Audio recording level varies in ATI 600 USB
 

It looks like the recording level for ATI 600 USB is not constant. This is not good. It's like AGC in video. For home made videos this is acceptable, but if you record music, you want to keep your recording level the same way as that on original source. Is there any way to make it constant? I determined this in a simple way. I captured an entire concert from a laser disc. Then I captured just the last 2 minutes of the same concert to sync the audio (I always do it). When I compared the same parts of the concert in SoundForge from these 2 takes, I found that the recording level of the 1st take was significantly lower that that of the 2nd take. Please advise. Thanks.

And one more thing. Do I need to check the checkbox sync audio to video in VirtualDub for this device? Since audio and video capture is done by the same device, shouldn't it be synced automatically?

I've never seen this. Is the concert perhaps too high, and the ATI 600 USB is compensating to make sure it doesn't clip? That's possible. (And a good thing, if it does exist!)

No. Not too high. I even deliberately put resistors on RCA audio that lower the volume by about 3-5 dBs. I will be using digital audio anyway that I will be capturing into another computer via optical toss-link, but thought I would share this.