# 4 Channel RCA'S?



## sriskie (Feb 6, 2010)

Is it better to run Y-splitters to bridge a 4 channel amp to 2 speakers then to just use a 4 channel rca? 

My deck has front and rear outputs and I have the 2 lefts connected to channels 1&2 and the 2 rights connected to channels 3&4. I am not at all happy with the sq I have right now and wondering if the outputs on the deck are slightly mismatched, then I'll have problems with sq. 

I'll have to disassemble half the interior of my truck to test this so I'd like to get some insight before tearing into this...please! 

My system;

2002 Dodge regular cab
Alpine 9886
CDT HD62-AS
Pheonix Gold RSD 500.4
I.D. IDQ12 V2
Kicker ZX750.1


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## Oliver (Jun 25, 2007)

sriskie said:


> Is it better to run Y-splitters to bridge a 4 channel amp to 2 speakers then to just use a 4 channel rca?
> 
> *My deck has front and rear outputs and I have the 2 lefts connected to channels 1&2* and the 2 rights connected to channels 3&4. I am not at all happy with the sq I have right now and wondering if the outputs on the deck are slightly mismatched, then I'll have problems with sq.


U can't bridge a head unit 

U can read about car audio here , though


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## Candisa (Sep 15, 2007)

I think he means he connected:

```
headunit   to  amp
frontleft      frontleft
rearleft       frontright
frontright     rearleft
rearright      rearright
```
Then he bridged the left speaker to the front channels of the amp and the right speaker to the rear channels of the amp so the left speaker gets "frontleft + rearleft" signal and the right speaker gets "frontright + rearright" signal.
Normally, a headunit gives puts out the same signal front and rear if the fader control is centered and there is no channel-independent processing enabled, so it should work the same as if he'd use Y-splitters to connect his frontleft signal to both front inputs of the amp and the frontright signal to both rear inputs of the amp...

It SHOULD work, unless, like he mentioned, the front and rear outputs of his headunit are mismatched...


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## bikerider (Dec 28, 2008)

OP, shouldn't you have the fronts connected to a channel pair (1/2) and the rears connected to the other (3/4)? Then at least your amp gains control front or rear, not the sides which would be harder to balance.

To bridge a 4 channel amp, take one set of outputs (front) and use y-splitters to connect the R output to a channel pair and the same for the L. Then you connect the speaker wires to each channel in bridge mode per your amp mfg's instructions. Unless you have another amp for the rear speakers you don't need the rear RCA.

There are other ways to do it, but I find this way to be the simplest.

If you bridge, you need to be more careful with what you connect speaker-wise to the amp. Most amps can't handle a 2-ohm bridged load (which is what you would get if you try to connect a 4-ohm front speaker and a 4-ohm rear speaker to the same bridged channel in parallel), and you can damage the amp if you connect less than a 4-ohm load to it.


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## sriskie (Feb 6, 2010)

But would there not be twice as much total voltage coming out of the deck using twice as many preouts compared to using one set and splitting them?


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## sriskie (Feb 6, 2010)

Bikerider, I'm only using two speakers on a 4 channel amp with a 4 channel rca. Left 2=front channel Right 2=rear channel.


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## Candisa (Sep 15, 2007)

Voltage stays the same if you split compared to each it's own pre-out. I would use splitters, but it shouldn't matter if the pre-outs aren't misaligned...


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## bikerider (Dec 28, 2008)

sriskie said:


> Bikerider, I'm only using two speakers on a 4 channel amp with a 4 channel rca. Left 2=front channel Right 2=rear channel.


Yeah I saw that after I posted. When I had a 4 channel amp bridged to run my passive frontstage, I used the y-splitters and it worked fine. No need to even use the rear outputs of the deck, there are really no gains to be had doing so.


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## sriskie (Feb 6, 2010)

So to summarize, there is no advantage to using a 4 channel rca over a y-splitter but it could be detrimental IF the outputs on the deck are not PERFECTLY matched front and rear...correct?

I guess I'll just have to bite the bullet and tear everything apart to change the wiring to see if that makes a difference.:annoyed:

Thanks for the input!


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## tanakasan (Sep 8, 2007)

sriskie said:


> But would there not be twice as much total voltage coming out of the deck using twice as many preouts compared to using one set and splitting them?


Just set your gains correctly and call it a day.

If there is twice the voltage from the RCAs, you would need to reset the gains lower. Just can't pump in 2x voltage w/o compensating somewhere. If your system not loud enough, get a bigger amp!

Robert


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## Candisa (Sep 15, 2007)

You won't have half the voltage by using splitters, it's like wiring in parallel, voltage stays the same but the impedance load drops. The input impedance of an amp is much much higher than the minimum impedance you have to put on the pre-outs of a headunit, so running Y-splitters is no problem at all and avoids the problem of possible mismatched pre-outs.
Ditch the 4ch RCA, run a stereo RCA from the front pre-outs of the headunit to Y-splitters and connect the Y-splitters to the amp. The worst case scenario would be no improvement (meaning the problem of poor sound quality is somewhere else in the install), but you have nothing to lose.

Isabelle


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## Austin (Mar 12, 2009)

Why not just use 2 channels of the 4 channel rca, not tear up your truck, and throw the Y splitter on at the amp...?

Just leave the 4 channel in there for a future upgrade. Its not going to hurt your audio or truck by leaving a set of rcas unplugged in there.


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## sriskie (Feb 6, 2010)

I just went out and picked up a couple of cheap y-splitters and gave it a try. I'm unable to discern any difference either way after switching back and forth several times. There may be some but my insensitive ears can't tell with any certainty so I'll stick with the 4 channel rca.

I've never heard of any sq issues with bridging an amp so now I'm back to questioning the sq of my componets.:mean: I've read so many good things about them I'm having trouble accepting that this is how they should sound.


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## Candisa (Sep 15, 2007)

Try an other amplifier first. Phoenix Gold made some very nice stuff over the years... most of it is a lot older than your amp.
Apart from the quality, PG amps tend to sound warm and very laid back, if your component set also has a very laid back sound, the combination might get too laid-back and become dull and suffer from a lack of detail.
That's why I rather use amplifiers that are more neutral. In my own car, I use Genesis amplifiers on my frontset, in Xenia's van, we'll use oldskool Clarion (McIntosh inside) amplifiers.
Personally, I think bridging an amplifier is not the way to achieve sound quality. It doesn't matter that much on a subwoofer and it's acceptable on midbasswoofers, but I would never run a midwoofer or tweeter bridged!

I'm not surprised you don't hear any improvement by using splitters instead of the 4ch RCA, because it shouldn't be an improvement. Now you know for sure your headunit is fine and the problem has nothing to do with the way you connected it...


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## sriskie (Feb 6, 2010)

I'm such a noobie!

I just changed all of the wires around and am now using just the front channel unbridged and it sounds the same...just as freaking loud! The manual and the amp both say it's bridgable but the power output seems the same...way more than I need.

So if nothing else I have a couple more channels I could use for something else...


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## Candisa (Sep 15, 2007)

You probably do have less power now you run the speakers non-bridged, but still more than you actually need. 
Does it sound better non-bridged?


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## sriskie (Feb 6, 2010)

You're probably right but the difference in output is neglegable. With the gain set about half way up and the volume on 20 out of 35 it's pretty uncomfortable...just like before. SQ seems about the same too.

I was just checking the local classifieds for a good deal on a decent amp to compare. I'm thinking I could resell it if it doesn't help.

I'm going to throw a different RCA cable on it later but I doubt that is the problem.

The speaker wire I'm running I bought locally wasn't cheap but one of the strands seems to be aluminum instead of copper but wire is wire...isn't it? 12 gauge everywhere except 16 guage from the crossover to the tweets should be overkill.

The sound is pretty flat without much smoothness...almost wooden and tinny somehow. They sound similar to the Infinity Kappa 6X9s I had in there before which I think sounded worse then the Clarion Pro Audio 6X9s run off a RF 2002 before that. I sold the 2002 and a 4002 when I bought the PG or I could try those.

I should probably try reversing the polarity on one side so I'll have to do some research on that.

I think it has to be just one thing because everything seems to be okay. I have too much into it to settle for this now...in for a penny, in for a pound.

Any more thoughts on this?


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## Oliver (Jun 25, 2007)

SISO = **** in ... **** out , use flac or some sort of lossless file for your input. Alpine is a very nice sounding HU!


> CDA-9886
> 
> Written by David, SF Bay Area, on Monday, March 1, 2010
> 
> Good points: Function, very clean good sound quality. (Hint for ipod users. If you like your music loud & with min distortion. Use .wav files. Open them in a wave editor and reduce the volume of the file)


The speakers are the final determinent of the sound ! > *Price:	US $189.99*

Try these: MM6 POLK AUDIO 6.5" MOMO COMPETITION COMPONENT SPEAKERS - eBay (item 130374116156 end time Apr-11-10 19:14:25 PDT)

with the other 2 channels freed up now ... mebbe some midbasses would bring that snap to the bass range you are still craving.

from Kicker 750 mono amp
# variable low-pass filter (50-200 Hz at 24 dB per octave) - set this as low as you are comfortable with
# variable bass boost (0-18 dB at 40 Hz)-don't use this 
# subsonic filter (12 dB at 25 Hz) - helps to protect subs from unloading in a ported enclosure that is tuned lower

from Phoenix Gold RSd 500.4



> * Amplifier signal-to-noise ratio 85 dB
> * Amplifier continuous power / channel qty 85 Watts x 4
> * Amplifier output 4-channel
> * Crossover type Active crossover
> ...


*Don't use this*


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## sriskie (Feb 6, 2010)

"SISO" I like that! True, I use the usb with plain old mp3s but I have tried original cds without much success.

So you think the CDTs are the problem? That would be sucks as I spent a fair bit to get them.

I'm concidering some kind of mid-bass but need to get the componets sorted out first.

You're right, the bass boost does really ugly things to those 6.5s.

Thanks for the input!


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## Oliver (Jun 25, 2007)

sriskie said:


> I'm such a noobie!
> 
> I just changed all of the wires around and am now using just the front channel unbridged and it sounds the same...*just as freaking loud!*


sensitivity of the polks = Efficiency: 87 dB

sensitivity of the CDT = Sensitivity: *91.2 dB*

Less output from the Polks for the amount of power in 

Those CDT's are all the current boner rage ... just resell em , cha-ching $$$$


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## Candisa (Sep 15, 2007)

sriskie said:


> You're probably right but the difference in output is neglegable. With the gain set about half way up and the volume on 20 out of 35 it's pretty uncomfortable...


Lower the gain! Try to find the maximum volume level where the headunit's pre-outs still give a clean signal (if you can't find that, 27-30 would be a good guess) and then set the gain to the maximum volume level you want to be able to listen at.


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## sriskie (Feb 6, 2010)

I have tried lowering the gain both bridged and not. I don't think it's a clipping issue.


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