Help with proper amp gain Setting

[phillyflapjak 10+ year member]

Hey everyone maybe someone can help me here. I need to set my gain on my amp correctly but dont know exactly how. I heard that your suppose to match the voltage from your deck on your amp? is that true?

I have a sony xplod MEX BT-2700 deck the pre-outs are 2volt

I have a Alpine MRP-650 MONO Block amp

The gain dial says this min. (which is all the way down) then 2 notches then the 3rd notch says norm. the 4th notch says like .04 then another notch and then max . Sorry if that confuses you guys. In the alpine manual the min. on the gain dial is 4V so which notch do i set it at?

My sub 2010 Kicker cvx 12.

Please help if you can

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[Carnivorous18 10+ year member]

From what I understand really the gain is how much power you have at each volume level. The higher the gain, the more power you'll have at each level. So say the level 1 volume. At low gain you get a low amount of bass. Say at the the 4th notch your gona get alot of bass even at volume 1. I kinda like to even it out so the sub dont overpower everything. Maybe a little higher. You have to be careful though as setting it too high could break your amp. I suggust never maxing out your gain. So long as you have good electrical maybe keep it at that 4th notch or lower. Hope this helps

 

[randpost 10+ year member]

Line drivers are pretty cool. instead of adjusting the gain, you can just adjust the the voltage your RCAs are pushing. People say I shouldn't, but I like having the ability to adjust my RCA voltage and Bass boost while driving. I also like the sound my subs produce through the line driver. I know that this isn't a line drivers purpose, but it works. can raise my stock RCA 4v to 10v.

:x

 

[Carnivorous18 10+ year member]

Aint that kinda what a bass boost remote is for though?

 

[randpost 10+ year member]

bass boost will increase the bass, yes. a line driver will increase RCA voltage which does a few things for the signal. more voltage, cleaner signal. higher voltage also reduces any electrical interference. I much rather increase my RCA voltage than increase the gains on my amp.

My original intent when I purchased the Line driver was just to boost my 4v preamp output to 6v, but having the unit mounted in the dash has me adjusting it all the time. I really shouldn't though, buts its fun to mess around with it along with my bass knob.

 

[ctt0002 10+ year member]

How To: Set your Amplifier Gain - SSA Car Audio Forum

 

[phillyflapjak 10+ year member]

Well i believe turning the gain up make the voltage to the sub go up correct? If i turn the gain up to much i could fry the sub.

I am getting confused in the kicker manual it says the gain setting is used to match the voltage from your head unit. Sense my head units pre-outs are 2volts i would have to match 2 volts correct? because when i look at all these tutorials about tuning your amp they have like 37 volts and stuff like that

 

[bubbagumper6 5,000+ posts]

My god...so much bad information...in one thread...makes my head hurt

OP follow this link, set your gain properly. Those notches mean nothing. You could have an HU with a 2v preout and have to turn the gain up pretty far, or your HU could have 8v preouts, in which case you wouldn't have to turn the gain up very much at all. The gain is simply there to match the output voltage of your HU, so you get normal power from the amp. If you just set it wherever the hell you want you'll likely be clipping it and cause either the sub, amp, or both to fry.

How To: Set your Amplifier Gain - SSA Car Audio Forum

 

[phillyflapjak 10+ year member]

OK thanks bubba ive been hearing mixed things about what gain really is

 

[outsideshot23 10+ year member]

From what I understand really the gain is how much power you have at each volume level. The higher the gain, the more power you'll have at each level. So say the level 1 volume. At low gain you get a low amount of bass. Say at the the 4th notch your gona get alot of bass even at volume 1. I kinda like to even it out so the sub dont overpower everything. Maybe a little higher. You have to be careful though as setting it too high could break your amp. I suggust never maxing out your gain. So long as you have good electrical maybe keep it at that 4th notch or lower. Hope this helps

Not this. you are right in your original post. have to matcht he gain with output. My d9's are set at 1/4 gaina nd thats where my best numbers are because my deck puts out so much voltage... so the higher you turnt he gain the louder you are is not necessarilty true

 

[Databyter 10+ year member]

Your confusing yourself with the reference to matching the voltage from your HU.

Yes, the gain adjustment is used to make sure the signal from the Head Unit Preout (regardless of the voltage) is pushed up to match what the amplifier primary circuit wants to see.

So, You're not trying to "match" 2 volts, your trying to "compensate" for it.

Just another example of someone who really knows what they are talking about using the wrong language in a manual or a tutorial and thereby confusing someone who doesn't know what he means and can only go by what he actually is saying

Your not trying to match 2 volts. Your trying to set the gain whether it is 2 or 4 volts or whatever so that it looks exactly the same as what the primary circuit on the amp. wants to see as it's starting point (voltage).

Also despite what some have said you want to have the gain as low as possible, if it's too high you will have more volume, but you will also reach a point of distortion, clipping and overdriving that pretty much defeats the purpose of having an amp in the first place. If your amp can't do what you want at the right gain setting, then you need to buy a bigger/better amp, period.

The advantage of higher voltage pre-outs is that the gain at the amp can be set lower, so any extraneous noise that it picked up from the head unit, or from the car which is also amplified, will be amplified less.

In other words, the signal to noise ratio will always be higher when the signal level is higher while the noise remains the same.

A 4 volt preout will have twice the headroom over the noise level as a 2 volt system. But in practice, every car and every HU has a different level of electrical noise, so you can get fine results from 2 Volts out if you use good cables and your HU is decent. With 4 Volts it's just that much better and that much easier to keep the noise threshold below audible.

By the way I have that head unit also, I'm thinking of upgrading though, I want to have 6 channel pre-outs at 4 volts and a built in HD radio. But so far it's served me well, it's just that I have 4 speakers and a sub, and with only 2 sets of preouts I will lose my ability to use the fade on the headunit for the 4 speakers.

 

[phillyflapjak 10+ year member]

Hey Databyter thanks for clearing that up. I have been told by many Audio professionals that 4 volt pre-outs are better like you said with the whole distortion thing. Now i no that i dont need to match 2 Volts like my Sony HU has. Well maybe you can help me databyter just by experience.

My Alpine MRP-650s gain is set to the first notch past minimum, My LP Filter is set to like 75hz and my Bass Boost is set to a little over half way. Do you think off the top of your head that i may be clipping? i keep my volume at like 21 and i think the max is like 40 or 50. My sub is a 2010 Kicker CVX 12 2ohm