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Chris Kidd[_2_] Chris Kidd[_2_] is offline
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Default Bose 901 EQ distortion

I have 33 Bose 102 ceiling speakers installed as under-balcony delay in the
theater where I work. It had a 102 system processor and analog eq/delay
units when originally installed. When the processing was replaced with a BSS
minidrive, the guy who eventually RTA'ed the room said he took a sample of
the 102's EQ pattern by sending a pink noise signal through it and analyzed
the output signal to see what kind of curve the processor provided and used
this as the basis for the minidrives programming "flatline" and then
correcting for room response with the rta. Could you take a new "DSP box"
and analyzer and make your own "901 EQ"?

Chris


"Peter Larsen" wrote in message
...
Richard Crowley wrote:

Is the curve of the Bose EQ box published anywhere?


It looks like the image of a gletcher valley cross-section ...

Someone over in a.a.p.l-s linked to an image of an analysis of it, i have
it somewhere on some harddisk, mostly I think it was about the 802's ...
but in case of the deq one just needs a measuring microphone and to aim
for the b&k living room reference curve, the simplified version is flat up
to 200 Hz and then drops smoothly to -6 dB at 20 kHz, aiming for
perfection at the extremes is folly.

The OP should remember that while there are many frequency analysis
displays that can be used with a pc most of them display white noise as a
horisontal line and pink noise as a line that slopes with -3 dB pr.
octave. It may be unwise to measure loudspeakers with white noise .... I
haven't got a DEQ, but I think it has measurement analysis built in, other
folks know a lot more about it.

The extra AD-DA conversion may be unattracive .... but it may also be
avoidable, depending on actual context.


Kind regards

Peter Larsen