**Amplifier Gain setting tutorial**

[jntar]

Originally Posted by tylers88

i just picked a volume for my fronts to distort at and put my rears on for one more than that un hooked my rca to my 4 channel and cranked my head unit put in the bass nob on my punch 75 25-life and started turning them up till they distorted then turned it down about a 1/16 of a turn re hooked every thing and she hits in the 130-137 db range all day long

Congrats...if they ever fail you know what when wrong. 2 things kills a speaker. Thermal failure and mechanical failure. Setting a gain by ear doesnt keep the amp from clipping. Clipping will cause excess heat and eventually ruin the speaker. This isnt a guarantee, but its a main cause. I can only suggest you set it with the formula in the first post.

[jntar]

Originally Posted by jdstephens

I am totally lost...
I get the idea, but figuring out what my voltage needs to be is a dinger for me...
I have 4 8ohm subs
using one channel@ 2 ohms/240 watts
I get confused easily...Can someone help me please?

I know its an old post, but PM me if you are still having trouble. My email isnt being nice to me at this point so PMs work best.

[IluvJDM]

Alright, I have a few questions...

I've got a JL Audio stealthbox, with the 10w3v2-D2, with 4ohm Nominal Impedence (got this info from the instructions for the stealthbox). The amp is a JL 250/1, and this is being added to the Bose system in an '03 ext. cab via the PAC AOEM-GM24 harness. I also have a voltmeter and 50Hz test tone that I can burn to a CD...

Using the JL tutorial it says I need 31.6V at 4ohm, and it says to turn off all EQ and bass and stuff on the headunit and turn to 3/4 volume. Now I know that when I listen to the radio right now, I stay around 1/4 volume, and I think that setting the headunit at 3/4 volume would blow all the speakers. So what's the process for setting the gain in my situation? Is there a way to set the gain with all the EQ, bass and treble settings like they are right now, and still have an efficient sub? I'm not trying to enter competitions, but I know having an efficient sub will make the system last (my priority)



thanks in advance for the help

-John

[jntar]

Originally Posted by IluvJDM

Alright, I have a few questions...

I've got a JL Audio stealthbox, with the 10w3v2-D2, with 4ohm Nominal Impedence (got this info from the instructions for the stealthbox). The amp is a JL 250/1, and this is being added to the Bose system in an '03 ext. cab via the PAC AOEM-GM24 harness. I also have a voltmeter and 50Hz test tone that I can burn to a CD...

Using the JL tutorial it says I need 31.6V at 4ohm, and it says to turn off all EQ and bass and stuff on the headunit and turn to 3/4 volume. Now I know that when I listen to the radio right now, I stay around 1/4 volume, and I think that setting the headunit at 3/4 volume would blow all the speakers. So what's the process for setting the gain in my situation? Is there a way to set the gain with all the EQ, bass and treble settings like they are right now, and still have an efficient sub? I'm not trying to enter competitions, but I know having an efficient sub will make the system last (my priority)



thanks in advance for the help

-John

I know JL states to turn off all the EQ settings. I however disagree with that. Keep you settings how you listen to your music. Turn your HU up till you either cant stand it any louder or the speakers begin to distort. Then set you gain on your sub.

[IluvJDM]

Originally Posted by jntar

I know JL states to turn off all the EQ settings. I however disagree with that. Keep you settings how you listen to your music. Turn your HU up till you either cant stand it any louder or the speakers begin to distort. Then set you gain on your sub.

ok, and when I set my gain do I still tune it to 31.6V, or will that number not work anymore since I have all the EQ settings on?

thanks for your help

-John

[jntar]

Originally Posted by IluvJDM

ok, and when I set my gain do I still tune it to 31.6V, or will that number not work anymore since I have all the EQ settings on?

thanks for your help

-John

You still want to set it for 31.6v.

My reasoning...If you set your EQ flat then set the amp gain. Your first instint is to reset all of your EQ settings. Now you risk clipping the amp because you are now turing up what was the max voltage for the amp even higher.

[IluvJDM]

Originally Posted by jntar

You still want to set it for 31.6v.

My reasoning...If you set your EQ flat then set the amp gain. Your first instint is to reset all of your EQ settings. Now you risk clipping the amp because you are now turing up what was the max voltage for the amp even higher.

alright, that's what I was thinking, but didn't know for sure so I thought I'd ask someone knowledgable.

thanks

-John

[Knuckles]

I see what your saying. However... Every production is diferent. What I meen is that some recordings are louder. Some suck. So take the best productions you have. Play them. Do the setting by hand, and ear. Then you shouldn't have a clipping problem, and be maxed out. According to your music collection, sellection. And taste.

[jntar]

Originally Posted by Knuckles

I see what your saying. However... Every production is diferent. What I meen is that some recordings are louder. Some suck. So take the best productions you have. Play them. Do the setting by hand, and ear. Then you shouldn't have a clipping problem, and be maxed out. According to your music collection, sellection. And taste.

Completly wrong way to look at this. Even though every album/artist/song is different, they cant go over a 0db tone. Therefor no matter what music it will be impossible to clip your amp. Setting by ear provides NO guarantee, its all what you "think you hear", it may not be what you actually hear.

[Atomic]

I think someone asked earlier but never got an answer...

In the calculations, if your using a Dual voice coil sub and its at 4ohms, but you have it bridged to 2 ohms, do you use the 2 or 4 in the calculations?

For instance my amp puts out 400wx2@2ohms bridged and im using a 400w rms sub (jl w6v2) which is dual 4 ohm.

So would my equation be V = sqrt (400x2) or V = sqrt(400x4)?

[jntar]

Originally Posted by Atomic

I think someone asked earlier but never got an answer...

In the calculations, if your using a Dual voice coil sub and its at 4ohms, but you have it bridged to 2 ohms, do you use the 2 or 4 in the calculations?

For instance my amp puts out 400wx2@2ohms bridged and im using a 400w rms sub (jl w6v2) which is dual 4 ohm.

So would my equation be V = sqrt (400x2) or V = sqrt(400x4)?

I answered your PM.

You would want to use the actual ohm load that the sub will be wired to. so sqrt(400*2)
Just remember what i said in PM...if your amp isnt 2ohm stable I HIGHLY recomend that you do NOT run it at that low of an impedance.

[roskey5205]

If you are using an amplifier that has an RMS rating of more than your speaker(s) can handle/rated for

Are you talking speakers RMS or peak handling.

[Atomic]

RMS, never peak.

How can you tell how many watts your speakers are putting out?

Whats the best frequency to set a sub with?

[odenthall1]

pm'd ya jntar

[jntar]

Originally Posted by roskey5205

If you are using an amplifier that has an RMS rating of more than your speaker(s) can handle/rated for

Are you talking speakers RMS or peak handling.

I always use the lower of the two. If the speakers are rated lower then the amps rating I use it. If the amp is rated lower, then I use the amps RMS power for the formula.

Always use RMS ratings when gain setting.

[jntar]

Originally Posted by Atomic

RMS, never peak.

How can you tell how many watts your speakers are putting out?

Whats the best frequency to set a sub with?

There really is no best, but 45-50 hz usually works well.

Speakers dont produce power. I am guessing you are asking how much power your amp produces when your speakers are hooked up.

[jntar]

Originally Posted by odenthall1

pm'd ya jntar

Never got it...

[ikon]

Altho this is a good way of setting your gains it can still result in your amp clipping. The best way to set your gains is with an O-scope. Now i realize that not very many people have access to this type of equipment due to the fact that it is very expensive. However, if you have access to one i highly recommend you use it.

[Atomic]

yea...how many watts they are putting out...how would I figure that?

[odenthall1]

hey,
I am fairly new to systems. I will give you as much info on the stuff I have as possible.

amp
rockford fosgate rf2002
RMS Power at 4 Ohms 50 W x 2
RMS Power at 2 Ohms 100 W x 2

subs: rockford fosgate p1 single voice coil.
Size 10"
Impedance 8-Ohm
Power Handling 150 Watts RMS
300 Watts PEAK
I plan on running 2 10"s in parallel which is what I got from the rockford website. which will bring them to 4 ohm if thats correct from the web site.

I was able to find a square root calc I just dont know what numbers to use.
thanks in advance
Robert