I have six Squeezeboxes (3 Classics and 3 Booms), so I am a big a fan of
Logitech’s products.  My only point is that most owners of a Squeezebox
shouldn’t feel left out of the party if they don’t own a Touch just
because of the new specs of 24/96 DAC’s because in the real world they
wouldn’t hear any difference.  

Of course if you are in the market for a Squeezebox anyway (e.g. don’t
have any Squeezeboxes yet or want to expand to additional rooms), the
Touch does look attractive.

On the issue of DVD-A source material, even here one has to pause
before gear lust overtakes reality.  

Here are some excerpts from a manufacturer of audio equipment on the
issues of what you can actually hear from a DVD player’s digital outs
due to copyright issues:

“many DVD transports currently on the market fail to transmit the exact
digital audio data bit-for-bit as it appears on the DVD. Of the DVD
transports Benchmark has tested (8 as of this writing), all of them
modified high-resolution audio data before sending it to the digital
output”

“Transports modify the high-resolution data in order to comply with
digital copyright obligations to the publishers and distributors of
music and video discs. The music and film industries are trying to
prevent bit-for-bit copying of the recordings. Consequently,
manufacturers of DVD transports have been forced to reduce the
resolution of digital outputs to prevent digital duplication.”

“However, the sonic consequences of these modifications can be
devastating to audio quality. We are able to measure sample rate, bit
depth, and conversion quality with our Audio Precision test equipment.
In almost all cases, the data modification includes poor quality
sample-rate conversion (SRC) and word-length truncation. These processes
defeat the benefits of high-sample-rate and/or high-bit-depth source
material, and severely degrade sonic quality. Although the SRC and
word-length reduction is being applied to reduce the quality of the
digital output to CD resolution, it actually degrades the sound quality
far beyond that of properly mastered CD resolution. In fact, these
transports will deliver higher performance from a CD than from a
high-resolution DVD.”

“Unfortunately, the SRC processing in the transports tested was of poor
quality. The distortion that results can be devastating to the quality
of the playback system. Also, it is often re-sampled to 44.1 kHz, which
inherently eliminates all the advantages of playing high-sample-rate
audio discs.”

“Most DVD transports reduce 24-bit digital recordings to 16 bits by
truncating the 8 'least-significant-bits' (LSB's). In other words, these
8-bits are simply removed without dithering. This type of truncation
adds quantization errors that result in significant levels of
distortion.”

http://www.benchmarkmedia.com/discuss/feedback/newsletter/2009/07/1/your-transport-giving-you-all-bits


Here are some excerpts from a manufacturer of audio equipment on the
issues of bit depth and sample rate:

“96kHz sampling also causes problems with the noise performance of low
frequency EQ stages (because the differences between adjacent samples
are smaller), so a 96 kHz system typically requires a longer wordlength
to achieve the same noise performance as a 48 kHz one.”

“Measurements which specify the dynamic range of the ADC or DAC in
isolation should also be treated with caution, since these are often
“data sheet” numbers supplied by the IC manufacturer which are rarely if
ever achieved in practice.”

“The ADC and DAC parts that we use are both "nominal 24-bit" items, but
this is essentially meaningless. If a manufacturer claims that they have
a "24-bit converter" in their product, then the next question to ask is
how you should measure the unit to confirm the 144 dB dynamic range that
this implies. In practice no-one is achieving even 20-bit noise
performance (=120 dB dynamic range) from a digital system of this kind
at the present time. The DN9848 achieves >114 dB dynamic range or "19
bits" overall from input to output. Note that this is an unweighted
figure (i.e. flat frequency response). Some manufacturers quote
"A-weighted" figures which flatter the unit's performance significantly
by applying a psycho-acoustic curve to the measurement. Measurements
which specify the dynamic range of the ADC or DAC in isolation should
also be treated with caution, since these are often “data sheet” numbers
supplied by the IC manufacturer which are rarely if ever achieved in
practice.”
“In the end, the one-sentence summary is "don't worry too much about
the bits and sample rates - trust the same real-world performance
measurements of noise and distortion that you would apply to analogue".

“And after that, there are always your ears...”

http://www.klarkteknik.com/faq-04.php

Finally, a recent study published in the journal of the Audio
Engineering Society concluded that not a single listener could
consistently distinguish between high-resolution audio and audio played
at the CD standard.

http://www.aes.org/journal/online/comment/?ID=14195


-- 
mortslim
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