Quote:
Originally Posted by Kabeer /img/forum/go_quote.gif
Hi,
I once found a site showing an ideal Freq. reponse graph for headpones (NOT flat as a ruler). It was called some fancy scientific name. But I can't find it again.
Does anyone know of it? Can you please post a link.
Thanks
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That's a very complicated question upon which experts do not seem to agree at all. It makes for lots of nice arguments though.
There are major problems in the design of headphones that don't apply to speakers. Due to the shape of the outer ear, which varies from person to person, big resonances can result from interactions due to the close proximity of the outer ear to the headphone drivers, especially in the treble frequencies (about 3 khz to 10 khz) resulting in very large treble spikes, especially if it's not considered in the design of the headphone. A little extra kick in the bass seems to be needed for headphones because we miss the visceral feeling of bass with headphones. The difference in imaging with headphones (no opportunity for the left ear to hear what is sent to the right ear and vice versa) can result in complications in the way the intensity of certain frequencies is perceived (for example, bass frequencies). There is a pretty well-established preferece for most people not to have neutral highs being blasted down their earholes (it strikes people as too much treble). And some people may want to listen to headphones at less than realistic live volumes, so the well-documented loudness compensation curve might come into play there. Etc.
Bottom line: There's still a lot of art in headphone design, IMHO.
I beleive that diffuse field equalization is just one school of thought for headphone design. The headphones I have heard that employ it I didn't really like at all (for example the AKG K240DF, I think it was called).
It seems to me that the really very difficult thing is, you can't run double blind tests with headphones as a practical matter, like you can with speakers, so it's not a problem that is susceptible to being solved with empirical data as to preferences using tests where you can scientifically remove bias. With speakers there is a lot of double-blind research and computer modeling and statistics as to what most people prefer. I don't think you could do that with headphones. So you may see patterns in the Senn sound, the AKG sound, the Grado sound, the Sony sound, the Beyer sound, each perhaps reflecting very different interpretations of how to navigate all of these problems.
Even just how to measure frequency response of headphones seems to be exceptionally problematic, much less what the ideal frequency response is if you think you can measure it.
Edit: I just noticed this link that ClieOS provided goes into a few of the issues I referred to in this post:
http://headwize.com/articles/hguide_art.htm#diffuse
One quote from the link:
A headphone with a true flat response will sound terrible, because what the ears perceive as a "flat" response actually has many peaks and valleys due to interaction of the sound with the listener's head before it reaches the ears. Instead, headphones are often equalized to sound flat.