the line voltage for pre-outs really affects dynamic range and resolution for the most part. the amplifier gains should be set to match teh line pre-out voltage, so it shouldn't matter. Eclipse is one of teh only companies who offer 16V pre-outs, and those can be set to 8V as well. If your unit has weak pre-outs in the 2V or lower range (under 4V) you can also add a line-driver to help improve that.
I am looking at a deck that I really like that has 6.5 volt pre-outs.
Unfortunately, one of my amps (my sub amp) says it only accepts up to a 4V pre-out input.
Can I still use these two in combination? Will I lose a huge amount of SQ?
over-driving can cause clipping, it's more like if you set the gains too high on the amplifiers.. the signal isn't clean and you end up with distortion caused by square waves.
look at audiocontrol for line drivers if you want to go that route. they vary in price based on waht you go with, but you can try that Pioneer with your amps and see how it works. you may be fine with 6V preouts.
i have a pioneer home theater receiver with a paradigm kick butt sub. the ub makes these funny pops whenever people on my DVD's say anything containing the letter "P" it is very frustrating! could this be because my receiver has high pre-out voltage and the sub doesnt accept it? or could it be that the voltage is too low for the sub?