Amp bridging advice

Post Fri Jan 06, 2006 9:13 pm

Hi,

Ive got a 4 channel 500w rms amp which i believe can be bridged to 2 x 250w channels. I only really want 1 decent sub in the boot but want to use the full 500w power of the amp. Can this be done by joining the wires or am i asking for trouble??

Thanks

Post Fri Jan 06, 2006 10:41 pm

What amp is it?

The only way you'll be able to get 500wrms into one sub is if it's a dual voice coil sub with two 4ohm coils. Otherwise you'll just get two lots of 250wrms.

Do you really need to use all that power for the sub? If that's your only amp you should use two channels for the front speakers and two bridged for the sub. If you use a 12" sub (or 15") in a good ported box you should be happy.

Post Fri Jan 06, 2006 10:48 pm

Hi

Thanks for your reply.

I have a Pheonix gold Octane R5.0:4 amp. I have 50w rms 10cm Alpine componants all round which dont need further amplification IMO.

I havent yet bought a sub, thinking of either a 400w rms Infinity Perfect VQ12 or SWR Alpine 12".

If im fcuked, as you say i'll have to buy 2x250w subs instead.

Whats your opinion mate?

Post Fri Jan 06, 2006 10:57 pm

BTW: The Alpine sub im looking at buying has dual 4-ohm voice coils

Post Sat Jan 07, 2006 12:08 pm

Are you sure your components are 10cm? that's 4 inches, the standard fit is 13cm. Anyway I always recommend that the front speakers should be amplified, because your headunit probably don't give more than 25wrms (max).

As for the sub, the alpine should work well with that amp and use all the power. Just make sure the gains are set correct so that each coil gets the same amount of power.

What type of box are you planing to use? If it's a sealed box you have in mind you could be better off going for a 250-350wrms sub in a well designed ported box which would give you as much bass as the alpine gives using 500wrms in a sealed box.

So I personally use two channels for the front speakers and two bridged for a ported 12" sub.

Post Sat Jan 07, 2006 1:41 pm

Yeah i meant 13cm componants.

The headunit is 4x50w so assumed that would be enough, but will consider what you've said.

I was planning a ported box with the port hole facing through the ski hatch (tech 2) to get some bass in the cab.

Thanks for your help, appreciated.

Post Sat Jan 07, 2006 5:35 pm

Most people put the sub where the ski hatch is, and if ported put the ports through the shelf.

On my previous car I cut the metal ski hatch port out, then I built the box as big as I could fit in the boot which is on a slope and pushed upto the back of the seats and sealed it. Then I marked and cut out the ski hole shape. Then fitted two 12" subs to the top of the box (facing the shelf) and the same to the front of the box (facing number plate) with the sub magnets facing out and wired opposite (+ and -) to the other 2 in the box. This way your using the boot as the box and the MDF box is just holding the subs. Depending on type of subs used this will give you big bass to MEGABASS!!! I only used a 900wrms amp with four 250wrms subs. Just an idea for you!

Post Sat Jan 07, 2006 11:58 pm

chu346 wrote:Most people put the sub where the ski hatch is, and if ported put the ports through the shelf.

On my previous car I cut the metal ski hatch port out, then I built the box as big as I could fit in the boot which is on a slope and pushed upto the back of the seats and sealed it. Then I marked and cut out the ski hole shape. Then fitted two 12" subs to the top of the box (facing the shelf) and the same to the front of the box (facing number plate) with the sub magnets facing out and wired opposite (+ and -) to the other 2 in the box. This way your using the boot as the box and the MDF box is just holding the subs. Depending on type of subs used this will give you big bass to MEGABASS!!! I only used a 900wrms amp with four 250wrms subs. Just an idea for you!

After reading it 3 times I know where your coming from & can picture what your saying! Thanks again for your advice - helped me loads!!