[ishmael]

In researching the LCD-2, Schiit Lyr, HE-6, etc... I've come across something I don't understand. It seems we are in a time of "power wars", and by that I mean sort of an arms race where more amps are coming out with more power (Lyr, Toucan, SR71B, EF6, etc). I notice more and more people saying things like "the EF5 is OK at 2watts per channel, but more power is better" (when discussing certain headphones of course).
 
My question is: is there really any evidence that we NEED this much power? That it is doing anything other than giving us an unrealistic and unnecessary maximume volume level, that would kill our headphones/hearing anyway?
 
I was reading this for example  http://www.leckertonaudio.com/2011/01/uha-6s-harmonic-distortion/ And he used the familiar measurement where even 1mW is giving reasonable volume with a Sennheiser HD600. I know ortho models are harder to drive but is there any scientific basis for needing 3, 4, 6, etc watts per channel? Or is it just like many other things, where we demand an incredibly oversized power supply even in something that doesn't really demand it (like a DAC).

 

[EthanWiner]

One good reason for plenty of power is to have enough reserve to handle brief but loud transients. This makes reproduced music much more lifelike. For example, a live snare drum can have a huge amount of SPL for a very brief time. So the overall level in the room is not ear-splitting. But to reproduce it accurately still requires a lot of current from the power amp. (The speakers also have to be able to handle loud brief transients without distorting.) I'm sure the same concept applies to headphones.
 
In my home recording studio I have a pair of very large "old school" JBL speakers. They're bi-amped with more than 1 KW from a pair of Crown stereo power amps. Yes, the overall volume can go very loud, but I rarely play above 90 dB SPL. The real reason for all that power is for improved clarity at more reasonable volumes.
 
--Ethan

 

[yuriv]

For digital sources, we can estimate the power requirements: Play your music as loud as you possibly ever want to listen to it. Hopefully, you're not running your amp too much into clipping. Next, play a test tone that's 40 dB below full scale and measure the voltage at the speaker terminals (or headphone jack with the headphones plugged in). 60 Hz tones work well because even cheap DMMs are accurate with them. Then do the math.

You can even adjust your reading to allow for your converted signal to momentarily overshoot digital maximum. Depending on your speakers' or phones' sensitivity, you may be surprised by how much (or how little) power you really need.