2 Replies Latest reply: Jul 11, 2013 3:00 AM by steve.kr RSS

    A recorded waveform appears shifted?

    steve.kr Community Member

      I recorded a piece playing on an internet site directly on my computer using Audition CS6. The waveform appears shifted, but only on the negative side. The negative side of the waveform has greater amplitude. The piece plays normally, however, and doesn't sound bad in any way. Does anyone know what this is or if I should be worried? Does anyone know what my threshold is? This is the first time this has happened to me.


      If it helps to know, I have a mid-2011 iMac 27" 2560x1440 Quad Core Intel Core-i7 hyperclocked, 16 GB RAM, running OS X Mountain Lion 10.8.4, and the best audio setup and audio settings I could put in it.


      Oh, and messing with my MIDI line-in settings didnt do anything. I use the MIDI AUX line-in for stereo direct recording from the output AUX of my computer. This way if I can't download something, I can record it at 96kHz and 24-bit with an extremely low noise-floor I can remove later. I don't actually use MIDI equipment. I change the input volume up and down as needed to

      make sure recordings don't come in clipped.


      Shifted Waveform.jpg

        • 1. Re: A recorded waveform appears shifted?
          SteveG(AudioMasters) Community Member

          Assymetric recording isn't unusual - a lot of instruments produce waveforms like this naturally, and so does the human voice. The only interesting thing is that almost invariably (because of the way waves travel through air) the assymetry is generally the other way around - the larger peaks are positive.


          One other thing that can cause non-symmetrical waveforms is a DC offset - but looking at the end of your file, there doesn't appear to be anything significant happening in that direction. So the only thing I think you have to do is to invert the signals. It's possible that some previous processing may have caused this to happen, obviously - but unless it happens with every single recording you make, there really isn't anything else to be done.

          • 2. Re: A recorded waveform appears shifted?
            steve.kr Community Member

            To be quite honest, I am very impressed. I did not think anyone would reply so soon, let alone reply at all to my question. You have given me quite a bit of info that will allow me to do plenty of trial and error to see, just for the heck of it, if I can't get a more even waveform. Thanks! It's great to learn new things! Since most of what I do, at least up until now, is simply remaster music, I haven't really had to deal with this phonomenon, but I suppose branching out will provide plenty of challenges along the way. Thanks again!