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I have an Eclipse CD8051 for my source unit. It has 8 volt preouts. My EQ is a Crossfire cfq5.2 and it says it only accepts up to 6 volts input signal. Is this what could be causing my system not to sound right? The mids and highs don't sound horrible but the bass doesn't sound right. I had an airleak and I fixed that, but that didn't fix my problem. The subs just don't sound as accurate as they should. On my head unit the nonfading preout (subout) can be set to full range and can be adjusted from zero to 16. If I turn this down to about 12, would that help? The EQ also has an input gain on it.

You need line level dropped to 6 at the EQ. You are overdriving it most likely. That's bad, it causes it to clip.

so since the non fading is adjustable fro 0 to 16 on my eclipse,and it's supposed to be 8v,that would be at 16 right,so if i turn it down to 12 it should be at 6 volts then right?i mean,theoreticaly i could take 8 and divide it by 16,that would give me .5 volts,so at 12 it should be 6 volts right,or do i need to get a different hu,or ditch the eq,i would like to keep both,but i am not that impressed with my eclipse,other then the fact that it will play about anything no matter the condition of the disc,otherwise it's not tremendously better than anything else i'v owned, so it wouldn't break my heart to let it go,i'm not that impressed with the eq either,but then again if i get everythin set up correctly i might be tickled shitless with it...damn it

very few components can actually handle 8 volts. not even Eclipse's amps. Here's the thing about the 8 volts, it puts out 8 volts at maximum peak. not all the time. don't get rid of anything, you just need to get it tuned in. do you have anything running off the deck? if so, set all the setings at the nominal poin bass, mid, treb at 0, sub at 0, etc. turn all the gains down. set the eq settings in the center point. turn the HU up until it it distorts. if it doens't, then leave it up. if it does, back off the volume until it stops distorting. next, turn up the sub control until the sub distorts, then back it off. now move down the signal path doing the same thing until you have reached the amps, turn the gain up until it distorts, then back it off. if you run into a point where you can't eliminate the distortion, you have a problem with that component or the one before it. If you have an oscilliscope, that would be even better as you can watch for the square wave, that's what I use. but using your ears will work too. be sure to set your bass boosts and all that at their lowest points or off. once you have found you decks max unclipped signal level, NEVER turn it past that point. Also, don't use the decks eq controls very much, they usually only mud up the system. Eclipse's is pretty good, but don't use the bass control, you don't need it. Also be sure you are taking advantage of the crossovers. set your system so that you don't have an overlap, you really want a slight gap between your xover points. for example: subs at 80, mids at 100, this is becaue the car environment naturally gives a slight boost in the mid frequencys andwill naturally cover the slight gap. thats why most car sound boomy in the mid range. follow this guide line and your system will sound great. Its all about the tuning.

Kiki would be best to answer this as hes an electrical enginner, but here is my guess.

If its an 8V out deck theres no way to adjustthe voltage. Im about positive you can not control the voltage by simply changing the setting on your deck such ass bass, volume and treble.

Kiki?

sorry, you are wrong. How else do you think volume controls work? they are basically a potentiometer, a valve if you will, they gate the levels of voltage sent out by the HU. same thing for gain controls, they regulate the output by contolling the voltage.


if you don't believe me, try this direct from AudioControl:

Here’s a simple procedure:
1. Set the amplifier level control to minimum sensitivity. This is the setting where the volume is
lowest.
2. Using either FM radio or a tape for a signal source, advance the volume control on the head unit
until you hear distortion or reach 100% rotation. If you reach distortion before 100% rotation,
reduce the setting of the control slightly until the distortion disappears.
®
3. Now adjust the sensitivity control on the power amplifier until you hear it clipping, or the
system is too loud.
Remember: you want as much signal going through the cable between the head unit and the power
amplifier as possible.

here's the entire article:
http://www.audiocontrol.com/techpapers/techpaper103.pdf

I fully understand how to set gains.

I am just not sure about the voltage being lowered simply by adjusting the bass/treble and volume.

I do know when I pick out my equipment I look into all things first, such as this for instance

I understand what you are saying. I was using that tech paper for clarification of my statement. the bass\treble controls alter the signal in the same way as volume. the vol. knob controls the entire bandwidth, a "master control", the bass treble controls those areas of the bandwidth. it all comes down to voltage. put a scope on your rca's on your hu and do some testing. you will find with most hu's the bass control will clip the signal really fast. you can even use a dmm and see the voltage change. of course you would need to be playing test tone, and not music as th voltage will be fluctuating because of the music. only a few hu's have non-clipping outputs meaning you can max everything out and not have clipping. higher end rf decks are non-clipping. the simplest way to explain it is this: the hu supplies a signal, that signal is measured in voltage, the higher the voltage the louder it will be. ALL audio controls on the hu will effect the voltage output. raise or lower

http://www.bcae1.com/audoutex.htm
first paragraph.

we're all here to learn or share knowledge. How that knowledge is presented determines the atmosphere of this forum. If people feel this is a hostile environment, less knowledge will be shared, and that hurts everyone in one form or another.

as for the pre-out voltage, if it's too high at max volume, one solution is to use a line driver that reduces the peak output to a usable level.
Another similar solution is to use a pre-amp with a master volume control and line driver. This allows you to set head unit volume to the voltage at max you desire, say 3/4 volume. Then you use the pre-amp as your volume control since it will be adjusted to never exceed the maximum desired voltage, such as 4V for example.

no intent to be nasty, sorry. I need to watch myself. I apologize for being a jerk.