[vysis]

Can you do a quick test: at the same amp level, which headphone is louder?
 
I have both and my HD650 is louder at the same level than my AKG K701. I thought the 300ohms of the HD650 should make it more difficult to drive?

 

[KG Jag]

Quote:

Can you do a quick test: at the same amp level, which headphone is louder?
 
I have both and my HD650 is louder at the same level than my AKG K701. I thought the 300ohms of the HD650 should make it more difficult to drive?

Ohms is only one measure pertaining to efficiency.
 
I can tell you that it takes a little more to push my Q 701 than my HD 600.

 

[obobskivich]

Can you do a quick test: at the same amp level, which headphone is louder?

I have both and my HD650 is louder at the same level than my AKG K701. I thought the 300ohms of the HD650 should make it more difficult to drive?

The "level" on the volume control dial tells you nothing - it does not correlate to output power or anything of the sort. It's completely irrelevant.

The HD 650s are more sensitive than the 701s (by about 10 dB, which is roughly 2x), so assuming the amplifier is invariant (or pushes out enough power that we don't care and can treat it as invariant), they should be "louder" under the circumstances you've described. If it chokes into the impedance load the 650s present though, then it'll have problems.

Ohms is only one measure pertaining to efficiency.

How many years until we get from "Ohm rating" to "nominal impedance" ? :blink:

Nominal impedance has nothing to do with efficiency. It has to do with complex resistance of the system. Efficiency for all dynamic drivers is VERY low.