Speaker output voltage??

[herculeshero 10+ year member]

So I've searched and searched on here trying to find this similar situation and I only found one with no answer that would help me. From what I've read and seen about setting amplifier gains you test the speaker outputs with a DMM according to ohms law with the wattage and resistance and all that. BUT when I test the speaker outputs i'm hardly getting 4 volts with my gain turned all the way up. I have a hifonics brutus 1200.1 with 4 gauge ground and power and when I wire my sub up(SA-10 dual 4ohm) it plays but not near as loud as I would expect with 900 watts going to it. I've tested the sub impedance and its wired correctly down to 2 ohms and the power going to the amp is good. Why am I seeing such little output?? Please help!

Click to read more...

 

[Umbra]

So I've searched and searched on here trying to find this similar situation and I only found one with no answer that would help me. From what I've read and seen about setting amplifier gains you test the speaker outputs with a DMM according to ohms law with the wattage and resistance and all that. BUT when I test the speaker outputs i'm hardly getting 4 volts with my gain turned all the way up. I have a hifonics brutus 1200.1 with 4 gauge ground and power and when I wire my sub up(SA-10 dual 4ohm) it plays but not near as loud as I would expect with 900 watts going to it. I've tested the sub impedance and its wired correctly down to 2 ohms and the power going to the amp is good. Why am I seeing such little output?? Please help!

Are you using a test tone? You can't take these measurements on music, there needs to be a steady sinewave. Also, are you talking about the speaker outputs on the amp, or the preamp RCA outputs on the head unit, because 4V is more common behind the head unit.

What kind of box do you have the sub in?

 

[Jeffdachef 5,000+ posts]

So I've searched and searched on here trying to find this similar situation and I only found one with no answer that would help me. From what I've read and seen about setting amplifier gains you test the speaker outputs with a DMM according to ohms law with the wattage and resistance and all that. BUT when I test the speaker outputs i'm hardly getting 4 volts with my gain turned all the way up. I have a hifonics brutus 1200.1 with 4 gauge ground and power and when I wire my sub up(SA-10 dual 4ohm) it plays but not near as loud as I would expect with 900 watts going to it. I've tested the sub impedance and its wired correctly down to 2 ohms and the power going to the amp is good. Why am I seeing such little output?? Please help!

First off, you arent getting 900 watts man, its due to impedance/box rise. Depending on your enclosure you might actually be on an average of 3 or 4 ohms. Its also hifonics, they try to make rated power but they are a tad overrated.

Second, you need a large size custom ported enclosure if you havent already done so.

3rd, use a proper test tone and turn subwoofer level to the max, turn the head unit to 80-90% volume then set gains again. Your head unit volume needs to be high up there to get proper output.

 

[herculeshero 10+ year member]

Sorry, yes I am using a sine wave. 60hz at -3db with my HU volume at 3/4 volume. And I set all my EQ settings to flat, loudness off, sound retriever, sla, everything off. The subwoofer is on and bass boost off. The box is 1.25 cubes tuned to 32hz, it's a custom box from CherryMan. The reason it's 1.25 is that's what sundown recommends for this sub.

And the volts I'm measuring aren't behind the HU. I'm putting the probes into the speaker output terminals of my amp and it seems that's all I get. Now if it's really just hifonics and being a weak amp then I'll be disappointed but I am open to getting a new amp. I think the sub sounds great, I just wanted a lot more headroom as I know this sub can really handle it. Thank you for your quick responses.

 

[herculeshero 10+ year member]

First off, you arent getting 900 watts man, its due to impedance/box rise. Depending on your enclosure you might actually be on an average of 3 or 4 ohms. Its also hifonics, they try to make rated power but they are a tad overrated.
3rd, use a proper test tone and turn subwoofer level to the max, turn the head unit to 80-90% volume then set gains again. Your head unit volume needs to be high up there to get proper output.

So I pretty much just turned my gain all the way up since my output seemed to be lower and since it's probably not putting out rated power I'm going to assume that I shouldn't have to worry about clipping? Also, my HU seems to distort before 80% so I left it at 3/4.

What amp would you suggest to run this sub?

 

[Jeffdachef 5,000+ posts]

So I pretty much just turned my gain all the way up since my output seemed to be lower and since it's probably not putting out rated power I'm going to assume that I shouldn't have to worry about clipping? Also, my HU seems to distort before 80% so I left it at 3/4.
What amp would you suggest to run this sub?

use a -6db 45hz test tone.

-3 db is too weak and 60hz is not what the box is tuned for man.

How do you know your head unit is distorting? Are you testing it with an O-scope?

Sounds like you might be having your mids and highs distorting. Go to the EQ and lower all other frequencies besides bass. As always you have to ALWAYS worry about clipping. Max gain = overdriven amp no matter how you look at it.

Most headunits need their volume knobs up really high in order to have proper output.

If those dont work then the best solution for you is either get another sundown 10" d4 in the future and wire em down to 1 ohm. Or if you want to stick with a single sub, Try to trade it for a D2. For future references man, if you only want a single sub setup, get a D2 man, make the most out of your power. Hell, I do half ohm runs on my brutus amps daily and they are fine. They dont do the 2400 rated but they are **** close, they arent garbage amps man, take a little time doing a little bit more tuning.

 

[Jeffdachef 5,000+ posts]

Also the position of the subwoofer box is important too, if you have it too far away from the trunk, you'll lose a ton of output. Have it 6-12 inches from the trunk, facing the trunk. (i'm assuming you have a trunk lol)

 

[herculeshero 10+ year member]

use a -6db 45hz test tone.
-3 db is too weak and 60hz is not what the box is tuned for man.

How do you know your head unit is distorting? Are you testing it with an O-scope?

Sounds like you might be having your mids and highs distorting. Go to the EQ and lower all other frequencies besides bass. As always you have to ALWAYS worry about clipping. Max gain = overdriven amp no matter how you look at it.

Most headunits need their volume knobs up really high in order to have proper output.

If those dont work then the best solution for you is either get another sundown 10" d4 in the future and wire em down to 1 ohm. Or if you want to stick with a single sub, Try to trade it for a D2. For future references man, if you only want a single sub setup, get a D2 man, make the most out of your power. Hell, I do half ohm runs on my brutus amps daily and they are fine. They dont do the 2400 rated but they are **** close, they arent garbage amps man, take a little time doing a little bit more tuning.

Yea, I tried getting some help before I bought all my stuff but I guess I got a little impatient. I'm not sure why I went dual 4 but I think I'll probably end up getting another. And yea, I meant my highs and mids distort. I also tried researching what test time to use but I couldn't find that either!

And I don't think the Brutus amps are garbage, I bought one for a reason! Also, if I turn my amp gain down would it be bad to use a little bass boost from my head unit? Or should I use the one on the amp? Also, should I mess with the subsonic or low pass filters?

 

[Jeffdachef 5,000+ posts]

Yea, I tried getting some help before I bought all my stuff but I guess I got a little impatient. I'm not sure why I went dual 4 but I think I'll probably end up getting another. And yea, I meant my highs and mids distort. I also tried researching what test time to use but I couldn't find that either!
And I don't think the Brutus amps are garbage, I bought one for a reason! Also, if I turn my amp gain down would it be bad to use a little bass boost from my head unit? Or should I use the one on the amp? Also, should I mess with the subsonic or low pass filters?

subsonic should be around 22 hz-25hz just guess where that might be, its just to save your sub from playing anything too low that might damage it. Low pass should be at 80hz. No bass boost whatsoever man.

Hows your box facing and location? Try the EQ thing i told you about, if you have a mids and highs amp, turn the gain down on that and crank up the head unit volume

Keep in mind, the DMM method is not really the most surefire way. You gotta train your ear to listen to distortion. Rule of thumb, if you turn it up and its not getting any louder, You've already gone past clipping levels, turn it back a few notches. Do your temperature tests and keep your nose keen for smelly coils.

 

[herculeshero 10+ year member]

subsonic should be around 22 hz-25hz just guess where that might be, its just to save your sub from playing anything too low that might damage it. Low pass should be at 80hz. No bass boost whatsoever man.
Hows your box facing and location? Try the EQ thing i told you about, if you have a mids and highs amp, turn the gain down on that and crank up the head unit volume

I'm not deadset on using a dmm, just really want to make sure I don't ruin my sub. I'll take a look at those and set those properly.

I do have a highs and mids amp but it's the stock infinity amp in my jeep so I'll just have to turn the EQ down. My box is facing the rear behind my back seat. I think I'm just gonna have to settle with getting another one.

 

[Jepalan]

I know this is a dumb question, but are you setting your DMM to measure *AC* volts and do you have the red and black leads plugged into the correct holes in the DMM?

Also, note that a -6dB test tone is actually lower in level than a -3dB test tone, so under the same circumstances you will measure even lower voltage. The idea behind going with a lower dB tone is to wind up with the gains a little higher to get a bit more out of the system and allow a little bit of clipping on peaks only.

Do try another test tone though - you may have a bad file.

 

[herculeshero 10+ year member]

I know this is a dumb question, but are you setting your DMM to measure *AC* volts and do you have the red and black leads plugged into the correct holes in the DMM?Also, note that a -6dB test tone is actually lower in level than a -3dB test tone, so under the same circumstances you will measure even lower voltage. The idea behind going with a lower dB tone is to wind up with the gains a little higher to get a bit more out of the system and allow a little bit of clipping on peaks only.

Do try another test tone though - you may have a bad file.

Yea, I was measuring AC, I tried multiple different settings to make sure if was getting the reading I was and I tried both different positive plugs. It seems my amp measures volt sensitivity? On one end it says 9v at the lowest and .2v at the highest. Does this make a difference? I will try another test tone, the 45hz -6db that was recommended. And I never thought about having a bad file. Also I uploaded it to my iPod instead of burning a cd. I'll try a cd next time as well. I'll try this stuff tomorrow and post my results. I'm going to sand my ground point too, just to be sure. Thanks for everyone's help.

 

[Jepalan]

Yea, I was measuring AC, I tried multiple different settings to make sure if was getting the reading I was and I tried both different positive plugs. It seems my amp measures volt sensitivity? On one end it says 9v at the lowest and .2v at the highest. Does this make a difference? I will try another test tone, the 45hz -6db that was recommended. And I never thought about having a bad file. Also I uploaded it to my iPod instead of burning a cd. I'll try a cd next time as well. I'll try this stuff tomorrow and post my results. I'm going to sand my ground point too, just to be sure. Thanks for everyone's help.

Wait. No you've got me confused. The 9v to .2v setting is for the amp gain and it is the level of the voltage coming *into* the amp. The reason it seems "backwards" is becuase when the input level is low (.2v) you need to turn the gain up (towards max), but when the input level is high (9v) you need to turn the gain down (towards min).

When setting gain using a DMM and the power calculation, you need to measure the voltage across the speaker terminals on the *output* of the amp. Don't measure your head unit's output, measure the amplifier's output.

 

[herculeshero 10+ year member]

So, recent breakthrough on this little problem I've been having. Seems that I can't turn my LPF off on my HU and found that once matched the LPF on the amp with the 80hz setting on my HU it got wayyy louder. I'm sure this is probably some noob mistake but can anyone explain this to me??

 

[los33]

So, recent breakthrough on this little problem I've been having. Seems that I can't turn my LPF off on my HU and found that once matched the LPF on the amp with the 80hz setting on my HU it got wayyy louder. I'm sure this is probably some noob mistake but can anyone explain this to me??

One was blocking the other of certain frequencies.

sound is unpredictable so the radio or amp wont all catch certain frequencies or block to much.