Gain Setting Tutorial

[bimma85 5,000+ posts]

Hey guys, quick ? here. I went to set my gain earlier, and threw a couple different test tones on. With them I got different voltages. I saw most people that mentioned the freq. they used they said 50hz. I saw this is what JL had on their site. I just wanted to make sure this is what I wanted to use. Also, all the test tones on the mention website in the first post... those are at 0db, right? Have another quick question. I have a MTX 1000d(old version of 81000d 1501d etc.) rated at 1000 watts at 12.5V (1158 i think on birthsheet) and rated 1500 at 14.4V. I don't see how 2 volts will add 50% power is this even correct? Anyways I have a 95 bmw 325i and I doubt its running more than prolly mid 13V. What would you guesstimate my power at?? I was thinking about 1300 watts. Thanks in advance e1 has been quite helpful the whole time i've been here. FYI I did search this out but did not find a clear yes or no answer //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif.

 

[95TsiAWD 10+ year member]

Ok Im a little lost on figure out how to do this on my amp.

I have an MTX 2300x amp. Birthsheet shows 660 watts RMS bridged at 4 ohms at 12.5 volts.

So do I put the voltmeter tips on teh bridged channel outputs and use the 660 watt figure?

What voltage should I end up with? I dotn understand the equation.

 

[ANeonRider 10+ year member]

SQRT(660W*4ohms) = 51.4V @ 12.5V

And yes, measure the bridged terminals.

 

[bimma85 5,000+ posts]

Ok Im a little lost on figure out how to do this on my amp.
I have an MTX 2300x amp. Birthsheet shows 660 watts RMS bridged at 4 ohms at 12.5 volts.

So do I put the voltmeter tips on teh bridged channel outputs and use the 660 watt figure?

What voltage should I end up with? I dotn understand the equation.

It would be 660wattsx4ohms=2640 then square root of 2640 approx 51.38V

However if car car runs at more than 12.5 you will be getting more power. I am not positive if u take that into account in the equation(i would assume yes.) Amp is rated 600 at 12.5 and 750 at 14.4 I believe. (oh that amp brings back great days never let go of that baby) If you're running at around 13.8 then your prolly getting about 725-750 but I am not sure on that one for 750 watts. It would be 750x4ohm=3000 then the square root of that which would be 54.77V. I think.

 

[bimma85 5,000+ posts]

Hey guys, quick ? here. I went to set my gain earlier, and threw a couple different test tones on. With them I got different voltages. I saw most people that mentioned the freq. they used they said 50hz. I saw this is what JL had on their site. I just wanted to make sure this is what I wanted to use. Also, all the test tones on the mention website in the first post... those are at 0db, right? Have another quick question. I have a MTX 1000d(old version of 81000d 1501d etc.) rated at 1000 watts at 12.5V (1158 i think on birthsheet) and rated 1500 at 14.4V. I don't see how 2 volts will add 50% power is this even correct? Anyways I have a 95 bmw 325i and I doubt its running more than prolly mid 13V. What would you guesstimate my power at?? I was thinking about 1300 watts. Thanks in advance e1 has been quite helpful the whole time i've been here. FYI I did search this out but did not find a clear yes or no answer //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif.

Bump

By the way long story but went to delete prvious thread as I saw his ? was answered but didnt see a Delete post anywhere. How do delete it?

 

[95TsiAWD 10+ year member]

It would be 660wattsx4ohms=2640 then square root of 2640 approx 51.38VHowever if car car runs at more than 12.5 you will be getting more power. I am not positive if u take that into account in the equation(i would assume yes.) Amp is rated 600 at 12.5 and 750 at 14.4 I believe. (oh that amp brings back great days never let go of that baby) If you're running at around 13.8 then your prolly getting about 725-750 but I am not sure on that one for 750 watts. It would be 750x4ohm=3000 then the square root of that which would be 54.77V. I think.

I think I run just over 14 volts, so should I use the 750 rating and add about 80 to it since th amp is underrated? So 830rms at 14.2 volts maybe?

I have 2 of these amps, the other runs my components, I picked them up from mitek factory outlet for $175 each new with warranty, hahaha.

 

[firearm 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.

I have the test tones and the meter but I don't know what eq settings I will use because I will be installing all new everything and of course can't know what settings I will like. How would one go about setting gains that would allow for eq experimentation? How far under the target voltage should the starting point be without risking clipping?

 

[MikeS 10+ year member]

Hey guys.....trying to set my gains but I'm a little unclear about what voltage I'm shooting for.

I'm bridging my amp with a 4 ohm load at 330w RMS. Since I'm bridging do I use 2 ohms as my load because each channel sees 2 ohms? i.e. sqrt(330*2)

Also, any reason I can't measure this from the end of the speaker cable I'm running to my sub? My amp is hard to get at so it'd be easier to just measure it on the cable.

Thanks!

Mike

 

[MikeS 10+ year member]

Maybe I figured it out. According to the JL tutorial I'd do sqrt(330*2)=25.7*2=51.4. Am I calculating this correctly?

Mike

 

[chefboyrlee 10+ year member]

mike, check out the specs on ur amp. what does it say bridged, 4 or 2 ohms?

 

[DRJDVM]

So the JL audio tutorial says to use a 1 KHz test tone for midrange speakers...

The link for the test tones has up to 80 Hz.........so should I just use that to set the gain for the 6x9's ????

I understand the process for the subwoofer, but want to make sure I get this right for my JL 6x9's too......

I'm running an Alpine head unit with a JL e4300 amp.........

150 W RMS @ 4 ohm (bridged) to drive my 10W3v2D2 subwoofer

45W x 4 @4 ohm to drive my TR690-TXi (6x9's)

 

[nauc 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.

jl says if you bridge an amp, its v=2*sqrt(power*half the resistance)

 

[El_dorado 10+ year member]

ok lets say my amp is a 1051s 2 channel amp fosgate 1050 rms (suppose) at what exactly each gain should have at what volts AC for each please help me out someone on this ??? thanks

 

[El_dorado 10+ year member]

correct yes I'm bridging at 4 ohm load, 32.4 AC volt should be for each gain then for amp .... Hey jmac thanks for the fast help very thankful.....

 

[El_dorado 10+ year member]

ok well my amp has 2 gains, left and right and if I bridge I asumme both gains have to be exactly the same please correct me if I,m wrong is a 1051s fosgate power amp