max97220 dongles are typically driven at a half (80mW/1.5vrms) or even lower of what they can actually do (125/3vrms) via hardwired negative gain. By running quiet you get good THD+N on a budget, just in general. Sometimes I wish there was a way to actually redline the darn things and use those spare 3db.
As for what the distortions sound like when I put on massive bass boost shelf, it's really hard to pin down what goes on because you won't hear it on a (polyphonic) sweep, not enough going on. Yet you can tell, say, crash cymbal sounding really hissy when the bass is playing certain note, yet sounding ok otherwise. Same for hissing in high guitar strings, closer to certain notes. And it manifests pretty differently with each chifi IEM I tried (zero 2, zsn zst, cca cra, castor...). I think a lot of (especialy kz) chifi is tuned to be ass bassy they can physically get away with given a crappy driver - i think the EQ just pushes it "over the edge" so to speak, and odd resonances that are driver / phase specific, not just predictable harmonics start to really pop out if you try to force significantly more bass from that tinny driver (I'm generally noticing this starting from +6db eq).
Understood. Things can just be tricky sometimes. I just wanted to ask about the intersample overshooting = distortion from clipping, because when I use UAPP and PowerAmp on my phones and EQ, I always have that kind of distortion if, for example, I boost a frequency by +10 dB with the software EQ, but forget to also reduce the software preamp by say -12dB. It has definitely happened to me at +6 dB and less, if I fail to take down the software preamp by the same amount or greater. This clipping can cause distortion even through a USB dongle set to low volume in the analog domain, because it's clipping that's introduced before the audio stream gets to the DAC, specifically to protect the DAC, if I understand correctly.
Unfortunately, if that doesn't fix your issue then it sounds like a lot of what you might be running into, with the bass interfering with cymbals, is actually in the master. It's definitely something I notice in real music tracks myself and I know a few musicians who record, track, and mix their own and others music and in listening to them I came to the conclusion that what you are describing, which I've also noticed, is probably directly from brickwalling or badly done leveling of some other kind. It's not so much that the part is busy, but it's already at software clipping volume and then the cymbal or bass hit happens and there's no digital headroom left, so it has the effect of ducking one or the other or both. This issue of having no headroom for added energy can similarly manifest when a crescendo is happening and the final volume is ducked compared to the middle of the crescendo, which is one of the most annoying things caused by bad brickwall dynamics.
One album that does what you described at even quiet volumes is
Putrevore's
Macabre Kingdom, which is super-brickwalled. It's a great album, but the cymbal crashes are crazy shimmery with every bass hit. Check out the first track from that album to hear if that's what you are running into. Unfortunately, if this is the issue, you literally can't solve it with your audio replay system, and it's not the headphones. In that case you can only hope for the loudness war to end and stop ruining otherwise good albums. I'm quite sure
Macabre Kingdom sounded great at some stage of production and was ruined when the mastering engineer brickwalled it to the garbage bin. I listen to very dense tracks that are mastered better and don't hear that issue, even at reasonably high volumes, so I'm fairly confident it's not the headphones, but it's impossible to be completely sure. I mean I can overload my headphones and my DAC/Amp too, so that's always an option at really, really high volumes.
Sadly, a mastering engineer can ruin any album with bad brickwalling and given that I own some of the sets you mentioned and don't run into that issue even at higher volumes than my preference, except on terribly mastered and brickwalled albums maybe that's what you are running into? The distortion in those sets is like -40 dB in the bass or less, so even a lot of bass lifting and high volume listening doesn't necessarily explain the phenomena you describe very well, if I understand correctly. Could be anatomical/resonance or your preferred listing volume I go nowhere near, but it sounds like you might be having an issue with brickwalling gone wrong. You could try a vinyl or a quieter digital recording of the vinyl version of the same album(s) where you run into issues. If the issue goes away, then it's the digital brickwalling, not your audio chain ... probably. I suppose the same bad mastering could be found in the vinyl version to, lol, at least nowadays, when vinyl masters could be literally the same as the digital master.
Cheers!
