setting gains with dmm's

[rsfm089]

I've read and heard u could set gains with a couple DMM's is this true and how do u do it. I have three of them if it helps

[Weigel21]

Yep, if you are sure your amplifier can produce clean power at the power you want to set it to produce, as well as if the subs can take said power.

Here's the method for setting gains via a DMM and test tones.

[rsfm089]

My amp for know is a planet audio ac3000.1 400watt RMS. The sub will be a hdc3 12. I know its not a good combo but I just can't afford to spend five hundred on an amp and buying used scares me.

[Weigel21]

You planning on running the amp at 1 ohm? Are you 100% sure the amp can produce 400RMS cleanly at whatever impedance you plan to run?

My recommendation would NOT be to set the gain with a DMM and test tones, but instead set it by ear using test tones. You can clearly hear when the test tone changes pitch at the onset of distortion. Normally, this method can be quite stressful on any drivers asked to play the test tone, but given you have a sub rated at 1500RMS, I don't see a test tone playing at 300-400RMS, or whatever the amplifier can truly do, harming the sub in any way within the amount of time it takes to get the gain set by ear.

[rsfm089]

The amp (not mine another post) was just tested and it did 4** watts rms. just don't want to clip the sub to death on 400 watts and ruin it. I don't have money to throw away

[Weigel21]

Yeah, I just noticed you were talking about it in the testing thread with me.

I wouldn't worry too much, the sub is rated for 1500RMS, even if that amplifier were to be set for 400RMS and clip like a MOFO, the sub is capable of handling over 3 times that and so a fully clipped square wave with that amplifier probably wouldn't kill it.

[Weigel21]

But I'd like to believe you wouldn't have the gain set as such, it'd sound like complete shit and be obvious to all but the deaf that it's clipping.

[rsfm089]

I wasn't worried about it until a guy unwound an hdc3 15 in about four seconds on a clipped signal but I think he was push more like 1k to his

[Weigel21]

Yeah, that I could probably see happening. However, as small of an amplifier as you have, a fully clipped signal would be only thing that's stand a chance killing the sub, in terms of dirty power. Even then, I'm not so sure you amplifier has what it'd take. A gain setting that sounds clean to your ears (using music) could well have some intermittent clipping, but it'd be far from what it'd take to kill the sub.

[rsfm089]

I don't want to say I know exactly where everything clips at bit I have had the amp for around a year and kind of know where the limits are at