I've had intermittant dropouts before, usually of right channel audio when making a poor connection or having a battery die, but last night I had something that's a new one on me.
Great recording DPA4060 > MMA6000 > Sony D50 until the final five minutes. Looking at the frequency spread in iZotope I see an intermittant dropout of the bass signal in both channels for a second or two, return of signal, dropout again, everything above say 200 Hz looks fine. The low-cut switch on the MMA6000 was pretty firmly off, and I was seated pretty quietly so I doubt I was accidentally toggling it. Anyone ever see something like this???
Jeff
Maybe it happened to the bass and thats what the PA spewed out ???
Symphony orchestra, no PA. Live it sounded fine, and the waveform didn't look obviously bad in the basic view in Wavelab, but you could hear a problem on playback and the frequency spread in iZotope showed that for a few minutes the low end was winking out and on, sometimes there were "holes" other times stuff was missing but just weak not gone entirely. A loud passage might bring it back for a moment, then it would go out again.
I cleaned all contacts, replaced the 9V cell in the MMA6000, then thought better of it and swapped out to a backup MMA6000, same mics and recorder last night and no problems. But of course that could be luck, it ran fine for over three hours with just four-five bad minutes the night before.
I just hate these random fails.
Jeff
I find these are due to cord failures, or a bad battery connection that is giving power, just not tight enough for full power.
I'm with Scooter on this one. I've had similar problems, and its usually been from bad contact in a connnector, failing solder joint to a connector or preamp battery related. It can be really frustrating sometimes chasing it down.
Random fails are always a bummer, but especially when the recording is otherwise great.
Quote from: WiFiJeff on August 18, 2011, 09:47:53 PM
replaced the 9V cell in the MMA6000,
How old was the battery?
The 9V cell in the MMA6000 was a Duracell good to March 2014, it showed 3 green lights out of 5 on my Universal Battery Tester after the incident. This means about half down. The MMA light was still blinking green, and I've gotten up to three and a half hours after it starts blinking red. So it might have been defective in an annoyingly random way (had that happen once, but it turned off the MMA6000 entirely until a loud noise woke it up). The D50 batteries are Imedion 2400 mAh rechargeables, about a year old and no problem with them before or since, they were only about 1/3 down at that point, I've run them to about 3/4 down.
Jeff
Quote from: WiFiJeff on August 22, 2011, 06:17:23 PM
The 9V cell in the MMA6000 was a Duracell good to March 2014, it showed 3 green lights out of 5 on my Universal Battery Tester after the incident.
That's 3 lights out of 5 with no load, and I think it's not exactly clear what "3 out of 5" lights mean. It would be more interesting to know what a voltmeter reads under load.
If you have this issue again, once you get home check voltage across the battery without disconnecting it from the preamp, with the preamp on. Then compare that voltage against a new battery in the preamp (or a known good and freshly charged if using NiMH), again connected and preamp on.
Thanks for the suggestions. I ran 5 1/2 hours straight Friday with no issues, so I hope contact cleaning and a fresh 9V cell cleaned it up, I just wish it were a reproduceable thing I could test out as fixed. I'll run again tonight, if we are spared further earthquakes.
Jeff