gain setting on multi ch. amps

[cshaw 10+ year member]

http://www.caraudio911.com/tutorials/GainSet/voltage.htm

so is this tool only useful for mono amps? im checking my amps gains with my meter after doing them by ear to see how close i came. i was spot on with the bmf1000d at around 33v's. how would ya do it for multi ch. amps?

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[cshaw 10+ year member]

bump

 

[cshaw 10+ year member]

think i should opt for 1k for my comps instead of 50hz as i used on the sub stage when setting the gain with a mm?

 

[ultimate157 5,000+ posts]

1k is fine.

Setting gain on multi ch amps is the same, just repeat the process for the other channels' gain knob.

 

[cshaw 10+ year member]

the problem i have is the equation to finding the output voltage at which to set an amp to, doest account for channels. its the sqrt (rmsxohms). and my amp is 2ch. only has one gain. when bridged it does 200x1 at 4Ω. so that gives me an output voltage to set the gain to around 28v's. so do i hook the meter up bridged then?

 

[thch 10+ year member]

obligatory note that max unclipped gain in no way is acoustically optimal, and should not be used if the levels are not readjusted elsewhere as needed.

 

[cshaw 10+ year member]

well it does 200 rms when bridged, if that, cause im never always at 14.5 volts. it does 75 rms x 2 but how would i calculate that into an output voltage at which to set my amp? i mean ive done it by ear, and both amps where set to a good balance, just seeing how close i came to being exact.

 

[cshaw 10+ year member]

so who likes to make there own black and tans? im off to the store, maybe some Sierra navada pale ale mixed with some porter sounds delish but id like to set my gains right....

 

[thch 10+ year member]

"correct" implies a goal. any gain setting is correct if it meets the criteria you set.

eg, one person might set the gain such that the amp acheives maximum undistorted output at 20/30 on the HU.

person two might set it such that the amp acheives the rated power of the attached speaker at 20/30 on the HU.

person three might set it such that the speaker acheives a desired "normal listening" SPL at 20/30

each person had a reason for the gain setting. really, all you can do with the DMM is check to see if you might be overpowering the speaker, or maybe clipping.