Are these measurements still accurate? I just got an Apple dongle and tried it with the Focal Utopia, which I was excited about as I thought they would be the one set of high-end headphones I could use with a phone. I did the following calculations:
Focal Utopia impedance: 80 ohms
Apple adapter power at 33 ohms: 31 mW
31 mW * (33 ohm / 80 ohm) = 12 mW
Focal Utopia sensitivity: 104 dB / mW
Max volume = 104 dB + (3 dB * log2(12)) = around 112 dB
That should be quite loud. But even when I turn the volume all the way up, the headphones are just barely listenable. I'm getting maybe 80 dB.
Anyone know what's up here? I know it seems silly to connect $4,000 headphones to a $9 DAC, and I of course have a desktop rig, but I was actually looking forward to this working. The calculations say it should but it's not.
Is the Apple adapter louder on iPhone? I'm using it with an Android phone.