Gains maxed. Is this normal?

[kingsxman 10+ year member]

Quick question on gains. I've got a Profile AP1040 4 channel (80 watt rms) running my fronts and rears. Fronts are Infinity Reference 75 watt rms speakers and rears are Alpine SPR-69LP 55 watt rms speakers. In setting my gains on the amp I set my volume on the deck at 3/4 of max. Then I slowly adjusted the gain until the speakers started to distort....whicn they didnt. They didnt distort and I'm almost all the way up on the gains. Does this seem right? I'm just wondering if its normal to be able to run your gains almost maxed.

BTW its pretty friggin loud. Sound isnt bad at all. I read through the gain tutorial a bit but thought I'd try the manufactures recommended way first. I was unable to find test tones for setting the gains via the tutorials method.

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[ProjectPat06 10+ year member]

if the amp doesnt put out shit

 

[UndercoverPunk 5,000+ posts]

if the amp doesnt put out shit

.... um.... wrong.

Set your gains with a DMM kingsman.

 

[avs20 10+ year member]

Read the gain setting tutorial again..and do it that way. For test tones go to http://www.realmofexcursion.com/ and click on downloads. Jmac put every test tone you could ever need on there.

 

[Beat_Dominator 5,000+ posts]

If they really are all they way then you're going to have to do it the DMM way.

 

[squeak9798 5,000+ posts]

The question no one has asked yet;

What headunit are you using?

If it's a low voltage output headunit, then it is not unlikely that, when using music, the gains are set close the maximum. If you, for example, have a 2V output headunit and are using music to set the gain.....you're probably only getting a maximum of around .5V RMS out of the headunit since most music is recorded around -6db (which means output voltage is reduced by a factor of 4 compared to 0db). And since most amps maximum gain setting (minimum input) is around .2V, you can see why it would be set so close to maximum.

Either that, or your deaf and don't know what distortion sounds like //content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[kingsxman 10+ year member]

The head unit is a Pioneer DEH-7400 MP. No idea what that puts out for voltage.

So if these are full range speakers that the amp is driving...(well....probably everything above 120 hz) what test tone would I use to set the gain?

 

[JimJ 5,000+ posts]

1KHz...

 

[kingsxman 10+ year member]

THanks. OK....I'm gonna ask a real dumb question:

What is the purpose of setting gains? I know its to match the voltage level from the deck to the amp. But...what does it give me? Reason I ask is that if I'm running the gains maxed already...and I'm not getting any distortion with deck at 3/4 volume....whats it gonna give me to set them properly?

 

[DIGIDIGIBOMBO 10+ year member]

Maybe yeah ur not getting any distortion, but what if ur overpowering ur speakers, if the amp is good then u can overpoer the speakers without having distortion, maybe with time the speakers will be damaged. I tried to set my gains like u did and beleive me i didnt hear distortion , and specially with the subwoofer it very hard to notice it. When i used the DMM i realized i was so f...g overpowering them.

 

[kingsxman 10+ year member]

I might be overpowering them...but if they can handle it....why not? Is there a sonic difference at the correct input voltage level? not trying to be a smart ***. Just wondering.

 

[squeak9798 5,000+ posts]

I might be overpowering them...but if they can handle it....why not? Is there a sonic difference at the correct input voltage level? not trying to be a smart ***. Just wondering.

If your gain is set too high, then you will allow the amplifier to clip. Which will sound like poop and possibly damage your speakers.

If your gain is set too low, then you are not allowing the amplifier to be driven to full output.

 

[Bake 10+ year member]

I might be overpowering them...but if they can handle it....why not? Is there a sonic difference at the correct input voltage level? not trying to be a smart ***. Just wondering.

As long as you are giving them a clean unclipped signal you are not likely to hurt the speakers by giving them a little extra power.

 

[kingsxman 10+ year member]

FYI, I did the gain setting tutorial today and tested my gains on the 4 channel profile with the 1khz signal and a voltmeter. After getting false readings the first time because one lead fell off the output of the amp (DOH!!) I found that my voltage level needed of 18.4 volts was.........pretty much where I had it! about 85-90% of max. Funny.

Guess it must be right.

 

[kingsxman 10+ year member]

Volume on my head unit was set at 75% of max when I checked. I dont think I want to run this any hotter as it already is a bit of a pain having so much "play" in the volume control. i.e. I want to turn the volume down I gotta roll the dial quite a bit to get a noticable drop. The higher you run your volume when you set your gains the more likely you are to run into that I would think.

I actually may have to turn the gains down a bit anyway. I set my sub level also (Profile 600 msx) via the tutorial method. I'd been runnig the sub amp quite a bit higher than it should be. Now, my fronts and rears are overpowering the sub so I should bring the 4 channel down a bit so my levels are matched better.