Speaker sensitivity, impedance, and calculating amp power

I have no idea how you would do it.  

How I would do it is not waste one minute of my time on hard to drive inefficient speakers. There are an awful lot of really great easy to drive speakers 86 dB or greater sensitivity. Pick any one of them and a really good 30 watt (tube, or 60 SS) amp is all you need. So why over think it?

Here’s another good reason to KISS: both sound levels and the power needed to achieve them are logarithmic. What this means in layman’s terms is that to go even just a little bit louder- arbitrarily picking 3dB as just a little bit, because it is- calls for not a little more power but TWICE as much.

So you can knock yourself out crunching numbers, for all the good it will do you, because they will always bring you back to what I said in the beginning. Either you get reasonably efficient reasonably easy to drive speakers, or spend the rest of your life hunting for the unicorn 1000 watt into 1 or 100 ohm amp. Which, sad to say, a lot of guys never do figure out and wind up doing exactly that.

Up to you. Choose wisely.

Honestly, as some one who does a lot of measuring and critical listening, this is difficult. It seems amps are more sensitive to speaker impedance than we think, so current is important, but the rated power at 8 Ohms is not really.  Usually 50-100 W is plenty for a modest listening area with your standard 2 or 3 way speaker.

Looking at the speaker impedance, look for dips below 4 Ohms, and that will tell you were it will challenge an amplifier, and what areas of music to listen for while buying.

Use your own ears. :)

Best,

Thanks, Erik. While this question may have a practical upshot, it’s really a theoretical question. I appreciate your efforts to answer it.