unwanted guitar buzzing/distortion

[bardogodspeed]

hello everyone,

I'm new here. I have a few years experience with computer recording years ago, now just getting back into it. I'm having the strangest problem with unwanted buzzing/distortion when I record guitar. It's probably not what you think - it doesn't seem electrical-related. I will explain why, but first my setup:

guitar -> tube amp -> mic -> USB Art Pre Interface -> laptop

The buzzing happens when I strum, and only when I strum. I don't hear any buzz unless I play back the recording (i.e. What I hear coming out of my amp is perfect). It isn't the mic because when I record my voice, it sounds perfect.

So I tried a different setup, thinking it was something weird with the amp. I took the amp and mic out of the picture and just went

guitar -> USB Interface -> computer

and still, the buzzing... it's almost like unwanted (bad sounding) distortion. I am not clipping on the USB interface. The waveforms look good, again no clipping. There is no buzzing or anything when I'm not playing. But as soon as I strum, the resultant sound the computer captures has this distorted sound.

I have tried moving far away from the computer, and rotating myself to face away... nothing has worked.

Seeing that one of the common denominators of each setup above is my guitar, could it be possible that my pickups or something are interfering?

I am using Acoustica Mixcraft for software if that helps. Also, my guitar is an American Strat (humbucker pickups).

Any help would be appreciated.
Thanks,
Corey

 

[gregsk777]

Are your laptop speakers dying and just distorting?

Did you try recording a crystal clean guitar sound? Also back way down on your USB preamp when recording and see if it helps.

 

[legionserial]

Sounds like you might be tracking too hot and it's clipping on the way in maybe. What level is it going in at?

 

[NYMorningstar]

Do you have a gate on? That would explain not hearing the problem when you're not strumming. Narrow it down, revisit your gain structure and if that doesn't work swap out parts one at a time like different cords, different guitar, different amp, mic etc...

 

[bardogodspeed]

I appreciate the replies, everyone.

@gregsk777: I'm using headphones right now, and they're fine. And like I said, recording vocals the problem isn't there, only this guitar.

@legionserial: I don't know what level it's going in, but I know it's not clipping. As I said, the waveform on the computer looks good, and I'm not getting any red lights on my interface.

@NYMorningStar: what's a gate? I'm going to try a different guitar, as that seems to be the one common denominator here.

I was hoping someone had some experience with a guitar interfering with something. Although this doesn't seem electrical. I'm still stumped.

 

[bardogodspeed]

could it be the pickups? but why wouldn't I hear it coming out of the amp? The sound out of the amp is great.

 

[gregsk777]

I really doubt it would be your pickups because that would be noticeable right away coming out of your amp. Maybe your mic is too close to your amp and it is distorting/overloading itself?

For shits, try another program like Audacity as a test. It is free and may help you narrow down the problem.

 

[bardogodspeed]

thanks. yeah, i'll try another free program, and a different guitar to help me narrow this down. I'll post if I solve the problem.

 

[Beemer]

Corey,

In my recent reading up on various multi track portable recorders e.g. Zoom and Boss I have read that they can exhibit digital noise when recording guitar. It did not go further but my guess is that it is the high impedance input that picks up electrical noise.

Are you monitoring another input whilst recording another track? You may be amplifying any existing noise.

Are you sitting near a CRT monitor?

Is your guitar and all other equipment properly earthed to the same point to avoid an earth ground loop?

If all else fails you can try a ground loop audio isolation transformer (Radio Shack/Maplins)

Can't think of any thing else.

Ian

 

[legionserial]

@legionserial: I don't know what level it's going in...

Whether it's relevant to your problem or not, this is really something you should know.

 

[legionserial]

Also, just because your waveform looks good, doesn't mean you aren't clipping somewhere in the chain. The heavily distorted guitars I record are essentially clipped all to hell at some point in the chain (ie inside the amp). The waveforms still look good. Don't mean a thing if it sounds like ass.

Get your input levels sorted. Know what they are, then go from there.

 

[bardogodspeed]

thank you all for the replies! I spent two hours on this problem last night and I'm more stumped than I ever was! It's driving me insane.

@legionserial: Here's the thing. In order to simplify (and narrow this down), I plugged my guitar directly into the USB interface. Same problem as when I was mic'ing my amp. Nasty buzzing sound on each strum, buzzing not present when not playing. As far as my levels, what I meant is that I couldn't give you a number, like 7 or something. What I'm doing is simple, I have my guitar turned up to 5 or so. On my USB interface (Art Pre Dual), I turn up until I get clipping red light, then back it off a little. At no point am I getting a red light. This is about as clean a tone as you could get: guitar->USB->computer.

I tried a different guitar. Same thing. Downloaded Audacity, same thing. Tried 5 different cables. So it's not the guitar, cables, or software. Then I thought something is wrong with the USB interface, but this doesn't seem likely because when I record vocals everything is crystal clear. But while my guitar was plugged in direct, I plugged my headphones into the back of the USB interface to monitor the sound, and it sounded great! It isn't until it gets to the computer that this happens.

Then I did another test. I mic'd my amp and recorded a 2min track of alternating between guitar playing and going over the mic and singing into it.

The entire 2minute track had the buzzing sound whenever I strummed, but the vocals sounded perfect! WTF????????

It's obvious something about a guitar tone (any guitar) is causing this. What could this be? I'm beyond hope. The only thing I can think of is that the USB interface is not working correctly, but then why do my vocals sound good?

Please, please... anybody have any clue why this would happen?

 

[bardogodspeed]

@Beemer: In light of what I posted above, do you think this problem could be electrical? I'm no expert, but it doesn't seem likely to me.

Yes, I am sitting near my laptop monitor. I have tried moving 5ft. away but nothing changes.

I plug my guitar in direct to the USB interface which is powered by USB bus. So the computer is the sole power source and is plugged into the wall with a 3pronger. Does this seem sufficient?

 

[gregsk777]

I can't remember if you mentioned if it was distorted guitar your were playing but it sounds like you are using the same mic for vocals and guitar. So maybe there is something wrong with your mic? Try screaming into your mic or other loud noises into it and see if distorts acts funny also.

 

[bardogodspeed]

Hi Greg,

Yes, if I scream into the mic it will obviously clip. But singing normally into the mic and setting my levels correctly, it's fine.

I don't think it's the mic because I'm getting this problem when I plug my guitar directly into the interface, like this:
guitar->USBInterface->Computer

 

[legionserial]

What I'm doing is simple, I have my guitar turned up to 5 or so. On my USB interface (Art Pre Dual), I turn up until I get clipping red light, then back it off a little.

What about in your DAW software? Have you checked for red lights on the input channel there?

Anyway, whether it's relevant or not, going in just under clipping if you're recording digitally is not the best idea. It's uneccessary and will only be detrimental if anything. You're giving yourself no headroom for starters, aswell as the issue that if you have a whole bunch of tracks going in just below clipping, when you put them all together, your master bus is pretty much guaranteed to clip.

Again, you really should know what levels things are going in at. I can understand how you wouldn't if you're taking the 'go in just below clipping' route. I don't know that any of this is going to solve your problem, but it's worth looking into gain staging and input levels, because what you're doing is not the greatest way to do it.

Have you at least tried recording at a lower input level to see if it solves the problem? I'm not saying it will, but it's worth trying given that your gain staging doesn't sound too good at present. You really don't need to go in any higher than an average of -18 to -12 dbFS (not peak, average-I tend not to peak over -6dbFS at most).

You need to pay attention to your levels. It's simple as that. You can't just ignore them and not know what levels you're going in at. You're asking for trouble that way. Gain staging is important. Not knocking you, just trying to help.

 

[gregsk777]

Well I guess it sounds like it all revolves around your usb preamp.

Have you tried recording guitar at a very low volume through the preamp, basically turning the usb preamp knob down to say 2? Then boost it on your computer to hear if it is still causing that strange sound when you strum.

 

[bardogodspeed]

I have tried setting my input levels very low, just to experiment. And yes, same problem. It can't be the mic because it's still happening when I take the mic out of the picture (plug in guitar direct). Right?

I think I have isolated the problem happening somewhere between leaving the USB interface and entering the computer. But as to how to fix it, I have no idea.

Like I said though, when I plug my headphones into the back of the USB device to monitor the sound, it sounds great. It's just when it enters the computer that the buzzing is occuring. And this happens when I set my input levels VERY low.

So strange, it's driving me nuts.

 

[bardogodspeed]

@gregsk777: yes, I have tried that. It's not a "clipping" sound, it sounds as if there's digital noise mixed in with the guitar sound. So strange.

For another test, I plugged the guitar into the soundcard with a 1/4 to 1/8 adapter. Sounded fine.

So something is bad happening somewhere in the space between leaving the USB interface and entering the computer, but ONLY for guitar and not vocals. ?!?!?!

 

[gregsk777]

Just as a check, what are the input/output setting of your recording software? The input should be set to your Art preamp sound driver. Sometimes Windows soundmapper or some other soundcard drivers get involved and mess things up.