Any car audio gurus in?

The kids were pestering me about making the van into a party bus – i.e. making the stereo louder – and so with an old 10″ sub I had in the attic from my boy racer days I thought I’d just wire up an amp and that would be it.

Bought a little Vibe Powerbox 400.1, should be good for about 170W RMS at 4ohms, wired in with 8 gauge direct from the battery and with a 60amp fuse inline. The sub I had was an old Vibe Slick s10, rated for 350W RMS at 4ohms. Underpowered a bit but should work. And it did, for about 2 minutes. I’ve checked with a multimeter and it seems OK, around 3ohms resistance across the terminals but just no sound. I put it down to just been too old so sense-checked everything else and bought a cheap Juice sub. Same deal, 4ohm sub rated at ~300W RMS. This one worked longer but has also gone on the blink, this time the multimeter is showing infinite resistance.

The amp is giving out a signal as it works if I connect a standard car speaker, but wondering if it might be knackered and somehow overloading the subs, but I’m not sure how that would be the case when it’s only around 1/2 the rated power of the speakers. Before I go throwing any more money at it, what am I missing? Other than the fact that this is a massively chavvy undertaking…

Have you got a good dedicated earth for the amp… If I remember from my days of being into that sort of thing you’d attach an earth cable to a suitable large bolt/fitting in the boot somewhere and keep the cable as short as practical.

Yeah it’s another 8 gauge wire, only about 12″ long and connected to one of the driver’s seat bolts. Amp is hidden under the driver’s seat.

The amp is giving out a signal as it works if I connect a standard car speaker, but wondering if it might be knackered and somehow overloading the subs, but I’m not sure how that would be the case when it’s only around 1/2 the rated power of the speakers.

You may have burnt out the voice coils in the subs by attempting to drive it with an amplifier that cannot supply the peak load that the sub requires, remove the drive units from the enclosure and I bet the voice coils have a particular smell of “napalm in the morning” about them

As a general rule (without getting into the math) it is best to have an amp with excess headroom.

So maybe better off with a 400-500W amp then?

Might just tell the kids to lump it in that case. It’ll rattle the windows out 😅

You’re better off having an amp too big for the speaker(s) rather than the other way around… Underpowered amps don’t cope well driving heftier speakers.

So Yeh I think I’d return that amp and get something fatter… You don’t have to dial the amps output all the way up to 11.