How does VOLTS = WATTS???

[mk5150]

I see on the forum that just about all references to power handling is measured in volts, "send (this many) volts to your speaker to break it in" and "do not push more than (this many) volts to this driver and so forth
I am not new to running sound systems and my current system is definetly no slouch, but i am lost when i hear the "volts" term, how do I translate Watts into volts? 1 watt equals how many volts or visa versa??

[Bill Fitzmaurice]

how do I translate Watts into volts?

Ohms Law. We don't consider watts because there's no way to either measure or limit them. Voltage is easily measured with a VOM/DMM, and limited with, of all things, a limiter. Besides, amplifiers aren't power sources, they're voltage sources, and speakers aren't driven by power, they're driven by voltage swing. Watts could be a useful measurement tool if loudspeakers presented finite constant impedance loads, but they don't.

[Grant Bunter]

Old electrical equation:
Where P = power in watts
I = current
V = volts

P= IV

We talk about volts here because you can measure volts.
Watts, as seen from the above equation, are calculated.

[mk5150]

alright, that all makes sense to me, now how do I test it? For example, crown xti 2000, how would i check voltage output and what tools are needed to do so?? And does the same apply to testing all power amps??

[Bruce Weldy]

Use this to calculate watts to volts and vice versa......

http://www.sengpielaudio.com/calculator-ohm.htm


Measuring voltage is very simple. Disconnect the speakers, crank the volume on the amp to the max, and apply an input signal. Use a voltage meter on the speaker outputs to determine voltage.

BTW, I was in the same boat.....ran sound for thirty years and had never considered volts.

[mk5150]

[quote="BTW, I was in the same boat.....ran sound for thirty years and had never considered volts.[/quote]




Thanks Bruce, I was hoping I was'nt asking a silly question, but ive never considered anything other than watts since basically that is what we are used to when referencing power in pro audio, it makes sense though to measure in volts, i will start using this, I recently just picked up a new volt meter, i really dont know much about using them though!! Good time to start!!

[Bruce Weldy]

[quote="BTW, I was in the same boat.....ran sound for thirty years and had never considered volts.

Thanks Bruce, I was hoping I was'nt asking a silly question, but ive never considered anything other than watts since basically that is what we are used to when referencing power in pro audio, it makes sense though to measure in volts, i will start using this, I recently just picked up a new volt meter, i really dont know much about using them though!! Good time to start!!

[/quote]

that's where the calculator comes in handy. It gives you a starting point on how many volts you'll need to run a particular cab, then you convert that to watts and then weed through the amp market to see who you think isn't lying to you about the wattage ratings.

[Grant Bunter]

If you're new to your multimeter,

To measure amp output in volts set it to the 200 AC setting

You may find a sine wave into the amp input will not fluctuate as much as pink noise...

[Gregory East]

If you follow the maths gingerbread trail

Power = volts squared / impedance

[mk5150]

I want to say THANKS to everyone who has replied, im learning alot of new stuff on these forums, i appreciate it guys

[Radian]

Measuring voltage is very simple.

Aww Bruce...you didn't just say that?!

I personally find that Sengpiel website tough to navigate through sometimes.

Take a look at these two sites:

http://www.the12volt.com/ohm/ohmslawcalculators.asp
and
http://www.net-comber.com/decibel.html

Same stuff, but a little cleaner UI, IMHO.

[Gregory East]

There is a sticky "how to set limiter" somewhere in hints or education sections.

[Bruce Weldy]

Measuring voltage is very simple.

Aww Bruce...you didn't just say that?!

I didn't say explaining it was simple, just measuring it.

In the context of setting limiters for a PA.....it seems pretty simple to me. Hell, it doesn't even matter if you mix up the black thingie with the red thingie when you touch 'em to those whachamacallits on the back of the amp.

[Grant Bunter]

They are so not whachamacallits.

They be dooveywattsers...

[Bruce Weldy]

They are so not whachamacallits.

They be dooveywattsers...

No, you are thinking about the thingamabobs.