Taperssection.com

Gear / Technical Help => Ask The Tapers => Topic started by: atxwolfattack on September 17, 2007, 06:10:10 PM

Title: Weird waveform?
Post by: atxwolfattack on September 17, 2007, 06:10:10 PM
So i know there are a million weird waveform posts, and i went through a lot but could not find my problem.

I didn't notice it in Audacity, but once i opened up the file in CD Wave Editor, i noticed that the waveform seemed lopsided. I don't know the correct definition for this. Also, if someone could tell me what DC Offset means and phasing means, i would appreciate it, i feel stupid for not knowing, but i hear people mentioning it with wav problems, and i can't find the correct meaning anywhere.


One was a super quiet song, one was a little louder.
Title: Re: Weird waveform?
Post by: pontiacb on September 18, 2007, 01:59:06 PM
Hi,

I've had this problem (asymmetric waveform) in the past and asked in another forum a year or so ago before I had plucked up the courage to ask on this site (I asked on the Dime Yahoo group). 

The response I got was that it could be the sign of the battery in my battery box going flat.  I also got told that it was nothing to worry about in terms of overall sound apart from in extreme cases it limited the volume to which the waveform could be amplified before clipping (the volume being effectively the average of the wave above and below zero).   Someone else reported that they had experienced the same in the final couple of recordings before their mics (SP-CMC-2s I think) went down (hope that's not the case for you).

DC offset - you should be able to find a good technical response by searching this forum - my understanding is you have a DC offset when in quiet or zero parts you notice the horizontal wave form is either above or below zero.  This can be corrected in Audacity or elsewhere and I believe that the correction should be performed before further processing (e.g. amplification) so that you don't amplify the offset further. 

Sorry not a very technical reponse, but you are not alone in experiencing both of these issues - they seem reasonably common from the responses I got.  I'm sure someone else can provide a better technical explanation.

Edit - I should add that the asymmetry in the wave forms I was getting was far greater than in your examples. 
Title: Re: Weird waveform?
Post by: boojum on September 18, 2007, 10:49:02 PM
I have gotten wave asymmetry with a pretty good setup so I figure it is nothing to worry about.  The sound itself is fine.
Title: Re: Weird waveform?
Post by: Petrus on September 19, 2007, 03:51:41 AM
Could it just be a strong bass signal and higher frequencies just piggybacking that? If it sounds fine and all? What is the frequency of the strong wave?
Title: Re: Weird waveform?
Post by: capnhook on September 19, 2007, 07:23:18 AM
Could it just be a strong bass signal and higher frequencies just piggybacking that? If it sounds fine and all? What is the frequency of the strong wave?

bingo  :)
Title: Re: Weird waveform?
Post by: taper420 on September 19, 2007, 08:05:30 AM
I noticed this when I was doing voice over work. After trouble shooting and posting here, I settled on it being the distinct signature of the voice I was recording. Other TS members pointed out that this is quite common with certain instruments. I can't quite remember but I wanna say it's certain woodwinds and brass.