So I've been trying to balance the subjective side of audio with the objective. I see, quite often actually, that people claim X amp can provide enough power to get Y headphone to sound loud, but Z amp has more power and it makes Y headphone really "sing." So from that comparison, people often say Y headphone really NEEDS a lot of power to "sound good."
The LCD-2 with the O2/ODAC is an example I see often.
What in tarnation does this even mean?
Yes I know the basic power calculations and how to determine how much power an amp needs to provide at a specific impedance:
Power (W) = (VRMS^2) / (headphone impedance)
Power needed to reach 115 dB SPL (loud-volume, dynamic music situation) = [headphone power to reach 90 dB SPL, as provided by Innerfidelity.com for example] * 2^8.3333
8.3333 = (115 dB SPL - 90 dB SPL) / 3
Doubling the power increases the SPL by 3 dB
For an LCD-2.2:
Power needed to reach 90 dB SPL: 0.87 mW
Impedance at 1 kHz: 58 Ω
280.603 mW to reach 115 dB SPL at 58 Ω
The O2 provides more than enough power if I am interpreting these numbers correctly:
355 mW at 150 Ω
613 mW at 33 Ω
Sure maybe with an HE-500, the O2 might not provide enough power for an HE-500:
Power needed to reach 90 dB SPL: 2.04 mW
Impedance at 1 kHz: 47 Ω
657.980 mW to reach 115 dB SPL at 47 Ω
But by these calculations, the O2 is just fine with the LCD-2.2, no? I've tried an LCD-2 with my own O2 and it sounds just fine. I would subjectively say that it actually sounded better than any tube amp setup I've heard them on.
So then my question is: what does "sing" mean for a headphone?
According to the Merriam Webster dictionary, by definition, sing means:
a : to produce musical tones by means of the voice
b : to utter words in musical tones and with musical inflections and modulations
c : to deliver songs as a trained or professional singer
: to make a shrill whining or whistling sound
a : to relate or celebrate something in verse
b : to compose poetry
c : to create in or through words a feeling or sense of song <prose that sings>
: to produce musical or harmonious sounds <birds singing>
So why do people suggest the LCD-2 needs more power than what the O2 can deliver? Are they suggesting that a 10 W amp is going to magically make the LCD-2 sound 500 times better than on the O2? People say Z amp sounds better with headphone Y than X amp, but do people ever consider that the amps are inherently different from the start and that their power output might not actually matter? Will an O2 with the exact same specifications but with 2 times the power output really make headphone Y "sing"?
I am utterly confused. Do so-called audiophiles even know what they are talking about when comparing amps with headphones?
Likewise for earphones actually. I've recently read a few inquiries about NEEDING an external amp with a PMP to provide power for earphones.
Even if the earphones were really inefficient and required 0.1 mW to reach 90 dB SPL at 16 Ω, you wouldn't need more than 15 mW to reach 111 dB SPL. A $40 USD Sansa Clip Zip provides more power than you really need for those purposes.
Edited by miceblue - 6/26/13 at 5:39pm