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Ive searched for the answer to this question and could't come up with anything. If it has been answered before could someone post a link to the thread? If not, here goes, the hu I have right now has 2v rca's and my sub hits hard enough for me with that, how important are 4v outputs when it comes to my highs? I was hoping to get the Alpine 9855 but not sure if we will have the funds for that this year, so I am considering the Alpine 9853. I am pretty stuck on Alpine, I have only bought 2 other hu's that were not Alpine, and both times I regret it. I appreciate any input anyone has.

All the voltage does is determine how you have to set your gain. You won't have to turn the gain up as far with a 4v as compared to 2v. A 4v won't make it any louder or anything.

Yep 2, 4 or 8 volt RCAs won't change the volume at all. It will give your amp a cleaner siginal to work with, and help a little if your going for more a SQ based setup.

Well...

4v is supposed to help lower induced noise from the RCA run.

Also it allows you to use less gain at any given volume to achieve X amount of spl. In this own right I would think it lowers THD as you dont need to use as much gain... It probably isnt a noticeable amount of THD anyhow...

well with my current 2v outputs, my gains aren't quite halfway up on my high end amp and the sq is pretty decent (for my crappy sony hu), so I guess I may be getting the Alpine 9853. Thanks for the input guys!

Another important consideration is the impedance output that has a big relelvance to the potential pick-up noise. And the layout of your wiring plays another inportant role in car/system-induced noise:

even in my first sound competition, where I had a lot to learn, I scored 20/20 in absence of noise and 20/20 in absence of noice with the car running. I still have no noise with 20 year-old interconnect, and before high voltage head units.

For instance for 22 years I haven't changed the basic wiring location. I run Monster cable Reference 2 interconnect (I wanted the david navone patented proXLN, but if it works, why fix it?) on the far right of the car along with the antenna wire. On the far left are all powerwires, turn-on wires from the distribution box at the battery. In the trunk Power wires used to intersect signal wires at right angles, now they don't even come near each other. All grounds are grounded to the same point.

Once when installing a stereo system for a friend, we got all finished and--no sound. We check the ground with an ohm meter. everything looked OK. Finally I took a power drill with a rotary steel brush and throughly cleaned the area. After reconnecting wires, we finally got sound. Apparently there must have been some slight resistance.

Also in my older cars, I'm especially careful to groud everything: chassis to body. engine to chassis. chassis to body in back, battery to body, etc.

Well put, going back to the everlasting phraze, "it's all in the install."

JeremyC wrote:Yep 2, 4 or 8 volt RCAs won't change the volume at all. It will give your amp a cleaner siginal to work with, and help a little if your going for more a SQ based setup.

Cleaner & stronger output are two VERY different things...
Justin is right in that the only diff will be in the amount of gain adjustment.

Poor quality amps may protray more noise floor as the gains are set, but that is a flaw in the amp. In such rare instances, having a higher voltage HU is a definite advantage.

High voltage outputs are a definite plus, but certainly offer no sonic advantage in tonal accuracy for a SQ setup.