Yes. Erhh, uhmm, ahhh.

... Seems as if I am getting long in the tooth and I have even made
the mistake of confusing millisecond with microsecond. ...
Ahemmm.

In reading through what you have written, it seems that we are in some
rough co-alignment, here. Perhaps, I had better stay "dense" with
respect to the technical side. Less confusing that way ...

Earl Dombroski wrote:
I think that we don't actually hear above 10-20 kHz, but we can hear
hear phase offsets in the sub-millisecond range. It's a common
misconception to mix the two. An 8 kHz signal is still an 8 kHz signal
even if it is offset in time (group delay). As I said, a common
mistake, and a well published one.
Reference ?

pretty please ?


The error in digital reproduction suffers the same bad print. ...

Confusion? ... Bad press? ... I am beginning to think, ' You have no
idea, as to how incredibly borked, all of this is ... even amongst
acoustic engineers .. or with engineers who hold PhDs and are
acknoledged exprts w.r.t. DSP and notch filters and the like. I have
tried to discuss these ideas with one such indivdual, at length. To my
exasperation, the person seemed *clueless*. ... This ' common mistake
' that you refer to seems to be an immense turkey. Many experts have
created, held, and more recently adjusted the standards for Digital
Audio. ... they still seem to uninformed. I just don't get it @#$@%.

Moreover, this lack of appreciation continues to roll over into much
more diverse application of using DSP to enhance public performances,
HDTV and the like. The same category of mistakes are made again and
again and again. Large sums of money are lost because the problem
passes unnoticed.

I shall try to provide some quick, dirty and nasty examples ...

1) The early days of digital dolby soundtracks for movies. ....

When they first started out using a digital soundtrack stripe, they
were using 10 bits to encode and pushing the bandwith (photographic
stripe) to the maximum that the technology had to offer at the time.
.... or something like that. From a psychoaccoustic sense, the sound
was maginificnet. ... Huge dynamic range. ... Multiple channels. ..
very low noise. .. clarity beyond belief !!!

.... just one problem. A huge one. I very distinctly sitting in the
cinema. Seeing the actors moving their lips, listening to the actors
saying their line with perfect clarity ... YET, being quite unable to
understand what they were saying. ... It was so utterly weird. .. It
was as if my ability to comprened the sound I was hearing was lost. I
couldn't identify or make sense of the words that seemed so very clear.

The purpose of introducing the Digital dolby was to make the movie
going experience more enjoyable. It strongly had very much the opposite
effect for me. ... Where was the understanding, here?

2) HDTV standard. As with the digital audio 44.1 khz standard, the
HDTV requirement is for a linear encoding of the picture. ... most of
that linear interpolation is wasted. ... The eye is insensitive to it.
... Yet in a rather narrow range of color/luminescence values ( ...
however it is done ) ... the eye is much more sensitive. ... It's
easy to see color quatitization bandings ... Some putz of an engineer
simply assumes that it doesn't matter. ... I can assure you that it
does. ... Just doesn't register immediately and up front. I am
willing to bet that our visual system does lots of DSP too! .. a big
topic with much research. ... I Haven't considered it, myself.

3) Sound augmentation in live thearter/musical performances.

O.K. the realities are that one needs a larger audience to make a live
performance feasible from a fiscal standpoint. ...

Given the large audience, it becomes more difficult to hear the
performers. .. and/or the opportunity now exists to use technological
solutions to improve the 'listening' quality. ... The rational is ...
if it sounds better and clearer, everyone wins ...

No problem, there.

The problem again is that 'sounding clearer' isn't the only thing that
is going on. By introducing artificial amplication and DSP in the
augmentation, .. all sorts of 'unexpected' Hell breaks loose. ...
this seems to pass unrecognized. Those who make money by putting on
public performances of theatre wonder why the public has stopped
attending ( ... assuming this is what does happen. ... and in a sense,
... in the margins, it probably does)

To back up what I am proposing, I need to sensitize/point you toward
some of that unseen/implicit "Hell". I do it crudely by suggesting the
following plausibility ( I leave the DSP issuses aside for now )

Listening to actors/singers strutting their lines in a performing hall
is hard at the best of times. .. one has to use one's brain to focus
in of some performer in the distance and listen to what is being
said/sung. .. We can do this. ... No problem. .. pushes our innate
ability to do so. .. that's how it's been done, down through the ages.

O.K. Halls get bigger. ... the actors are further away. etc.

Let's amplify thier voices so that the audience can hear better (
ignore the DSP. here)

... good idea! ... Bad idea!

In providing artifical amplification, the performers voice is
dislocated in space from where the eye tells the viewer that the
performer is located. I am sitting there watching a show looking a a
performer in one location, yet what I hear emmanating from that actor
is arriving to me from another point in space.

O.K. .. we have the ability to re-intergrate. ... Like watching TV or
going to the movies. ... but with TV or cinema we are woring with a
foggy, fuzzy 2D image.

A performer on stage is a much clearer target, ... much better signal
to noise in the visual sense in some aspects. ... and the disembodied
sound part of the signal is *now* much more sharply .. or abruptly ...
or violently disconnected and redirected from where the eye says it
ought to be.

Yes, we compensate ... but not as easily as when watching TV or a
movie ... which have POORER signals, actually.

Moreover, the theatre spectacle is all razzle dazzle, ... the senses
being bombarded with rich eye/ear candy coming at the viewer from
everywhere.

... and the summed effect of all this is to make the background part
of our brain work very, very, very hard to try to integrate a
deliberately 'fractured' whole image.

Hard work. ... produces a headache. ... no longer able to just sit
and enjoy. ... even if the listener can follow and re-integrate
everything.

Add DSP to this mess of confusion .. ... and it becomes the srtraw
whicvh breaks the cammel's back.

In each of the last 3 or 4 times that I went to a large big budget
performence, I got burned.

I refuse to go and see a musical, anymore. ... even if someone would
give me a free ticket. For myself, it has become an unenjoyable
experience. ... Yuk.

4) People have stopped bying records/CDs ... The trend is toward
mp3.

Why? No more records. .. even if there were, most receivers now have
DSP processing ... meaning that what is heard is A to D sampled and
then D to A reconstituted, anyhow ...

CDs are clear and convenient. ... just aren't as easy going and
enjoyable as they used to be. ...

I was a late adopter for DAT recorders. ... Used records were cheap.
.... so I was stuck there.

When I got my first DAT recorder ( .. as if many people ever owned one!
), it was as a remaindered item. ... paid $200 for it, *new* or
something like that. ... Up to this time I also had very little
experience with CDs.

DAT has the choice of LP record or standard 44.1 khz.

.. the first thing that I did was say wow, wow, wow! ... this is
wonderful. ... perfect clarity! .. etc. .. and it really was that
way.

And, of course, the very next thing was to decide do I record in
LongPlay or StandardPlay. ... In LP, it's half the cost for the tape.
... So what is the downside?

I would go back and forth ... A/B ing LP and SP recordings. ... I was
tickled pink ... I couln't really tell any difference. The first times
I did it, the half speed non-linear encoding sounded exactly the same
as the more costly 44.1 khz.

Over the space of a few days, I became sensitized to the difference in
sound. ... It was very, very subtle. Actually, I don't think that I
can either rememer or describe the difference, now.

Some audiphile nut; an earely adopter of CDs; mentioned to me the
phenomeneon of 'CD fatigue' ... "BNull ****", I thought. ... wishfull
thinking.

After a few months of enjoying my DAT tapes of some of my records, ...
I came to realize that I just wasn't enjoying it as much anymore.
Sounded great. .. just not turning my crank the way it used to do ...
when I listend to records. .. or cassete tapes of the records


So, I went and A/B'd the digital LP ( ...I was still sensitized to the
LP versus SP difference at that time ..) against the record. This
wasn't easy. The receiver amplifier that I was using had the accursed
DSP feature hard wired into it.

Anyhow, somehow I managed to A/B records versus LP DAT ... and after
doing this for a while, I became further sensitized tomthat 'Digital'
sound. I also discovered that whereas records were terrible. All the
ugly things that I remembered and hated about them. ( I tended to tape
records and listen to the tape ... ) were still there.

The thing was, listening tom records was fun. It was soothing, easy
going. ... natural.

.... along with all the pain and irritation of changing the records and
the dust .. and scratches ... and having to be careful in handling
them .. and *knowing* that I was degrading them as I played them, etc
....

Frankly, the whole experience peeved me sorely.
I had a choice. ... this queer sort of 'cold, unejoyable' feeling that
went along with 'Digital' ... or the PITA factor and/or lousy fidelity
of the record/tape format.

Not the *best* of both worlds ... rather the worst of both worlds.
Yuk.

So what's with the popularity of the degraded mp3 format?

With the addition of some pychoaccoustic nonlinear compression ...
crappier signal - higher noise ... it really doesn't sound so bad.
.... better, in fact when played back on low-fi equipment.

The advent of the CD spelled the death of Hi-Fi equipment. ... CD's
sounded all the worse on the high end stuff. More to the point. ....
Listening to music, seriously ... or as a background whilst doing
something else. ... no longer was as enjoyable. Too much work. .. just
not fun ... not soothing. ... not enjoyable.

Lost interest ...

Yeah, I have experience with the $50k to $100k ( pre-used) audio
equipment route.
A progressive learning experience. Another story ... I know what you
are saying, here.

My last set of speakers? ... Wilson Watt puppies 5.? a few years ago.

How, those speaker ever became a commerical success, I will never know.
They are so sensitive that they are just plain *unpleasant* with most
(as in 90% + ) of the stuff that's put behind them. Utterly brutal. A
person needs to be very deliberate and commited to experimentation to
find a viable configuration of equipment with them.

Given the atitude of the audiophile consumer, I don't see it happening
that often. Either they seem too stuck within 'specifications' and flat
line zero distortion ...

... or in cloud cukoo land with shiatke stones and laquered finishes.

Only minority of those audiofool crazies seem to have sufficient hard
nosed objectivity to "trust" what they hear over what they are told ..
or what they would like to imagine.

Audiophile equipment is an interesting thing. ( And I say all this 5
years out of date. ...)

The hard science doesn't exist .. or is wrong/misleading/misdconstrued
....
The subjective aspect can lead one, very, very seriously astray ...

In the main one has to experience, experiment, decide and 'listen' for
one's self .. to make tangible progress in the topic.

More specifics concerning phase information, later ...


RL

... If you
have a smoothly curving ramp (think sine wave) then quatize (digitize
it), then ask a transitor to reproduce those points, and assume the
points are "x" in time apart (all same, as this is generally the case
in modern digital systems), then the xistor is told to go to a certain
level for a certain time, then the next level for the certain time and
so forth. In other words, instead of a smooth curve, you get a
staircase.

Most publications in the audio biz (are truly atrocious and have zero
understanding of digital signal processing) then go on to explain the
signal difference in terms of the "frequency" response.

Digital impulses equate mathematically into a non-bandlimited case,
whereas analog signals do not. Much is made of the mathematical
mistake, not usefully if other factors are controlled.

The inertia of a moving cone or other diaphram tends to far outweigh
the differences of the staircased signal - in other words, no matter
the damping factor and power (for all practical terms), even though a
staircase is input, each step puts the speaker cone in motion and the
motion doesn't track the staircase because of physical inertia. (Hope
that's clear.)

What many people complain about in their digital reproductions are
misidentifications of newly-heard distortions previously unheard. The
listeners, either because of low training in listening (the old
audiophile days are gone) or because of age (ear/brain deteriorates,
part of life's rich tapestry), tends to miss the new information
(actual sound) and "discover" problems with the digital source, when in
fact, these are really problems with speakers, amplification and wiring
that weren't driven to the problem levels before. If one had a
several-thousand dollar turntable in 1970's money (as very many claim,
but very few did), then one actually heard these same distortions and
could attack them.

In the 70's, about $50k to $100k was required to solve these
colorations in total. The same price tag, even adjusted up, exists
today for true reproduction.

It takes a very expensive (due to engineering complexity) system of
electronics, wiring, transducers (speakers) and the listening room to
expose the digital part of the problem.

Many have heard proof to the contrary. But the causality isn't what
you might necessarily think. Cheap op-amps are being used in most
digital sources, and the distortion in these tend to far outweigh the
distortions of digitization - but they don't tell you that. The new
product launch of the newer, higher digital sources are accompanied by
better electronics. As the price comes down, the component quality is
lowered, and the distortions creep back in.

Consider vacuum tubes, on another, but similar subject. Many ooh and
ahh about their great sound, but they distort to a very high percentage
- all as even harmonics, which the ear (half-wave recifier) cannot
detect. But sub-percentage distortion of a class B xistor amplifier is
nearly all odd harmonic, and the ear hears it quickly. But if one were
to ever hear a really good pure class A high-powered xistor amp, the
tubes lose immediately.

BTW, a word about the "half-wave rectifier" talk. Remember the ear has
the eardrum that presses against the hammer and so forth. But when the
pressure is relaxed, the eardrum doesn't pull the hammer back, that
happens as a function of the system's own relaxation. So, overpressure
pushes hammer, starts chain of events. Underpressure doesn't pull
hammer, hammer responds on it's own - so only the push part of the wave
is acted on - in other words, a half-wave rectifier.

But yes, records can sound clearer than CDs - but it depends on many
factors as to whether this is as universally true as most would have
you believe.

Sorry for length of thread, but the song as many notes as it needed to
have.

Pearl

"Amadeus, Amadeus since 1992."