By the description you give of the issue, I will assume that the sound you are noticing is clipping. This is a term used by people in the pro-audio industry to discribe non-harmonic distortion of your output. In other words, certain frequencies are exaggerated, and not the good ones. The result will be an immediately recognizable timbre.
We all know what a "blown" speaker sounds like. Clipping inside a DAW will sound somewhere between that an the sound effect you hear in music when someone leans in extremely close to the mic and screams.
If it is just clipping, this is great news, because it is an easy fix. There is no troubleshooting to narrow down the source, because the source doesn't really matter to us...
If a fader is too far open causing clipping, that does not mean you need to turn down that same fader. To understand this, we need a certain understanding of audio signals.
A signal, at any one point in time, can be thought of as actually being an infinite amount of separate signals. Each of these signals goes on to reproduce a different frequency. The volume of a subsignal does not matter; only the volumes relative to each other matter. If A is twice the volume that B is, you need it to stay that way unless you explicitly change it using something like a guitar amp.
Thankfully, with the proper settings the mapping of relative VUs stays pretty consistent. At lower volumes it is ok as well, although with Digital audio, it is harder to accurately record the relative to each other. This is because digital signals are not continuous like analogue. The explanation is out of scope here, but I recommend that you look it up. It is fairly interesting, imo.
Anyway, If the signal is a bit 'left of center' at one point in your chain, you can usually fix it at the next point, so long as those relative levels do not move. Once they are skewed, however, you will need special software to fix, and that only masks. This last part only really affects audio recorded at a clip, so you are good ther.
Anyway, if I have made my intended point, you likely already see the solution. If you take away some of the signal at a point before the corruption, you will counteract it without having to locate it.
