Voltage calculation for DMM help

[nstillmatic 10+ year member]

I'm not sure if I did this calculation right. This is what I have with the component set + amp listed in the sig.

sqrt(125w rms x 4 ohm) = 22.3v

The polks are 125w per side.. so should I be inputting 250w instead of 125w or is this correct? Also, the mm6501s are technically listed as 2.7ohm, I'm assuming there is no way for them to be wired this way so it's really at 4ohm. Should I raise the voltage up some to make up for this or does the rated rms already consider that?

Click to read more...

 

[Immociide 10+ year member]

If those speakers are really 2.7 ohms then you should enter 2.7 in your calculation. You can check with your dmm, just set it to ohms and touch the - and + of the speakers. It has nothing to do with its wiring Its just how its parameters came out. Most companies aren't as precise tho.

Anyways 125 watts is correct. This is assuming you are running each side on its own channel. I got 18.37.

Also remember this isnt an exact science so you still will have to listen for distress/distortion. Or even a funny smell...

 

[SpeedEuphoria 10+ year member]

your better off doing it by ear but the calculations should get you close

The amp should put out closer to 150-165w per side at 2.7ohms which would be 20.1-21.2v

from what little I read they are really 2.7ohm which is good for you as it will draw more power from your amp and the speakers should take it no prob

you'll just try to tune out the high spots using whatever eq you have till you get the sound you like

 

[nstillmatic 10+ year member]

I thought the 125W RMS per side was taking into consideration that it runs at 2.7ohms already? Is it safe to bump up the voltage to give it 150-165w?

 

[SpeedEuphoria 10+ year member]

well the amp only puts out what it will depending on what ohm speakers you hook to it

the amp does 125w per channel at 4ohm and 200w at 2ohm. Your at 2.7ohm so it should be capable of about 150-165w when you set the gain to that

As long as its clean power its safe as long as you listen and your not getting distortion from pushing them to hard. Passive x-overs eat up a little power so not all of that is making it to the speakers. But you should be fine.

People push 200rms to components that are rated at 100rms just fine, same with subs. You just have to realize that if they sound distorted they are getting too much and dont keep it at max volume for 10mins cuz they wont like that and may fail. If they still sound clean and loud then they'll be fine.

 

[keep_hope_alive Premium Member]

power output is dynamic - the reason you set gains for amplifiers at their rated output is so that you understand the gain structure and prevent clipping the outputs. you use a 0dB test tone for a source so that the source is as strong as any recorded music can be - and so that you can easily measure the amplitude out of the amp with your DMM. this is assuming your DMM measures true RMS - something to take into consideration as those DMM's are more expensive and listed as such.

if you set your gains for 125W per side, then realize you'll probably never actually see that output unless you plan on listening to 0dB tones at your determined maximum volume. this is why it is common to get amplifiers more powerful than you need, so you can actually achieve rated power (dynamically of course).