waves not symmetrical

After 6 years of not working with Audition I want to digitalise again some records. First thing I come across is that the waves are not symmetrical around the infinity db line but a little bit (halfway between infinity and -21 db) shifted upwards.
Is that anything I need to worry about and if yes, how would I correct this ?
Thanks for your help
Manfred

Offhand that sound like a DC offset. This is an equipment problem, often with the soundcard. Somewhere the signal ground and the equipment electrical ground are at different levels. There are ways to make corrections within the program but the proper thing is to fix the hardware.

At recording time:
Check the box to "adjust for DC on record" on the Device settings tab.
After recording:
Check the "CD Bias Adjust" in the Amplify dialogue. You should read the help on this to see what, if anything, should go into the % fields. I've never had to use this, so I'm not sure of the details.
Alternatively after the fact:
Running a high pass filter on the file to eliminate the very low frequencies (e.g. rumble), should do the trick for some significant amount of offset. A rumble filter is always a good idea anyway as the TT is sure to have some.

Thank you Andy !