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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

Showing 4 responses by tomic601

tomic601's avatar
tomic601
12,744 posts
 
Impedence and phase angle, there is always that nasty and...

I always liked the late great Roger Modjeski advice on the subject ( which you find w search this site ), measure SPL and use a DMM at speaker terminals.

OP there was nothing wrong with your post, as you can see there are some awesome contributors this site
tomic601's avatar
tomic601
12,744 posts
 
Question 3 is about duty cycle....

is that “ word salad “ enough ?

its easy but math and science based...
tomic601's avatar
tomic601
12,744 posts
 
The 2nd question, so you can get started on it is: what is the spectral density of the music you listen to ?

fewer still own and pay attention to a RTA ( real time analyzer )

a current “ client “ of mine ( pro bono ) is using three tracks to evaluate potential systems and size his speaker/amplifier...

the difference in spectral density is off the charts different and proof he does not need a subwoofer... just well engineered full range speakers.. 
tomic601's avatar
tomic601
12,744 posts
 
It’s not always about educating or helping the OP, as many will read this thread but fewer actually contribute in a positive way other than to ascribe a narrow view , perhaps just personal bias.

we in the business of helping studios, bands, mastering engineers, recording artists and audiophiles start with a discussion of target SPL. Most people, including on this venerable free admission site don’t actually own an accurate SPL meter or have any idea how loud a trumpet is from
say 30’ ?

so OP, let’s start there, how loud ?
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