Lasherž
CarAudio.com Elite
I've never heard that particular sound before coming from subs. My guess would be a loose connection on the signal cable or the amp going into protect like Buck said. It's possible that it's also a weak ground since it starts later on in a song. Do you get it while the car is at speed too? Lower voltage isn't quite as capable of bridging a bad connection gap as charging voltage. Instead of looking at your subwoofer I'm curious what your amp looks like while this is all going down. Any spark sounds near the connectors? Any lights flickering?
If it's the subwoofers then it's going to be the coils, but you'd smell them before getting to this point. Did they start stinking recently?
Spotify uses a lot of crappy compression in their audio but in general it should be fine. It doesn't sound like a clip to me and that's what would happen unless that box is wholly inadequate for those subs. They don't look like they're bottoming out either and the bass intensity didn't change between when it was having an issue and when it wasn't.. The only likely things that change throughout a bassy song with the same background rumble is that the coils heat up a little bit, the battery voltage goes down (and amperage goes up), and things that don't fit right are likely to vibrate loose.
If it's the subwoofers then it's going to be the coils, but you'd smell them before getting to this point. Did they start stinking recently?
Spotify uses a lot of crappy compression in their audio but in general it should be fine. It doesn't sound like a clip to me and that's what would happen unless that box is wholly inadequate for those subs. They don't look like they're bottoming out either and the bass intensity didn't change between when it was having an issue and when it wasn't.. The only likely things that change throughout a bassy song with the same background rumble is that the coils heat up a little bit, the battery voltage goes down (and amperage goes up), and things that don't fit right are likely to vibrate loose.