thats what my friend said.. that his car is a lot loduer cause his pioneer HU puts out more volts than my sony? is this something to take into consideration if i buy a new HU?

 

It is a consideration... the more power an amp gets through the input signal, the easier it is for the amp to amplify the signal, thus you'll get more sound. Its also helpful for rejecting noise.

There are also other factors involved though, not just preamp output power. The way things are tuned, amplifier output power, wirring configuration, the vehicle its in, the damping applied to the car....... there are a ton of things that contribute to one being "louder" than another.

 

:werd: i was just wondering if the voltage had anything to do with it. i thought it did, just makin sure

 

Most amps are able to make full power with just about any head unit. It won't make the amp any more powerful youll get the same amount of power either way as long as the gains are properly set. You just won't have to turn the gains up as far, which is a good thing because that is where a lot of noise comes from. It can be a consideration but i think its not a deal breaker on a new head unit if it has everything you want. You can always get line drivers to up the voltage coming from the head unit if it is a major problem. His speakers may just be more efficient.

 

The only real benefit is that now the amplitude of the noise is small in comparison to the signal - so does it have the chance to be cleaner, yes, more power, no

 

i dont mean to be rude or anything, but where are these assumptions coming from? are these hearsay or does anyone have any actual backing on this. can anyone show me an equation or a physics relationship describing how the input voltage off the HU is going to increase/decrease noise, or supply/not supply more power? thanks

 

It's almost a common sense relationship here....

First it has nothing to do with increasing or decreasing noise....it's more about taking a clean signal from the head, then keeping it clean to the amplifier.

Think about it....if I have a head that outputs 0.5V and a second that outputs 4 volts of signal. Both will theoretically pick up the same level of noise along the signal chain. The 4 volt signal's amplitude is 8 times higher then the 0.5v signal. Therefore, the noise will be less significant on the 4V line then the 0.5v line.

Also, as voltage increases, you can decrease the gain on the amplifier....and we all know that's a good thing. The lower the gain the better!

Heres some additional reading for you to prove it's not heresay...

http://www.eatel.net/~amptech/elecdisc/gaincon2.htm

 

I just upped my HU from the RF RFX9000 with 2.3v pre-outs to the RF RFX9210 with 5v pre-outs and it made quite a difference. Its not that the sound is much louder, but its much more full, and much crisper. Its really about clarity, the amps are going to make it loud regaudless, but if the signal is distorted, the ampification will also be distorted.

The system sounds 100% better with stronger preouts. (IMO)

 

My Alpine comes with 3 sets of 4v pre outs, I got a Clarion EQS-560 EQ/Line driver that ups the output voltage to I believe 7 or 8 volts. Made a noticeable difference in clarity and SQ. It goes just as loud as it did before, only it sounds better now.

 

an amp has a gain for a reason, the gain is to match up the input voltage to the output of the amp...

your 2.3v output may make it necessary for the gain on the amp to be around, oh lets say, 60%, whereas the 5v may only need to be @ 35% (just giving #'s).