Gain / Frequency / Bass Boost Settings

[NViejeP]

I had a few people briefly explain to me what gain is. However I still don't really know how to set it.

Right now my Kicker KX550.3 is sitting in my trunk powering my JL Xr650CSi components. They set the gain + frequency when they installed it.

However, I'm goign to be on my own instaling my sub, is there a tutorial on how to set gain, frequency, and bass boost settings? Do I just tune it to what sounds the best?

[JL Man]

gain controls the watts driven to the speakers. freq allows you to only let certain freqs thru. bass boost i can't really explain, but it is self explanitory. it boosts your bass. makes is louder basically.

[lotas]

Gain really should be labeled input sensitivity (as JL does). The purpose of the "gain" knob on the amplifier is to match the amp's input with the HU's output. Just don't think of it as a volume knob. Goto JL's site, under Tutorials they should have a gain setting tutorial. Like I said though, they will call it input sensitivity.


As far as frequency goes it's really quite simple. Do you understand the range of frequencies from, say, 20hz - 15khz? The sub plays approx. 20hz - 80hz (obviously it depends on the setup, but just for sake of arguement) and then you have your midbass, midrange, then your tweeter kicks in at the high high frequencies. The higher the frequency, the shorter the wavelength, this is why the bass goes BOOM (its got a low frequency, so a long, stretched out wavelength) and the tweeter sounds like a little mouse squealing away (very short and rapid wavelength). So when setting your crossovers, you might be using one on the HU, and then the one on the amp. Do whatever you'd like, but just realize you only want to give your sub the frequencies it's meant to play (the lower frequencies, usually around 80 and below, so a lot of people will set their subs LOW PASS filter around 80hz) and then in turn you can set your speakers HIGH PASS filter either on 80hz, or (and this gets a little more complicated, so I'll just mention it) you can set it around 100hz and let the overlapping occur between the 80hz and 100hz (I can't think of the damn name for it). Anyways you set a high pass filter on your speakers because they are NOT designed to play those low low bass notes, hence why I get in my buddy's car, running his 6x9's off his HU and pretty much clipping his amp in his HU simultaneously, as his speakers are loose as a ....well, in conclusion you dont want your speakers doing things they shouldnt So you take care of them and you give them a lovely little HP filter.

Sorry if that confused you more, its really really late and I'm running on an empty stomach, and sorry if I mixed anything up with freq/wave you fellow physicists. Correct me please!

[JL Man]

yeah lotas got good and deep for ya . . . i learned more things also, thanks man

[Robert Wollenberg]

If you turn your gain up higher than where it should be, it sounds like your amp is getting lowerder which would lead you to believe you're getting more power output to your speakers. And in a sense you are. But what you're doing is redusing the headroom of the amplifer. And that's not good.

If you have the gain set where it should be, probably closer to being turned all the way down, when listening to soft music and there's suddenly a loud part, the amp has the ability to jump up its output and reproduce that louder part as it's recorded.

If you crank up the gains and play that same piece of music, you've reduced the headroom so much that when it comes time to play that loud piece of music the amp is already maxed out and can't increase it's output for that particular piece. The amp just can't get any louder and also is probably cliping really bad.

don't think of your gain as a volume control. That's not what it is. It's more of a gate. Like a toll booth area on the interstate. If you only have one lane open, traffic will back up and the booth area won't be as effective. But if you open all the lanes, now traffic is fighting for position for the two lanes of highway and causing all sorts of problems and accidents. So you only open enough lanes so that you can pass through the most cars you can without backing up too much traffic or causing accidents on the other side. How was that? lmao

[JL Man]

lol, that was a nice analogy. and a rather well explanation

[Robert Wollenberg]

Thanks. Gain is something that gets misused and abused frequently. Back in the day we used to set the gains then superglue them in place so people couldn't mess with them. lol.

[JL Man]

lol, the gain on my 4-channel goin to my subs in turned up a good bit because the subs are only getting 75watts each when they are supposed to get 300

[JL Man]

if gain is turned down all the way on a jl which produces the same watts at 11-14 would you still get 75watts rms if the gain is all the way down??

[High Society]

Thanks. Gain is something that gets misused and abused frequently. Back in the day we used to set the gains then superglue them in place so people couldn't mess with them. lol.

what happens, if there HU goes dead and they get a new one? Good luck setting the gain now :)