Ultrasone S-Logic
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Ultrasone S-Logic (Plus)" i innlegg
#9 inkl. en referanse til Tyll Hertsens' "
World's Best Headphone Review: The Ultrasone Edition 8" (skrevet for HeadRoom 12.01.2010).
Senere har Tyll Hertsens skrevet om "Ultrasone’s S-Logic" for InnerFidelity i "
The Ultrasone Edition 10":
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Ultrasone’s S-Logic
Ostensibly a method to improve the audios spatial qualities on headphones, Ultrasone’s S-Logic attempts to improve the image presented by placing the driver off-center, somewhat forward and down from the entrance of the ear canal. It’s widely known by headphone enthusiasts that moving headphones forward and down some generally improves the audio image. I’ve experienced this myself and agree that there’s some truth to it. In Ultrasone headphones, this placement is somewhat further forward and down than one could normally move a pair of headphones as they would no longer fit on the ear normally.
Ultrasone claims that by placing the driver this far forward and down next to the jaw, sound travels past the ear in a more natural way, eliciting acoustic reflections off the pinna (outer ear) that create the psycho-acoustic cues used for audio localization. Ptschyeah right, sound from my living room speakers doesn’t travel from my jaw and move up the side of my head past my ear. Sound from a speaker is essentially a planar wave front hitting your head at an angle.
In his 2004 AES Convention Paper: “The Causals of Headphones Tone Coloration Variations related on the Human Pinna Influence,” Ultrasone’s President, Florian Konig talked about the evidence for this belief, and had this to say about the measured observations of people wearing S-Logic Headphones:
“One [headphone] with a spatial reproduction of sound was much more conspicuous statistically, because of a higher quantity recommended sound quality judgements as 'too much' and 'less high frequency range' parallelly.”
What he’s saying here (I think --- the paper is terribly confusing to read, and I’ve attempted to understand it a half-dozen times over the years) is that the evidence that S-Logic works can be seen from the fact that people’s opinion is strongly split as to whether there’s too much or too little high-frequency response, and that strong deviation person to person is because their outer ears are able to do more spatial filtering of the sound. I don’t understand this logic. I would think if sound is more lifelike on the headphones, then people would tend to have a more consistent impression of it being lifelike. (I’ve linked to the paper in the resources at the end of this article. If you can figure it out, I’d love to hear about it.)
There are a number of headphones out there that are almost universally recognized as painting a good aural picture; the Sennheiser HD 800, some Stax, AKG K1000, are all very consistently heard as having good imaging. The common characteristic of these cans is that they project a planar wave at the listener’s ears from a slightly forward angle. It is believed that this plane wave coming at the ears produces a geometrically different set of reflections than a normal headphone where the small driver essentially acts as a point source and radiates a spherical section wave front towards the ear. I think I agree with this, and the improved imaging of moving a pair of headphones slightly forward is, in my opinion, just getting it closer to the angle at which sound approaches from speakers.
The Ultrasone S-Logic position is, however, dramatically off-center, and creates a situation where virtually no sound is radiated from the driver directly into the ear canal. (How many people think the Bose 901 Direct-Reflecting speaker imaged well? [crickets] Yeah … didn’t think so.) When I read the threads discussing Ultrasone headphones and the imaging performance of S-Logic, I see a lot of diverse opinion, that’s for sure. If Ultrasone was going for a headphone with lots of “sound quality judgements as 'too much' and 'less high frequency range' parallelly,” well, they’ve done it. Doesn’t sound like a good theory upon which to design good sounding headphones to me, though.
