Horrible CD audio quality (and more)

johnmeyer wrote on 7/25/2006, 1:35 PM

I just burned a track-at-once CD directly from the Vegas 6.0d timeline, and the audio quality is awful. It sounds like the peaks are clipped. The WAV file itself (which is 44.1) sound just fine on the timeline, but when the same audio file is played from the burned CD, in the computer CD drive (so that I have the same audio system for both the WAV and the CD), the audio is terrible. I have also played this in the CD/DVD player in my home stereo and it sounds exactly as bad there.

I have re-done the project in Nero, and the audio is perfect.

Anyone ever had this problem? I seldom have burned a CD in Vegas, but since this product started as an audio program, I thought this would be a piece of cake.

In addition, when I burned this "track-at-once" CD directly from the Vegas 6.0d timeline, there are no tracks on the resulting CD. The help file says "choose Track-at-Once Audio CD from the submenu to save your project as a track on an audio CD." I guess that this statement implies that the entire project will be saved as one single track. Of course, neither Roxio or Nero do this -- their track-at-once functionality creates a track "chapter stop" between each WAV file.

Once I had the problem, I repeated the burn on a CD-RW and verified the lousy audio quality. I then burned on the exact same media, using Nero (just dragged the same exact WAV files into Nero), and the audio was pristine.

I did this on my Dell Inspiron 6000 laptop.

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Comments

essami wrote on 7/26/2006, 5:15 PM

Hi Johnmeyer and everyone,

I read the whole thread and I've had two similar problems as you. I've burnt hundreds and hundreds of cd's with Vegas all the way from Vegas 1 to Vegas 6 but Ive only come accross these problems with Vegas 6.

Once and only once I got a totally silent 6 track disc with no audio on it. I immeadiately thought I had the mute on but I could not find anything wrong with the project. But I gave this no further thought since I burnt another disc straight away and it worked fine and has since.

I've had strange clipping occur with cd's and also during playback from the timeline. And when it's been playback doing the clipping it's been a normalize issue, turn it off and on again and it's fine. With cd's its been so random and rare that I've never found out why it has done that. It has been just basically very "soft" clipping, like tape distortion more then digital peaking. Its happened 2-3 times only.

It's all been so random and I havent had any major disaster with these issues so I've never posted or asked about it here.

I just wanted to let you know. I'll certainly be more careful with normalising when doing masters from now on.

Sami

farss wrote on 7/26/2006, 5:34 PM

Turning it off and on causes the amount of gain being applied to be recalculated. I think that's possibly the clue.
Rather than do it using 'switches' I always do it using event properites, that way I get to see the amount of gain being applied.

Also be aware of a big trap with Eq. Attenuating a band or adding a rolloff adds gain at the knee frequency, depending on the slope there can be quite a bit of gain there. Of course this only matters if there's anything at that part of the spectrum but the end result can be clipping at places that'll have you scratching your head. In summary those dinky little response curves that the track Eq displays lie.

Bob.

johnmeyer wrote on 7/26/2006, 6:53 PM

Once and only once I got a totally silent 6 track disc with no audio on it. I immeadiately thought I had the mute on but I could not find anything wrong with the project.

I had exactly this same thing happen during the course of troubleshooting this project. The track was definitely not muted. I couldn't recreate the problem.

So you post us a sample that's at a very low level (-30dB) except that's a recording made of the CD being played out in your PC. This means it's been through the analogue circuits in your PC / soundcard.

That's true for the clip I posted because that's the only way to get the audio I am hearing and let you listen to it. However, I think I mentioned somewhere along the line that I put this disc into my home stereo system, and I get exactly the same audio. Thus, if I play the source WAV file in media player or on the Vegas timeline, it sounds fine; if I burn that WAV file onto a CD using the Vegas burn to CD feature, I get this audio problem. Some of the problems are FAR more massive than what I posted, and happen at low, intermediate, and high levels of sound.

I have burned over a dozen CDs today in an attempt to trace this problem to its roots, and I have unfortunately now found that the problem is NOT repeatably related to the Normalize function. I burned several CDs yesterday, and the problem definitely went away when Normalize was turned off. I created a CD from that and thought I was home free, because the sections I had been testing now sounded fine. I later found out, however, that OTHER tracks which HAD been fine, were now messed up.

If I ever get this figured out, I will certainly post a solution back here.

farss wrote on 7/26/2006, 8:33 PM

John,
I think the way you're approaching the problem you have too many variables. You need to run way too many tests to fill in all the points in the matrix. Here's what I'd do'

1) Starting off with your problematic project render out to a new wav file.

2) Bring that into a new Vegas project. Inspect it, look for any clipping tec. Make certain it sounds clean

3) From this new clean project burn a CD. Again I repeat, no FXs, no normalisation.

4) Rip the CD back as a wav.

5) Bring the rippsed from CD wav back into the same project 2) on a new track.

6) Invert the phase of the new track. You will now hear the differences from the burning and ripping part of the process. For a final test you could render out from that project to another new wav file. Bring that into yet another project. It should be totally flat lined. If there's any bumps you can correlate that point on the T/L back to see if it relates to anything noticeable.

Bob.