when you use a 2 channel amp and bridge it to run a subwoofer what gain control do you use. Each channel has a diff gain **** do you turn each up the same or when you bridge it does it change the setup where you only use 1 gain control??

rockford fosgate amp 301s

 

I think one of the ***** i labeled x-over and the other is labeled gains. Gains need to be set where it is loud but not distorting. X-over should be set low for subs. I think mine is like 40 hz. Make sure you got the amp in low pass mode. Maybe that will help.

 

You use both gains and set them equally.

What tool do you guys use to set your gains. I still need to set mine, but I cant find anything small enough to fit.

 

i have so small screw drivers that came in a tool set....but if you can find any eyeglass repair kits, they usually come with a small flat-head screwdriver that would be perfect to use

 

I shoulda thought of that. I finally jsut took a really small drill bit that was broke in-half and used that. Didnt work the greatest but at least i got them set.

 

haha...whatever gets the job done

 

What subs do you have, or better yet what comps do you have (specfically midbass)? With a set of Utopias in my truck I can barely xover a sub at 40 Hz with out leaving a gap ( I couldn't do it with the set of Polyglass' I used to have(at least I don't think)), and even so I still perfer to cross them over around at least 50 Hz. Simply beacuse I don't risk leaving a gap and because a sub can do 50Hz no problem and it won't draw your soundstage to them. Also so I dont really have to worry about the speakers naturally rolling off too (not this is a big issue, but when factored in with the xover roll off I suppose it could cause some issues pending what you are doing) The average person crosses the subs over at 80 to 120 Hz usually, but it does depend on the set too. Usually the higher you cross over the speakers the better sounding they get and are able to go louder. Anything above 120 Hz gets into the midbass region and tends to draw the soundstage towards the subs and once you get to midbass you really need stereo. Also, in most SQ cars they crossover the subs fairly low, so the lower you can crossover the speakers the better, but usually you have to give and take a little.

Also if you have a comp set you can usually cross them over a little lower than you can a coax set. Even better is a 3 way comp set at least in my book, but then you get into phasing problems and multiple pointsouces.

When setting gains it usually better to keep them as low as possibly because it helps to keep the noise out of the stereo. Generally the best way to set the gains is turn them all the way down then turn your HU up to 3/4th volume (asumming you can with out blowing the speakers) because this is on average where mos HUs clip (however my eclipse 8051 did not fully clip at full volume) if it is up to 3/4ths volume and you are content with the volume of the stereo then leave the gains down. If you need more volume slowly turn up the gains, if you hear anything bad/unusual then stop and turn them down. Really the best way to set the gains is with an O scope to make sure your not clipping, but the above way can help you get an idea of where they need to be. Also the gain isn't really a volume control, but rather it matches the voltage comming off the HU. So if you have a DMM you can figure out the voltage comming off the HU and compare it with the input sensitivity of the amp and determine the gains from that information also. Basically you want to keep the gains at their lowest while givining the listening level that you (asumming you have the power) with minimal to no clipping because clipping can kill speaker. When an amp clips it can put out more power than it is rated for, also it causes the coils in the speaker to 'hang' which can cause a build up in heat thus frying the speaker.

Read here: http://www.eatel.net/~amptech/elecdisc/caraudio.htm Great site, one of the best IMO.