RCA Wiring Help

[agentrice009]

I tried searching but can't really find a solution :/

I already have a Kenwood 8105D amp powering 2 subs installed in my car. I recently bought 4 new speakers and a Pioneer GMD9500F 4 channel amp got all that hooked up and jazzy but now I can't figure out how to wire the RCA's. I have a Sony MEX BT 2600 head unit with front and rear/sub outputs. Both amps also have outputs on them. Just confused on how to wire the RCA's :/

Thanks for the help //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

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[Spike243 10+ year member]

you could run a set of rca's off of the front output to the 4 channel then use splitters to fill all rca inputs on that amp. Then you could run your sub amp off of the sub output on your amp. That would be the best way to wire this set up i believe

 

[mikelaubach 10+ year member]

Run 4 RCA leads to the rear (either a single 4-channel RCA, or two 2-channel RCA's).

Do not rely on the one pair to feed everything, give yourself some in-seat adjustability over your output.

Run the output from the 4-channel to the sub amp.

 

[Spike243 10+ year member]

Run 4 RCA leads to the rear (either a single 4-channel RCA, or two 2-channel RCA's). Do not rely on the one pair to feed everything, give yourself some in-seat adjustability over your output.

Run the output from the 4-channel to the sub amp.

You would lose the head unit control over the sub if you wired it this way.

If you run a set of rcas from the front output on your head unit to your 4 channel amp and use splitters to fill in the rca inputs on that amp and then you run another set of rcas from the sub output on the head unit to your sub amp. This would give you control over both of the amps from the head unit

 

[mikelaubach 10+ year member]

You would lose the head unit control over the sub if you wired it this way.

True.

If you run a set of rcas from the front output on your head unit to your 4 channel amp and use splitters to fill in the rca inputs on that amp and then you run another set of rcas from the sub output on the head unit to your sub amp. This would give you control over both of the amps from the head unit

You would lose the control of front to rear fade if wired this way. //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

I personally can deal with the lose of sub control in the way I mentioned. Do folks really control the amount of bass in this manner? I would state:

1) use the "bass/treble" settings in the radio to increase bass by adjusting the equalization if you want more or less bass on demand.

2) [not useful for all amps] use the amplifier's sub gain control knob to adjust the output of the subs.

 

[agentrice009]

I would rather lose control of the sub. So front out on HU to front on 4 ch amp, rear/sub out on HU to rear on 4 ch amp, output on 4 ch amp to input on mono amp. That's how I should wire it?

Would I set the LPF on the mono amp or on just the 4 ch amp, or both?

 

[Fiendstolemyamp 10+ year member]

Would I set the LPF on the mono amp or on just the 4 ch amp, or both?

Just the mono, the preamp-out from the 4 channel should be fullrange & usually isn't affected by crossover settings on the amp, it's just a pass-through.

 

[agentrice009]

alright sounds good. Oo I'm also assuming since it's a selectable rear or sub out, I would change it to rear out on the head unit?

 

[Fiendstolemyamp 10+ year member]

alright sounds good. Oo I'm also assuming since it's a selectable rear or sub out, I would change it to rear out on the head unit?

Yup

 

[agentrice009]

Finally got everything wired and running. Speakers sound great but now my subwoofer sounds half as loud as it did before, thus I don't hear that "fill" they should be providing. The cones are moving though. Any thoughts as to why its not hitting?

 

[mikelaubach 10+ year member]

If I understand correctly, you have all four channels running to the full-range amp, and the full-range amp's output to the sub amp, correct?

Keep in mind that the source of the signal is now different. It had been the head unit previously, and it is now the full-range amplifier. This will force you to re-tune the system's settings. Most specifically, the gain on the sub amp. Use the DVM/DMM method to set the output to the required voltage to gain the necessary output for your sub. Bang, back in business.

If you did not set the gain on the full-range amp, I'd start there with the DVM/DMM and then move to the sub amp.

 

[Spike243 10+ year member]

This is the same thing that happened to my system when I had to do that same thing as you are now. Just reset your gains as mikelaubach said and all should be well

 

[agentrice009]

Yes, you are correct. My head unit pre amp outputs are rated at 2V which is why I had both amps set to 2V. Are you saying the 4 channel amp does not output at 2V? I thought it just sends the same signal as the head unit?

Edit: Looking through the manual, I was able to find that the 4 channel amp says the average current draw at my set up of 2 ohms, 100W X 4 is 10.7 amps. I'm not too physics saavy, but is this enough to calculate the voltage?

 

[mikelaubach 10+ year member]

Yes, you are correct. My head unit pre amp outputs are rated at 2V which is why I had both amps set to 2V. Are you saying the 4 channel amp does not output at 2V? I thought it just sends the same signal as the head unit?

I would suggest that the answer is no, but have not checked those amps.

Edit: Looking through the manual, I was able to find that the 4 channel amp says the average current draw at my set up of 2 ohms, 100W X 4 is 10.7 amps. I'm not too physics saavy, but is this enough to calculate the voltage?

No. Unfortunately. The "average" you mention is gotten (most likely) from a run of different amps that are tested. It is why some of the expensive amps have "birth sheets" that indicate the true values - some amps can be advertised at 1000W and push out 1400W!!

The right thing to do is to determine the power (in RMS) that the speakers can handle. Let's say that is 100W, and that they are 4O speakers (the norm). And let's say the amp can put out 125W per channel. Disconnect the speakers, connect the two leads for the DVM/DMM and set it to AC voltage. Now, set your EQ to flat, loudness off, and turn up the radio to about 3/4 (to stay out of the distortion band at the top). Now increase the gain knob until you see 20 volts AC. Less than 20VAC will be less than 100W, and more than 20VAC will be more than 100W.

If you are using 2O speakers, for 100W output from the amplifier, you will want 14.14VAC.

It is best to use a test CD with a 0db signal, but I have no idea where to tell you to get one.