"gregs" wrote in message
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In article , "Arny Krueger"
wrote:
"TonyP" wrote in message
u
"Don Hills" wrote in message
...
In article ,
(Curious) wrote:

Probably having many dynamic super-tweeters would do the job. If
their are 140 speakers each playing at 1 dB, you get around 140 dB
if they are facing the same direction. Right? Wrong?

Wrong.
1 tweeter = 1 dB.
2 tweeters = 4 dB.
4 tweeters = 7 dB.
8 tweeters = 10 dB.
16 tweeters = 13 dB.
32 tweeters = 16 dB.
64 tweeters = 19 dB.
128 tweeters = 22 dB.

Close enough to 140 tweeters for you?

The 3dB increase each time is debatable, it depends on whether you
get phase coherence or not, but it's close enough for this example.

I think it's safe to assume 128 real tweeters will not produce phase
coherence due to the physical distances involved.

This problem could be addressed by adjusting the phase/frequency
characteristics of the drive to each speaker. In these days of
cheap-but powerful DSP and power amp chips, it's not totally
unthinkable.

I read with interest the original post. I'm still waiting to hear
what tweeter has the highest SPL. I suppose I could research myself,
but I don't want to. I don't really belive the EV T350 has the most
SPL, but I could be wrong. I invision a larger diaphram/ voice coil
to absorb more watts.

I would expect that modern compression drivers and horns from sources like
JBL, EV (current production), TAD and Community could outperform the old
T-350.

http://www.jblpro.com/pages/components/componts.htm

http://www.jblpro.com/pages/pub/components/2447.pdf - 30% rated efficiency

http://www.electrovoice.com/electrovoice/EVfiles.nsf/lookup/ND6Xeds/$File/ND6xeds.pdf -
28% rated efficiency

ftp://ftp.voicenet.com/communit/specs/new/vhf100.pdf

http://www.pioneerelectronics.com/pn...188429,00.html