Sunday, July 03, 2011

A Problem


Before I go much farther, I have a small problem I need to address and maybe some of you audio types out there can help me. The waveform above seems to illustrate what I'm seeing, although my ears can't hear the issue. See on the bottom channel, which I think is right, there do not appear to be any peaks exceeding about -0.7db? And it doesn't look to be symmetric about the x-axis? The top channel (left) looks normal, almost a mirror image about center. What's causing this? This is a recording of a mono signal, so both channels should be virtually identical. If I had to guess, and this is a big guess, I think it's because my stylus is not perpendicular to the groove on the record. I've torn the headshell apart and put it back together several times now and it still comes out so that the needle is at a slight angle. I can't seem to find any adjustment for it. Anybody out there want to take a stab at this?

4 comments:

stubbysfears said...

My guess is--and its just a guess--that's perfectly normal, likely the result of previous play. I'm no audiophile per say, but I don't think I've ever encountered a used record (mono or stereo) where the tracks showed equal dynamics--not on my turntable and not on the radio station turntable where I do most of my transfers (and that one has the added feature of a bit of compression). I'm not sure I've even encountered a new record where both channels were the same. And it's always the bottom one (right channel) that seems deficient. I think that's just the way it is, Ernie. Or, to quote Outer Limits, there is nothing wrong with your set....

But clearly Lee is the man to ask. Best ears and skills in the game, for my money.

Ernie said...

Well, I've always found that one channel is usually louder than the other. I always level that out in post-production. But in this case, the waveform just looks wrong. I need to get some little washers or spacers to see if I can straighten out this stylus... Hunting around the web, I think it's called azimuth, but I don't have an adjustment for that on this turntable. I'll shoot an email to Lee and Buster.

Jonathan said...

I took your question to the local expert; my brother Richard. Here is what he had to say:

"I run into problems like Ernie when I transfer records and other recordings. I think some of it is cartridge and tonearm alignment and I can minimize the problem on good recordings. I think though that it can never be perfect on some records. Remember they did not have the ability to look at the audio waveform when they were recording, mastering, and pressing the records. Anywhere along the line, the process could add such problems and they show up on the pressed record or whatever format of the final product. I get rid of some of the error by using the BBS sound enhancement software that I have as a plug in to Adobe Audition."

Anonymous said...

Another problem may just be in the recording itself; how old is it? I've known lots of mono LPs where, in order to reproduce 'faux stereo', the one channel is slightly off from the other- either in volume or tone (remember Capitol's Beatle Stereo?)

Bottom line is: if it sounds good, don't worry about it. In this age of digital perfection, it's possible to read to much into a waveform. Trust me, I've done it!

-Tim