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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?


hilde45

Showing 2 responses by audiokinesis

audiokinesis
2,764 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
audiokinesis
2,764 posts
 
Thank you very much, Tvad.

Hilde45, at the moment the best place to see my home audio designs is actually the James Romeyn Music and Audio website. My own website is under revision.

But my feelings would not be hurt if you ended up with something by Jim Salk. He offers a wide variety of extremely well-thought-out designs in heirloom-quality enclosures.

Duke
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