Carl wrote:
I was looking at the Philips SACD
so i read this thing says f/r = dc - 44kHz
and s/n = 115db
However, it doesn't do both at the same time.
The SNR of 100 dB is conditioned on a brick wall filter at 20 KHz. Above
20 KHz the noise level is allowed to increase, dramatically.
not only that but it is linear =/- a few db
True below 45 KHz or so. However, response tolerances this tight need only
be maintained up to 17 KHz or less.
So i am asking myself thusly
"Self, when was the last instance upon which you heard a 44kHz tone at
35db +115db?
The answer is never, but that is not the given pretext for response that
high. There is an easily-falsified belief that the audio CD system's brick
wall filter at 22 KHz has audible effects. A few mislead persons believe
that substituting a somewhat gentler (but by no means gentle) filter will
alleviate the non-existent audible effects of a well-designed brick wall
filter at 22 KHz.
and rushes to me the conclusion that while perhaps such a
signal do indeed exist, perhaps in combat situation, or supersonic
flight, that I have never heard this such tone regards musical
reproduction.
In fact musical instruments produce sounds at a wide variety of ultrasonic
frequencies. This is well-documented, and I documented this again a few
years ago at
http://www.pcabx.com/technical/sample_rates/index.htm .
However, it is easy to show that a well-designed brick wall filter operating
as low as 16 KHz or even less, is completely undetectable.
And then I pondered, inasmuch as this is possible to record on this
SACD, how much amplifier power would i need to reproduce 5.1 channels
at this sounds pressures?
I seriously doubt that many who tout SACD or DVD-A actually have audio
systems capable of exploiting the technology. In fact the people who brag
about the extended resolution of these formats specfiically mention
recordings that unbeknownst to them were made in obsolete analog formats
that have 80 dB or less dynamic range, and have zero usable response above
25 KHz or so. In the real world, these aren't serious problems in terms of
musical enjoyment and potential realism. However, in the make-believe world
of SACD and DVD-A, they are harsh indictments of their own presumed
listening acuity.
To wit i described to myself "Perhaps this SACD is a thing for which I
do not needs have?"
The extended response and dynamic range of SACD and DVD-A is audible to
creatures with ears to match, like bats. The audiophiles who fall for this
snake oil may therefore be thought of as being "batty".