simple amp to sub question

[eletromagnetica]

I've got my speakers/tweets and the sub hooked up straight to my amp. the sub is hooked to left-side-positive and right-side-negative cause it worked.

its a polk marine series that i put in my fd rx7. I decided to add a sub but there is no sub channel on the amp.

What would be the best way to have a separate sub channel without adding another amp?

I want to keep the front speakers on the amp because my cd player isn't powerful enough.

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[mylows10 5,000+ posts]

I've got my speakers/tweets and the sub hooked up straight to my amp. the sub is hooked to left-side-positive and right-side-negative cause it worked.its a polk marine series that i put in my fd rx7. I decided to add a sub but there is no sub channel on the amp.

What would be the best way to have a separate sub channel without adding another amp?

I want to keep the front speakers on the amp because my cd player isn't powerful enough.

if the amp is not bridgable ,then wiring this way could damage the amp and or sub

 

[eletromagnetica]

it seems to be bridgeable and its worked so far but the sub sounds terrible cause its putting out highs. do i just need a crossover?

 

[eletromagnetica]

Amplifier Power Specs

RMS Power at 14.4V

Watts per channel NOT bridged @ 1 kHz

4 ohms 90 watts

2 ohms 125 watts

Watts per channel bridged

4 ohms 250 watts

Dynamic Power at 14.4V

Watts per channel NOT bridged @ 1 kHz

2 ohms 200 watts

 

[eletromagnetica]

ok it's a 4channel amp. so can I bridge the sub to the rear channel then to a crossover?

 

[mylows10 5,000+ posts]

ok it's a 4channel amp. so can I bridge the sub to the rear channel then to a crossover?

has to go thru the crossover first then to the amp

 

[eletromagnetica]

what can i put between the amp and sub that will have the sub putting out only lows? a volume adjust would be nice but not necessary

 

[mylows10 5,000+ posts]

what brand and model amp ?

 

[eletromagnetica]

polk pa500.4

polkaudio.com/products/pa500_4

 

[mylows10 5,000+ posts]

get a crossover rca's from the deck to the crossover then to the amp.set the amp portion for the subs on l/p

 

[eletromagnetica]

but if the crossover is before the amp wont it effect my speakers as well? I'm missing something. i've got one left and one right channel going to the amp then to my front speakers and sub.

 

[mylows10 5,000+ posts]

should have 4 rca inputs

 

[eletromagnetica]

ok thats it i need to run another rca set to the amp and put the crossover on that line. thanks

 

[squalor 10+ year member]

Hey, I have a FD too. Where do you have the sub ? In a box between the shock towers or in the spare tire well ? Where is the amp ?

That Polk looks like a nice amp but maybe we could help more if you told us what HU (radio) you have. Your amp is TriMode capable so that is prolly why it's working but you could do better. Assuming you have only one pair of RCA cables on your CD player running to the Polk you get a pair of RCA splitters(single female to 2 male) so you can plug into all 4 channels of the Polk 500.4 and run the front speakers from channel 1 & 2. They're getting all the sound from the RCAs but use the HP crossover on the amps 1/2 channel to throw away any signal under 80Hz. Use the 3/4 channel as your sub amp. "left-side-positive and right-side-negative" as you said you hooked the sub up. This is called bridging and makes a single more powerful channel for your sub. Use the 3/4 channel LP crossover to throw away the treble and only play 80Hz and below. Study the 500.4 manual to get the particulars of how to do this. Now if your CD player has a bass channel and a separate set of RCAs it probably has a crossover built into it too. If so, this is the way to go because it is better to use the HU for sub level control than to adjust levels with the gain knob on the amp.

In fact, do a search on setting gain. It's a very misunderstood feature and setting it correctly can really improve sound.