Setting Gain Perfectly

[Annnarbor84 5,000+ posts]

So today i picked up a multi meter but im not quite sure how you use it to set the gain. Looking for some help, Thank you.

You dont need a multimeter, just turn your gain all the way up and let it rip The gain button is a volume button, everyone knows that, duhhhhhhhhh

 

[18lexusowner 10+ year member]

You dont need a multimeter, just turn your gain all the way up and let it rip The gain button is a volume button, everyone knows that, duhhhhhhhhh

good man...

 

[Savag3 10+ year member]

QUOTE=annarbor84;6181717]You dont need a multimeter, just turn your gain all the way up and let it rip The gain button is a volume button, everyone knows that, duhhhhhhhhh

//content.invisioncic.com/y282845/emoticons/wow.gif.23d729408e9177caa2a0ed6a2ba6588e.gif all this time and you finnaly tell me ur secret . . *turns gain all the way up*

 

[James Bang 5,000+ posts]

ears

 

[nineball 10+ year member]

All amps are regulated, some just tighter than others.I don't see why you can't set it with a DMM. Just use a more conservative power number assuming the amp output will fade when/if the voltage fades.

My information came directly from Jason at Cadence. He told me that the txa line power sources were not regulated and they could not be set with a dmm. I did not ask for specifics nor do I claim to know why this is the case but if Jason tells me that I will believe him. He has proven himself on many occasions and his customer service is some of the best that I have ever encountered.

 

[duece212 5,000+ posts]

crank it until something breaks, then back it down a bit

 

[PV Audio 5,000+ posts]

SEARCH!!!!!
but to sum it up

take the max RMS you want to run and multiply it by the ohms it will be running at (ie 1200 watts x 2 ohms) Then get the square root of that product.

On your amp, turn off hp, lp, bb, and turn the gain all the way down and make sure your subs are not connected. Turn your head unit volume the absolute loudest you will ever listen to it at.

Put your multimeter on the + and - speaker leads on the amp and make sure your meter is set to AC. Put on a test tone (most use 50hz) and slowly increase the gain until it as at or very close to the square root you got in the first part. Then set your filters and you're good to go.

Just in case anyone didn't know (it sounds like pretty random math), all this is is ohm's law using the power equivalency P=IV with a substitution. V=IR is ohm's law which means that I=V/R. Plug that into P=IV and you have V^2/R. You're just solving for the output voltage that can make the power you need RMS (maximum output power divided by the square root of two) with the impedance of the sub. Make note to do this impedance calculation with the sub NOT connected to anything or playing as the impedance will be all over the place due to inductive effects.

Just in case anyone was wondering. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[smoka 10+ year member]

Am I the only one who believes an Oscope is the only way to set a gain? There is an exact point in the gain when clipping starts and an Oscope is the only way to find it....

 

[audiolife 5,000+ posts]

Am I the only one who believes an Oscope is the only way to set a gain? There is an exact point in the gain when clipping starts and an Oscope is the only way to find it....

depends on what the material is being played. Simple test tones will work in spl but in sq/daily you are better off using the oscope and DMM as a reference rather than the final say. Different listening material may be recorded at a higher level. This is wherea trained ear comes in mighty handy and its a good idea yto listen to some cd's mps you listen to that you feel are recorded at a higher level so you know as you set the system up. Its a good idea to make sure the tweeters are heard without the subs to make sure you are not going to cook them especially in an active set up if you don't know what you are doing.

 

[soundstreamer 10+ year member]

I think a termlab is a critical instrument when setting the gain...

 

[bdawson72 5,000+ posts]

reading is your friend.....
http://www.installer.com/tech/gains.html

But, but, but. It says o-scopes are a no no. I'd like 2 see a gain tutorial that actually incorperates o-scopes as well.

 

[DNick454 10+ year member]

whats a good mutimeter to buy can i just pick up a craftsman at sears?

There was a sale article in the newspaper I got, bought one from Menards for 4.99 lol. It's nice too, all functions, came with prongs and everything //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[AVSTANG02]

Turn it up till your speakers blow.. then turn it down..

Replace speakers and you should be good to go..

 

[PV Audio 5,000+ posts]

But, but, but. It says o-scopes are a no no. I'd like 2 see a gain tutorial that actually incorperates o-scopes as well.

I stopped reading immediately after the first line of the second paragraph. I can't take anything else they say seriously after seeing that.

 

[PV Audio 5,000+ posts]

******* it, why do people keep spreading around false information? A gain control and a volume control are COMPLETELY different things. If anything, they are near opposites.