Setting gains with DMM

[thizzkid 0]

hey everyone, so today i went to harbor freight tools, got a DMM on sale for 3.00 dollars, the name brand was cen-tech, heres the link CEN-TECH MULIMETER

so anyways i got home, logged on, looked on the stickies for the Setting gain with DMM tut and i done everything i was suppose to, minimized HU Settings,bass,treble,etc, used a 50 hz tone 0 db, and when i connected the DMM to the speaker output with no load, i had to set the gain almost at 3/4 to get my voltage

i have a hifonics bxi 1200 watt amp at 1 ohm load on 2 12" pioneer 308D4 rated at 400 rms per sub

HU is kenwood MPC205, 2 volts at sub pre-out

1200 wrms at 1 ohm load

so 34.64 Volts is what im striving for on my dmm right? For some reason my meter can only read up to 3 digits for example, when i set my gain 3/4 up, i get to 34.6 volts as a reading on my DMM, is that ok? i dont want to overstress my amp, so would lowering the volts to 33.6 be safer on my amp?

and by the way i forgot to mention that the DMM can read ACV at a 750 volt scale or a 200volt scale and i set it to 200 volt scale is that ok?

thanks again guys

Edited March 4, 2010 by thizzkid

[CrazyKenKid 64]

lower is always better! and safer

keep in mind your gain is set so high due to the low preout voltage forexample my gain is set about half the way up and i have a saz2000 and i have all 2krms pushing 1-15inch ns my h/u is a jvc avx88! (5v preouts)

so it is a trade off high preout voltage= lower gain settings (less stress) or lower preout voltage= high gain settings

overal setting to the lower voltage is what ... 20rms difference? overal the stress isn't to be worried about now if you had the gain set full out the signal COULD (most likey) be clipped send a garbage signal to your subs

[thizzkid 0]

thanks CrazyKenKid for the feedback, so with that all being said, im pretty much set on my gains,

one other question, lately my cars been smelling like the new subwoofer smell, i havent push my subs to hard since its still pretty new, is that normal?

[CrazyKenKid 64]

yes sir! with any and ALL new subs you get that small for ... say 2-4wks ish! it is my favorite smell so far lol!!

[jcarter1885 995]

thanks CrazyKenKid for the feedback, so with that all being said, im pretty much set on my gains,

one other question, lately my cars been smelling like the new subwoofer smell, i havent push my subs to hard since its still pretty new, is that normal?

Yeah that is just the glue burning from the sub, your cool but if you keep smelling it and for long periods of time its not glue and probably voice coils (means your reaching the subs thermal handling rating).

[thizzkid 0]

hell yea super fast response, thanks for the input guys deeply appreciated SSA FTW!!

[Duran 387]

hell yea super fast response, thanks for the input guys deeply appreciated SSA FTW!!

We know

[Typicaljawaiian 3]

Now, to set the gain(s):

1. Start the vehicle, and pop the test tone CD in the head unit.

2. DO NOT hook up the sub(s) or speaker(s) to the amplifier while doing this, just leave the outputs unused at this time.

3. Now, time to set up the head unit.

a. If the loudest you listen to your music at on a regular basis is 22/35 with bass @ +3 and treble @ 0 with MX (or any other sound processor) on, use those settings. NEVER turn the headunit above 3/4 of the maximum volume.

b. Remember to have the car turned on.

c. If you want to use bass boost on a sub amp, set it prior to setting the gains on the amp and use the center frequency of the bass boost (45 Hz for most amps) as your test tone.

d. Please remember that if you have a subwoofer volume control on the headunit and/or a bass knob for the amplifier, set it to the maximum before you set the gains on the sub amp.4. Take the leads from the DMM and but them on the outputs from the amp.

5. Set the gain so that the outputs of the amplifier equal the voltage you found above. This is a MUST.

Just wanted to verify what was correct. Because I just did this process yesterday. In the OP the person said he lowered all his HU settings. Maybe thats why he hed to set his gain so high.

When I did my amp, I had to turn my gain all the way down and still could not get the voltage. So my gain is all the way down now and I also had to lower HU settings.

My testing went like this

JL Audio 1000/1 pushing Fi BL 15'' Loaded (dual 2 ohm) wired to 4

Pioneer AVH-3100 DVD (2 din) 4 volt output

First Test

Main Volume - 28 out of 40

Subwoofer Volume (level) - +6 (-24 to +6), it says to max this out

Bass Boost - Off

Bass Knob - All the way down

Amp Gain - Half

Results - 98.7******* volts

Second Test

Main Volume - 28

Subwoofer Volume (level) - 0

Bass Boost - Off

Bass Knob - All the way down

Amp Gain - All the way down

Results - 74.3******** volts

Final Test

Main Vol. - 28

Sub Vol. - -4

Bass Boost - Off

Bass Knob - Fully Down

Amp Gain - Fully Down

Results - 62.********* volts

I will run my system like this untill I can put it on an O-Scope. I have reconed the BL once, and I know it was because of dirty signal.

[thizzkid 0]

well yea i followed those instructions, my settings on the HU when i setted it was -8 bass, -8 treble. After i setted the gain with my DMM, i turned the treble up to 0.

[Typicaljawaiian 3]

Where was your volume set at. Tutorial says to have it at the loudest you'll listen to it, but not to exceed 75%. Also have all other settings where you usually set them on a daily basis before setting the gain (sub level, bass, treble, etc). Also if you use bass knob turn that all the way up.

[thizzkid 0]

I dont use the bass knob, heard from to many people that it increases distortion, IE, the dirty signals, so i keep it off. My HU maxes at 35, so the max i go up to is 26. When i did my gains with the DMM, 26 was the highest i went on my HU with the 50 Hz tone on repeat

[Typicaljawaiian 3]

I think basically, the thing to do is have all your settings in thier normall daily positions. Set your HU volume at around 75% of max (or max listening volume) then go ahead and set gains.

Yeah, as for why you had to set your gains so high, maybe cause your HU output is 2volt.

Find an O-Scope. That's what I'm gonna do.

[Typicaljawaiian 3]

well yea i followed those instructions, my settings on the HU when i setted it was -8 bass, -8 treble. After i setted the gain with my DMM, i turned the treble up to 0.

Have these settings at normal daily driving levels before setting the gain. If your daily setting for bass is -8 then your good. Also, do you have a seperate subwoofer volume control on your HU. If so turn that all the way up before setting gains

Now, to set the gain(s):

1. Start the vehicle, and pop the test tone CD in the head unit.

2. DO NOT hook up the sub(s) or speaker(s) to the amplifier while doing this, just leave the outputs unused at this time.

3. Now, time to set up the head unit.

a. If the loudest you listen to your music at on a regular basis is 22/35 with bass @ +3 and treble @ 0 with MX (or any other sound processor) on, use those settings. NEVER turn the headunit above 3/4 of the maximum volume.

b. Remember to have the car turned on.

c. If you want to use bass boost on a sub amp, set it prior to setting the gains on the amp and use the center frequency of the bass boost (45 Hz for most amps) as your test tone.

d. Please remember that if you have a subwoofer volume control on the headunit and/or a bass knob for the amplifier, set it to the maximum before you set the gains on the sub amp.

Edited March 5, 2010 by Typicaljawaiian

[thizzkid 0]

when im bringing home more money, ill take a O-scope into consideration, but as of right now, i think the DMM is doing just what i need, I AM A redo my gain settings, i need to set the treble before i start adjusting the gain.

SSA FTW! thanks guys

[TRP 42]

I bought the same DMM!!! Thing broken the second i opened the package!!! HAHA!!! Oh well still alright! GL with the settings!

[Typicaljawaiian 3]

when im bringing home more money, ill take a O-scope into consideration, but as of right now, i think the DMM is doing just what i need, I AM A redo my gain settings, i need to set the treble before i start adjusting the gain.

SSA FTW! thanks guys

No problem man, I did mine the day before you and just wanted to make sure I was doing it correct also. I learn mad s**t on these forums everyday. I just wish someone would post something that could solve my money problems!!!

[thizzkid 0]

same here bro, ive been searchin forums left and right for info, but this site right here, gives you all the info you need plus a great a** community, full of people who know what there doing.

one more time, SSA FTW!!

[CrazyKenKid 64]

car audio = solvable on SSA forums

money issue = good luck lol! in this ecomony it is hard to get a darn job some days lol!

[thizzkid 0]

very true, damn you recession, its because of you, i cant manage to have 4 12"s in my ford explorer pushin air lmao

[CrazyKenKid 64]

lol b/c of me b/c i am a Canadian Eh lol!! jk!!

I like how you put that PUSHING AIR lol so true but yet expensive! but to push air wouldn't a fan be ideal? lol !!!

[Typicaljawaiian 3]

lol b/c of me b/c i am a Canadian Eh lol!! jk!!

I like how you put that PUSHING AIR lol so true but yet expensive! but to push air wouldn't a fan be ideal? lol !!!

Interesting concept. Two twelve inch floor fans in a 6 cubic foot box tuned to 32 hz. Hmmmmmmmmm!!! Just make sure you set your GAINS CORRECT!

Edited March 7, 2010 by Typicaljawaiian

[CrazyKenKid 64]

try it out! let me know how it works lol and how how many dbz you getl ;p

[Duran 387]

lol b/c of me b/c i am a Canadian Eh lol!! jk!!

I like how you put that PUSHING AIR lol so true but yet expensive! but to push air wouldn't a fan be ideal? lol !!!

Interesting concept. Two twelve inch floor fans in a 6 cubic foot box tuned to 32 hz. Hmmmmmmmmm!!! Just make sure you set your GAINS CORRECT!

It's called a rotary woofer.

[thizzkid 0]

lol b/c of me b/c i am a Canadian Eh lol!! jk!!

I like how you put that PUSHING AIR lol so true but yet expensive! but to push air wouldn't a fan be ideal? lol !!!

not you, i meant the recession lol, a fan would be ideal to push air, but i meant pushin air with ported boxes haha