Setting the Gain Settings Properly....

[brfitzp 10+ year member]

I've read quite a few guides and they're all a bit confusing. I'm Trying to set the gains on an amp for a sub and it needs to be set to push 850 watts.

I used this guide to do it how it's set now, but then someone told me i shouldn't used a tone like -6 and instead should have been 0

So i used the -6db tone at 60hz then turned the gains up until the multimeter reached the right number for the wattage i needed. Only thing is When i play another song such as young jeezy put on it goes over that number with all the sound levels still set the same.... Is that ok? I dont wanna let the sub clip and die again...

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[hrtbrk1 5,000+ posts]

if da speaker blows..u did it wrong...

anyways i used a 50hz note at -3dB...

 

[brfitzp 10+ year member]

well last time i didnt do any measuring and used a different amp.

Is it ok for the numbers to go higher than the numbers at the tested frequency? Do those numbers mean the amp is really getting that many watts?

Also i wanted to test my friends car cause he has two kicker 12" subs, fairly cheap ones and a cadence txa3004 amp, he's running them each bridged so it should be 300 watts per sub, when i hooked up the multimeter and played the tone he was getting about 550 watts per channel and even higher with normal music, and thats playing it as loud as he would ever normally play it. That definatly clipping right? It's a 600 watt amp and he was pushing 1100 out of it

 

[hrtbrk1 5,000+ posts]

i in all honesty do not know...

but i vote yes

 

[hrtbrk1 5,000+ posts]

or it could be the lpf/ his head unit controls/ and what not making the voltage spike up like that

 

[brfitzp 10+ year member]

I just created a 0db 50hz tone so ill go adjust all gains with that then test out other songs and see what i get.

 

[brfitzp 10+ year member]

Ok i did that and it sounded quite low, so i decided to try a few loud bass songs.

I did some jeezy stuff, too short, and lil jon, none of them were hitting above 34 volts which on my setup is

Volts= SQRT( watts*ohms)

So 34^2= 1156/4ohms=289 watts?!

So i raised the gains so it was hitting about 55-60 volts, unless i'm playing unattenuated bass tones i'm never going to go over that right?

 

[Boomintempo 10+ year member]

You know, it seems that these settings you're supposed to use are for a impedance that your amp probably never see's.

For example, my setup is a 1 ohm load. Once the subs are hooked up to the amp, my amp sees the load as 3 ohms...nice impedance rise. It's confusing, because then it seems like you need to factor in impedance rise to get the wattage you want. Obviously you purchased an amp that puts out max power at whatever impedance that you need...

Confusing. Seems like you should ALWAYS purchase a larger amp than what you need to have the gains set properly and not too high.

 

[DBfan187 5,000+ posts]

use -10dB tones for gain overlap, google it

 

[PIITB Wut Wut 10+ year member]

dont over think this... try to match rca's level to amps gain as best as possible but unless you have something to actually read clipping it wont be EXACT.....

the only i match is RCA's to the amp... set it at 3v or 6v depending on the amp at 3/4 the way up with a nominal level on my headunit.

 

[Boomintempo 10+ year member]

Yeah, it just seems like the whole "Just use a DMM to setup your amp" is pure BS. Seems like the most important thing to do is match gain setting to preamp voltage. Unless you have an O-scope. I know back in the day we didn't use DMM's to set our freakin' gains...just matched to preamp voltage and listened for distortion (which isn't easy to hear in all ported enclosures and bandpass)

 

[PIITB Wut Wut 10+ year member]

lol only problem is... some people dont hear distrotion...or at least understand what they are hearing..

 

[Boomintempo 10+ year member]

lol only problem is... some people dont hear distrotion...or at least understand what they are hearing..

Very true! Some people confuse crazy loud bass with crazy loud distorted bass.

 

[t1990le 10+ year member]

Yeah, it just seems like the whole "Just use a DMM to setup your amp" is pure BS. Seems like the most important thing to do is match gain setting to preamp voltage. Unless you have an O-scope. I know back in the day we didn't use DMM's to set our freakin' gains...just matched to preamp voltage and listened for distortion (which isn't easy to hear in all ported enclosures and bandpass)

x2 i set all my ish by ear. //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[peas247 10+ year member]

by ear ftw!!!