Join Date: Jan 2013
Location: Central California
I've done a lot of messing around with the auto volume in order to do some research for my aftermarket sound system. So far as I can tell, the auto volume has no effect on the sound quality. It simply turns up the volume for you when at speed.
If you had your gain set so that your amp started clipping at a volume setting of 25 with the auto volume off, you don't want to turn your volume up past about 15 or so at a standstill (with auto volume on low) as it will get turned up to around 25 at cruising speed.
I think the amp manufacturers recommend against using auto volume because it's too difficult to gauge just how much it turns your volume up. Without knowing the auto volume's upper limit, it is difficult to dial in the gain correctly. If you mistakenly set it too high, you run the risk of damaging your amp or speakers and I think they just want to avoid the warranty issues.
All that being said, I ride with my auto volume set to low. I like that it takes the edge off when stopped at a traffic light or cruising slowly through a neighborhood. I don't feel the need to make those around me listen to my music.
'04 Kingpin - Blue w/ Tribal Flames (sold)
'12 Cross Country - Imperial Blue