Posted by WillStG on 06/30/06 05:43

Ty Ford wrote:
> I have had some weird effects caused by subsonic sound as Phil describes. It
> was an outdoors shoot. I could hear the REALLY LOW energy on my MDR7506
> phones as it pushed the limiter. Could have been the wind, although I don't
> recall it being windy that day and we weren't taking typical wind hits. I was
> using a Countryman B6 and a Shure FP410 automixer.
>
> If you have it again, engage the high pass filter and see it that stops it.
> In a few situations I have experienced a lot of low frequency energy pulling
> down the power supply on battery powered mixers to a point where they get
> wacky, especially if the headphone level is relatively high.

I have noticed this a _lot_ mixing TV, even coming down the line
from remotes or on tapes. If you aren't listening loud enough to hear
the real low end stuff, you might wonder at your limiters going crazy
for no apparent reason. Whoever is mixing the location shoot *has to*
engage their filters or every protection device in the tramsmission
path between them and the studio can react unpredictably, and sometimes
the limiters will just bury the voice in noise you can't hear!

Another good one, very similar but different, is that sometimes you
can get a digital line coming in, that when not properly
encoded/decoded before it gets to you, can't be recorded or decoded
past a generation - almost like copy protection, but not. We had some
Sattelite digital audio from the Olympics that we could hear on the
digital mixer's 2 buss, but that _would not pass_ through the mix minus
busses and that the digital tape decks recorded as silence! Fortuntely
Master Control that day was an analog studio, so it did get passed to
the net, but the show histories being recorded for updates recorded
that section of the show as silence. Very weird, we had to convert to
analog in master and distribute it around the plant analog to work
around the problem.

Will Miho
NY TV/Audio Post/Music/Live Sound Guy
"The large print giveth and the small print taketh away..." Tom Waits

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