Any way to tell ?

[highfigh]

He would also need a good RMS voltmeter to give true values beyond 60 Hz.

And most people don't want to spend the money on a true RMS meter.

 

[highfigh]

The peak spl calculator that ADTG posted upthread can provide a ballpark estimate of how much power at whatever chosen spl you care to plug in. Try it out.



Your thoughts on the test described in this thread and perhaps something the OP could perform. Just about any cheapie multimeter would suffice.

You might want to read the details for non-RMS meters- they're made for 50-60Hz electrical service measurements, not for accurately measuring wide bandwidth audio signals. For that, it's much better to have a scope.

 

[ski2xblack]

You might want to read the details for non-RMS meters- they're made for 50-60Hz electrical service measurements, not for accurately measuring wide bandwidth audio signals. For that, it's much better to have a scope.

Did you or mtrycrafts even read the test procedure at the link?

The test employs a measurement strategy that sidesteps multimeter frequency response issues. The multimeter is not used to measure voltages of music, but steady-state sine waves at frequencies where even a basic unit will be rather accurate. No need for a wide bandwidth volt meter or scope. (The idea was to suggest something to the OP that he could actually try, that is at least somewhat accurate, and that does not require an expensive multimeter or special equipment like a scope).

 

[mtrycrafts]

Did you or mtrycrafts even read the test procedure at the link?

The test employs a measurement strategy that sidesteps multimeter frequency response issues. The multimeter is not used to measure voltages of music, but steady-state sine waves at frequencies where even a basic unit will be rather accurate. No need for a wide bandwidth volt meter or scope. (The idea was to suggest something to the OP that he could actually try, that is at least somewhat accurate, and that does not require an expensive multimeter or special equipment like a scope).

Yes, a steady state sine wave also needs a true RMS meter if he wants to know power or current through that 0.1 Ohm resistor, even at 500 Hz. Guessing that your meter will be true at 500 Hz is just that.

 

[ski2xblack]

Mtry, the test requires no 1 ohm resistor or testing at 500hz. Linky, and another linky describing the procedure.

 

[mtrycrafts]

Yes, that 0.1 Ohm resistor was mentioned by another as 500 Hz.
Equal loudness curve is not important for power calculations. As to that other link, again, it assumes an 8 Ohm load. While that may work to approximate, the OP wanted a better measurement at different frequencies, I believe, no?
And, again, RMS was mentioned. That meter may or may not provide good enough figures as you go beyond 60 Hz.

 

[ski2xblack]

Your concerns are addressed in the first and second post of the thread on diyaudio. Yes, an approximation, just as Peng's test would only apply for power at 500hz.

 

[ski2xblack]

Equal loudness curve is not important for power calculations.

Oops, wrong link...HERE is the diyaudio thread.

 

[mtrycrafts]

I may have to try this with that precision 0.1 Ohm resistor and see. At least the impedance is fixed at all frequencies.
I'll know the current into the speaker and can also measure the volts at the speaker.
Now to test what frequency my meter goes off the RMS value.

Yes, that link shows how to approximate. Now to know closer.
Thanks.
ps. may have to rethink that resistor

 

[PENG]

I may have to try this with that precision 0.1 Ohm resistor and see. At least the impedance is fixed at all frequencies.
I'll know the current into the speaker and can also measure the volts at the speaker.
Now to test what frequency my meter goes off the RMS value.

Yes, that link shows how to approximate. Now to know closer.
Thanks.
ps. may have to rethink that resistor

If the speaker impedance is 8 ohm at the frequency used for measurement, the volt drop in the 0.1 ohm resistor is about 0.035 V at 2.83 V output, so you need to pay attention to the accuracy/tolerance of your multimeter.

 

[PENG]

If you are going to use the resistor method, it is better to use more resistance, say 4 ohms and a little higher voltage just to figure out the impedance of the speaker at the test frequency.

After that you can remove the resistor, lower the voltage until you get the same spl and then V/Z will be the current. Z is the calculated impedance in the 1st step with the 4 ohms resistor in series.

 

[mtrycrafts]

If the speaker impedance is 8 ohm at the frequency used for measurement, the volt drop in the 0.1 ohm resistor is about 0.035 V at 2.83 V output, so you need to pay attention to the accuracy/tolerance of your multimeter.

Yep, that is why I need to rethink this method. I need to re-read my Fluke 75 manual for its millivolt capability.

 

[PENG]

Yep, that is why I need to rethink this method. I need to re-read my Fluke 75 manual for its millivolt capability.

I really think it is better to use a higher ohm resistor. It takes a little more work as you have to take one more measurement, but you get more accurate result and more fun.