audio distortion question

hello,

this has happened to some of my audio:

it's because i was playing some loops in ableton live, and recording the result. some of the loops were originally recorded through a very shitty old sound card around 2005ish, and are obviously distorted - when layered on top of each other, the effect is multiplied and starts clipping even though the audio levels are low.

does anyone know what this is called, or if there's a program that can fix these files?

it's a very noob question but it'd be great if you could find a solution!

cheers

Fuck. This looks like rectification. I have no idea how this can happen non-deliberately though.

.....no one?

I've read up on this and IMO it's an electrical problem. Shitty wires, maybe the soundcard is busted... anyways, see if it happens with other wires, otherwise the soundcard is the problem and save for opening it and checking you need a new one.

Or (doesn't look like it, but) maybe the loops you're talking about had DC offset (http://en.wikipedia.org/wiki/DC_offset) and layering several summed up the DC offset to clipping values. Try putting a hi-pass filter on your master buss, set around 30hz with as steep a curve as possible. Or use DC offset removal on the .wavs if your DAW has it.

cheers mate, looks like it's a dc offset problem on the original wav loops, caused by recording through a shitty soundcard. i thought it was amplitude distortion but then again i have no idea about anything.

this is a better image to explain what's happening with the wav loops:

i've added a hi-pass filter to the output on ableton live and that's helped a lot.

the original soundcard is now in a skip somewhere, and i've lost the original samples and buzz file, so the loops are all i have.

edit: apparently i can fix the original files in audacity using the "normalise" function without actually normalising the files and ruining the dynamics, so i'll see what i can do with that....if this works, i'll have your children.

If you have a lot of files with the same affected dc offset you could maybe have a manual dc offset vst effect on the channels you need fixing. Something like this - http://brb.notatruck.net/vst.html (go right to the bottom of the page)

  On 5/1/2010 at 6:34 PM, margaret thatcher said:

 

i've added a hi-pass filter to the output on ableton live and that's helped a lot.

the original soundcard is now in a skip somewhere, and i've lost the original samples and buzz file, so the loops are all i have.

 

edit: apparently i can fix the original files in audacity using the "normalise" function without actually normalising the files and ruining the dynamics, so i'll see what i can do with that....if this works, i'll have your children.

Oh yeah, based on that pic it's defo DC offset. DC offset, in layman's terms, is (traditionally) an electrical glitch that creates square waves so low that it's practically impossible. So you lose headroom artificially. If this fake gain of these fake sound waves is considerable, one single hi-pass filter might not have enough of a steep curve. Use two or more in succession to completely eliminate the problem. FL studio has a very very neat DC offset removal functions, it does it automatically, removes all of it and centers the wave so you basically see the correction happening. So either get a quick FL Studio demo and sort if out (that is, if you don't condone piracy), or 2-3 hipasses.

Normalizing won't do squat, also normalizing doesn't ruin dynamics. Normalizing detects the highest peak in the audio, and adds the same amount of dB to the entire audio as the amount it would take to raise the highest peak to digital fullscale (0 dB). Normalizing DC offset probably resulted in adding negative amounts to the audio because the dc offset was making it go over digital fullscale. So i made the peaks not go over (so no more distortion) but youve still got DC offset in the audio, so when limiting it for mastering purposes you could only push it SO FAR because of the fake headroom usage.

cheers! i didn't actually mean normalising - there's a function in audacity where you can remove dc offset in the normalisation effect plug-in....and it worked! genius!

i've rerendered the files and it's worked beautifully. lube saibot, i'm all yours.

Does everybody use a fucking browser with really small fonts? Almost everybody reads Luke instead of Lube, it's fucking silly.

aaah such is the beauty of being an ekt plus, no one will ever know, lube.

Highpass will do nothing to fix the clipping that is there already(in the source, it will help the layered clipping effect you describe), but its still a good idea.

good timing

hey you said you use ableton, right?

you have a DC button there