Setting the gain with a DMM?

[Mast0rMason_]

I know how to set the gain with a multimeter, but is there a reason why all eq and extras should be flat? If I set the gain and then play with the EQ a it will that not send the amp into clipping or something?

Thank you!

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[Jeffdachef 5,000+ posts]

I know how to set the gain with a multimeter, but is there a reason why all eq and extras should be flat? If I set the gain and then play with the EQ a it will that not send the amp into clipping or something?

Thank you!

As long as you are using cuts and not boosts you are good. If anything else you just leave a couple notches on the volume off the table so you dont clip. Multimeter is just a general starting point. Its up to you to fully learn your system limits. Keep your nose sharp abd regularly feel the temperature of your gear and monitor your voltage drops.

 

[Mast0rMason_]

As long as you are using cuts and not boosts you are good. If anything else you just leave a couple notches on the volume off the table so you dont clip. Multimeter is just a general starting point. Its up to you to fully learn your system limits. Keep your nose sharp abd regularly feel the temperature of your gear and monitor your voltage drops.

Ah wicked thank you. Also the amp I'm testing is 460W rms, if I put the voltage to about 450W 440W would that suffice the voltage drop? The manual says 460W RMS at 14.4. Is the a mathematical way to work it out of its dropped to say 13.6V when the bass hits? As the voltage drops then goes up a tad once the car realises it needs the alternator spinning more.

Do I set the sub gain with a -10db tone too?

Also what happens if the speaker wires too thin? Think theirs like 12 or 10 strands of copper in the speaker wire, but each ones receiving half as its wired in parallel.

 

[Graves]

Do I set the sub gain with a -10db tone too?

I like to do 0db personally but -10db would be fine as long as you are not maxing out you system with music that was recorded higher than -10db... -5db would be a safer bet especially if you are planning on EQ boosting.

I don't know the gauge of the wire but speakers wire carries AC and like you said each circuit is only seeing ~230 watts, sounds like you have plenty to me.

As for the math just multiply your impedance by the desired RMS wattage (for the channel) then the square root of that will be your target.

i.e. 460 x 4 ohm = 1840
sq rt of 1840 = 42.9 volts

or 30 volts if you have a 2 ohm load.

 

[Mast0rMason_]

I like to do 0db personally but -10db would be fine as long as you are not maxing out you system with music that was recorded higher than -10db... -5db would be a safer bet especially if you are planning on EQ boosting.

I don't know the gauge of the wire but speakers wire carries AC and like you said each circuit is only seeing ~230 watts, sounds like you have plenty to me.

As for the math just multiply your impedance by the desired RMS wattage (for the channel) then the square root of that will be your target.

i.e. 460 x 4 ohm = 1840
sq rt of 1840 = 42.9 volts

or 30 volts if you have a 2 ohm load.

So if I do it across a bridged channel would I set it to 30V as a 4ohm load would be 2ohms bridged wouldnt it? As when I playing with a tone generator you can really hear the clipping at 40hz but 50hz sounds okay, for the clipping to go at 40hz I need to turn the volume down by 2. Or would I set it to 42.9V measuring across the bridge? I set it to around 41.5V just to be safe.

Or if I turn the bass extension off it doesnt clip at 40hz. Is it better to leave it off or on?

 

[Graves]

So if I do it across a bridged channel would I set it to 30V as a 4ohm load would be 2ohms bridged wouldnt it? As when I playing with a tone generator you can really hear the clipping at 40hz but 50hz sounds okay, for the clipping to go at 40hz I need to turn the volume down by 2. Or would I set it to 42.9V measuring across the bridge? I set it to around 41.5V just to be safe.

Yes, if you have two 4 ohm voice coils ran in parallel you have a 2 ohm total load the amp sees. (30 volts AC)
Yes you want to measure the same spots (bridged) you hook up your speaker wires to.


I don't know what bass extension is, is that adjusting Q factor or EQ boosting something? Personally I leave everything flat and have a lot of power going to the sub (with some headroom) when the sub volume is at the lowest setting. This allows me to know Im safe at the lowest bass volume setting for any track at any master volume. This also allows me to turn up the sub volume when Im playing a track that I know has low or modest bass by trusting my ear. I set my 4 channel with a DMM but my sub amp gain has been set by slight adjustments over time until I have found exactly where i like it.