DC Offset with Bias Peak and USBPre A/D converter


Details below, but the basic problem is that after I record a vinyl album side (no matter how short or long) and save it, applying the DC Offset process to the file results in the meters in Peak not behaving the way they do before the DC Offset. What will happen (about 50% of the time) is that the meter for only only one channel will indicate audio, or neither will. I can still hear sound in both channels though.

On the surface this seems like a bug in Bias Peak, but it didn't start happening until recently.

For a long time now I've been successfully recording vinyl on my Mac using a USBPre 1.5. I use Bias Peak to record, remove the DC Offset and archive for later processing with Cool Edit, etc. But one day Peak froze on save, and the drive would not reboot. So I replaced the hard drive on my Mac Mini. I set everything up and at first things were back to normal. But then, one day, the USBPre control panel refused to quit and I had to do a hard reset again. I did some diagnostics, installed TechTool stuff, what not. I may also have moved my USBPre to a different location at the same time.

After this, I began to have a DC Offset problem that now occurs in about 50% or more of my recordings. Basically, it screws up my project.

One theory I have is that the USBPre is somehow messed up due to driver problems or some hardware problem (waiting to hear from SoundDevices about this) even though I have the latest driver now. I'm also waiting to hear from Bias about what it means if the meters stop showing both channels. This is a long weekend, so they may yet get back to me.

But I'm wondering if anyone else has seen this problem or can suggest what might be wrong.

I suppose one work-around is to just not apply DC Offset, if all I'm going to do is fix clicks. But I like to combine both sides of the record into one file and adjust the gain. If one file is OK DC-offset-wise, but the other isn't, that will distort the result. This would be true whether or not I attempt DC offset. I hope (fingers-crossed) that Bias will tell me not to worry about the meter issue but it would still bug me.

Thanks,
-gritingrooves
gritingrooves
Today I did a test with Audacity for OS X and Cool Edit for Windows. I opened files that give me the meter problem in Peak and removed the DC Offset. When Peak opened the files I had modified in Audacity and Cool Edit, it metered the sound correctly. Somehow Peak is sensitive to something in the file that does not bother the other apps, and when the other apps have adjusted the DC Offset, Peak is happy. Peculiar.

I'm thinking about recording with Audacity now instead of Peak. I'm still concerned that something is wrong, though, since I don't understand the problem.

Audacity is tricky to set up for 24-bit though. Keeps crashing.