Measure real wattage with an dmm?

[qccoles]

I have an Crunch PZI.30001.d and an sa 12 d4. I know the sub is underated, but I know the amp overrated. The amp is 3000w @ 1 ohm, 1500 @ 2 ohm, 750 @ 4.

I believe it really does closer to 1500 rms @ 1 ohm. I want to give it more than 600w but I don't know how much my amp is really putting out at 1 or 2 ohms. I dont want to blow the SA-12(but from what ive seen, 1500 cant even really blow it)

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[hispls 5,000+ posts]

(but from what ive seen, 1500 cant even really blow it)

You are terribly wrong there.

Really you'll need to learn what will damage a woofer and to spot the warning signs. You can certainly run a woofer with an amp that can make much more than rated power, but you'll need to really pay attention to where your mechanical and thermal limits are and know when to back off before you hurt it.

 

[Force-fed]

you can measure the wattage with a dmm, but if im not mistaken the only way to tell if its clean or not is to use an oscilloscope, they can take 1500 clean, but if its clipping you'll damage it

 

[Slobalt]

You are terribly wrong there.
Really you'll need to learn what will damage a woofer and to spot the warning signs. You can certainly run a woofer with an amp that can make much more than rated power, but you'll need to really pay attention to where your mechanical and thermal limits are and know when to back off before you hurt it.

he's right do some research

 

[MerkConvoy501]

Do a clamp test that will tell you your rms. But be careful of clipping. Distortion kills woofers not power

 

[trumpet 5,000+ posts]

Do a clamp test that will tell you your rms. But be careful of clipping. Distortion kills woofers not power

Apart from mechanical failures, heat is what kills a woofer. If you have a sub or speaker that is getting too much power for too long, regardless of whether that is undistorted and unclipped power, it will lead to failure. "Distortion kills speakers" is a myth.

There is also the diminishing returns of overpowering subs. At some point your system stops getting louder even as power continues to increase. That is power compression. I believe this is also called "box rise".

 

[trumpet 5,000+ posts]

I have an Crunch PZI.30001.d and an sa 12 d4. I know the sub is underated, but I know the amp overrated. The amp is 3000w @ 1 ohm, 1500 @ 2 ohm, 750 @ 4.
I believe it really does closer to 1500 rms @ 1 ohm. I want to give it more than 600w but I don't know how much my amp is really putting out at 1 or 2 ohms. I dont want to blow the SA-12(but from what ive seen, 1500 cant even really blow it)

The DMM method of gain setting is a very poor way to test your system when the amplifier can greatly exceed your subwoofer's RMS power handling. It will not tell you the actual watts. It will not tell you if the signal is clipped. Clipping will introduce more heat faster than an unclipped signal, and that's the #1 danger to your subwoofer in this scenario.

 

[hispls 5,000+ posts]

they can take 1500

Really? I defy you to take one, measure a 1500W "clean" sine wave into it for a few minutes and video the results.

 

[qccoles]

So how can I safely adjust the amp without knowing the real rms of it? Back off when it starts to distort?

 

[Force-fed]

u can use a dmm to get an idea of what the amp is putting out, use a test tone and listen for the speaker to clip, search for a vid to show you how if you don't know what youre listening for, with out setting the gain with an o-scope, that's gunna have to do

 

[trumpet 5,000+ posts]

So how can I safely adjust the amp without knowing the real rms of it? Back off when it starts to distort?

Basically, yes. Setting gains by ear has its own procedure, starting with music you know very well, as well as having a good idea of what the equipment should be capable of. If you know someone experienced who can help you that's the best way to learn this. I have dialed in systems completely by ear, then I make more adjustments with the customer present before they take the vehicle home.