tune amp gains, etc with ALC on or off?

[builthatch]

The BOSE headunit in my GT has ALC. i've used this since day one, and even have tuned my amp and re-q gains around it on ALC level 3 (highest level). ALC as per the owners manual increases volume and "sound quality" (whatever that means- tonal levels i guess?) according to vehicle speed. interestingly enough, with the ALC off and the car not moving/off, the levels are very quiet and 'flat' sounding vs. even ALC 1, let alone ALC 3. so that leads me to believe that it's boosting more than just volume; it's taking a flat signal and making it not flat even if the car is not moving, and then increasing that modifiied tone set per vehicle speed.

So, my question is, should i tune my system without this enhancement engaged? It seems like i could get more out of my gains without this enhancement engaged. everything i've ever read about this type of thing seems to point to not using enhancements and that you want to tune as flat of a signal as possible, but i guess the confusion lay in exactly what ALC does. i love the volume increase part, i know it does that as the vehicle is moving, but it's the level compensation that worries me and makes me think that i'm missing some potential from my amps because of the gains being tuned with these levels in mind.

 

[Abaddon]

Strickly speaking... you shouldn't use ALC at all.. because it will screw up your gains. It increases output level, leading to clipping at a lower volume.

you "should" turn ALC off, set your gains, and leave it at that.

Personally.. I like the EQ that the ALC gives to the system, so I turned it on after I set my gains..

 

[derspi]

Trust your own logic - ALC should be turned off altogether. I'm pretty sure it's not just simply cranking up the volume as speed increases, it's probably also boosting the highs & lows or some combination of the two. Setting your gains or EQ, etc. with ALC on seems counter-productive since the Bose unit will vary the volume and/or change the EQ curve depending on speed or road noise and you really can't tune for something that's variable. Whatever it is you tune for will get thrown off as soon as you turn ALC on. Maybe if you only have a sub & amp setup then it won't matter but for guys like me who build their system around a 30-band EQ, I want as little interference from the factory HU as possible.