Re: What's the use of a 192 kHz sample rate?

In rec.audio.tech Jerry Avins <jya@[EMAIL PROTECTED]
> wrote:
> John Phillips wrote:
> > On 2008-05-07, Steven Sullivan <ssully@[EMAIL PROTECTED]
> wrote:
> >> ...              It seems extremely likely, for example, that no one 
> >> can actually *hear* frequencies above the mid-20 kHz.  They can be 
> >> perceived via bone conduction, if the signal is  generated right at 
> >> the skin surface.
> > 
> > This seems to be confirmed in Ooha****'s 2006 "Hypersonic effect" paper
> > [1] which seems to show that the "inaudible high frequeny content"
> > of his test material is not perceived directly through the ear but is
> > perceived through the body surface.
> > 
> > In this development from his 2000 paper [2] he seems to show that his
> > subjects' highest comfortable listening level is increased by the 
> > presence of inaudible content when not applied just to the ear.
> > 
> > [1] http://linkinghub.elsevier.com/retrieve/pii/S0006899305019499
> > 
> > [2] http://jn.physiology.org/cgi/content/full/83/6/3548

> Does he call the effect "bone conduction"?


Depends on which paper you look at.

In the older one (2000):


From an authentic view of human auditory physiology, it is not
straightforward to explain the 
neuronal basis of the hypersonic effect characterized by the fact that
HFCs showed significant 
physiological and psychological effects on listeners only when presented
with audible sounds. 
Although how inaudible HFCs produce a physiological effect on brain
activity is still unknown, 
we need to consider at least two possible explanations. The first is that
HFCs might change 
the response characteristics of the tympanic membrane in the ears and
produce more realistic 
acoustic perception, which might increase pleasantness. However, this
hypothesis is unlikely 
to explain the fact that the subjects who showed significant hypersonic
effect were not 
necessarily aware of the difference of sounds in a conscious manner. An
alternative 
explanation is that HFCs might be conveyed through pathways distinct from
the usual 
air-conducting auditory pathway and therefore might affect the CNS,
including the deep-lying 
brain structure. It was re****ted that the vibratory stimulus of ultrasound
modulated by the 
human voice activated the primary auditory cortex (Hosoi et al. 1998) and
was successfully 
recognized by people with normal hearing as well as those whose hearing is
totally impaired 
(Lenhardt et al. 1991). Recently evidence has ac***ulated that stimuli
outside the frequency 
and amplitude boundaries of an auditory neuron's receptive field can
influence responses to 
stimuli inside the classical receptive field determined with pure tone
stimuli (e.g., Schulze 
and Langner 1999). This modulatory interaction between inside and outside
the classical 
auditory receptive range is noteworthy. However, we cannot conclude that
the neural mechanisms 
incor****ating ultrasound hearing, including the bone-conducting auditory
pathway, are the 
system responsible for the hypersonic effect, which involves the brain
stem and thalamus. 
These regions showed decreased activity compared with the baseline when
HCS [high-cut sound] 
was presented and thus may not belong to the conventional auditory
perception system. 
Therefore participation of nonauditory sensory systems such as
somatosensory perception also 
needs to be considered in further investigations.


In the newer one (2005)

Another example comes from a recent re****t on ultrasonic sound hearing
(Lenhardt et al., 1991 
M.L. Lenhardt, R. Skellett, P. Wang and A.M. Clarke, Human ultrasonic
speech perception, 
Science 253 (1991), pp. 82.85.). People with normal hearing as well as
those whose hearing is 
totally impaired due to a disturbance of the inner ear can successfully
recognize speech 
signals that were modulated into the ultrasonic range and presented as
vibratory stimulus. 
Such a bone-conducting auditory system may have some effect on the
emergence of the hypersonic 
effect.




-- 
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