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Scratchy fuzzy noise in voice-over recording

judithwest

I record audiobooks in my home studio, and over the last year, have been occasionally getting a terrible scratchy noise during some recordings.
  • The creepy-scratchy overlay (voice is audible "under" the noise) is not present at all in monitoring the recording, only in playback.
  • The noise can happen at any point at which I started or resumed recording.
  • When it has occurred, it generally doesn't happen the next time I restart during the same session.
  • No changes have been made (nothing replugged, reset, etc.), other than stopping and starting.
  • There's no discernible pattern to the recurrence of this anomaly.
  • It doesn't seem to be associated with any external, nonrecording event.
  • It started happening with my (recently jettisoned) Pro Tools system and has continued with my new Sound Forge setup --for both of which I use/d my original Mbox as an interface and a Glyph external hard drive for sound file storage. (I work on an IBM ThinkPad T42 running Windows XP.)
I'm pretty thoroughly befuddled. And, though I'm not even slightly audio-astute (just know what I need to know to get by), I've wondered if this might be an electrical, rather than electronic, problem.
For some reason I'm guessing this a hardware problem. Hope someone here can help or recommend something.
Cheers,
Judith
September 1, 2009 @09:27pm
Andrew_Malloy

Does it happen when you are on battery power, AC power or both?
September 1, 2009 @09:30pm
judithwest

Does it happen when you are on battery power, AC power or both?

I don't run on battery when recording, so only happens on AC.
September 1, 2009 @09:34pm
Andrew_Malloy

Try running on battery power. I have seen it happen quite often where you will get noise from the power supply in the audio interface. If that is the problem, there is a simple solution.
September 1, 2009 @09:35pm
judithwest

Try running on battery power. I have seen it happen quite often where you will get noise from the power supply in the audio interface. If that is the problem, there is a simple solution.

Andrew -
I don't think my battery would last long enough to get a useful test, unless the problem just happened to occur right off the bat. I can only run for an hour or so on battery, and my sessions tend to run at least three hours each. I'd have to stop and recharge every hour.
Is there another alternative? Do you think it might be a grounding issue or something? (Caveat: I don't know enough about electricity except to say "grounding" and look pleased with myself!)
Thanks for responding.
- J
September 1, 2009 @09:47pm
Andrew_Malloy

You could try recording for a few mins with it plugged in, wait for the noise to happen, then unplug it to see if the noise goes away.
September 1, 2009 @09:50pm
judithwest

You could try recording for a few mins with it plugged in, wait for the noise to happen, then unplug it to see if the noise goes away.

I'll experiment with plugged/unplugged and see what I learn. Since it only happens when I start or restart recording, and since I only find out during playback whether or not it's happened at all, it may take me a bit to determine if battery power has any effect. Especially since it doesn't happen with any kind of regularity or frequency. (Maddening!!)
But I'll definitely let you know if I discover any correlation.
Thanks again.
- J
September 1, 2009 @10:07pm
yeahforbes

Considering the circumstances -- a home studio where nobody is going to sue you -- I'll recommend trying an AC ground lift. 3-to-2 prong adaptor. Put it right on your computer's power cord. I know a lot of people that do it, including myself, and have never had any adverse effects.
September 1, 2009 @11:50pm
judithwest

Considering the circumstances -- a home studio where nobody is going to sue you -- I'll recommend trying an AC ground lift. 3-to-2 prong adaptor. Put it right on your computer's power cord. I know a lot of people that do it, including myself, and have never had any adverse effects.

Very interesting. And sounds alarmingly simple. I'll be dancing in the booth if it works!
Will post results.
Thanks!
- Judith
September 2, 2009 @12:14am
judithwest

Very interesting. And sounds alarmingly simple. I'll be dancing in the booth if it works!

No dancing, sadly. It went all wacky the first time I restarted recording -- and I recorded for 35 minutes before finding out. Most frustrating.
The particularly frustrating thing is that I have to stop and play it back to know if there has be a problem. And if there hasn't been, that's no sign that there won't be even I turn right around and step back into the booth.
It's way arghghghg...
September 4, 2009 @01:09pm
yeahforbes

Can't you have your software pass the input signal right to the interface's output (mixed with whatever's already recorded) and monitor that with some headphones while you're recording?
Only super fast systems like Pro Tools HD make this a viable way to really record (32 samples of latency = 0.7ms @ 44.1) but for troubleshooting purposes deal with the annoyance so you can hear changes without having to hit play.
September 4, 2009 @02:19pm
judithwest

Can't you have your software pass the input signal right to the interface's output (mixed with whatever's already recorded) and monitor that with some headphones while you're recording?
Only super fast systems like Pro Tools HD make this a viable way to really record (32 samples of latency = 0.7ms @ 44.1) but for troubleshooting purposes deal with the annoyance so you can hear changes without having to hit play.

Hmmm. I'm not sure I understand. Nothing is "already recorded." This is one voice, on one track, nothing added (no plug-ins during recording). So there is no mix involved. I can monitor my recording just fine -- but the problem never shows up then. It only appears on playback.
September 4, 2009 @02:58pm
5454stevef

Hmmm. I'm not sure I understand. Nothing is "already recorded." This is one voice, on one track, nothing added (no plug-ins during recording). So there is no mix involved. I can monitor my recording just fine -- but the problem never shows up then. It only appears on playback.

The mbox "monitors" by passing the input signal directly to the outputs, so it's no surprise you're not hearing it when recording. The most that can tell you is:
It's not the mic.
It's not in the preamp.
It sounds like it's not part of the recording, if I understand what you're saying, since it goes away if you re-start the session... does it occur randomly or typically at the same place?
The nature of the sound, scratchy rather than some kind of hum or continuous noise, makes me suspect something in the MBox rather than a power thing. Ditto for the fact that it has persisted when you switched to Sound Forge. And you say it never happens when recording, which can almost be said to rule out something in your playback system or computer (you don't say how you're monitoring).
Surely it's not anything as prosaic as a scratchy pot or a connection that needs cleaning. I have a preamp that has a couple of switches that occasionally will develop intermittent hash noises and you have to flip them a few times. It took a while to narrow it down to these switches because the unit would just start doing it without the switches being flipped. A shot of contact cleaner helps at times. I've had three different Digi interfaces and none of them have ever developed any "physical" noise ailments like that, but it's possible.
When things like this happen to me, I start by swapping the cheap and easy stuff around, like cables, etc. You'd be surprised how things can just go bad while sitting there, or just unplugging and plugging back in can help. I'd even swap out the USB cable on the mbox to see if anything changes.
Oh, yeah.. does the noise come from both the right and left while playing back, or is it restricted to one side? If it's on both that probably rules out a cable or connection. And is it happening more frequently as time goes on, and get worse the longer you have the Mbox on?
Honestly, it actually does sound like the kind of things some electronic componenets do when they start to go bad, which would mean goodbye to the MBox, but I'd rule out the easy stuff first.
SF
September 5, 2009 @03:20pm
judithwest

[INDENT]I'm not sure I've found The Key, but I'm definitely continuing with superstitious zeal to unplug and then replug my computer's AC cord anytime I stop recording and then start recording again. I've done this over the space of two 45-minute chapters, with 3 stop-and-starts in each, and had no noise-hash problems at all. I'm sure that they'll start up again as soon as I log off this thread and begin recording Chapter 3, of course, since I'll have broken the spell or whatever it is by talking about it...
[/INDENT]It sounds like it's not part of the recording, if I understand what you're saying, since it goes away if you re-start the session... does it occur randomly or typically at the same place?[INDENT]I think I wasn't clear enough about the restarting situation. It "goes away" in the sense that, after I've played back a just-recorded noise-infested/hash-ridden section (i.e., in Pro Tools, a region), I don't get the noise-hash in the next section/region of the track at which I start recording again. The noise remains with the file, and is heard or even sometimes first called to my attention by editors, proof-listeners, and others who receive the unedited file from me. Which means, I assume, that the noise is part of the recording, yes?
[/INDENT][INDENT]The noise-over (as I've begun referring to it) occurs randomly, and with variable frequency.
[/INDENT]The nature of the sound, scratchy rather than some kind of hum or continuous noise, makes me suspect something in the MBox rather than a power thing. Ditto for the fact that it has persisted when you switched to Sound Forge. And you say it never happens when recording, which can almost be said to rule out something in your playback system or computer (you don't say how you're monitoring). [INDENT]I monitor with headphones run from one of the MBox headphone jacks into a Behringer Powerplay Pro HA4600 headphone amp, sending input to me and to the booth. Playback runs from the MBox line-out through the amp to the same two phones. Noise-over registers the same, whether running through the amp or directly out of the MBox.
[/INDENT]When things like this happen to me, I start by swapping the cheap and easy stuff around, like cables, etc. You'd be surprised how things can just go bad while sitting there, or just unplugging and plugging back in can help.[INDENT]I am surprised. Thrilled, in fact! Just a tidge short of getting evangelical about it since I've had my hopes dashed before. But place that football again, Lucy, because this Charlie Brown is always willing to fall on her ass one more time in a good cause!
[/INDENT]Cheers,
- Judith
September 7, 2009 @05:40pm
5454stevef

Judith, I hope the "ritual" continues to ward off the gremlins. I have to say I admire your good humor, considering that this involves your livelihood.
I was thinking more about input/output cables, etc., rather than the power supply cable, but there could have been an iffy connection at the power jack, I suppose. With luck the problem goes away and never returns.
Laptops seem to have more of this kind of thing, I suppose because their power supplies are a lot less robust and probably not as well-filtered as those in desktop machines; if you haunt these forums often enough you will see the same kinds of things coming up repeatedly. You'd think for what they cost you'd get something better, but I guess the thinking is that the main function of the supply is to charge the battery - noise creeping into the system isn't an issue for typical users.
Good luck,
SF
September 8, 2009 @05:03am