

Going from memory it was +1,+2,-2,0,+2,+2,-1 for the 7 unit array and +1,-2,+2,+2,-1 for the 5 unit array. The "-" amplitudes are accomplished by wiring the driver out of phase. I wired the 2's in parallel and the 1's in series to allocate the power accordingly. I think the 5x5 is 1st row the same as the first column, so the minuses run diagonal.
1st row +1-2+2+2-1
2nd row -2+2+2-1+1
3rd row +2+2-1+1-2
4th row +2-1+1-2+2
5th row -1+1-2+2+2

[feds27]

John,

Thanks for your reply. I'm tempted to try it out with some cheap $5 McIntosh tweeters that are available at the following link. I'm curious as to how this might sound as a center channel.

Regards,
Fed

$5 McIntosh Tweets

[Landroval]

I did a little digging and found this bessel thread. feds27, what happened to your experiment? Anyone else using this technology with any success?

[johninCR]

In my post above, I made a mistake. The 5 driver bessel has no -1, otherwise it is correct, but just one of the 2 pwer factor drivers is wired out of phase.

Sorry, I haven't touched a bessel since I found the lack of imaging. ScottG mentioned one time that he has used a 5 driver bessel with tweeters with success.