Using DMM and Setting Gains

[seg_representin 10+ year member]

I was shootin for 34.64 and when i got that reading i thought the gain was a lil low. How do i check the volts at the battery? And how would this make a difference. I had my car on while doin this and then did it witch my car off and got the same reading. Any suggestions. Or should i just try it by ear and see how that goes and if it sounds good with no distortion then i should be fine right? Yea i got another question. I know they say the nine.1 is underrated. They say it will do around 1400 at 14 volts. So in setting gains do i still just go by 1200 or should i do it for 1400?

 

[xluben 10+ year member]

put the DMM leads on the power input of the amp to check battery voltage.

 

[Ctminime 10+ year member]

put the DMM leads on the power input of the amp to check battery voltage.

yea its best to measure that at the amp.... then u can acutally tell exactly what voltage the amp is getting... somtimes voltage lowers going thru the wiring...

 

[DeuceLee 10+ year member]

pardon my noObness but doesn't the rca voltage have something to do with it too?

i mean, a HU with a 4 volt output should send a cleaner signal to the amps and thus need less voltage reading (lower gain on amp) to get teh same output as a HU that only sends a 2 volt output to the amp...

or does it even make a difference? cus something is smelling funny...

 

[luvinthebass 5,000+ posts]

your head unit proly isn't gettin the full 4 volts prolly more like .5 of a volt and clipping the shit out of your sub/s. where di dyou set your maximum unclipped volume on your head unit when you set your gain? you should set it a volume below where it clips, my pioneer clips at 23/30 and i setted my gain at 22/30 an easy number for me to remember.

 

[seg_representin 10+ year member]

Alright ill go out and check the voltage and i'll let you know what i get.

 

[seg_representin 10+ year member]

Alright i checked it with the car on and i was gettin 13.98 volts. So because its over 12.5 do i recalculate the number i need to set the gains? But then i recalculated what i would get a 14 volts and its 1344 watts and that still only gave me about 37 volts to set the gains.

 

[kicker06 10+ year member]

Having a higher battery voltage if I'm not mistaken will allow you to have your gain on the amp set lower to achieve the same voltage, which will reduce the stress you put on the amp.

This is my guess, and it's what makes sense.

 

[xluben 10+ year member]

Alright i checked it with the car on and i was gettin 13.98 volts. So because its over 12.5 do i recalculate the number i need to set the gains? But then i recalculated what i would get a 14 volts and its 1344 watts and that still only gave me about 37 volts to set the gains.

calculate voltage for the output. it should have nothing to do with the input power to the amp.

 

[kicker06 10+ year member]

calculate voltage for the output. it should have nothing to do with the input power to the amp.

Well checking the input power just tells you the true voltage @ the amp.

 

[seg_representin 10+ year member]

Yea should i check the voltage i'm getting from my rca's. And how would i do that exactly. My manual says i'm gettin 2 volt preamp outputs. My deck is the alpine cda 9851. I just think the gain should be set higher for the amount my preamp outputs are.

 

[kicker06 10+ year member]

you coudl try it if you wanted.

 

[kicker06 10+ year member]

your head unit proly isn't gettin the full 4 volts prolly more like .5 of a volt and clipping the shit out of your sub/s. where di dyou set your maximum unclipped volume on your head unit when you set your gain? you should set it a volume below where it clips, my pioneer clips at 23/30 and i setted my gain at 22/30 an easy number for me to remember.

How do you tell where it clips? My pioneer headunit goes up to around 58, and I set my gains @ 48/58.. Would that mean that the headunit would be close to putting out it's full 2.2v?

 

[questionaire 10+ year member]

(power*resistance)sqrt

400@ 2ohm is 28.28 correct??

 

[DeuceLee 10+ year member]

Yea should i check the voltage i'm getting from my rca's. And how would i do that exactly. My manual says i'm gettin 2 volt preamp outputs. My deck is the alpine cda 9851. I just think the gain should be set higher for the amount my preamp outputs are.

i'm in teh same boat you are bud....

anyone care to elaborate?