I found this fascinating, but I don’t know everything in detail. Here’s what I just did.
I downloaded a music track of a guitar playing from Bandlab. When I imported into my DAW, I noticed that the waveform was not centered. It appeared to be above the mid-line, leading me to think there was a DC component. It was present through the whole track.
I exported it from the DAW and then reimported it as an additional track. It was centered. It looks like the DAW export might have done some processing.
The differences brought me back to my EE days. The top image with the ‘DC’ component shows a step function. The image in the bottom has eliminated that DC component. Looking at the point where the step was, it looks like a little pulse remains, with some ringing afterwards.
I noticed in my DAW, I did have some other processing going on. By process of elimination, I found out that the ‘console emulator’ was what had cleaned up the signal. Here is a link to more information about the console emulator. https://www.cakewalk.com/Documentation?product=SONAR%20X2&language=3&help=ProChannel.8.html
With only the console emulator in the processing path, here is what the difference looks like on the stereo signal.
It looks like another component added some additional processing in the first image because there appears to be more of the ‘ringing’ activity after the pulse.
I guess the takeaway is that the console emulator, which I usually have on each track, contains some sort of brick wall high pass activity, and will remove the DC component for you.