sounds like an alternator problem to me, park up against a wall in the dark, put main beam on and rev your engine and see if the lights get brighter, with stereo off!

Right, im not an expert. but i will tell you what i know. Assuming all your stereo equipment is fine it must be you r alternator.

as you are probably aware an amp will produce more power at 14.4 volts which is what the alternator puts out than at 12.6 volts which is what the average battery puts out. Now it sounds like you got a nice amp (60 amp fuse on it). At a guess your amp may be putting out another 150-250RMS at 14.4 volts , so will sound louder.

Now ive been told by a bloke that supplys alternators that it dosent kick in (produce current) until about 1500RPM. If this is the case you now know why the subs go louder at certain revs.
However i think hes wrong because my voltage displays show 11-13 volts with the engine off and 14.4 volts with the engine running at idle. This must mean the alternator is putting out some current.
Can any body correct or agree with me?

Its also worth knowing that your alternator will put out more current at higher rpm.
ie a 100amp alternator puts out 100amps when engine is at maximum RPM.

Im guessing your amps about 500wattRMS and the amp gunna need some power to produce it.

First i would recomend doing the big 3 cables under your bonet. Even if this dosent solve your problem its still a worth while and cheap upgrade to do to any car with extra gear on it.

2nd upgrade your alternator. If your car has a 55amp alternator defo upgrade to a 70amp. Get em off ebay for a tenner. If you got a 70 amp u could upgrade to 100amp, but this will cost more. (£70)off ebay.

Hope this helps

ah rite.

whoops

:|

i think he meant is it a good earth

how does this matter where its earthed?

i hear a few people have this but i dont know why it matters, so long as its a good earth? :boggle:

where's your earth?

the subs will go louder at a certain rev, such as 2000 rpm, n then off agen.
y is this?
i think theres a power problem but im not sure how this is happenin cos its only 1 amp thats 2x30amp fuses.