seventysixvette

Late last fall I installed an aftermarket sound system. My radio/head unit only has four RCA jacks out. RF, RR, LF, LR. My amplifier has five in, the one different being a subwoofer input. My quick fix was just to stick a 'Y' cable into one of the rear speaker wires to feed a siginal into the sub input.

My sub sounds.....muddy. I've got other things happening other than a clean, low sound coming out of the sub.

What am I missing? Is there something made that will isolate the sub siginals before I feed them into the amp? Or do I have to have a unit that has the five RCAs out instead of the four? Any help is very appreciated!


John

Durango_Boy

It sounds like it's not the RCAs but the wire connections to the sub. Backwards, or out of phase, and they will sound muddy. That or the way it's wired has it at a lower resistance and the effective handling of the sub is diminished.

Post the model and brand of the head unit, amp, and sub. All details you can think of, and details of how you wired it. I can certainly give you much better help with more specific information.

seventysixvette

Thanks DB. I'm not up on car audio, but I've got a pretty fair ear musically. It sound to me like the sub is trying to deliver a whole spectrum of sounds instead of just low.

I posted at another place and a fellow tells me I need a simple subwoofer crossover that will only allow the low siginals through. They're about $30 on e-bay. I might try something like this.

Thanks for your reply!

John

Durango_Boy

Yeah you might need a crossover, but that can be determined with some model and brand numbers. Then, knowing how those components are wired and where the 'Y' connectors are, we can figure out if you really do need a crossover or maybe just an alternate wiring plan.

seventysixvette

The amp and sub was together in a set. They're TIS (what ever brand that is). The amp is five way, 700 watt, one hundred to each corner speaker and 300 to the sub. The sub is a 10". The whole system sounds good, with all the bass I need. It just has 'mumble' or something happening with the sub.

The wiring was very simple, and with the RCAs, just kinda plug and play. I found a set of 8' RCA wires so I didn't have to coil them up anywhere running from front to back.

I used heavy speaker wiring on the amp output terminals to the four small speakers, the largest automotive speaker wiring I could find to the sub. I used very heavy power wires.

I unpluged the RR RCA at the amp input (it was the closest to the sub input) plugged my 'Y' into it then plugged one side of the Y into the RR input on the amp, and the other leg of the y into the sub input on the amp.

John

1nicecorvette

too much "sound" from the sub tells me there is no crossover or its crossed too high. your amp should have a HZ switch or in the old days a dial to turn and adjust the frequency. the lower the number the less "sound" HIGHS ,VOICES, muddyness you get

Durango_Boy

What is the head unit make and model?

Is this the amp?



Knowing the make and model of the head unit will help a lot. Also, that amp has line level inputs meaning you can use the head unit harness front speaker sire sets to give the amp your front signals. Then use the front RCA sets for the rear speakers, and use the rear RCA set for the sub input.

Then simply use the amp's built in crossover to control the frequencies.

seventysixvette

Yeah, that's the amp exactly. The amp model is T510PK. The radio is a Custom autosound USA-2.

The amp wiring book has warnings in big type that says:

DO NOT USE HIGH LEVEL INPUT WIRES IF YOU ARE USING THE LOW LEVEL INPUT RCA JACKS.

It seems I can use one or the other, not both.


John

Durango_Boy

Hmm...cheap guts. Oh well.

Okay, then check the filter selectors on the amp for channel 5. You'll want it set at LPF, and turn the frequency selector to 60 Htz to start with. See if that helps.

Oh and while you are in there, check to make SURE that the wiring to the sub is POS to POS and NEG to NEG.

seventysixvette

But what I don't understand, even if I could use both sets of inputs, if I would have the front speakers going into the amp on the front high inputs, and had the rear going into the fronts RCA jacks, wouldn't both the front and rear siginals be coming out the amp front speakers outputs? The sub would be using the amps rear speaker outputs. (the amps bridgeable, I would still have 200 watts for the sub on the rear speaker circuit)

John

Durango_Boy

The front and rear signals from the head unit are the same so it doesn't matter if you have all four speakers run from the front or rear set. Music is recorded in two channels, left and right. Front and rear has nothing to do with it.

The only thing you need to do is get the sub wired so it has a low frequency signal and you just need to get the amp wired so you can use the amp's built in crossover so you won't have to buy one.

Traditionally 5 and 6 channel amps are used with head units that have SUB out RCAs along with the front and rear RCAs.

seventysixvette

I understand now. Right and left sterio seperation wouldn't be affected, just front to rear fader operation.

Thanks for your help!

John

boardroomjimmy

The sub needs both left and right input. Feeding it only RR input would also muddy up the sound. Try using your y plugs to split the " front" feed to the 4 channels in, take your "rear" l&r to feed sub input. You will be feeding the sub section a full spectrum signal so adjust the output filter < 100 hz or so. Now your "fader" is a sub level control.