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Gear / Technical Help => Ask The Tapers => Topic started by: fleish on November 21, 2011, 12:52:58 PM
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So I recorded the Infamous Stringdusters & Emmit-Nershi Band over the weekend. Upon opening it up and looking at the wavform, I immediately noticed lots of outliers on the left channel. After I finished freaking out, cussing up a storm, & :banging head: ... I checked my notes and was reminded I had lowered my right channel for clipping around 16:47. And sure enough, there's weirdness in the right wavform @ ~16:34. Thing is, I've seen clipping in my waveforms in the past, but I think it usually just goes flat at the top or bottom ... I've never seen it go diagonal like it appears to be doing here. There are a few other spots that also look weird to me - and only happened on 1 channel. My left was running a little hotter than the right until I finally lowered it @ ~32:50. So my question is this, is this normal? Did it just clip really bad? Or could something else have happened here? I can provide sound samples too if needed (I swear on some of these I can't even hear much different - while on others I believe I can hear the sound drop out), but for now here are some screenshots.
(http://www.fleish.org/pics/isd-probs/isd1.png)
(http://www.fleish.org/pics/isd-probs/isd2.png)
(http://www.fleish.org/pics/isd-probs/isd3.png)
(http://www.fleish.org/pics/isd-probs/isd4.png)
(http://www.fleish.org/pics/isd-probs/isd5.png)
(http://www.fleish.org/pics/isd-probs/isd6.png)
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Possibly voltage issues?? Are the spikes audible?? Or just "drop outs" as you mentioned?
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That looks like what I've had happen when there was a short or some other type of electrical anomaly - sometimes even if there's just a glitchy place on a gain knob that gets noisy when you cross it. If you hear them as "pops" that's what I'd think it is.
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Looks like bad connection or cable but something electrical
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Possibly voltage issues?? Are the spikes audible?? Or just "drop outs" as you mentioned?
I'll try to cut up some samples and post them. I may have called them "drop outs" in haste, but I could definitely hear something weird when I listen to some of these.
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Check out the samples (@24/48) below. Out of these, there is only one where I can "hear" it.
http://www.fleish.org/sounds/isd-probs/isd1.wav (http://www.fleish.org/sounds/isd-probs/isd1.wav)
http://www.fleish.org/sounds/isd-probs/isd2.wav (http://www.fleish.org/sounds/isd-probs/isd2.wav)
http://www.fleish.org/sounds/isd-probs/isd3.wav (http://www.fleish.org/sounds/isd-probs/isd3.wav)
http://www.fleish.org/sounds/isd-probs/isd4.wav (http://www.fleish.org/sounds/isd-probs/isd4.wav)
http://www.fleish.org/sounds/isd-probs/isd5.wav (http://www.fleish.org/sounds/isd-probs/isd5.wav)
http://www.fleish.org/sounds/isd-probs/isd6.wav (http://www.fleish.org/sounds/isd-probs/isd6.wav)
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Sounds like it's surging almost. I hear "it" in t5 t3 & t2.
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I had a bad capsule on my LSD2 (Studio projects replaced them both for free) where dampness caused it to arc-out. It sounded like "pop and then slowly recover", and they look differently from what you have. I saw a huge instantaneous excursion, and a decay curve as if goes back to normal over a second or two. That's not what you have here.
Any other attributable cause? Cable connection that's looking flakey? Anything that might contribute to dampness issues? In Maine in the winter time for instance, you have to avoid having mics get cold in the car, then when then hit the warm air in the bar they will "fog up" like a pair of eyeglasses.
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I encountered similar wavform phenomena and determined I had a loose connection in my battery box, which in essence was a voltage issue.....
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Unless the problem reoccurs, I'm going to assume I had a bad connection somewhere in the chain. However, here are a few more data points. This was the first time I'd used the mics in a few months. They are always stored in a pelican case, wrapped in anti-static bubble wrap so moisture shouldn't be an issue. Having now looked over the wav file from the opener it appears there were no issues for the first ~57 minutes of recording. When the issue did occur, it was almost always on the left channel. I think I found only 1 instance where it happened on the right channel as well and I believe it also happened to a lesser extent on the left channel around this same time (you can see this in the 2nd image in the OP). My recording from the next night using the same gear in the same venue (slightly different location) shows no signs of the issue. AK40 > KM100 > short XLR interconnects were disconnected and reconnected between the two nights.