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How much power do I need? Find out using this method...

I've been hanging out on diyaudio and ran across this simple technique to measure the power used by your speakers.  So many discussions here revolve around this question that I thought I'd post the method...

If you have a multi meter, you can use the test tone & technique provided here to calculate how many watts your speakers actually use: https://www.diyaudio.com/forums/multi-way/204857-test-voltage-power-speakers.html

It’s super informative & useful: all you do is set your volume at the max listening level you use, then play the -12db 120hz test tone while measuring voltage at the speaker terminals. Square that value and you’ve got the maximum watts needed. Plenty to read at the link...
cal3713

Showing 3 responses by elevick

elevick
2,638 posts
 
For a speaker rated at 90db:
1 watt should produce 90db
2 watts 93 db
4 watts 96 db
8 watts 99 db and so on...
Keep doubling the power to gain 3db.
Every 10 db should double the "perceived" volume.
elevick
2,638 posts
 
mijostyn,
I'm confused with the 6db being an earthquake?  Are you referring to 95 as the base line and +6db as the earthquake?  My system isn't so unusual but 95 db is a joke.  My Coincident speakers are 94db at 1 watt.  My 325 watt Mac is overkill to attain 95db.  My other amps are 100 watt tube monoblocks which obviously have different distortion than the Mac.
Would I call 95 loud?  Sure.  95 for a movie is more likely.  Dynamic headroom is a big difference.  No one listens at an exact sound pressure level the whole time.  I'm a bit confused.
elevick
2,638 posts
 
Sorry, but I never use a sound pressure meter while listening.  I have listened to the Dead drum solos many times...but never "sober".
I wish I could hear a 1db difference.  All I know is my work system is only 10 watts but with 95 db single driver speakers...
Maybe I'll try a sound pressure meter at work, not while tripping :-)
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