[LAU] Behringer ADA8000 phase

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To: Linux Audio Developers <linux-audio-dev@...>, Linux Audio Users <linux-audio-user@...>
Date: Monday, July 1, 2013 - 9:30 pm

Hello all,

The incredible happens.

The electronics of the 'Lampadario' at the Casa del Suono in
Parma consists of a rack with an RME ADI468 converting MADI
to 8 ADAT outputs, 8 Behringer ADA8000 converters, and 8 QSC
amplifiers of 8 channels each. The rack was wired (very neatly)
by a firm specialising in this sort of work.

When I installed the software four years ago, I found out
that 25 of the 64 channels had their phase inverted. For one
of those it was an error in the speaker wiring, which was easy
to correct. The other 24 corresponded exactly to 3 groups of 8,
and the speaker wiring was OK. I assumed that the cables between
the ADA8000 and the amps were to blame - this is a non-standard
cable which had to be hand-made by the whoever did the wiring.
If two technicians had worked on that, they could have had
different ideas of what were the correct connections.

Since I didn't want to take the rack apart, resolder 24 wires
and put it all back, and since there was only one SW app driving
the installation at that time, those 24 inversions were corrected
for by that software. So far so good.

Recently I re-measured the IRs of the whole thing. There
were again 24 channels out of phase. But not the same ones.
One of the groups of 8 had turned in-phase, and another
one was now inverted.

The only thing that has happened to the installation over
the last years is that some of the Behringers failed (power
supply blown up, one per year on average) and were replaced.
So I checked those separately. And yes, some of them had their
output phase inverted w.r.t. the others. Apparently the thing
exists in two versions, but apart from measuring there's no
way to tell which is which. So I'll have to recheck things
each time any of them are replaced again. Thank $GOD we didn't
use those for the WFS system.

The incredible happens.



A world of exhaustive, reliable metadata would be an utopia.
It's also a pipe-dream, founded on self-delusion, nerd hubris
and hysterically inflated market opportunities. (Cory Doctorow)

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Messages in current thread:
[LAU] Behringer ADA8000 phase, Fons Adriaensen, (Mon Jul 1, 9:30 pm)
Re: [LAU] Behringer ADA8000 phase, Ricardus Vincente, (Mon Jul 1, 10:24 pm)