Setting Gains

[ejschultz 10+ year member]

Okay, I've been trying to read about setting the gains on my amps and I'm confusing the f*ck out of myself. If anyone lives in NW Indiana or southern Chicago land, let me know if you'd like to help me out in setting my gains properly. I've got an analog multi meter, not a digital one. There's been a lot of talk about using an oscilloscope too, however, those are rather pricey and I don't have one. Maybe someone could break it down on here for me dummy style. Where do I measure the voltage I should be getting? My hu puts out 5 volts. That 5 volts isn't going to be at full volume, but somewhere around 3/4 of the way up, right? Also, I should have everything set to flat, and the loudness turned off. There's some things I know, but others are just really confusing to me. I'd like to get everything set correctly. Any help will be greatly appreciated.

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[kyleorsini 10+ year member]

isnt there a sticky on how to

 

[Qbenjamin 10+ year member]

//content.invisioncic.com/y282845/emoticons/search.gif.e79a63b2b580b39b282dff402646b704.gif the forums for numerous threads on this topic

 

[tEh ShOcKeR]

Unhook you subs from your amp, run a 50hz tone at 75% volume on your HU and read the voltage from the output terminals on your amp. There is a sticky in the Amplifier section on this site that has all this info and the chart to determine what your readings should be.

 

[ejschultz 10+ year member]

I've searched. I'm confused. I'm looking for some one on one help.

 

[tEh ShOcKeR]

I've searched. I'm confused. I'm looking for some one on one help.

What subs are you running? How many? How are they wired?

 

[ejschultz 10+ year member]

Unhook you subs from your amp, run a 50hz tone at 75% volume on your HU and read the voltage from the output terminals on your amp. There is a sticky in the Amplifier section on this site that has all this info and the chart to determine what your readings should be.

Would 50hz be the best frequency to run for the mono amp? What would be a good frequency for my 4 channel?

 

[tEh ShOcKeR]

50hz is for your substage.

 

[ejschultz 10+ year member]

What subs are you running? How many? How are they wired?

Subs are the ones in my sig, 2 12 inch Kicker CVXs, dual 2 ohm, wired to a total 2 ohm load. The amp is an Alpine MRD-M605, putting out 638 watts rms (birthsheet). My speakers are the Focal 136V components 60 watts rms 4 ohm, my rears are Infinity Kappa 693.7i which are 110 watts rms and are 2 ohm. My amp is 70 watts at 4 ohms and 100 at 2 ohms.

 

[tEh ShOcKeR]

(600 * 2) sqrt = 34.64 volts

 

[ejschultz 10+ year member]

So, for my 4 channel, I should be doing the same thing? (70*2)sqrt=11.83 and (100*2)sqrt=14.14? What frequency do you recommend for the 4 channel? I'm sure I can make a CD with the test tones in Goldwave. If not, I'll figure out some way to make it.

 

[ejschultz 10+ year member]

For the fronts it should be (70*4)sqrt=16.73

 

[tEh ShOcKeR]

So, for my 4 channel, I should be doing the same thing? (70*2)sqrt=11.83 and (100*2)sqrt=14.14? What frequency do you recommend for the 4 channel? I'm sure I can make a CD with the test tones in Goldwave. If not, I'll figure out some way to make it.

What ohm are your speakers on the 4-channel amp? I think you might be confusing the *2 for how many speakers rather than their ohm load.

You're first formula would be (70 * 4) sqrt = 16.73

70 watts @ 4 ohms

I'm assuming you came up with 100 watts for the other channels because of a 2 ohm load per channel so your formula would be right for those.

I believe you are supposed to use a 1khz tone for those.

 

[tEh ShOcKeR]

For the fronts it should be (70*4)sqrt=16.73

Correct.

 

[ejschultz 10+ year member]

Yeah, I realized the impedance of the speaker was in the equation. I didn't realize what the 2 was at first. Also, what do you recommend for test tones? 0dB, -3dB? How do I get the test tones? If I make them in a program, how do I know their sensitivity?