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Speaker sensitivity, impedance, and calculating amp power

This is an elementary question, but I'm not quite understanding how to match amp power to speakers. When I searched around on this forum, I found many discussions which went deep into the weeds. I am hoping for a way of calculating the level of amplifier power I need for speakers with different sensitivities and impedances.

If you have the patience, here's the basic question. So, I've learned that one must consider a number of factors to calculate the amount of amplifier power to drive the speaker:

Sensitivity of the loudspeaker
Loss of db at the listening position
SPL desired at listening position
Amount of headroom desired

Most discussion of the demands a speaker will make on an amp focus on the speaker sensitivity. But the speakers I'm considering vary also in their impedance. How would I use both of those factors to estimate necessary amplifier power to drive them with a comfortable amount of headroom?


128x128hilde45
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audiokinesis
2,713 posts
 
Hilde45 quoting the great Jim Salk: " While the RMS meter registered 5 - 8 watts, the peak-reading meters hit peaks of 200 - 250 watts during instantaneous transients (drum hits and the like). " 

This is very interesting information. The implication is that we would benefit from 14 dB to 17 dB of headroom above our average SPL, which corresponds with having from 25 to 50 times more power available.  

Obviously it’s easier to get there with high efficiency speakers, though elsewhere in the passage hilde45 quoted Jim makes some insightful arguments for the lastest drivers having modest efficiency. 

Duke
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hilde45 OP
4,783 posts
 
@audiokinesis Right -- and, FWIW, I think the speakers mentioned here are that way because they're small and yet can do bass pretty well. Other speakers Salk makes are not as insensitive, e.g. the  Song3 Beats. 

@tvad Good suggestion. That may be the way to go. I'm going to hear some Atolls tomorrow and some Quicksilver. Just to hear them -- and they'll play through Dyn Evoke 10s, so we'll see how they perform. Later, when I have the Salks, I'll try out some amplification in my home, and maybe via Reno. 
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hilde45's avatar
hilde45 OP
4,783 posts
 
Thanks -- I am so glad to know that, and will go take a look at his speakers. 
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