[Headdie]

Stereophile: Between the Ears: the art and science of measuring headphones

 

[Nocturnal310]

Headphone pr0n...i always love it.

 

[G-man]

An interesting article, but as Stereophile often does, there was an overuse of jargon. Still, the most interesting part of the article was at the start, when he talked about the the rise in sales. It is most definately reflected in the market. There is a huge influx of "mid" end phones, 100-200 dollars, or in UK standard 50-100 pounds (at the time of the article).

I would not surprise me if people just got bored of the article half way through. Although I am not advocating their other type of journalism (you what I mean), and it is refreshing to see some use of science in this market, the article does portray a very evident problem. The information can be too esoteric for most people to use it in an effective way. I know I didn't understand all that was said, and i am sure few people did.

Still, it is nice to see a rise both the acceptance of headphones, and the use of science in reviews.

G-man

Edit:
Perhaps this would be better suited for the science forum?

 

[rederanged]

I read that article in Stereophile last month, and was hoping they'd post it on their web site. Thanks for the link. I thought the discussion of the free-field versus the gestalt model was interesting. It may at least partially explain why a "flat response" headphone is hard to find: no one can even agree on what "flat" means when it comes to headphones!

 

[dosquito]

interesting

 

[eruditass]

i just read the first page and still do not understand why it is hard to consider what is flat for circumaural headphones. Flat sound is flat sound before it interacts with the skin and the outer pinnae, with the very slight exception of air attenuation, while maintaing everyone's unique biological ear transfer function.

HRTF's are meaningful for imaging, but not frequency response of one side of a headphone. If anything, supra-aural and earbuds/inears are what is impossible to agree on flatness, but circumaural should not be nearly as hard, save the direction of the drivers hitting the pinnae. The one paragraph seems to state the opposite.

I've never understood the desire to create fake ears when you are only adding to the problem, except in the case of supraaural and in ears. The microphone should be outside of the fake ears in a room with as little reflection as possible to observe "flat" sound to circumvent everyone's unique ears and have us each color the sound with our outer ears the way we naturally do. as for non circumaural headphones.. you're SOL. However consideration of reflections off of the skin arond the ear is understandable to take into account.

The other problem is sound engineers not using the agreed upon flat sound, resulting in a colored record. even things like different room shapes or distance from monitors, angle of monitors, etc. can influence this.

edit: i see that DF/FF is what takes most of the cake for the problems and think that study should focus on this instead of fake ears for circumaural phones to isolate the problem.

as for impedance matching, i didn't think it had this much of a problem at lower frequencies (i've delt with it in high frequency digital systems) but i suppose it does, and this is where everyone should start believing in synergy. however, I was under the impression that higher impedance means less current which means less volume, so the way they superimposed the images is in reverse.

 

[nikongod]

Quote:

Originally Posted by DoomzDayz /img/forum/go_quote.gif i just read the first page and still do not understand why it is hard to consider what is flat for circumaural headphones. Flat sound is flat sound before it interacts with the skin and the outer pinnae, with the very slight exception of air attenuation, while maintaing everyone's unique biological ear transfer function.

While I agree that you can establish a flat response in an "ideal situation" I think this is no different than people who buy a speaker designed for flat response in an adiabatic chamber, only to see the **** they get when they put them in a real room.
Quote:

as for impedance matching, i didn't think it had this much of a problem at lower frequencies (i've delt with it in high frequency digital systems) but i suppose it does, and this is where everyone should start believing in synergy. however, I was under the impression that higher impedance means less current which means less volume, so the way they superimposed the images is in reverse.

What is weird is that the effects of "correcting source impedance" are very different for different headphones. The headphones that change the most when you change output impedance are the ones with big fluctuations in their impedance.

If you compare a "120 ohm" source to a "0 ohm" source with levels matched at 1khz, the fluctuations in the impedance in the bass region will cause a BIG output level spike there. The voltage output of the 0-ohm source is the same when feeding a 32 or 300 ohm load. The voltage output from the 120 ohm source varies GREATLY when driving a 32 or 300 ohm load. this variance in voltage output interacts with the load impedance and puts more voltage and power through the driver in this region. Thus the spike in output level.

 

[rederanged]

Quote:

Originally Posted by DoomzDayz /img/forum/go_quote.gif i just read the first page and still do not understand why it is hard to consider what is flat for circumaural headphones. Flat sound is flat sound before it interacts with the skin and the outer pinnae, with the very slight exception of air attenuation, while maintaing everyone's unique biological ear transfer function. HRTF's are meaningful for imaging, but not frequency response of one side of a headphone. If anything, supra-aural and earbuds/inears are what is impossible to agree on flatness, but circumaural should not be nearly as hard, save the direction of the drivers hitting the pinnae. The one paragraph seems to state the opposite.

The comment about the in-ears / earbuds struck me as strange, too.

This is my understanding, so please correct me if I'm getting something wrong.

There's an underlying assumption that headphones should try to reproduce the experience of listening to stereo speakers in their traditional forward location. With headphones, the sound is coming more or less directly in from the side, so the pinnae and other parts of the head do not have the same spectrum of attenuation. There are also delay and crossfeed aspects of imaging which I don't believe are addressed. Putting those aspects of imaging aside, and assuming we had a "correct" HRTF, then, since music is typically mastered with stereo speakers in mind, it should at least be possible to produce a headphone response curve that would be perceptually flat for someone with a head shape corresponding exactly to that for which the HRTF was created.