Gain of an IIR Filter

glen herrmannsfeldt <gah@ugcs.caltech.edu> wrote in 
news:6dednUImAoWPokLbnZ2dnUVZ_qCgnZ2d@comcast.com:

> 
> Musical signals are processed in a different part of the brain,
> though with some overlap (otherwise the stereo people would
> be out of business).  It seems that this sense is not so
> sensitive to phase.

All the ITD and ILD processing are built right into the brain stem.  Music 
can't skip over them.

-- 
Scott
Reverse name to reply

glen herrmannsfeldt <gah@ugcs.caltech.edu> wrote in 
news:6dednUImAoWPokLbnZ2dnUVZ_qCgnZ2d@comcast.com:

> I have been told that the ear generates nerve impulses at the
> peak of the sine for low frequencies, and at the peak of some
> (but not all) sines for higher frequencies.

The former is correct, the latter isn't.  

-- 
Scott
Reverse name to reply

Scott Seidman wrote:

> glen herrmannsfeldt <gah@ugcs.caltech.edu> wrote in 
> news:6dednUImAoWPokLbnZ2dnUVZ_qCgnZ2d@comcast.com:

>>I have been told that the ear generates nerve impulses at the
>>peak of the sine for low frequencies, and at the peak of some
>>(but not all) sines for higher frequencies.

> The former is correct, the latter isn't.  

The one who told me that actually does experiments putting electrodes
in the aural nerves and watching the impulses.  What source do
you have that disagrees with that?

-- glen

Scott Seidman wrote:

> glen herrmannsfeldt <gah@ugcs.caltech.edu> wrote in 
> news:6dednUImAoWPokLbnZ2dnUVZ_qCgnZ2d@comcast.com:

>>Musical signals are processed in a different part of the brain,
>>though with some overlap (otherwise the stereo people would
>>be out of business).  It seems that this sense is not so
>>sensitive to phase.

> All the ITD and ILD processing are built right into the brain stem. 
> Music can't skip over them.

I didn't mean that the signals skipped over them, but the processing.

That is, the part that senses musicalness.  (Pleasing tones vs. harsh
tones.  Trombone from trumpet.  Anything other than the direction
of the source.)

-- glen

glen herrmannsfeldt <gah@ugcs.caltech.edu> wrote in 
news:0YWdndSZU5Xd033bnZ2dnUVZ_jOdnZ2d@comcast.com:

> Scott Seidman wrote:
> 
>> glen herrmannsfeldt <gah@ugcs.caltech.edu> wrote in 
>> news:6dednUImAoWPokLbnZ2dnUVZ_qCgnZ2d@comcast.com:
> 
>>>I have been told that the ear generates nerve impulses at the
>>>peak of the sine for low frequencies, and at the peak of some
>>>(but not all) sines for higher frequencies.
> 
>> The former is correct, the latter isn't.  
> 
> The one who told me that actually does experiments putting electrodes
> in the aural nerves and watching the impulses.  What source do
> you have that disagrees with that?
> 
> -- glen
> 
> 

http://www.amazon.com/Introduction-Physiology-Hearing-
Second/dp/0125547544

Of course, everythings a continuum, and we can argue about how high is 
high.  This has more to do with the fastest neural discharge rates than 
anything else-- the neuron can only fire so fast, and above that rate, 
phase locking just can't happen.  So, in some frequency range, both ITD 
and ILD are available, but above that frequency range, ILD only are 
available.  ITD cues are dependent on the peak detection, which just 
can't happen above some frequency.



-- 
Scott
Reverse name to reply

glen herrmannsfeldt wrote:

> Scott Seidman wrote:
>> glen herrmannsfeldt <gah@ugcs.caltech.edu> wrote in 
>> news:6dednUImAoWPokLbnZ2dnUVZ_qCgnZ2d@comcast.com:

>>> I have been told that the ear generates nerve impulses at the
>>> peak of the sine for low frequencies, and at the peak of some
>>> (but not all) sines for higher frequencies.

>> The former is correct, the latter isn't.  

While looking for a reference, I instead found this one:

http://www.cco.caltech.edu/~boyk/usenet.htm

I think it is relevant to the discussion, though not to this
specific question.

-- glen

Scott Seidman wrote:

(snip on phase detection in the ear)

> http://www.amazon.com/Introduction-Physiology-Hearing-
> Second/dp/0125547544

> Of course, everythings a continuum, and we can argue about how high is 
> high.  This has more to do with the fastest neural discharge rates than 
> anything else-- the neuron can only fire so fast, and above that rate, 
> phase locking just can't happen.  So, in some frequency range, both ITD 
> and ILD are available, but above that frequency range, ILD only are 
> available.  ITD cues are dependent on the peak detection, which just 
> can't happen above some frequency.

http://www.pnas.org/cgi/content/full/pnas;97/22/11787

I now realize that the person who told me about phase detection
does (and did) experiments on owls.  They may have even higher response
than humans, but it seems likely that even human nerves can't keep
up at 20kHz.  The link above may or may not answer the question, but it
is by the person who told me about phase detection.

-- glen

In article <1189061830.798679.327070@19g2000hsx.googlegroups.com>, 
rbj@audioimagination.com says...

>
>Robert, with as much respect/deference as i can have, i think i must
>disagree.  in ABX testing, the subject hears two sounds, A and B, then
>a third sound, X, (or X might actually come first) which ostensibly
>would be either A or B, and is asked "which is X or which is X most
>similar to? A or B?" and the subject must choose either A or B.  is
>that not the case?  ABX is to try to answer "which one is better?",
>not "is this one good enough or not?"
>
>> ABC/hr answers the question: "Can I hear a difference and if
>> so, how subjectively important is it?"
>>
>> See ITU Recommendation BS 1116-1 and pcabx.com for more info.
>
>indeed at the pcabx.com site:
>
>"1.2.3 PCABX is a test paradigm that compares the performance of all
>equipment to a well-known ideal: Sonic Accuracy. Two different pieces
>of equipment can also be compared to each other, but the focus of most
>comparisons is sound quality relative to a perfect ideal which is the
>original audio signal prior to passing through the audio product under
>test."
>
>i don't have access to the ITU pub, but the statement above appears to
>agree with my understanding of ABX.

The scoring system in ABX has no provision for recording "how much difference 
is there," although one could presumably modify it appropriately. OTOH, ABC/HR 
specifically uses a scoring system that requires the subject to assess the 
quality difference between the (hidden) reference and the device under test. 
ABC/HR is more commonly used to assess the quality of items like codecs that 
are expected to degrade the original source material by determining whether 
their artifacts are anywhere from "very annoying" to "imperceptible," 
typically on a 1-5 scale. ABC/HR is known to be very sensitive and repeatable, 
which is why it is the gold standard for subjective testing of codecs whose 
goal is perceptual transparency.