Measuring power output in real time

Nicholas Bedworth · Aug 25, 2010

What easy ways are there to monitor power output? Are there any devices that can be clipped on to a system, and ideally feed up to a software application? It would be fun to have some big McIntosh style meters, on my PC or perhaps use the data to modulate some on-screen lava lamps.

Seeing visible proof of how hard my investment in electronics is working for me is very satisfying

.

DonH50 · Aug 25, 2010

How much do you want to spend, do you want to build or buy (or maybe buy some and integrate), what OS?

I mst warn you that if you hook them to your lava lamps I may resort to mild violence.

Nicholas Bedworth · Aug 25, 2010

I was hoping that someone would have a module that one could clip onto the amplifier output terminals to get the measurements, and a software user interface that would display the power. Buying parts and integrating is certainly possible as well. Armed with a soldering iron and DVM, we can rule the world (or at least, a very small part of it).'

BTW given that you're in CO, do you know Jeremy Ramsey of Audio Magic in Aurora? http://audio-magic.com/ He has several very interesting audio "accessory" lines (cables, power conditioners, etc.) and, most importantly, a LARGE collection of lava lamps.

DonH50 · Aug 25, 2010

Last time I checked there were all sorts of modules with meters (analog, LED, LCD), including an old one I have with a nice LED display. However, I have not looked lately, and am not sure there is one with a USB interface (sounds like a neat idea). I'd start by checking Parts Express, then Google/Dogpile/whatever. We could certainly make one as there are gobs of cheap protyping systems that we could build on. With media PC's becoming more prevelant maybe there's a market? Hmmm... Shhh, don't tell anyone!

- Don

amirm · Aug 26, 2010

If you want pretty lights and meters which move inaccurately, there are more solutions than you can count

. Recall that the McIntosh meters move back and forth even without a speaker hooked up!!!

The way we measure power is that we hook up a resistive "dummy" load and the measure the voltage across it. Then we apply watts = voltage * current = voltage * voltage / resistance (of dummy load). With a speaker and its impedance changing based on frequency, this formula (and hence the meter) do not show the real thing.

DonH50 · Aug 26, 2010

Yeah, but... but... but the lights are sooo pretty!

I'd forgotten all about the "moving M(a)c meters" -- ghost in the machine!

There are plenty of systems that accurately measure power, but probably not the typical audiophile meters sold in the back of the magazines.

Nicholas, a couple of Extron meters (not as good but much cheaper than Fluke, Agilent, et. al.) with the USB interface might do the job. I don't think the cheap ones are real-time, though.

microstrip · Aug 30, 2010

Nicholas Bedworth said:
What easy ways are there to monitor power output? Are there any devices that can be clipped on to a system, and ideally feed up to a software application? It would be fun to have some big McIntosh style meters, on my PC or perhaps use the data to modulate some on-screen lava lamps.

Seeing visible proof of how hard my investment in electronics is working for me is very satisfying .

For looks I use the Darkwood designs audio peak meters :
http://www.darkwood.demon.co.uk/PC/meter.html

For serious mesurements the spectraplus software is great .
http://www.telebyte.com/pioneer/
The full function demo version works for 30 days.

Bruce B · Aug 30, 2010

We use meters by Dorrough...

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Measuring power output in real time

Nicholas Bedworth

WBF Founding Member

DonH50

Member Sponsor & WBF Technical Expert

Nicholas Bedworth

WBF Founding Member

DonH50

Member Sponsor & WBF Technical Expert

amirm

Banned

DonH50

Member Sponsor & WBF Technical Expert

microstrip

VIP/Donor

Bruce B

WBF Founding Member, Pro Audio Production Member

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