how do I set gain with dmm

[Beatin' 10+ year member]

So after all this trouble, you're still relying on your ears, some common sense, and the volume knob.

easier with highs than bass....

 

[T3mpest 10+ year member]

So after all this trouble, you're still relying on your ears, some common sense, and the volume knob.

Ding, ding, ding.. So why they both I have no idea.. Yeah your "not clipping" until any tone goes above -7db in a song, which happens fairly often.. Good news, you don't hear it and unless your amp is way overpowering a little clipping won't damage speakers. How people constantly blow speakers is beyond me.. You can hear when things are getting pushed too hard.

Gain knobs are NOT to match a hu preout with the input sensativity of the amplifier. They are to match the output levels of various speakers, when each has different sensativity and input requirements at both the speaker and amplifier ends.

 

[argenis69 10+ year member]

I just did this but was I supposed to set everything on the radio to 0? Eq sla ect...is the amp crossover supposed to be where I wanted it?

Ding, ding, ding.. So why they both I have no idea.. Yeah your "not clipping" until any tone goes above -7db in a song, which happens fairly often.. Good news, you don't hear it and unless your amp is way overpowering a little clipping won't damage speakers. How people constantly blow speakers is beyond me.. You can hear when things are getting pushed too hard.
Gain knobs are NOT to match a hu preout with the input sensativity of the amplifier. They are to match the output levels of various speakers, when each has different sensativity and input requirements at both the speaker and amplifier ends.

Ok, so how do you suggest is the best way to set the gains? With ear, with dmm, with the oscilloscope, or which combination of these tools?

 

[BoomTaco64]

it depends who you talk to and get your help from in this forum..some will say one thing and then others will help you in other ways. the best is to take advice from one person and go with that.

personally, i use my DMM w/scope (TPI 440) for the gain and the rest by ear.

 

[argenis69 10+ year member]

it depends who you talk to and get your help from in this forum..some will say one thing and then others will help you in other ways. the best is to take advice from one person and go with that.personally, i use my DMM w/scope (TPI 440) for the gain and the rest by ear.

So you say, that you check for clipping on the signal from the radio's rca's with the oscilloscope and then set the volume of the amp of each speaker by ear?

 

[BoomTaco64]

I check for unclipped signal from the radio and from the amp with the dmm scope then adjust the rest by ear...thus using both... Using the dmm will give you the actual power you are getting via ac voltage....

 

[fly_marlin]

This is how you do it:

GlassWolf's Pages

 

[T3mpest 10+ year member]

Ok, so how do you suggest is the best way to set the gains? With ear, with dmm, with the oscilloscope, or which combination of these tools?

Just use your ears. A DMM can get you in the ballpark if your really inexperienced though. The issue is people think with a DMM they are being exact, they aren't. When you set a gain with a DMM your assuming a speaker is a static load when you do the power calculations. It isn't, the impedance of the driver is all over the place, both higher and lower than the nominal load your calculations are based on. So the gain setting in that regard is already off.. Then when you look at musical content vs tones it only gets worse.. If you set your gains with lets say a -6db tone, your getting realistic power from the amp on most music, but since some tones DO go above that you can and will be clipping from time to time.. If you set with a 0db tone, you won't be clipping unless your playing a frequency where the impedance of the woofer drops lower than you calculations, BUT you also won't be getting anywhere near full power from the amp for 99% of music either.

At the end of the day, music is dynamic and varies in output level, speakers are dymnamic and constantly change impedance. It's like trying to hit a moving target while your on a moving object yourself, using "calculations" that assume your both standing still, it's NOT the same lol. It's best to just use intuition and take your best guess..

For subsonic Basic rules of thumb, tuned at 40, SSF at 35. Tuned at 35, set it at 30-25hz tuned at 30 set it at 25 or 20, depending. Basically the lower you tune, the lower the SSF can go, since there is less bass at maxed out levels as you go lower in tones.. General rule is 1/2 octave below, which works, but only on lower tunings, as you tune higher for SPL, you'd set it closer to tuning. Also if you get REALLY low tunes, you also put it near tuning. Again, use common sense, play some tones, watch the excursion and make sure nothing is bottoming out.. -3db tones work well for this, but once your done, play some low *** C&S music if your into that, and watch the woofer move, see how it's doing and tweak it from there. (for SSF don't use your ears, use your eyes lol)

Anyway for gains, turn the HU up to 3/4 find some bass heavy music and turn it up until it stops getting louder.. You'll notice it'll gain slowly at first then all at once the sub will come "alive" as you barely turn the knob. Somewhere in the upper end of that range is where clipping usually starts because that's where your amp is really beginning to put out power. Voltage off a HU and gains is logarithmic, so it jumps quickly. Just don't be stupid.. Once it stops getting louder, turn it back down a bit until you tell it got quieter by a little bit, leave that last little bit in the tank. If you have quiet recordings, turn the HU up a little higher than where you set your gains at to compensate.. As long as your listening to it's actual output levels your not going to damage anything, once you know how loud it CAN go, dont' attempt to push it past that.. That's what fries speakers.. "Oh, it stopped getting louder and started sounding dirty at 25 my volume knob, but I want more output, so I'm listening at 32"

 

[argenis69 10+ year member]

Just use your ears. A DMM can get you in the ballpark if your really inexperienced though. The issue is people think with a DMM they are being exact, they aren't. When you set a gain with a DMM your assuming a speaker is a static load when you do the power calculations. It isn't, the impedance of the driver is all over the place, both higher and lower than the nominal load your calculations are based on. So the gain setting in that regard is already off.. Then when you look at musical content vs tones it only gets worse.. If you set your gains with lets say a -6db tone, your getting realistic power from the amp on most music, but since some tones DO go above that you can and will be clipping from time to time.. If you set with a 0db tone, you won't be clipping unless your playing a frequency where the impedance of the woofer drops lower than you calculations, BUT you also won't be getting anywhere near full power from the amp for 99% of music either.
At the end of the day, music is dynamic and varies in output level, speakers are dymnamic and constantly change impedance. It's like trying to hit a moving target while your on a moving object yourself, using "calculations" that assume your both standing still, it's NOT the same lol. It's best to just use intuition and take your best guess..

For subsonic Basic rules of thumb, tuned at 40, SSF at 35. Tuned at 35, set it at 30-25hz tuned at 30 set it at 25 or 20, depending. Basically the lower you tune, the lower the SSF can go, since there is less bass at maxed out levels as you go lower in tones.. General rule is 1/2 octave below, which works, but only on lower tunings, as you tune higher for SPL, you'd set it closer to tuning. Also if you get REALLY low tunes, you also put it near tuning. Again, use common sense, play some tones, watch the excursion and make sure nothing is bottoming out.. -3db tones work well for this, but once your done, play some low *** C&S music if your into that, and watch the woofer move, see how it's doing and tweak it from there. (for SSF don't use your ears, use your eyes lol)

Anyway for gains, turn the HU up to 3/4 find some bass heavy music and turn it up until it stops getting louder.. You'll notice it'll gain slowly at first then all at once the sub will come "alive" as you barely turn the knob. Somewhere in the upper end of that range is where clipping usually starts because that's where your amp is really beginning to put out power. Voltage off a HU and gains is logarithmic, so it jumps quickly. Just don't be stupid.. Once it stops getting louder, turn it back down a bit until you tell it got quieter by a little bit, leave that last little bit in the tank. If you have quiet recordings, turn the HU up a little higher than where you set your gains at to compensate.. As long as your listening to it's actual output levels your not going to damage anything, once you know how loud it CAN go, dont' attempt to push it past that.. That's what fries speakers.. "Oh, it stopped getting louder and started sounding dirty at 25 my volume knob, but I want more output, so I'm listening at 32"

This makes sense^ . You say use ears and eyes only and it will do best?

Ok, so in your experience what is the best db level to set gains with? for real everyday music, on the bass amp, and on the mids amp?

 

[T3mpest 10+ year member]

This makes sense^ . You say use ears and eyes only and it will do best?Ok, so in your experience what is the best db level to set gains with? for real everyday music, on the bass amp, and on the mids amp?

Don't use tones.. Tones on speakers at that level can damage them, as well as your hearing.. Your going to be listening to music on the system, so use the music you listen to. For rap, I usually use something that peaks in the mid 40's, Jeezy's white girl, BME Click, something like that for the sub.. To set my mids and highs, just some well recorded rock music in most cases. If you want to use tones to get you in the ballpark, use a -6db tone and then back that up with your ears.. Once it's set with a dmm using tones, try playing real music and see if the system has anything more in it on the heaviest music you'd normally listen to, or if you hear it already distorting, turn it down some from there.

 

[argenis69 10+ year member]

Don't use tones.. Tones on speakers at that level can damage them, as well as your hearing.. Your going to be listening to music on the system, so use the music you listen to. For rap, I usually use something that peaks in the mid 40's, Jeezy's white girl, BME Click, something like that for the sub.. To set my mids and highs, just some well recorded rock music in most cases. If you want to use tones to get you in the ballpark, use a -6db tone and then back that up with your ears.. Once it's set with a dmm using tones, try playing real music and see if the system has anything more in it on the heaviest music you'd normally listen to, or if you hear it already distorting, turn it down some from there.

But, it's best to set gains with ears method, correct?

Also, do you use -6db on bass and on the mids amps?