would one of you more experienced guys like to talk rest of us through what is involved with setting gains with a digital multimeter or DMM

oh yea i almost forgot .... please

 

Ill give it a shot, I suck at explaining stuff though


TOOLS NEEDED:
Digital MultiMeter
CD with a test tone on it. A 50 Hz tone should cover most sub amp setups, and a 1000 Hz tone should cover most speaker amp setups.
There are sites that you can download them from and burn them onto a cd, someone might know a link and post to one.

*EDIT* Found these through a search. http://realmofexcursion.com/downloads.htm

First, you need to use this formula to find the voltage you will be aiming for
The formula is (POWER*RESISTANCE) SQUARE ROOTED
So for example, if you have a amp that puts out 300 watts continous (RMS) at 4 ohm, you take 300*4, which equals 1200, then square root that number, which comes out to be 34.6. Write this number down. This is the number you want to see on your DMM.

STEP ONE:
Disconnect your speaker wires from the amp and turn the GAIN/INPUT level on your amp all the way down.
STEP TWO:
Hook your DMM to the amp. I usually stick the test lead ends into the speaker outputs and screw them down with the set screw so I have one less thing to hold onto later on. Just put the + lead from the DMM on the + output on the amp, and the - on the DMM to the - of the amp.
STEP THREE:
Turn your truck ON (engine running) and with your DMM on the 200 VOLT AC setting, play the test tone through your HU. Put your HU's volume at the highest level that YOU listen to it at. For example, if the loudest you turn your radio up is 45/60, then turn it to 45. Just dont turn it up ALL the way, or your HU will probably clip (which is bad). If you dont really have a set level that you listen to, turn it up about 3/4ths of the way, and dont turn your radio up higher than that once you are done with this prodedure.
STEP FOUR:
Turn your GAIN/INPUT **** up slowly untill your DMM reads the voltage that you previously figured up with the formula and stop when you reach that number.
STEP FIVE:
Turn off your truck, disconnect the DMM, reconnect your speaker wire, and rock out. Your Done.

If its to loud, you can turn your GAIN/INPUT **** down some, but DO NOT turn it up and higher. Doing so can cause a clipped signal, which can kill your amp and sub. And the whole reason we did this is to get away from clipping

Remember to eject your test tone cd, or at least turn down the volume when you are done or you might give yourself a heart attack when you jump in it the next morning and have a test tone playing as loud as possible

And if you break anything dont come blaming me, please

 

Remember to eject your test tone cd, or at least turn down the volume when you are done or you might give yourself a heart attack when you jump in it the next morning and have a test tone playing as loud as possible
don't you hate it when that happens

 

Make sure to disconnect the RCAs form your other amps (if you have more than one). For example, setting the gains on a sub (mono) amp, disconnect your amps to your components, if not, you can damage your components.

 

Bartak1
you don't suck at all at explaining stuff very well done thank you for taking the time to go thru it for us i am going to try this this weekend now that i finally have all my stuff installed in my truck and looks like we will be getting a break in this cold weather we've had as of late it will be nice to finally have my complete system up and running fully it will make that 6 hour ride to lansing michigan for the Michigan buggy builders show next weekend more enjoyable
here is my take about the installation of my system
1)install new hu leave stock speakers in ... huge improvement
2) remove stock front speakers replace with pioneer 6870rs ... again a significant improvement
3) remove new frt pioneer speakers dyna mat doors (did whole door not just around speaker opening ) ... not as much of an improvement as i had hoped for but an improvement none the less
4)repeat same deal on rear doors with pioneer 6840r 's first speakers then speakers with dynamat ... i hope this does not ruffle any feathers but if i would have known then what i now know i think i would skip this step i was very dissapointed how small an improvement this made but that is just my opinion but hey i allready had the speakers and dynamat
5) hook up 2 10" visonik subs (i know not the greatest subs you guys probabilly consider them junk) in a dual downfiring 3/4" mdf box with my 780 watt pioneer amp no gains set ... ok now we are bumping and thumping and we are happy on a side note if i blow the visoniks up they can always be replaced by a better quality sub

again Bartak1 many thanks regards 2088bob

 

Yes, thats probably a good idea too. The HP filter on the amp should protect them, but it never hurts to be cautious and pull the fuse or disconnect the RCA's as Bry said.


No problem Bob.

 

The reason to do this is why? Is it to set your system to where it wont be damaged or to be at its loudest or what? Great find(thanks bry)

 

Kinda both.. its to set your system so that you know what the loudest you can turn it up without Clipping your amps.. and in result damaging your speaker/amps..

techinally when your clipping your subs will play loudered, however they wont sound as good and ill not last long at all.. clipping=blowen sub.


The best way to set your amps would be with a O-Scope, but since most people dont have one, a DMM works for a good alternative.

 

interesting. I think ive got my gain all the way down.... might play with this at some point if im not too lazy to do it.

Oh thats right im selling my subs nvm
-Patrick

 

BestNTx, like bushtree said, its so you know how loud you can turn it up before you start clipping and blow stuff up Now, with most good amps that are underrated, you would be able to set your gains with your volume at say 60, and be able to turn it up a couple more notches before it starts clipping. However there is no way to tell when it starts clipping, so, the best thing to do is just never turn it up past the volume you set your gains at unless you know what your doing and what to listen for.
If you have an amp with a birthsheet that shows a wattage higher than what your amp is rated at, you can use that wattage in your formula, just go a little lower with the number to be on the safe side (say you have an amp RATED at 600 watts, birthsheet says it puts out 720 watts really, you could get by using 700 watts in your formula)

Or as he said, use an Oscope so you can tell exactley when your amp starts clipping, and get the most out of your amp. But, a lot of people dont have an Oscope like he said.

Patman, getting rid of the eDuhs huh What do you plan on replacing them with?