VO-BB - 20 YEARS OLD!

tokyofan · Posted: Mon Feb 16, 2015 8:09 am Post subject: Mystery static

Again, I'm going to say I haven't changed anything in my vocal chain (other than upgrading to a new Mac-mini and Yosemite).
I've recently been getting some weird static in the audio that just comes out of nowhere. I don't hear it in my phones when recording--just at playback.

Sounds like this (normal to static):
https://www.dropbox.com/s/ywsz8u8t560uign/Static.wav?dl=0

signal chain: CAD E100s-->GAP 73-->RME ADI-2-->Mac-mini (via Toslink)-->Amadeus Pro

I noticed a little of the same static with another mic I used the other day.

Any ideas?
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vkuehn · Posted: Mon Feb 16, 2015 1:38 pm Post subject:

Maybe external electronic interference. Ham radio transmitter nearby? Someone have an electric welder in a garage nearby? Traffic light controller box nearby? Maybe someone's cell phone behaving badly. Could be a vacuum cleaner nearby.

My hunch is that it is something external to your audio chain.... but a bad cable in your audio chain could be enabling an external noise that normally would be ignored.

Frank F · Posted: Mon Feb 16, 2015 6:05 pm Post subject:

What he said... plus try moving you Mac Mini around a bit - and further away from the other parts of your chain and monitor. Crossed power cables and/or audio/USB/mic cables can cause this kind of "static".

A bad/tired/unsheilded cable can ruin your whole day.

F2
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sounddguy · Posted: Mon Feb 16, 2015 9:21 pm Post subject: Re: Mystery static

That is a radio transmission. If it occurs rarely, most likely a mobile unit passing by. If more often, ham, cb or other type transmission.

tokyofan · Posted: Tue Feb 17, 2015 7:09 am Post subject: re:

Thanks for all the troubleshooting! Instant Genius Bar!
I'm still a little stumped as I've been living in the same apartment (recording in the same booth) for 10 years and have never experienced random, intermittent interference like this before. As mentioned, I think it must be some kind of radio/data transmission as I swapped the mic, mic cable, pre, and DAW, and still get static now and again. sigh.
The only new variable is the upgraded Mac-mini which always sits on the floor under the desk far from the other gear, booth, and cables. No phones, cell phones or wi-fi routers near the booth either.
Perhaps something coming from a unit upstairs or downstairs? This just started last Friday so we'll see if it sticks around. Fortunately, the static doesn't last too long.
Heres's another sample. Just recorded some game music off an iPad and got hit with static 3 min in.
https://www.dropbox.com/s/t0prqgv827j2zjp/Static2.wav?dl=0
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Lee Gordon · Posted: Tue Feb 17, 2015 10:50 am Post subject:

I was recording an audiobook and the producer complained of brief noises that cropped up randomly in a couple of places. It was baffling for a while, but what it turned out to be (I think) was, an incandescent lamp that was in its death throes. I can't be sure that's what it was, but the noise never came back after the bulb finally crapped out.
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Frank F · Posted: Tue Feb 17, 2015 11:27 am Post subject:

As I said earlier; move the Mac Mini. They are un-shielded. Turn it, move it to another location (off the floor), cover it with aluminum foil. Change it's location.

I think that covers it.

Frank F
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vkuehn · Posted: Tue Feb 17, 2015 2:52 pm Post subject: Re: re:

tokyofan · Posted: Tue Feb 17, 2015 5:36 pm Post subject: re: Mystery Static

Sorry for the low levels on that last clip.

Anyway, I put a piece of foam under the Mac-mini, turned it, checked the cables again, uncrossed them. Still intermittent static, often 3 min in (oddly). But if I quit and re-record right away, no noise.

Another clue: I just noticed the same (or similar) noise/static emitting from my left studio monitor very faintly, in non-record mode. So, maybe it is something in the system? I un-plugged/re-plugged the monitor cable, switched it on/off. Also turned on/off my ADI-2. And, so far, NO STATIC today with about an hour of recording. Fingers crossed that will stick thought I can't explain WHY that helped.

Would something like this help?
http://www.alectrosystems.com/alectro/catalog/product_info.php?cPath=30_36&products_id=41

Will check in later if things go awry again! Thanks!
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