Weird "broken" sound/delay on recorded audio

J

Josh Bass

Veteran
Hi. I know there are a few audio geniuses in here so hopefully someone can help me. I was recording some audio FX recently, at home. Most of it was fine, but a few things came out with a weird artifact/effect to them. I don't really know how to describe it. . .it almost sounds like a very short delay or like the audio is "broken", like the beginning and the end of the sound are there but the middle's missing. This occurred specifically while I was recording microwave beeps and me scratching at a piece of velcro with a grape stem. So these were very short little sounds. . .could it have something to do with the sample rate? I was at 48 khz, 24 bit. I know some folks are all over the 96 khz but I was under the impression that was for FX you planned to play with speed/pitch on, or for high end orchestral recording. Neither of this really applied here.

So here's my setup:

recorded with at4050, cardioid setting, into an Apogee Duet, into an Imac 2011, into Logic Pro X. I recorded some other FX on the mic the same night that sound right, and some vocals shortly before that, so I don't think it's the mic. I guess it could be some recording error/lateny issue/something like that?

I feel you guys might ask for a sample and that's fine, just wondering before I provide it if anyone knows what I'm talking about just from the description. Thanks.
 
I assume the file format was PCM. (WAVE or AIFF).
Otherwise data compression can induce bizarre artifacts..
Could be an analog connection issue as well.. or a acoustical phase anomaly. UFOs in the vicinity maybe.
Post a clip.
 
Sounds like your computer just lost the stream - maybe doing some unexpected HD housekeeping in the background. There is no data in the silent bits, so safe to discount the mic and pre-amp. The problem is between the Apogee and the HD. I occasionally get this on Cubase running on a pretty swish PC. I discovered a virus checker running in the background, which I had not asked for, but had changed preferences when it upgraded. This causes the HD to simply be too busy to maintain the continuous audio data stream. I have also had just a couple of occasions when the firewire connection to my main audio device did this. No obvious reason, but restarting the entire system cured that one. My Mac did this just once, talking to a Lexicon Omega - again, quitting the recording software, unplugging and re-plugging the audio interface cured it. In this case, the problem was very evident in the headphones - and on the waveform building on the screen - which showed the errors.
 
I had headphones on while recording but didn't hear anything unusual, and it was a one-man operation so couldn't watch the waveform build. I guess I'll just make sure to reboot right before starting recording. Also, there has always been some weird issue with the Apogee and other drives/devices. Let's say I have it on, and it's working fine (I use it to output to two near field monitors as well as for recording). If I turn on a drive, all of sudden the audio will get distorted coming out of the monitors. I go back to built in speakers, it's fine. If I reboot, the apogee/near field audio is fine. It doesn't do that 100% of the time, but close enough so that a reboot is usually in order. This has been an issue on two different Macs.
 
Makes sure ALL background programs are shut down when recording, especially anti-virus, anti-malware, and disk optimizers that try to defrag when the keyboard or mouse is inactive for a while. If you can afford it, try to have a dedicated computer devoted exclusively to your recording and editing activities with no other software - internet, email, Office, etc - on it at all.
 
I'll take the background programs advice into account. Don't have any malware etc. stuff running. Can' really afford to have but one computer, yet.
 
Yeah, I just recorded something last night and it was fine. Made sure to reboot right before, killed all other programs, turned off wifi.
 
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