Hi RL,

Slow down, big fella, yer off to the races and I wasn't. :-)

Raving Loonie wrote:
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.

Not true - 10 us is .01 ms, hence, submillisecond.

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 ?

Razzlesnats! OK, now I have to hunt. Twenty-plus years ago I was in
the audio biz. Info cited comes from journals of the Audio Engineering
Society. We took the Audio Review's Grand Award for Engineering
Achievement with computer-assisted engineering for phase-correct
crossovers the year that Sony came in second place for the Hi-Fi Beta
Recorder. IOW, I'm substituting credentials while trying to figure out
how to bring correct references forward. ;-)

(Before I moved on to govt work, where I was recognized for DSP work
(see Applied Computational Electromagnetic Society 5th Annual
Proceedings, Rediscovering the Significance of Langzos' Sigma
Factors).)

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 @#$@%.

Ah, but I'm with you - I do know how incredibly borked all of this is.
There's even an application note floating around from the old HP where
just about everything Nyquist said was misquoted, misapplied, and flat
freaking wrong. And engineers buy the equipment, use the ap notes and
come to bad conclusions, bad implementations and bad products.

It's like any other field. I'd meet some jerk with "fifteen years
experience" and it turned out he has 1 year of experience, 15 times.
(Hence the smiley when I presented credentials.)

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 ...

No need, I experienced the same, agree the same with you on those
points.

snip

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.

In a good hall, things should actually improve. What passes as "Great
halls" just aren't.

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.

Correct. Instead of a live performance, you're seeing a simile of it
while merely listening to reproduced sound. (Regardless that they call
it reinforced sound.) And given that *not everywhere* can be optimized
for sound reproduction, you can't expect to have an enjoyable
experience with luck of the draw tickets. Given that they try to
"optimize" for the entire space, there's usually no optimal location.

A few years back, for Sting's first Jazzfest appearance, I spent a
whole day field mapping the entire area to know where to be for that
performance. There were two - exactly two - sweet spots, one very
close to the stage, one far away. We took the one far away a few shows
ahead of time. As we drew friends into the space, their eyes lit up -
the difference of being a few meters in/out of the spot was
astonishing.

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

Yep, we somehow preferentially seem to be willing to overprocess visual
data mentally. Probably something tied to evolution. If you think
about the structure of the eye - cones for color, rods for brightness,
it takes a whole lot of signal processing in the brain to make as much
visual sense of the world as we have.

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

YMMV. It can hurt or help, depends.

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.

Yep, wasn't trying to portray absolutely that this isn't so - just that
there are a lot of factors that may make this true or not for various
individuals and Madison Avenue is the typical evil coachman here,
that's all I meant.

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

I'd guess expediency over quality. We live in a time-compressed age.
Nothing's ever good enough - deliver at the speed of hitting "Send" is
the new mantra.

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.

I wonder about cause and effect there. The advent of the CD was also
the advent of the mass-popular PCs and the shift in how we trained
engineers, what the "hot" field(s) were and where the talent went.

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.

You couldn't be more right - then or now.

Pearl

"My brother-in-law's speakers are really tall, so they sound great
since 1992."