setting the gain
 

Hi all,
My HU is a Panasonic CQDFX572U with (I believe) 2.5V pre-outs and one of my amps is a Clarion APX201.2 200W 2-channel.

My amps range on the gain control is 250mV to 2.5V for RCA inputs.

I have Alpine 6.5" Type R component speakers on this amp that can handle 50W RMS.

Can I estimate what my optimal gain setting should be given these numbers? I don't have a very good ear so I can't really notice the first sign of distortion as I crank up the gain at 75% volume.

I've always heard that you should set up all your volumes at 75% and then adjust with the volume control closest to your speakers wiring-wise.

sorry, man. but you lost me there.

the way i've heard to do it is:
set your HU's volume to 75% with amp gain at zero. then start cranking the gain till you hear distortion, then back off slightly.

but this is going by ear and i don't have very good ears.

I doubt that your ears are bad enough to not be able to detect distortion. Using the method you speak of (which seems to be pretty accepted), just go till you detect distortion (use a recording that you are very familiar with), and back off until you detect no distortion, then a wee bit more, and you will be safe.

The suggestion of using the speakers closest to you (i.e. the fronts) is a good one - disconnect all other speakers (back, sub), adjust using the distortion and back off method, then set the gains for the rest of the speakers based on balancing them with the fronts to get a good soudstage. In any cases I have encountered, you will likely not be overdriving anything if you set things in this order. If you encounter significant distortion from one set of speakers this way, then use that set of speakers as a reference for distortion, then set the gains to balance for the rest.

Make sense? I hope so! I am sure BluLEDZ or 1st MP3 or Dave Cameron will have some wise suggestions on this topic.

here ya go! :)

Nasty Totoro's Gain Setting Page

Ouch Man! There is some good info there, but not everyone (like me!) belives a little clipping is a good thing brother!
www.davidnavone.com
will sell you CD's you can use to set the gains without clipping.

Turn the radio t 80% then turn up the gain till it distorts, back off a little bit and your done. You may want to listen and play for a bit though.

true, this was posted on car audio forum sometime back. just posted as a reference... :)