Cant get gain right (dmm)

 

Bronze Member
Username: Schinner

Post Number: 24
Registered: May-07
so ive got my subs in and the amp in and sounds good but im trying to set the gain and i cant get it right.

my dmm reads only like 3volts when my target is 38volts.....any ideas?
 

Gold Member
Username: Nd4spd18

Southeast PA

Post Number: 2469
Registered: Jul-06
Are you using a 50 hz 0 db test tone?

Are ALL settings on your HU turned off or set at zero?

Is you HU's sub level all the way up?

Is your meter on AC voltage?



^^^^^

Those are the mistakes people usually make.
 

Bronze Member
Username: Schinner

Post Number: 25
Registered: May-07
yes

yes

? sub level ?

yes
 

Gold Member
Username: Van_man

Boston South, MA

Post Number: 2391
Registered: Mar-06
have the ddm on ac volts? voulume 3/4 up? on the right ddm scale?
 

Gold Member
Username: Nd4spd18

Southeast PA

Post Number: 2470
Registered: Jul-06
Some HU's have a level adjustment for the sub outputs. It yours has it, it needs to be all the way up.


Also, check that the LPF on your amp is set to about 80-100 hz.
 

Gold Member
Username: Naledge503

Http://com4.runboard.c...

Post Number: 1338
Registered: Jun-06
subs disconnected from amp?
 

Gold Member
Username: Mgbcs

Maple Grove, Minnesota

Post Number: 1341
Registered: Dec-06
I have the EXACT same problem and it's pissing me off. I'll be watching this thread closely lol
 

Bronze Member
Username: Kpa2727

Post Number: 71
Registered: May-07
the only way this reading ever happend to me , the crossovers or a eq was on. even though i assume your smart enough the subs MUST NOT be connected. the volt meeter should be on ac voltage like this.Upload
 

Silver Member
Username: J_c_wheeler8

Columbus, IN United States

Post Number: 578
Registered: May-06
Yea... I never got mine figured out either...
 

Bronze Member
Username: Schinner

Post Number: 26
Registered: May-07
alright im thinking you put hu up to 75% cause thats where most ppl listen to it at....so i set mine at where i usually have it...volts are seriously 3....with loudness on it jumps to about 38, with bass boost too.

cant i just set the gain to match how i usually listen to it at....

hu vol 15 out of 50
loudness on
bass boost at about 9


????? sounds right when i adjust to match where i usually listen to it at.
 

Gold Member
Username: Johnfiac

A-ToWn, Kingkong ain... I got Chuck ...

Post Number: 2849
Registered: Mar-06
burned out amp? i had that problem with a crossfire 1000d....i bought used
 

Bronze Member
Username: Kpa2727

Post Number: 78
Registered: May-07
hu should be a 45 percent, 3/4 = 3 out of 4th way up so like 4 of 25 % = 100% so yes 75% up.
 

Gold Member
Username: Ctmike

Ct.

Post Number: 4374
Registered: Feb-06
you set the gain with the volume that low, everytime you start cranking it you'll start clipping.
 

Bronze Member
Username: Schinner

Post Number: 29
Registered: May-07
thats the thing....with loudness on its loud at 15...hu is crazy, 20 is cranked.

i think the amp is fine....when i adjust the gain so its at 35 volts at 15 with loudness....the subs pound! without clipping!
 

Bronze Member
Username: Schinner

Post Number: 30
Registered: May-07
okay....dont you set the gain with the hu around the 3/4-highest vol lvl you will have it at????
 

Gold Member
Username: Nd4spd18

Southeast PA

Post Number: 2486
Registered: Jul-06
Kyle:

When setting gain, bass boost of OFF, loudness is OFF, and volume is at 3/4 of maximum (if 50 is max, it should be at 38).


IT DOES NOT MATTER WHAT SETTINGS YOU USE FOR NORMAL LISTENING
 

Gold Member
Username: Nd4spd18

Southeast PA

Post Number: 2487
Registered: Jul-06
Follow this tutorial:

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


It works for all amplifiers, just ignore JL's voltage table and use the voltage you calculated.
 

Silver Member
Username: Big_edge_head

Milwaukee, Wisconsin USA

Post Number: 143
Registered: Mar-07
hey, i set my gain with the loudness on but with no bass boost and my subs are perfectly fine. (2 12'' audioque sd2.5s) if you put your loudness on before u set your gain it will be fine. u just wont be able to turn up the volume nob as high as before. i used to turn it up to 40 when i had the gain set without loudness but then i reset the gain with the loudness on and i turn it up to 35 and never higher. it sounds better too when loudness is on.

another thing: as soon as your subs dont get any louder when turning up the volume thats when it starts clipping. so if you turn it up to 35 and the then try turning it up more and it doesent get any louder than when the volumes at 35 then your clippin the signal.
 

Gold Member
Username: Nd4spd18

Southeast PA

Post Number: 2490
Registered: Jul-06
^^^^^ Both of these things are not true

1) Loudness must be off when setting gain. If you knew what loudness does and how it works, you would know why. I really don't want to write an essay explaining it here.

2) You cannot hear clipping until there is a large amount of it. The only way to ensure that the amp does not clip is to set the gain properly.
 

Bronze Member
Username: Schinner

Post Number: 35
Registered: May-07
alright thank you M.S.

ill do it that way...

but after setting it right...can i still use loudness or no??
 

Silver Member
Username: Big_edge_head

Milwaukee, Wisconsin USA

Post Number: 144
Registered: Mar-07
well, all i kno is that my subs are fine with loudness on and the gain is set right
 

Silver Member
Username: Big_edge_head

Milwaukee, Wisconsin USA

Post Number: 145
Registered: Mar-07
well, all i kno is that my subs are fine with loudness on and the gain is set right. another person on this site agrees with me too. i forgot who tho. maybe snarl?
 

Silver Member
Username: Imalik

SD2.5......ED9.1=Boom, New Jersey Audioque...N...

Post Number: 319
Registered: May-06
Ed thats not correct reset your gains with the loudness off...True they may sound good now, in the long run you can damage your Subs and or amp
 

Silver Member
Username: Big_edge_head

Milwaukee, Wisconsin USA

Post Number: 146
Registered: Mar-07
my gain is fine drivingreckless agrees with me too. i have bass boost unpluged from my amp and bass at 0 on HU. subs never run hot. always sound fine.
 

Gold Member
Username: Nd4spd18

Southeast PA

Post Number: 2526
Registered: Jul-06
Ugh, damit I guess I'm gonna have to explain it:


Lets start with understanding what loudness does. It is an equalizing function. And a bad one at that. It boosts low and high frequencies and cuts midrange frequencies. It is the equivalent of setting an equalizer in a "smiley face" pattern, which is almost never the correct setting for a system to give a flat frequency response (this is the goal for a system to sound good).


Now, on to why having equalization in effect is wrong for setting amplifier gain: When you set your gain, you play a test tone of a frequency within the range that the amplifier will play. 50 hz is the standard to use for sub amps b/c it is almost always within the frequency range that the subs will play. However, any frequency within that range will work. For example, if your subsonic filter is set to 30 hz and your LPF is set to 85 hz, any frequency from 30 to 85 hz will work, b/c that is the range of frequencies that the sub amp will play. It will not matter what frequency you use within that range.

Now, remember how the loudness function boosts some frequencies and cuts others? If it is enabled when setting the amplifier gain, you will get a different reading on the DMM depending on what frequency you use. If you use a frequency that has been cut, you will set your gain too high and the amp will clip when playing frequencies that have been boosted. On the other hand, if you use a frequency that has been boosted, you will set the gain too low and will not get full power from the amplifier.

This is why loudness, EQ, and anything else the alters the signal must be off when setting the gain on an amplifier.
 

Gold Member
Username: Van_man

Boston South, MA

Post Number: 2417
Registered: Mar-06
a flat frequency response

OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO

NOT a flat frequency response

O....................O
.O..................O
..O...............O
...OO.........OO
.....OO......OO
.......OO..OO
........OOO


Lol, Good Explination MS
 

Gold Member
Username: Nd4spd18

Southeast PA

Post Number: 2538
Registered: Jul-06
lol


Thanks Marc.
 

Silver Member
Username: Imalik

SD2.5......ED9.1=Boom, New Jersey Audioque...N...

Post Number: 323
Registered: May-06
I dont think anyone is going to change Ed's mind... one person agreed with him and thats all he needs, no matter how many ppl tell him that he is incorrect
 

Gold Member
Username: Nd4spd18

Southeast PA

Post Number: 2544
Registered: Jul-06
I really don't care what he thinks, lol.


I wrote that so that nobody else reading this thread would take incorrect advice.
 

Silver Member
Username: Imalik

SD2.5......ED9.1=Boom, New Jersey Audioque...N...

Post Number: 327
Registered: May-06
I was just making a comment in just, not speaking to you directly,LOL
 

Silver Member
Username: Mash4kash

Lafayette, LA

Post Number: 293
Registered: Feb-06
is bbe the same as loudness?
 

Gold Member
Username: N2audio

Lawrence, Ks USA

Post Number: 1314
Registered: Mar-04
if the "loudness" function Edge is referring to is really "loudness" then at high volumes it shouldn't have any effect, and I don't see a problem with setting the gain with it on - assuming the volume was high enough that it was inactive, and at ~75% I would guess that it was.
 

Gold Member
Username: Nd4spd18

Southeast PA

Post Number: 2578
Registered: Jul-06
The only "loudness" I've seen is the equalization function..... are you talking about something else?
 

Bronze Member
Username: Cutthrote

Post Number: 23
Registered: May-05
Nobody ever seemed to answer Kyle's last question and since I am curious to know the answer as well I'll bring it back up.

After setting the gains of an amp using the method of EQ's set to flat as well as any boost or loudness options turned off, can you use these features after setting the gain? If so, it seem that this would defeat the purpose of setting your gain using this method since they would probably increase the voltage readings after they are adjusted.

Most people seem to just say "set your gain with everything off" but never seem to talk about what should or shouldn't be adjusted after this point when your actually listening to music
 

Gold Member
Username: Nd4spd18

Southeast PA

Post Number: 2605
Registered: Jul-06
Bass boost should always be off...... it creates a peak at one specific frequency. Not a good effect.


Of course you can use your EQ. Just remember that the proper way to EQ a system is to cut frequencies that are too loud before boosting frequencies that are too quiet.
 

Bronze Member
Username: Cutthrote

Post Number: 24
Registered: May-05
Another question

On receiver's with a sub level, such as my pioneer in dash, why should the sub level be all the way up. I've read the explanation concerning Alpine receiver's, but Ive never read any explanation or instructions to do this for all units? Are you saying that all bass boost or bass level controls should be off (or at the lowest position)... specifically the one's on an amp itself and the bass control knob that can be connected to the amp
 

Silver Member
Username: Big_edge_head

Milwaukee, Wisconsin USA

Post Number: 150
Registered: Mar-07
i kno that most people say that u have to turn everything off. but when my loudness is on i dont see any diff. with diff. frequencys at all. its just not a muffled sound and it sounds more clear with it on.

but people that do set there gain with everything off do they turn on the loudness and custom EQ once the gain is set?
 

Bronze Member
Username: Cutthrote

Post Number: 25
Registered: May-05
Anybody want to take a stab at these last few questions?
 

Gold Member
Username: Nd4spd18

Southeast PA

Post Number: 2635
Registered: Jul-06
" Are you saying that all bass boost or bass level controls should be off (or at the lowest position)... "

Off or at 0 (not + or - anything)




" why should the sub level be all the way up "

It attenuates the sub outputs as you turn it down. All the way up is the normal setting for a sub level control and that's where it needs to be when setting the amp gain.




" i kno that most people say that u have to turn everything off. but when my loudness is on i dont see any diff. with diff. frequencys at all. "

Did you actually make that test by disconnecting the speakers, connecting a DMM to the amp, and playing different frequency test tones with the loudness enabled? My guess is no.
 

Silver Member
Username: Big_edge_head

Milwaukee, Wisconsin USA

Post Number: 153
Registered: Mar-07
but when loudness is off my front speakers sound all muffled and not very clear same with the subs
 

Gold Member
Username: Nd4spd18

Southeast PA

Post Number: 2707
Registered: Jul-06
Your speakers must not be very good if the treble has to be boosted (what the loudness does) that much to get them to sound good. Either that or the systems frequency response is really far off and needs to be properly equalized.
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