I worked at Mostek maintaining the Fairchild Sentry testers used to test the Z80s when they first began to manufacturer them. The second computer I every
built (parts, pcb, solder) was the SDB-80 which was the Mostek Software Development Board for the Z80 with 16K bytes (8 - MK4116 16K bit) dynamic RAMs
which Mostek also made. The first wire wrap board I ever made was a 48K byte dynamic RAM board also using MK4116s that worked with the SDB-80. I can
tell you there were a bunch of happy technicians when we were told that Mostek would be second sourcing the Z-80 and even happier when we were told we
could buy SDB-80 kits and build them ourselves! Those were really fun days. I still have a Zilog Z80 in a ceramic package that says it was manufactured in
Dallas even though Mostek was actually in Carrollton a suburb in Dallas County just north of north-west Dallas.
"Like oscilloscopes, sound should be sampled at about 5x or more than the desired maximum bandwidth", COMPACT wrote.
This ex-Tektronix test & calibration engineer couldn't agree more, but ... at the time of development, this was technically way out of reach for the
people working on e.g. the quadrophonic sound registration on vinyl, as well as those working on the Red Book standard.
Nowdays, cartridges with a frequency range of up to 50 kHz are available, serving people who have been convinced that they need super-tweeters
at the other end of their music reproduction chains ...
"And how does one get a speaker to playback perfect square waves?", COMPACT asked.
Peter Walker of QUAD Mfg fame came pretty close; in fact it was his ultimate way of testing (300 Hz) his almost single-handedly developped ESL
(Electrostatic LoudSpeaker; (fifties). Ever auditioned one ? You will never forget the listening experience ! We've also enjoyed Martin Logan's CLS
very much; of the electrodynamic units, Manger and Dynaudio probably have the best pulse responses. With ED speakers one tries to avoid square
waves because reproducing the top part would mean sending DC trough the poor unit(s), which very few would survive eventually. Furthermore,
audio is about reproducing natural sounds, not technical noises*; and music is the most complicated of sounds. Faithfully reproducing it means
getting the rise and fall right - these coïncide with the attaque of the musical instrument played, and the decay of the resulting sound. The most
demanding instrument attaque-wise, in terms of amplifier slew rate, turned out to be the harpsichord (& family), which is easy to understand once
you look at its playing mechanism. The same cousin who introduced me to electronics via his self-built Xtal receiver, made replicas of famous old
European harpsichords, together with his father (my godfather). I quickly grew to like the sound, that many audiophiles loathe. A possible cure might
be listening to the first chords of Bach's Italian Concerto in a harpsichord rendition (as it was meant to be) - it sings so much more that way than on
the piano ! (Try Glenn Gould's fifties recording vs. his almost anemiatic eighties registration by Sony).
(to be continued)
Ray
* I know, that same Peter Walker in an interview made a statement in relation to his ESLs that seems to argue otherwise ...
I do like your down-to-earth way of enjoying your music, COMPACT !
As audio advisors, we've always aimed at improving someone's music enjoyment for reasonable money. In the age of streaming, and what have you,
it's hard to pin-point that to a fixed amount, but in the nineties we felt, you could not expect the average customer to be willing to spend more than say
$ 5.000 on a decent player, amp, and pair of speakers (cable-mania was not yet wide-spread then). Of course, this statement immediately raises the
question: what is 'decent' ?
Objectively: equipment, apart from reliable and user-friendly, should be free of apparent flaws like hum/hiss, disturbing 'plops', or distortion levels that
were considered acceptable before the seventies. Furthermore limited performance is less of a problem than a lack of balance*.
Subjectively: equipment should raise the enjoyment level of the customer at least to 'content', but we were only really satisfied, when he reported
"having heard details in his music, he had never heard before", "discovering his music anew" - that sort of thing ... (one customer even declared:
"You have enriched my life" - he has become a friend). Best proof of having succeeded in improving matters came from the wife, though. If she made
a spot-on remark while removing the emptied coffee cups, we knew we had hit bull's eye. Why ? Because women just listen without any prejudice,
while men (audiophiles) are busy trying to hear what they have read ... ; sadly, didn't do much for the WAF (Wife Acceptance Factor).
Cheers
Ray
* that is a.o. why 2-way mini-monitors (not the Bose crap !) can be so very satisfying - certainly if they've been designed by Andrew Jones
P.S.: thank you for the Faggin-link, COMPACT - I'll dive into it
Our universe conspires to prevent perfect recording and playback and audiophiles are passionate of what constitutes a great sound.
I wish that some Astronauts would set up some speakers and microphones outside the International Space Station to see how well they work.
Here is one audiophile's take on things. Have a listen for 90 seconds.
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The Australian company RODE is successful making microphones and associated paraphernalia. The recorded sound may not be technically perfect but it sure does sound crisp and clear.
Their latest offering is a wireless Lavalier microphone transmitter receiver combination for digital cameras. ("Go") which is very convenient.
The questions you've raised are certainly worthwhile, albeit far from new ...
First of all, there is broad consensus, that audio is the art of reproducing sounds, recorded in one acoustic environment, in an other - usually totally
different. As a (recent) result, room acoustics have become a hot item; with DSP prices coming down, ever more components in the reproduction
chain - both amps and active speakers e.g. - are equipped with some form of electronic adaptation. While this may seem progress, oldtimer audio
buffs (like us ?) probably wonder, what has become of good (?) old tone controls, or - a bit more sophisticated - equalizers ? The 'tilt control' on the
QUAD 34 pre-amp, beloved in the eighties (and not much unlike RIAA equalization, COMPACT), springs to mind. DSP-based room-correction
circuitry is said to spare you fysical adjustments, like COMPACT described; I don't think I'm convinced.
As to equalizers, in the nineties we were allowed one afternoon to 'play' with the famous Cello Audio Palette, originally intended for studio-use, and
the wet dream of many an audiophile. Although we really had a great time at the circular controls of that gem, we had second thoughts afterwards:
had we not in fact been indulging ourselves in 'bettering' recordings of top-notch mastering engineers ? Who did we think we were ?! Our host had
'encoded' the favourite tracks on his discs with the letters of the controls and the corresponding numbers of the scale settings ... (audiot).
Live vs. recorded comparisons were popular in both the UK and USA during the fifties, aiming at answering the question: how close have we come
with HiFi ? It was reported frequently that even highly experienced audiences (regular concert visitors) sometimes had trouble discerning one from
the other. But this only works in the same room, with the speakers exactly positioned, where the instruments/vocalists were before (and everything
else also kept constant, preferably). So there's not much hope of ever bridging the gap from concert hall/studio to listening room ... And "Bringing
the concert hall to your living room" a bluddy (marketing) lie !
The 'being there (present)' experience /illusion is in fact the last frontier in high-end audio. When auditioning a Cello set with Martin Logan CLS,
a much more experienced audiophile commented: "Ah, this is precisely the sort of set that enables you to hear a fly fart on the rear wall of the
recording studio !". That made us think: are we chasing ultra resolution in sound reproduction, or is our real aim musical satisfaction ? It took some
time to cure ourselves of 'audiophilia nervosa', but we have since been enjoying our music via much more down-to-earth equipment.
Stereo is btw. as much an illusion (and this goes as well for 'glued-together-again' digital signal samples, in an attempt to mimic analog sound).
I believe, though, ultimately most people do not care that they are listening to illusions, nor how far off they are from reality - they've simply come
to like them !
I hope you see my point: this kind of discussions is in fact a thing of the past, and when repeated all the same, bound to be ... pointless.
