source of drop-outs?

[Paul Bravmann]

i'm in the middle of filming a autobiographical documentary with a GL-2. sound-wise, i use a wired AT-899 lav and a camera mounted AT897 shotgun, routed through a beacthek DXA-4P. i keep the beachtek's gates wide open and the camera's audio settings on automatic (per alan barker)--i've got enough to think about re: the visuals w/o stressing over sound levels. up until today, this system has worked out just fine.

today, however, things went a bit haywire. reviewing the footage of a 10 minute self-interview (no phones), i was dismayed to hear the left channel (shotgun) dropping out near the beginning, and only becoming audible for a few, intermittent seconds over the duration of the take.

what i know: the battery is pretty fresh. the cable is new, and doesn't seem to have a short. the connections are tight.

i wonder if this could have been a phase problem between the shotgun and the lav. do phase problems cause dropouts? or might the dropouts be the cause of something else entirely? any thought on the matter would be much appreciated. i'm stumped.

thanks,
phb

[Douglas Spotted Eagle]

Describe the dropout in greater detail? Is it a fast dropout or fading dropout?
Why is cam in automode anyway? should be in manual mode.

[Paul Bravmann]

<<<-- Originally posted by Douglas Spotted Eagle : Describe the dropout in greater detail? Is it a fast dropout or fading dropout?
Why is cam in automode anyway? should be in manual mode. -->>>

dropouts were sudden and total. left channel completely dead. (until it lit up again, for a few intermittent seconds, later in the tape.)

cam is on auto because, after much deliberation, and taking into account the fact that i am a one man crew with limited experience, i decided to follow the advice of documentary sound man alan barker:

http://alanbarker.com

and as i said, the setup was working just fine for me. until today.

phb

[David Ennis]

What you describe is not a mic phasing problem, which would not result in dead silence but rather a reduction in volume that affects lows more than highs.

When you say the battery is fresh, I assume you mean the AA in the mic. So it seems that the possibilities narrow down to dirty heads, a bad tape or an intermitttent connection somewhere in the chain.

A tape that bad is unlikely, but weird things do happen in manufacturing. At any rate, it's easy to check by recording a new tape and rerecording something on that one, which you've probably done by now.

Don't second guess or try to test the cleanliness of the heads, just clean them to rule that out.

For electrical intermittents, the likeliest sites are where electrical continuity is intended to vary by design, such as switches and potentiometers. My number one suspect would be the channel's trim pot on the Beachtek, since you are running it wide open. Manufacturing defects in potentiometers where the slider loses contact at the high and low adjustment limits are common. Another contender is the manual/auto switch on the cam. To test these or any other intermittent mode that you can manipulate by fiddling, just watch the cam's recording level meters while you fiddle. You may temporarily or permanently "repair" a bad connection by fiddling and never know. That's the upside of the special hell called intermittents.