What does more power do for Magnepans?

Mr. T,

Wasn't picking on you, just wondered. About where I sit from my 1.6's.

I know you like solo and small ensemble acoustic music and evidently the smaller tube amps work well for you. It is just so opposite from my (I will admit, limited) experience.

I went from single 170w integrated, to two 170w amps in a passive biamp, and finally two 170w amps in an active biamp configuration and enjoyed an improvement with each addition of power.

Different strokes for different folks!

Jim S.

i listen to orcehstral as well as small ensembles. i just don't listen loud and low power amps seem to work for me.

I tried to go back and study some of the math about maggies and power. These were pointed out by others; I am just trying to pass on their work and analysis correctly.

First thing I ran across was the way Magnepan spec's the efficiency. 86db/1m/2.83V. Evidently 2.83V into 4ohms is 2 watts and not the traditional ~db/1m/1w scale. At 1m/2w efficiency works out to 83db.

If you listen to music at a level that produces 83db peaks (fairly restrained, but still dynamic) and sit 3 meters away it flows like this.

2w/1m = 83db with one speaker
Second speaker adds 3db for 2w/1m = 86db
Subtract 3db for each additional meter away from the speakers 2w/3m = 80db
Each additional 3db doubles power required - to add 3db – 4w/3m = 83db
Figure the peaks @ 83db are 6db above the average spl = 1w/3m/76db

This ignores room loading, absorption, and the fact that the 2w/1m/83db is with a test tone, but on the surface, the amount of power needed doesn’t seem that great for modest listening levels.

If you listen at a level that produces 95db peaks it would go something like this…

2w/1m = 83db with one speaker
Second speaker adds 3db for 2w/1m = 86db
Subtract 3db for each additional meter away from the speakers 2w/3m = 80db
Double power for each additional 3db;
4w/3m = 83db,
8w/3m = 86db,
16w/3m = 89db,
32w/3m = 92db,
64w/3m = 95db

64w. Still not a lot of power for what, to me, is a fairly loud 95db peak.

It doesn’t match my (admittedly limited) experience, so I am fairly assured that I have stated something incorrectly or there is another important factor that is missing.

You won’t hurt my feelings by pointing out the flaws in the above but I do find the result interesting if it holds true

Jim S.

One thing wrong with your calculation. One subtracts 3db for every doubling of the distance, therefore 2m=-3db, then 4m=-6db, not 3m=-6db. 3m would be close to -5db, I suspect.

Bob P.

The biggest problem with that calculation is that to obtain a subjective doubling of loudness requires ten times the amplifier power. See: (http://www.gcaudio.com/resources/howtos/voltageloudness.html)