Gain Setting Tutorial

[swoosh 10+ year member]

Here's something I hope you can will all use to your benefits. As you may or may not have noticed, most equipment dies for one simple reason : Most people push their equipment beyond its limits. Whether its the amplifier or subwoofer or speakers, clipping is the number one cause of failure that I see. To prevent clipping, I've made this tutorial (Well, JL Audio did, but I've been doing this for years before they put it on their site).
Okay, before I post the links, there's just one problem that I have with the following guide. It says to use 75% of max volume. I don't agree with this at all because, with some head units, you can crank it up to full without distortion and with others, it may only be 60% ... To set your gains, use the MAX settings you'd NORMALLY use ... If the loudest you listen to your music at on a regular basis is 22/35 with bass @ +3 and treble @ 0 with MX on, by all means use those settings. Also remember to have the car on //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif It should also be noted that if you want to use bass boost, set it prior to the gains and use the center frequency of the bass boost (45 Hz for most amps) as your test tone ... Please remember that if you have a subwoofer volume control, set it to full before you set the gains on the sub amp ...

Here's the formula you'll need ...

Sqrt(Power*Resistance) = Voltage

(i.e. If you bridge a 4 ohm subwoofer to your amplifier that is rated to produce 100 RMS @ 4 ohms in bridged mode, you would want Sqrt(4*100) = 20 volts)

Gain Setting tutorial ...

http://www.jlaudio.com/tutorials/Input_Sensitivity/Input_Sensitivity.html

Test Tones ...

http://www.teamtreo.com/view.php?showme=Free_Test_Tones

Hopefully, this will all result in greater longevity of your products and cleaner bass. Some people still insist on cranking the gains after using this tutorial because it's "not as loud as it was." If you choose to do so, you may be putting your equipment at risk. If you find that you find the output is too much, feel free to turn the gains down.

Dead link for the gain setting tutorial //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[Decado 10+ year member]

Dead link for the gain setting tutorial //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

http://mobile.jlaudio.com/support_pages.php?page_id=143

and anyone happen to know the answer to my question? ^

 

[swoosh 10+ year member]

http://mobile.jlaudio.com/support_pages.php?page_id=143
and anyone happen to know the answer to my question? ^

Thank you //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[DBfan187 5,000+ posts]

just bought one of these. http://cgi.ebay.com/Velleman-10-Mhz-Handheld-Oscilloscope-HPS10SE_W0QQitemZ7541048099QQcategoryZ104247QQrdZ1QQcmdZViewItem

 

[DIGIDIGIBOMBO 10+ year member]

Hi all, i cannot understand y we must turn off the amplifier built in crossover when setting the gains to reach t he right voltage. Jmac also said that the last step should be the set up of the crossover, but when setting up the crossover we might even increase the voltage that we have reach while setting the gains, and thus we will be into clipping. Can anyone clear up things for me? thx.

 

[DIGIDIGIBOMBO 10+ year member]

Hi again, well i tried setting my voltage while my amplifier built in crossover was set to full, there is( LPF,FULL,HPF), and after i picked the HPF and set the crossover frequencies relying on my hearing(kept turining the HPF level down till i started to have good bass on my speakers), i then tried to put back the 1KHz test tone and the voltage was higher than what i had when the crossover was at Full. isnt it a problem??? I am using 1KHZ test tone for speakers and 45Hz for the subs.Setting the HPF at 45Hz for example means that everything above t he 45HZ will pass and setting LPF at 45HZ means everything under 45Hz will pass?Thx again

 

[Lakota 5,000+ posts]

My Kicker amp's wattage is rated 295x2 (4 ohms) at 14.4 volts and 180x2 at 12.5v. Which wattage should I use for the equation?

 

[alpine3612 10+ year member]

well, whatever voltage your closer too i guess

 

[DIGIDIGIBOMBO 10+ year member]

Anyone can answer my previous question plz?//content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

 

[kuijo 10+ year member]

What kind of speakers you have that you're setting the crossover at 45hz? Whats the slope on the crossover?

 

[DIGIDIGIBOMBO 10+ year member]

Hi no no man, i am not setting the crossover to 45Hz i said lets consider that i set the HPF to a certain value X everything above the frequency X will pass? For LPF if i set it to X..//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif everything under X will pass? and plz anyone can tell me about when i am using the HPF...i used my test tone cd and i got a higher voltage than when setting it when the crossover was off, so its better to set voltage gain when cross over is on? Jmac told me nope, cant undertand y thx again

 

[duece212 5,000+ posts]

Ok, wanted to check a few things. I'm running a lanzar opti 2000d and 7 re8's for a theoretical 1.14 ohm final load. Should I test the actual load with a DMM and use that for my calcs instead of using what the speakers are supposed to be?

Also I'm guessing the calcs for voltage depend on your amp actually doing its rated power. My amp is rated at 1600w at 1.3 ohm (I have a 260 amp alt so hopin it makes that much power)

My calcs with 1600w at 1.14 ohm comes out to 42.7 volts, does that sound right?

 

[DIGIDIGIBOMBO 10+ year member]

yep, i am 99.99% sure this the right voltage(42.7). Once i have used the 1KHZ test tone cd and set the gain, etc...i am finding myself adjusting the bass settings...from the HU with every type of songs. Using the HU settings at which i set the gain level the music of type house is great a the volume level of 45 out of 62. When playing trance, i cannot exceed beyong the volume level of 30, eventhough my initial gain settings were conducted at a volume of 45. Is this normal??? also with low volume recorded music, and music with too little bass i cranck the volume till 50, so the level 45 is not normalized for all kind of music, thus we are relying on our hearing to decide on how to change the HU settings, volume with every song, so whats the purpose of doing the voltage stuff and using a DMM to set the gain...:S

 

[norcalSRTrida 10+ year member]

after reading the JL tutorial and jmac's...im still lost.

i let some1 else set my gains last time, and i blew my avalanche. so its getting reconed as i speak.

when i get it back, i plan on setting everything myself.

1st off, i want to set it so my subs seeing a lil less than its rms ratting (800w), so at around 700-750w. with that being said and me using a 1000w amp @ 1ohm...

SqRt(750*1) = 27.39v

and with me knowing that, do i start off by setting all my eq's and bass boost, etc at 0 and then set my Max playing vol.? or do i need to set my eq's and such 1st, then check my output reading?

and i check the readings while a 50hz sine wave is playing at my max playing level correct?

tia

-mike

 

[tRiGgEr 5,000+ posts]

Set your EQ to what you normally have it set to when you set the gains. You really should not ever use the Bass Boost.

Everything else //content.invisioncic.com/y282845/emoticons/thumbsup.gif.3287b36ca96645a13a43aff531f37f02.gif