Setting gains for 10w7 / HD750.1

[gc76]

I just got a 10w7 in a sealed box hooked up to an HD750.1. Should I get a voltmeter to set the gains properly or is it OK to just do it by ear?

I have everything flat on the HU except sub output is turned up and I have the gains pretty high on the amp. I don't know how to tell what this speaker can handle. From listening by the trunk there's just a little buzz on some notes but inside it sounds clean. Just don't want to blow it.

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[Cruzer 10+ year member]

if u blow a JL sub rated at 750 rms by a JL amp that does 750 rms, at least u know ur money was well spent!

but seriously it should take the gain maxed out i would think

 

[tonka 10+ year member]

Isnt it bad on the amp to have the gains maxxed out? And from what I under stand, your amps RMS should be within 75%-90% of your subs raiting. I suppose to make up for under raited amps and/or over raited subs? and to answer your question, I would just do it untill it souds like you want it.

 

[rosrock 10+ year member]

if u blow a jl sub rated at 750 rms by a jl amp that does 750 rms, at least u know ur money was well spent!
But seriously it should take the gain maxed out i would think

wow

 

[Cruzer 10+ year member]

Ive never came close to maxing my gain out before it sounded good, or was clipping.

I dont see why a manufacturer would make their amp at full gain hurt the amp. What would be the logic behind that? to ruin the amp and the buyer never buy from them again, and pass along that the amp sucks?

if u cant buy a 750rms sub and a 750rms amp from the same company and run it without it damaging something, i wouldnt want it...

i could understand if they were different brands, or even different lines from the same company

 

[tonka 10+ year member]

I was just stating what my understanding to this subject was

 

[rosrock 10+ year member]

ive never came close to maxing my gain out before it sounded good, or was clipping.
I dont see why a manufacturer would make their amp at full gain hurt the amp. What would be the logic behind that? To ruin the amp and the buyer never buy from them again, and pass along that the amp sucks?

If u cant buy a 750rms sub and a 750rms amp from the same company and run it without it damaging something, i wouldnt want it...

I could understand if they were different brands, or even different lines from the same company

u fail

 

[Cruzer 10+ year member]

I was just stating what my understanding to this subject was

no im sure ur right and im wrong, rosrock says im wrong.

Im just stating my opinion.

Just like why do amps come with bass boost when 99% of people say dont use it, its bad for ur subs or amp.

makes no logical sense to put that on the amp then if its bad for either ur subs/speakers, or the amp itself

 

[tonka 10+ year member]

Well its the same reason that car manufactures dont put rev limiters on engins when they are in drive, or why alot of 4 or 5 speed vehicles dont have RPM Tachs on them. So that they break, but technicly it will only break if its being abused so then its not the manufacures fault. But they want the consumer to pay an "approved technician" to fix it, there for resulting in more money for the manufaturer.

And if automotive isnt your thing, Think about this. Why did it take Microsoft so long to fix the "red ring of death" problem on the Xbox 360 eventhough it was common knowlage that the problem was caused by over heating? They knew it was a problem, so then they put out an opptional "intercooler" that you could BUY that would prevent this from happening (I hear it only slowed it down though). They marketed on this problem untill sails whent down, then they acctually fixed the problem.

It all points to one thing. More money for the manufacturer.

Sorry to go on a rant but this is just my 2 cents on the subject.

 

[Cruzer 10+ year member]

All i know is, if i had the setup the OP has, and anything damaged or went bad, i wouldnt buy that brand again... i matched the pieces together by their specs, which should not have any problems.

 

[audioholic 5,000+ posts]

All i know is, if i had the setup the OP has, and anything damaged or went bad, i wouldnt buy that brand again... i matched the pieces together by their specs, which should not have any problems.

Amplifier gains are sensitivity adjustments for the input stage on the amplifier. But before I get to that, let me back up a moment and explain a basic aspect of an amplifier. Imagine the output of the amplifier (watts) as a pushing force. An amplifier.... always pushes with the same force.* Doesn't make sense, right? The amp clearly has more power output at higher volume settings on the h/u. The difference to create that output difference? Signal strength (volts). The amp always pushes with the same force, but the signal voltage of the h/u dictates how much 'material' there is to start with. The amplifier increases voltage, so if the signal to start with is already at a higher level, even though the amp is pushing with the same constant force, output will be higher. This is how your volume knob works, the higher you turn it, the higher your signal voltage in your RCA's becomes (maxing at manufacturer published specs).

Knowing this, the signal voltage your h/u is capable of producing becomes very important. If the amp maker builds the amp to accept only up to 4 volts of signal input before it starts clipping, and your h/u is capable of producing 8 volts, the amp will clip at 50% volume. Conversely, if the amp was built to accept up to 8 volts, and your h/u was 4v, you'd never get the full potential out of the amp. In short, the amp maker has no idea what h/u (and its signal voltage) will be hooked to their amps, so they have to have an adjustable input sensitivity, a 'gain' knob. This gain adjuster allows you to tune the amp's input sensitivity into the potential signal strength of whatever h/u you are running.

So, under most circumstances, you will never need to have a max gain setting to achieve full (unclipped) output from your amp. If you have to turn your gain to max, you must have a really crappy h/u with a very weak signal strength (like a Legacy deck from 1993).

Most manufacturers give you at least a few marks on the knob to indicate voltages. This should get you in the ballpark (because you've looked up your h/u's signal voltage), and you can fine tune it by ear from there by following the sticky (at the top of this forum iirc). It wont get you the optimal gain setting, but it will generally get you close. You can also use the DMM method if you want. Its not a perfect way to set gains either, but some people feel more comfortable trusting math and gadgets than they do their ears. To each their own on that one.

Yes I know, long post. I was in a typing mood.

*ignoring system voltage variance with a loosely regulated power supply

 

[rosrock 10+ year member]

LOL proof i love u man.

 

[Cruzer 10+ year member]

So, under most circumstances, you will never need to have a max gain setting to achieve full (unclipped) output from your amp. If you have to turn your gain to max, you must have a really crappy h/u with a very weak signal strength (like a Legacy deck from 1993).

Like i said, ive never had to turn my gain all the way up before it sounded good.

Also u prove one of my points with your post... If i match the rms of the amp and subs and i damage something all because my head unit uses 4 volt outputs and my amp is designed for 2 volt. That just means that amp sucks...

A good amp should not be designed for 2 volts because they should know there are 4 volt head units out there and to make sure their stuff does not cause problems or fail, they should design for 4 volts.

everyone on this form can prove me wrong, and say im an idiot, but i still wouldnt buy something that fails when everything was matched and installed right.

 

[tonka 10+ year member]

You got it wrong man, the gains are so that you can take that "2 volt" amp and turn down the gain and run it perfectly fine with that 4 volt h/u

and epic post Proof, thanks for that info

 

[Cruzer 10+ year member]

You got it wrong man, the gains are so that you can take that "2 volt" amp and turn down the gain and run it perfectly fine with that 4 volt h/u

I understand that... but if todays head units are being made with 4 volt outputs, amps should be made to handle all 4 volts without clipping...

none of this gay, oh gotta turn gain down cuz amp cant handle it right, or cant turn it up much cuz amp isnt made for 4 volts...