[Brent Hutto]

So in reading up on various closed, circumnaural headphones that might fit my listening preferences some of them are always discussed with the caveat that an amplifier is required because their impedance or lack of sensitivity makes them "hard to drive". What is the actual sound of a headphone being driven insufficiently?

My only experience is with plugging my PX200 into the headphone jacks of a) my iPod Mini, b) my old Adcom CD player and c) my Onkyo home theater receiver fed by a DVD player. I'd say there's a slightly more lively sound when the HT receiver (and incidentally its DAC) is converting a CD into headphone juice for me as compared to the iPod but it's pretty subtle. The Adcom CD player must be sort of in between because it's hard to tell a difference between it and the iPod on one hand or it and the Onkyo on the other.

So assuming that the receiver and CD player have somewhat more robust headphone outputs than the infamous iPod Mini with the easy-to-drive PX200, would plugging in something like an AKG K271 be just a worse version of the same effect? Or would a low-sensitivity, 55-ohm headphone cause an obvious breakdown in the sound quality i.e., crackling or distortion or tinny "AM radio" sound?

The reason I ask this is that I'm fundamentally of the attitude that I'll believe it when I hear it and maybe not even then. Many years ago when I spent too much time hanging around high-end stereo shops I got the point where I'd declare something "almost unlistenable" that my wife or friends would think sounded out of this world great. I found that staying away from audiophile gear for a decade or so mostly extinguished the urge to try and hear the flaws in a musical reproduction that is actually very, very good. For instance, with my PX200 I can hear that 128kbps AAC files tend to sound flat and crummy at times but when I try to compare 192kbps and 320kbps ones to the original CD it's a matter of listening very carefully to short segments of music over and over until I can pick out some particular artifact or missing inflection. So I just encode them at 256kbps and quit listening to see if I can spot the errant bits.

So I have this idea that a K271 will sound just great plugged in to my CD player with no headamp. Heck, I'll bet I can plug it into my iPod Mini and that lovely warm midrange will sound...well, lovely and warm. Now would an A900 or DT660 do a better job on the iPod's puny headphone jack? I guess it's plausible enough that they might. But if I don't want a U-shaped tonal quality with bass and treble but "recessed" mids (A900) or a super-bright lively Jack Russell terrier sound (DT660) then I don't really care how fully they reach their potential on my portable rig, do I?

So what's your vote? Are we talking a subtle shortcoming whereby "needs an amp" means I'm missing out on a tighter sound with a little more detail audible? Or is it a case of "needs an amp" in order to sound better than a pair of Apple earbuds?

FWIW, all this is in the context of bluegrass and Celtic acoustic music, female vocals and the odd 80's rock song for variety. No hip-hop (not that there's anything wrong with that) no screamin' guitars or mess-your-pants subsonic bass thumps needed.

 

[Kirosia]

I personally wouldn't run a power-hungry phone straight from a portable, with a few exceptions. It won't necessarily sound bad, but it probably won't be great. And that's what we're shooting for right? "Good" means nothing!

If your CD player already has a decent built-in headphone amplifier or you have a good phone-friendly receiver, it can be hit or miss. Some of have said their players did a good job, others say it's sucketh donkey parts. Either cause the amp is horrid, or the impedance is an issue. Or both.

 

[bigshot]

It wouldn't necessarily be crackly sound or distortion... it would be weak bass and flattened dynamics (no punch).

See ya
Steve

 

[jbunniii]

Quote:

Originally Posted by bigshot It wouldn't necessarily be crackly sound or distortion... it would be weak bass and flattened dynamics (no punch).

Additionally, you may not be able to get the volume that you want. I tried my old Sennheiser HD-600 briefly with a portable CD player at work before giving in and buying an amp. Even with the volume maxed out, it wasn't very loud. Bass was present but somewhat weak and not nearly as tight or well controlled as with an amp.

On the other hand, I've had pretty good sound with Grados (especially the RS-1) straight out of an MP3 player's headphone jack.

-jbunniii

 

[Jahn]

extremely distant, quiet, muffled, 2-D sound.

 

[TheSloth]

'Hard to drive' is not as simple as it sounds. High impedence 'phones are described as 'hard to drive' as they require a relatively high voltage - in reality they are easy to drive, requiring low current. Very low impedence 'phones are hard to drive as they require a relatively high current. Portable systems have trouble with very low impedence 'phones just as much as they do with high impedence. It just seems more obvious with high impedence as they simply don't play at reasonable volume.

 

[South_Korean]

bad... hard to drive means hard to drive, if you dont have the sufficient amount of current going to them, youll end up like the people who forgot to amp their DT770's and asked: "wheres the bass?"

 

[Buster Sword]

Sounds like a concert listening from outside the stadium or the wall next to it at best.
dark very dark sound.

 

[nikongod]

my portable drives my k-240-m's to reasonable volumes, but it is buga-jilions of times better with the amp.

 

[adhoc]

for voltage hungry phones (generally high-Z), they'll just be soft.

for current hungry phones (generally low-Z), there will be a bit of distortion.