Katie, who is 11, was helping me in the workshop today. She told me how
some of her class been in trouble for filming the teachers covertly. Of
course I told her how, in 1965, I'd made a sound recording of our maths
teacher, with the class deliberately winding him up just to make it more
fun. I then found myself trying to explain about reel-to-reel tape
recorders. I could see that Katie just couldn't grasp the concept.
Finally she asked, "But how much memory did it have?"

Bill

On Sun, 27 Apr 2014 20:31:27 +0100, Bill Wright wrote:

Katie, who is 11, was helping me in the workshop today. She told me how
some of her class been in trouble for filming the teachers covertly. Of
course I told her how, in 1965, I'd made a sound recording of our maths
teacher, with the class deliberately winding him up just to make it more
fun. I then found myself trying to explain about reel-to-reel tape
recorders. I could see that Katie just couldn't grasp the concept.
Finally she asked, "But how much memory did it have?"

I don't know whether to laugh or cry...

It's slightly scary that there's people wandering around who regard the
CD as pre-historic. I feel old.

On Sun, 27 Apr 2014 21:37:57 +0000 (UTC), Adrian
wrote:

On Sun, 27 Apr 2014 20:31:27 +0100, Bill Wright wrote:

Katie, who is 11, was helping me in the workshop today. She told me how
some of her class been in trouble for filming the teachers covertly. Of
course I told her how, in 1965, I'd made a sound recording of our maths
teacher, with the class deliberately winding him up just to make it more
fun. I then found myself trying to explain about reel-to-reel tape
recorders. I could see that Katie just couldn't grasp the concept.
Finally she asked, "But how much memory did it have?"

I don't know whether to laugh or cry...

It's slightly scary that there's people wandering around who regard the
CD as pre-historic. I feel old.

I regard not only CD as pre-historic but DVD and Blu-Ray[1] too. It's
not that that makes me feel old, just the effects of old age creeping
up on me.

[1] or BD if you prefer.
--
Regards, J B Good

In message , Bill Wright
writes

Finally she asked, "But how much memory did it have?"

grin You sound like an older father, although perhaps Katie is your
Granddaughter. My son has just turned 13, and I'll be 62 shortly. I do
try to complete his education, explaining what life was like pre
mobiles, computers, game machines, tablets etc. All sorts of stuff -
our first black and white TV, with two channels and very little TV for
children, our first phone tied to the wall with a cable, our 'wireless',
first fridge all of which arrived in my lifetime. His Grandma (and
mine) operating the mangle every Monday, deliveries of milk, bread,
paraffin, no central heating, clockwork toys, my first wind up
gramophone, 45s, 78s, LPs, reel to reel, my first CD, cassette tapes,
Walkman, Commodore 64, Atari etc. Things that arrived during my
lifetime, yet were gone by his. Pirate radio. Trying to explain that
there was no Radio 1, no local stations, no TOTP, no YouTube. Just
David Jacobs :-) Highlights of the week including Ready Steady Go,
Thank Your Lucky Stars (Oi'll give it foive!), Juke Box Jury.

The impact of Elvis and The Beatles. Luckily, he hears me playing
golden oldies, is used to us having an open fire, drives my Minor in the
garden, eats with us at the table in the dining room and plays with my
tinplate trains. He even enjoys traditional board games at Christmas.
He doesn't like Meccano, though.

The other side of the coin, of course, is that he keeps me up to date
with what his generation loves. Funny thing is, although he and his
friends will spend hours in front of a screen, they also do so much that
I did, 50 years ago. Out on their bikes, messing about by the river,
building dens and dams. What really delighted me, when he first
started school, and understood humour, was the jokes. He and his
friends were laughing at *exactly* the same jokes as amused me at that
age. He also adored the same cartoons, like Huck Hound and Yogi Bear.
The difference was we saw them once a week on B&W TV - he watched them
constantly, in colour, via DVD. Oh well ...
--
Graeme

Adrian wrote in news:ljjtbl$6au$2
@speranza.aioe.org:

On Sun, 27 Apr 2014 20:31:27 +0100, Bill Wright wrote:

Katie, who is 11, was helping me in the workshop today. She told me how
some of her class been in trouble for filming the teachers covertly. Of
course I told her how, in 1965, I'd made a sound recording of our maths
teacher, with the class deliberately winding him up just to make it more
fun. I then found myself trying to explain about reel-to-reel tape
recorders. I could see that Katie just couldn't grasp the concept.
Finally she asked, "But how much memory did it have?"

I don't know whether to laugh or cry...

It's slightly scary that there's people wandering around who regard the
CD as pre-historic. I feel old.

With the old devices we all had some inkling of how they worked and if we
were to survive some sort of massive global disaster we would have known
enough about the principles to get these devices back in use. Nowadays the
ability to make or even understand common devices is in the hands of very
few people. Who remembers using a pin and some rolled up card to listen to
a 78rpm record?

Well, terms for storage have changed over the years I suppose. I once worked
out that on a ZX Spectrum, about 5 minutes of cassette tape equalled
32Kbits at 1200 baud, but of course the special loaders games used pushed
the baude rate up so the loading was much faster, and of course less
reliable.

Then of course reel to reel could have several speeds, and the difference
was in frequency responce and noise performance as it was analogue.
If you can explain the difference between analogue storage and digital
storage it might make the penny drop.

Did you know that the Gallileo probe to Jupiter had a tape storage system
on board for use to send the stored data to earth. It started to stick with
age so they had to spool it back and forwards a bit each time theywanted to
use it.
More modern space vehicles use Flash ram of course, but these have issues
that tweak their bits when they get hit by a cosmic ray.

More useless information from the web.
Brian

--
From the Sofa of Brian Gaff Reply address is active
"Bill Wright" wrote in message
...
Katie, who is 11, was helping me in the workshop today. She told me how
some of her class been in trouble for filming the teachers covertly. Of
course I told her how, in 1965, I'd made a sound recording of our maths
teacher, with the class deliberately winding him up just to make it more
fun. I then found myself trying to explain about reel-to-reel tape
recorders. I could see that Katie just couldn't grasp the concept. Finally
she asked, "But how much memory did it have?"

Bill

Yes indeed, and I still play them and Vinyl as well. I'm in the market for a
good quality reel to reel deck as well.
Brian

--
From the Sofa of Brian Gaff Reply address is active
"Adrian" wrote in message
...
On Sun, 27 Apr 2014 20:31:27 +0100, Bill Wright wrote:

Katie, who is 11, was helping me in the workshop today. She told me how
some of her class been in trouble for filming the teachers covertly. Of
course I told her how, in 1965, I'd made a sound recording of our maths
teacher, with the class deliberately winding him up just to make it more
fun. I then found myself trying to explain about reel-to-reel tape
recorders. I could see that Katie just couldn't grasp the concept.
Finally she asked, "But how much memory did it have?"

I don't know whether to laugh or cry...

It's slightly scary that there's people wandering around who regard the
CD as pre-historic. I feel old.

I loved meccano. I used some the other month to make a door closer for my
porch.
Incidentally, Meccano made me a phonograph together with some bits of tin
and a cardboard horn. The cylinder was made from baco foil and of course had
a clunk every rotation, but did actually work surprisingly well to
demonstrate the principals, though speed variability was a bit of an issue,
as was recording time.. grin.
Brian

--
From the Sofa of Brian Gaff Reply address is active
"News" wrote in message
...
In message , Bill Wright
writes

Finally she asked, "But how much memory did it have?"

grin You sound like an older father, although perhaps Katie is your
Granddaughter. My son has just turned 13, and I'll be 62 shortly. I do
try to complete his education, explaining what life was like pre mobiles,
computers, game machines, tablets etc. All sorts of stuff - our first
black and white TV, with two channels and very little TV for children, our
first phone tied to the wall with a cable, our 'wireless', first fridge
all of which arrived in my lifetime. His Grandma (and mine) operating the
mangle every Monday, deliveries of milk, bread, paraffin, no central
heating, clockwork toys, my first wind up gramophone, 45s, 78s, LPs, reel
to reel, my first CD, cassette tapes, Walkman, Commodore 64, Atari etc.
Things that arrived during my lifetime, yet were gone by his. Pirate
radio. Trying to explain that there was no Radio 1, no local stations, no
TOTP, no YouTube. Just David Jacobs :-) Highlights of the week including
Ready Steady Go, Thank Your Lucky Stars (Oi'll give it foive!), Juke Box
Jury.

The impact of Elvis and The Beatles. Luckily, he hears me playing golden
oldies, is used to us having an open fire, drives my Minor in the garden,
eats with us at the table in the dining room and plays with my tinplate
trains. He even enjoys traditional board games at Christmas. He doesn't
like Meccano, though.

The other side of the coin, of course, is that he keeps me up to date with
what his generation loves. Funny thing is, although he and his friends
will spend hours in front of a screen, they also do so much that I did, 50
years ago. Out on their bikes, messing about by the river, building dens
and dams. What really delighted me, when he first started school, and
understood humour, was the jokes. He and his friends were laughing at
*exactly* the same jokes as amused me at that age. He also adored the
same cartoons, like Huck Hound and Yogi Bear. The difference was we saw
them once a week on B&W TV - he watched them constantly, in colour, via
DVD. Oh well ...
--
Graeme

In article ,
Bill Wright writes:
Katie, who is 11, was helping me in the workshop today. She told me how
some of her class been in trouble for filming the teachers covertly. Of
course I told her how, in 1965, I'd made a sound recording of our maths
teacher, with the class deliberately winding him up just to make it more
fun. I then found myself trying to explain about reel-to-reel tape
recorders. I could see that Katie just couldn't grasp the concept.
Finally she asked, "But how much memory did it have?"

Its memory is the tape.
Struggling to remember, but ISTR a tape lasts 30 mins at 7.5"/sec.
The frequency response at 7.5"/sec looks to have been up to 15kHz.
In thinking of this digitally, that's a sampling rate of 30kHz as
per Nyquist. I've no idea what the dynamic range is, but let's guess
it's at least 8 bits worth (it's probably more). That works out at
30kbytes/sec, or 60kbytes/sec for two-channel (stereo). So for a 30
min tape, that's just over 100Mbytes.

Today, that would be mpeg compressed on a personal player, so perhaps
just 50Mbytes (won't get as good compression as modern digital recordings,
because original data is already at a reduced resolution).

So best answer is that the tape player has no memory, but each tape
corresponds to perhaps a 50Mbyte SD card today (way smaller than
anything you can buy today).

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On 27/04/2014 20:31, Bill Wright wrote:
Katie, who is 11, was helping me in the workshop today. She told me how
some of her class been in trouble for filming the teachers covertly. Of
course I told her how, in 1965, I'd made a sound recording of our maths
teacher, with the class deliberately winding him up just to make it more
fun. I then found myself trying to explain about reel-to-reel tape
recorders. I could see that Katie just couldn't grasp the concept.
Finally she asked, "But how much memory did it have?"

When my daughter was fairly young (4 ish perhaps) she had mastered the
video and DVD player and could watch various films / programs /
compilation tapes over and over[1] - quite often the same one several
times a day for weeks at a time. She was sat with mum watching a
broadcast of one of the Albert Campion series of shows... at the end
said "again mummy, again!" It was then mum had to explain the whole
concept of broadcast TV to her!


[1] Clangers, Bagpus, Ivor the Engine, The Trap Door etc, plus loads of
classic Cartoons.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 28/04/2014 10:24, Jethro_uk wrote:
On Sun, 27 Apr 2014 20:31:27 +0100, Bill Wright wrote:

Katie, who is 11, was helping me in the workshop today. She told me how
some of her class been in trouble for filming the teachers covertly. Of
course I told her how, in 1965, I'd made a sound recording of our maths
teacher, with the class deliberately winding him up just to make it more
fun. I then found myself trying to explain about reel-to-reel tape
recorders. I could see that Katie just couldn't grasp the concept.
Finally she asked, "But how much memory did it have?"

Bill

A work colleague was recently telling how her grandson (4) tries to
"swipe" books like an iPad when they read ...

10 Years ago my son had to do a little project (IIRC it was on castles).
Quite naturally, he laid his work out like a web page, with "back" and
"home" buttons drawn around the edge.

Its one of the ways teachers can spot the less than skilful
plagiariseation of web based stuff for homework - they still leave the
hyper-links in ;-)


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

Brian Gaff wrote:
I loved meccano. I used some the other month to make a door closer
for my porch.
Incidentally, Meccano made me a phonograph together with some bits of
tin and a cardboard horn. The cylinder was made from baco foil and of
course had a clunk every rotation, but did actually work surprisingly
well to demonstrate the principals, though speed variability was a
bit of an issue, as was recording time.. grin.
Brian

Wow! It's amazing that it could record time at all. Once you sort the
issues out, you couldn't record a bit for me, could you? I'm sure it
will come in useful in a few years time when I wish I had a bit more.

"Andrew Gabriel" wrote in message
...
In article ,
Bill Wright writes:
Katie, who is 11, was helping me in the workshop today. She told me how
some of her class been in trouble for filming the teachers covertly. Of
course I told her how, in 1965, I'd made a sound recording of our maths
teacher, with the class deliberately winding him up just to make it more
fun. I then found myself trying to explain about reel-to-reel tape
recorders. I could see that Katie just couldn't grasp the concept.
Finally she asked, "But how much memory did it have?"

Its memory is the tape.
Struggling to remember, but ISTR a tape lasts 30 mins at 7.5"/sec.
The frequency response at 7.5"/sec looks to have been up to 15kHz.
In thinking of this digitally, that's a sampling rate of 30kHz as
per Nyquist. I've no idea what the dynamic range is, but let's guess
it's at least 8 bits worth (it's probably more). That works out at
30kbytes/sec, or 60kbytes/sec for two-channel (stereo). So for a 30
min tape, that's just over 100Mbytes.

Today, that would be mpeg compressed on a personal player, so perhaps
just 50Mbytes (won't get as good compression as modern digital recordings,
because original data is already at a reduced resolution).

So best answer is that the tape player has no memory, but each tape
corresponds to perhaps a 50Mbyte SD card today (way smaller than
anything you can buy today)

My estimate would be 30 minutes at 3 3/4 inches per second, mono, 10 kHz
frequency response, signal to noise ratio 40dB.

That converts to 1800 seconds at 20 k samples per second. 40 dB would be
about 8 bits, but 8 bit audio sounds rougher than tape, so I'd guess 10 or
12.

10 bits x 20k x 1800 = 360 Mbits = 45 MBytes.

Has she ever seen a VHS cassette? They come out at 1000 times more.
3 hours, 2.5 MHz frequency response, 30 dB s/n, converts to

6 bits x 5000k x 10800 = 324 Gbits = 40 GBytes.




---
This email is free from viruses and malware because avast! Antivirus protection is active.
http://www.avast.com

On 28/04/14 10:48, John Rumm wrote:
On 27/04/2014 20:31, Bill Wright wrote:
Katie, who is 11, was helping me in the workshop today. She told me how
some of her class been in trouble for filming the teachers covertly. Of
course I told her how, in 1965, I'd made a sound recording of our maths
teacher, with the class deliberately winding him up just to make it more
fun. I then found myself trying to explain about reel-to-reel tape
recorders. I could see that Katie just couldn't grasp the concept.
Finally she asked, "But how much memory did it have?"

When my daughter was fairly young (4 ish perhaps) she had mastered the
video and DVD player and could watch various films / programs /
compilation tapes over and over[1] - quite often the same one several
times a day for weeks at a time. She was sat with mum watching a
broadcast of one of the Albert Campion series of shows... at the end
said "again mummy, again!" It was then mum had to explain the whole
concept of broadcast TV to her!


My very young niece was caught having out several coins into the floppy
disk slot (or maybe zip drive slot) of a Mac G3 to 'make it work'

[1] Clangers, Bagpus, Ivor the Engine, The Trap Door etc, plus loads of
classic Cartoons.



--
Ineptocracy

(in-ep-toc-ra-cy) €“ a system of government where the least capable to
lead are elected by the least capable of producing, and where the
members of society least likely to sustain themselves or succeed, are
rewarded with goods and services paid for by the confiscated wealth of a
diminishing number of producers.

On 28/04/2014 09:59, Dave Liquorice wrote:
On Mon, 28 Apr 2014 01:40:04 +0100, Johny B Good wrote:

I regard not only CD as pre-historic but DVD and Blu-Ray[1] too. It's
not that that makes me feel old, just the effects of old age creeping
up on me.

Presumably old age is having its normal affect on hearing and sight
so you don't notice how crap downloads and/or streaming are compared
to CD or Blu-Ray (or even DVD come to that). B-)

What worries *me* is that many teenagers are of the opinion that
downloads are better quality than CDs.

Even at my age, I can tell the difference, even on earbuds and small
screens.

--
Tciao for Now!

John.

In article , Andrew Gabriel
wrote:

Struggling to remember, but ISTR a tape lasts 30 mins at 7.5"/sec.

Erm. That would depend on the length of the tape. Which in turn pun
depends on the size of the spools and the tape thickness.

The frequency response at 7.5"/sec looks to have been up to 15kHz. In
thinking of this digitally, that's a sampling rate of 30kHz as per
Nyquist.

Chances are that a decent R2R will record above 15kHz at 7.5ips. Depends on
the tape, heads, etc. Unlike LPCM there's not sharp cutoff.

Even a decent home machine like the old Tandberg 3000 would do 40 - 20k at
+/-2dB running at that speed. And could record higher frequencies provided
they were're high level and you accepted a drop in output. The unweighted
noise approached -60dBref and you could also record above ref for
mid-frequency signals. And I'm sure there were better decks around.


I've no idea what the dynamic range is, but let's guess it's at
least 8 bits worth (it's probably more). That works out at 30kbytes/sec,
or 60kbytes/sec for two-channel (stereo). So for a 30 min tape, that's
just over 100Mbytes.

Its likely to be more than 8bits worth, but again depends on the tape,
deck, etc. And it isn't easy to estimate because the response and noise
floors aren't flat in-band. Nor is the max signal level limited by an
abrupt ceiling. Instead by a rise in distortion that depends on the details
of the signal being recorded.

Plus, of course, a tendency later on the use Dolby level compansion which
further complicates the issue. And ignoring the detail of if you are
thinking of a full/half/quarter track for mono or stereo. I'm assuming
the usual home machine width and format. :-)

So 20kHz bandwidth and about 60dB range would be a closer guide, but
probably still not give a really representitive value for some 'Mbytes'
result.

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

On 28/04/14 13:47, Jim Lesurf wrote:
In article , Andrew Gabriel
wrote:

Struggling to remember, but ISTR a tape lasts 30 mins at 7.5"/sec.

Erm. That would depend on the length of the tape. Which in turn pun
depends on the size of the spools and the tape thickness.

The frequency response at 7.5"/sec looks to have been up to 15kHz. In
thinking of this digitally, that's a sampling rate of 30kHz as per
Nyquist.

Chances are that a decent R2R will record above 15kHz at 7.5ips. Depends on
the tape, heads, etc. Unlike LPCM there's not sharp cutoff.

Even a decent home machine like the old Tandberg 3000 would do 40 - 20k at
+/-2dB running at that speed. And could record higher frequencies provided
they were're high level and you accepted a drop in output. The unweighted
noise approached -60dBref and you could also record above ref for
mid-frequency signals. And I'm sure there were better decks around.


I've no idea what the dynamic range is, but let's guess it's at
least 8 bits worth (it's probably more). That works out at 30kbytes/sec,
or 60kbytes/sec for two-channel (stereo). So for a 30 min tape, that's
just over 100Mbytes.

Its likely to be more than 8bits worth, but again depends on the tape,
deck, etc. And it isn't easy to estimate because the response and noise
floors aren't flat in-band. Nor is the max signal level limited by an
abrupt ceiling. Instead by a rise in distortion that depends on the details
of the signal being recorded.

Plus, of course, a tendency later on the use Dolby level compansion which
further complicates the issue. And ignoring the detail of if you are
thinking of a full/half/quarter track for mono or stereo. I'm assuming
the usual home machine width and format. :-)

So 20kHz bandwidth and about 60dB range would be a closer guide, but
probably still not give a really representitive value for some 'Mbytes'
result.


You are pushing your luck with that on any but seriously pro kit. Th
pre-emphasis on the treble means you only have a few db range above 10kHz.

Which is why disks and data tapes use a completely different encoding
system.

Id say a fast tape - 15 ips or more would net you perhaps 60dB at 2Khz
bandwidth if reliability needed.

Tape was truly AWFUL.

CD MUCH better.

Id doubt that a tape was capable of delivering much more than a good
modem over a phone line, 64kbps.

Bandwidth and S/N are similar.
so 8KB/s

You only need to look at the mess that videotapes were on all but
massively expensive kit at stupendous speeds to see that getting to the
Mbps was almost impossible

Of course the wider the tape the better..




Jim



--
Ineptocracy

(in-ep-toc-ra-cy) €“ a system of government where the least capable to
lead are elected by the least capable of producing, and where the
members of society least likely to sustain themselves or succeed, are
rewarded with goods and services paid for by the confiscated wealth of a
diminishing number of producers.

"Bill Wright" wrote in message
...
Katie, who is 11, was helping me in the workshop today. She told me how
some of her class been in trouble for filming the teachers covertly. Of
course I told her how, in 1965, I'd made a sound recording of our maths
teacher, with the class deliberately winding him up just to make it more
fun. I then found myself trying to explain about reel-to-reel tape
recorders. I could see that Katie just couldn't grasp the concept. Finally
she asked, "But how much memory did it have?"

A 1970' nine track tape deck [for a computer] - about 2Gb

Before they were phased out a DAT tape also held about 2Gb.

Of course the recording on audio reel to reel recorders was analogue, so a
data capacity is not so meaningful.


Bill

In article o.uk, Dave
Liquorice scribeth thus
On Mon, 28 Apr 2014 01:40:04 +0100, Johny B Good wrote:

I regard not only CD as pre-historic but DVD and Blu-Ray[1] too. It's
not that that makes me feel old, just the effects of old age creeping
up on me.

Presumably old age is having its normal affect on hearing and sight
so you don't notice how crap downloads and/or streaming are compared
to CD or Blu-Ray (or even DVD come to that). B-)


I think I find them more objectionable as time goes on Dave!...
--
Tony Sayer

You are pushing your luck with that on any but seriously pro kit. Th
pre-emphasis on the treble means you only have a few db range above 10kHz.

Which is why disks and data tapes use a completely different encoding
system.

Id say a fast tape - 15 ips or more would net you perhaps 60dB at 2Khz
bandwidth if reliability needed.

Tape was truly AWFUL.

If your over this way anytime have a listen to my old Studer B67
replaying a tape of steam driven fairground "gallopers" recorded
outside.

People can't believe that was done on 60's tech....


CD MUCH better.

Id doubt that a tape was capable of delivering much more than a good
modem over a phone line, 64kbps.

Bandwidth and S/N are similar.
so 8KB/s

You only need to look at the mess that videotapes were on all but
massively expensive kit at stupendous speeds to see that getting to the
Mbps was almost impossible

Of course the wider the tape the better..




Jim




--
Tony Sayer

The first digital audio recorders used video tape transports. Indeed the
CD 'red book' was based on how long a standard U-Matic tape ran. So it
would be fair to call it a memory - just not a RAM one. ;-)

--
*Sometimes I wake up grumpy; Other times I let him sleep.

Dave Plowman London SW
To e-mail, change noise into sound.

In article , The Natural Philosopher
wrote:
On 28/04/14 13:47, Jim Lesurf wrote:


So 20kHz bandwidth and about 60dB range would be a closer guide, but
probably still not give a really representitive value for some
'Mbytes' result.


You are pushing your luck with that on any but seriously pro kit. Th
pre-emphasis on the treble means you only have a few db range above
10kHz.

You'd have to define more clearly what you mean by "only have a few db
range above 10kHz" before I could comment. Can you point to some measured
results that show this? If not, I may have a swan though old AES material
to see what I can find.


Id doubt that a tape was capable of delivering much more than a good
modem over a phone line, 64kbps.

Again, you'd have to be more specific wrt details wrt the basis of your
belief. Bearing in mind of course that speech and music don't normally have
a uniform power spectral density, etc.

Also bearing in mind that most of the music recorded before c1980 for
commercial release or by the BBC was onto analogue tape rather than a
digital system. Yet can sound pretty good nowdays if it was recorded and
kept well.

Bandwidth and S/N are similar. so 8KB/s

Curious to know how you get to claiming that R2R tape and a phone line
having the same bandwidth and SNR.

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

Stephen wrote:

My estimate would be 30 minutes at 3 3/4 inches per second, mono, 10 kHz
frequency response, signal to noise ratio 40dB.

My little tape recorder had a non-standard speed of 4ips and also had
the tape wound in a funny way so it played backwards on a normal
machine. For tapes I used to strip down 1/2" computer tape. My uncle
worked at IBM and he used to get it for me.

Bill

I see, make a career of misreading then? Who is she?

Brian

--
From the Bed of Brian Gaff.
The email is valid as
Blind user.
"Norman Wells" wrote in message
...
Brian Gaff wrote:
I loved meccano. I used some the other month to make a door closer
for my porch.
Incidentally, Meccano made me a phonograph together with some bits of
tin and a cardboard horn. The cylinder was made from baco foil and of
course had a clunk every rotation, but did actually work surprisingly
well to demonstrate the principals, though speed variability was a
bit of an issue, as was recording time.. grin.
Brian

Wow! It's amazing that it could record time at all. Once you sort the
issues out, you couldn't record a bit for me, could you? I'm sure it will
come in useful in a few years time when I wish I had a bit more.

In article ,
Bill Wright wrote:
Stephen wrote:

My estimate would be 30 minutes at 3 3/4 inches per second, mono, 10
kHz frequency response, signal to noise ratio 40dB.

My little tape recorder had a non-standard speed of 4ips and also had
the tape wound in a funny way so it played backwards on a normal
machine. For tapes I used to strip down 1/2" computer tape. My uncle
worked at IBM and he used to get it for me.

Bill

There was one from Shoppertunities? which had no capstan so ran at a
different speed depending on where the tape was on the reel...

Happy days.

--
*I'm really easy to get along with once people learn to worship me

Dave Plowman London SW
To e-mail, change noise into sound.

In article , Dave Plowman (News)
scribeth thus
The first digital audio recorders used video tape transports. Indeed the
CD 'red book' was based on how long a standard U-Matic tape ran. So it
would be fair to call it a memory - just not a RAM one. ;-)


Wasn't that the F1 ?? or some such unit?..
--
Tony Sayer

On Mon, 28 Apr 2014 09:59:42 +0100 (BST), "Dave Liquorice"
wrote:

On Mon, 28 Apr 2014 01:40:04 +0100, Johny B Good wrote:

I regard not only CD as pre-historic but DVD and Blu-Ray[1] too. It's
not that that makes me feel old, just the effects of old age creeping
up on me.

Presumably old age is having its normal affect on hearing and sight
so you don't notice how crap downloads and/or streaming are compared
to CD or Blu-Ray (or even DVD come to that). B-)

Well, there's some small element of truth in what you say[1] but the
point I was making was that it seems so futile to 'archive' gigabyte's
worth of audio and terabyte's worth of TV recordings and mpeg movies
onto optical disk media of questionable durability and limited
capacity.

As a backup medium (other than for bootable storage for OS installs
and stand alone software diagnostic tools for use on older PCs that
don't properly support booting from USB flash memory devices), the
limited storage capacity and writing speeds detract immensely over
that of the utility of hard disk storage whether it's in the form of a
simple external USB drive or a NAS box full of HDDs.

A modern 4TB WD RED drive represents about a thousand DVD-R disks
(and around about 200 Blu-Ray disks), so the costs per GB of optical
storage is somewhat similar but without the convenience of HDD and
with a huge performance penalty (less than 25% the speed at best if
you forgo the verification pass required to assure that the data was
successfully written to the media - in practice, with verified writes,
the time penaly is more like getting a mere 10% of the backup speed of
HDD based storage.

Life's just too short to waste on such 'pre-historic' archival
methods (and space so limited too - I gave up using DVD-R archival
storage after writing some 400 DVD's worth when the cupboard started
getting full).

I decided that I would do just as well using the homebrewed FreeNAS
box (now running NAS4Free) to archive my growing collection of media
files, upgrading the jbod array of disks piecemeal to to keep pace
with my ever increasing storage capacity demands.

I've now got a total storage capacity of 13TB's worth of HDDs in the
NAS box and looking to upgrade the smallest (2TB) drive to another 4TB
WD RED by the end of the year.

I'm looking forward to the larger 6TB units becoming available at a
less than eye watering price before the end of 2015. I've been running
a file server of one sort or another for almost the past 3 decades now
and it's rather sobering to think that it all started with a 300MB
full height ESDI HDD in an NEC Powermate II (8MHz clocked 80286 CPU)
running NW 3.11) connected to a 'CheaperNet' lan.

I've now got some 40,000 times that storage capacity today and I dare
say I'll almost certainly have 100,000 times the original storage
capacity before the end of this decade.

[1] As a matter of interest, I was listening to an MP3'd episode of
the Goon Show whilst I was reading your post which I'd extracted from
a 7GB stereo wav file captured from a 24 hour internet radio broadcast
just over nine years ago.

I'm pretty certain I deleted the original 7GB wav file once I'd
processed it into a 54 episode MP3 collection because I couldn't
afford to tie up so much disk space. It'd be a different story today
now that 7GB is such 'a mere trifle' on a 4TB disk but back then, it
wasn't so trifling. Oh, how things have changed in less than a decade!

The station, afaicr, was called "GoonShow Radio" and had a repetoire
of 54 episodes contained in its daily endlessly looped output. I used
Winamp to capture the stream and send its output to a wav file,
letting it run for just over 24 hours. This proved sufficient to
captue all 54 episodes with an episode or three spare.

I'd previously been listening directly to the audio stream for a few
days before, noticing that they were simply repeating a limited number
of episodes every 24 hours, and realised that I could archive the lot
by leaving WinAmp to run for just over 24 hours. I'm glad I did
because the station dropped out of existence a week or two later.

The point is that the original stream was just 64Kbps mono (a
reasonable match to the AM radio broadcast quality most listeners of
the day would have experienced) which, being MP3 rather than the
crappy MP2 standard of DAB was quite sufficient quality (no bubbling
mud effects so typical of a 64Kbps mono DAB broadcast).

Mind you, a higher bit rate would have been appreciated but this was
just over 9 years ago when bandwidth was at more of a premium. The
source material was almost certainly taken from the original studio
recording tapes which could have justified higher bit rates to emulate
FM radio quality rather than the AM radio quality it was re-broadcast
in.

Be that as it may, I still enjoy listening to these shows despite the
limitations of the low bit rate mono MP3 storage method (24 hours
worth packed into the space of a single data CD!).

I've digitised a portion of my reel to reel tapes and vynil to wav
files which I _have_ retained. The 192Kbps stereo MP3s which I
carefully crafted for 'easy listening' purposes are almost
indistinguishable in quality from the original wavs.

The deficiencies only become obvious when I use the "3D Surround"
options on the PC speakers which uses anti-phase cross mixing to
simulate a wider stereo image otherwise the straight playback of this
material seems to be just fine to my aged ears whenever I bother to
compare the MP3 against the original wave file playback.

If I wanted to create a compressed archive of all this audio
material, I'd choose a lossless format to preserve the original detail
in the wav files regardless of my own hearing abilities. The storage
costs for digital audio, even with flash media, is cheap enough these
days to call into question the value of lossless compression.

Lossless compression eliminates unnecessary redundency making the
task of reconstructing the original from a moderately corrupted
compressed file all the more problematic.

I f you want to add an extra level of robustness against 'bit rot' in
the storage media, an effective way is simply to duplicate or even
triplicate the archive files since the ddrescue application can
recreate a bit perfect copy from such corrupted duplicated backups.
IOW, use two or three times the storage media for each backup and keep
ddrescue on hand to refresh your archives as soon as your annual 'spot
checks' reveal the first signs of 'bit rot'.

All archival methods need some level of maintenance to retain their
integrity over protracted periods of time. Even well proven ink on
paper materials need to be checked from time to time even if it's a
matter of maintenence intervals measured in half centuries.

With modern digital storage, we'd be pushing our luck with 5 year
maintence intervals. The only saving grace being the ease with which
exact duplicates can be created on replacement and novel media.
Optical disk storage lost its 'Novelty Factor' decades ago hence my
regard of CDs and the like as being positively 'pre-historic'.
--
Regards, J B Good

In article ,
tony sayer wrote:
In article , Dave Plowman (News)
scribeth thus
The first digital audio recorders used video tape transports. Indeed the
CD 'red book' was based on how long a standard U-Matic tape ran. So it
would be fair to call it a memory - just not a RAM one. ;-)


Wasn't that the F1 ?? or some such unit?..

Not sure Tony. Never actually saw one. The first digital recorder I came
across was IIRC the 610 - which used a Sony Betamax as the transport. That
had a slightly wider video bandwidth than the low band U-Matic. It was
short lived as DAT arrived soon after.

--
*Wrinkled was not one of the things I wanted to be when I grew up

Dave Plowman London SW
To e-mail, change noise into sound.

In article 6,
says...

Adrian wrote in news:ljjtbl$6au$2
@speranza.aioe.org:

On Sun, 27 Apr 2014 20:31:27 +0100, Bill Wright wrote:

Katie, who is 11, was helping me in the workshop today. She told me how
some of her class been in trouble for filming the teachers covertly. Of
course I told her how, in 1965, I'd made a sound recording of our maths
teacher, with the class deliberately winding him up just to make it more
fun. I then found myself trying to explain about reel-to-reel tape
recorders. I could see that Katie just couldn't grasp the concept.
Finally she asked, "But how much memory did it have?"

I don't know whether to laugh or cry...

It's slightly scary that there's people wandering around who regard the
CD as pre-historic. I feel old.

With the old devices we all had some inkling of how they worked and if we
were to survive some sort of massive global disaster we would have known
enough about the principles to get these devices back in use. Nowadays the
ability to make or even understand common devices is in the hands of very
few people. Who remembers using a pin and some rolled up card to listen to
a 78rpm record?

Much too high tech.

Hold the pin between your teeth & rely on bone conduction.

--
Sam

On Sun, 27 Apr 2014 20:31:27 +0100, Bill Wright
wrote:

Katie, who is 11, was helping me in the workshop today. She told me how
some of her class been in trouble for filming the teachers covertly. Of
course I told her how, in 1965, I'd made a sound recording of our maths
teacher, with the class deliberately winding him up just to make it more
fun. I then found myself trying to explain about reel-to-reel tape
recorders. I could see that Katie just couldn't grasp the concept.
Finally she asked, "But how much memory did it have?"

Bill

Yup, but I bet that in 10 minutes you could have taught her how a
reel-to-reel worked and she would have pretty much understood. No
chance of that with modern mp3 digital equipment.

Thats the biggest difference between the tech of my youth and now -
old stuff was understabndable to the average person.

On a related note, I looked inside a TV that we were binning last
week. Just 2 small circuit boards with precious few components. A
triumph[?] of modern design. The TVs of my youth were full of glowing
valves and thick cables. A thing of wonder, but now look like
something from a Jules Verne film.

How many components in a valve TV?

Incidentally, check out 'photonics' for some amazing old
electronics... eg:

Mercury Arc Rectifier [100 yrs old]
http://www.youtube.com/watch?v=QY6V2syGnZA

In article ,
tony sayer wrote:
In article , Dave Plowman (News)
scribeth thus
The first digital audio recorders used video tape transports. Indeed the
CD 'red book' was based on how long a standard U-Matic tape ran. So it
would be fair to call it a memory - just not a RAM one. ;-)


Wasn't that the F1 ?? or some such unit?..

I think the F1 did the AD conversion.

--
From KT24

Using a RISC OS computer running v5.18

Dave Plowman (News) wrote:

In article ,
Bill Wright wrote:

My little tape recorder had a non-standard speed of 4ips and also had
the tape wound in a funny way so it played backwards on a normal
machine. For tapes I used to strip down 1/2" computer tape. My uncle
worked at IBM and he used to get it for me.

There was one from Shoppertunities? which had no capstan so ran at a
different speed depending on where the tape was on the reel...

What about the one which somehow took its drive from a record
player? I'm sure I didn't imagine it, but can't find any details
right now.

Chris
--
Chris J Dixon Nottingham UK


Plant amazing Acers.

"Dave Plowman (News)" wrote in message
...
In article ,
Bill Wright wrote:
Stephen wrote:

My estimate would be 30 minutes at 3 3/4 inches per second, mono, 10
kHz frequency response, signal to noise ratio 40dB.

My little tape recorder had a non-standard speed of 4ips and also had
the tape wound in a funny way so it played backwards on a normal
machine. For tapes I used to strip down 1/2" computer tape. My uncle
worked at IBM and he used to get it for me.

There was one from Shoppertunities? which had no capstan so ran at a
different speed depending on where the tape was on the reel...

Like the Grundig Cub.

--
Max Demian

different speed depending on where the tape was on the reel...

What about the one which somehow took its drive from a record
player? I'm sure I didn't imagine it, but can't find any details
right now.

Chris

I really craved one of those. They were always advertised in the back pages
of the various hobby magazines. It was never clear what you needed to do to
hook it up to the amplifier so I never bought one.

On 28/04/2014 13:14, John Williamson wrote:
On 28/04/2014 09:59, Dave Liquorice wrote:
On Mon, 28 Apr 2014 01:40:04 +0100, Johny B Good wrote:

I regard not only CD as pre-historic but DVD and Blu-Ray[1] too. It's
not that that makes me feel old, just the effects of old age creeping
up on me.

Presumably old age is having its normal affect on hearing and sight
so you don't notice how crap downloads and/or streaming are compared
to CD or Blu-Ray (or even DVD come to that). B-)

What worries *me* is that many teenagers are of the opinion that
downloads are better quality than CDs.

Even at my age, I can tell the difference, even on earbuds and small
screens.


There must be something wrong with me then because I can't really tell
the difference

--
Dawood

"gremlin_95" wrote in message
...
On 28/04/2014 13:14, John Williamson wrote:
On 28/04/2014 09:59, Dave Liquorice wrote:
On Mon, 28 Apr 2014 01:40:04 +0100, Johny B Good wrote:

I regard not only CD as pre-historic but DVD and Blu-Ray[1] too. It's
not that that makes me feel old, just the effects of old age creeping
up on me.

Presumably old age is having its normal affect on hearing and sight
so you don't notice how crap downloads and/or streaming are compared
to CD or Blu-Ray (or even DVD come to that). B-)

What worries *me* is that many teenagers are of the opinion that
downloads are better quality than CDs.

Even at my age, I can tell the difference, even on earbuds and small
screens.


There must be something wrong with me then because I can't really tell the
difference

Ditto - originally I thought MP3's were inferior [to CD] because they were
not lossless compression (like zip), however for most purposes you really
can't hear the difference.

PS typical digital audio streams are 44 - 48k samples per second.


--
Dawood

In message , Chris J Dixon
writes
Dave Plowman (News) wrote:

In article ,
Bill Wright wrote:

My little tape recorder had a non-standard speed of 4ips and also had
the tape wound in a funny way so it played backwards on a normal
machine. For tapes I used to strip down 1/2" computer tape. My uncle
worked at IBM and he used to get it for me.

There was one from Shoppertunities? which had no capstan so ran at a
different speed depending on where the tape was on the reel...

What about the one which somehow took its drive from a record
player? I'm sure I didn't imagine it, but can't find any details
right now.

Chris

Gramdeck. I once had one. The tape speed was 7ips (at 78rpm). It used a
permanent magnet erase. The quality was actually pretty good.
http://www.youtube.com/watch?v=1PJHaSZbH5k
et al.
--
Ian

In article ,
"Dave Plowman (News)" writes:

There was one from Shoppertunities? which had no capstan so ran at a
different speed depending on where the tape was on the reel...

I bought my first cassette recorder from Shoppertunities!
ISTR the make was Monotone ;-)

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Dave Plowman (News) wrote:
In article ,
Bill Wright wrote:
Stephen wrote:

My estimate would be 30 minutes at 3 3/4 inches per second, mono, 10
kHz frequency response, signal to noise ratio 40dB.

My little tape recorder had a non-standard speed of 4ips and also had
the tape wound in a funny way so it played backwards on a normal
machine. For tapes I used to strip down 1/2" computer tape. My uncle
worked at IBM and he used to get it for me.

Bill

There was one from Shoppertunities? which had no capstan so ran at a
different speed depending on where the tape was on the reel...

Happy days.


Oh I remember that. Mine was far superior to that though.

Bill

On 28/04/2014 19:37, R. Mark Clayton wrote:
"gremlin_95" wrote in message
...
On 28/04/2014 13:14, John Williamson wrote:
On 28/04/2014 09:59, Dave Liquorice wrote:
On Mon, 28 Apr 2014 01:40:04 +0100, Johny B Good wrote:

I regard not only CD as pre-historic but DVD and Blu-Ray[1] too. It's
not that that makes me feel old, just the effects of old age creeping
up on me.

Presumably old age is having its normal affect on hearing and sight
so you don't notice how crap downloads and/or streaming are compared
to CD or Blu-Ray (or even DVD come to that). B-)

What worries *me* is that many teenagers are of the opinion that
downloads are better quality than CDs.

Even at my age, I can tell the difference, even on earbuds and small
screens.


There must be something wrong with me then because I can't really tell the
difference

Ditto - originally I thought MP3's were inferior [to CD] because they were
not lossless compression (like zip), however for most purposes you really
can't hear the difference.

Do the same experiment that I did with some colleagues.

Record a band they know well. (I used a band from Stoke called Halcyon
Dayz, most of whose members worked at the same place we did.)

Mix the close mic'd multitrack recording to your taste.

Play back the stereo mix at 16 bit, 44.1kHz sample rate.

Repeat using a 320kHz bitrate mo3 file using the same playback system.

Repeat using "FM radio" quality settings of 128kHz bitrate.

Almost anyone will note a deterioration in sound quality the further
down the chain you go.

Repeat using a decent choir and a crossed cardioid mic setup. Play to
the choirmaster.

Find exactly the same results.

I use a lot of mp3 files to play background music while I'm driving, as
I can't justify the storage cost for CD quality .wav files with many
horsepower of diesel engine drowning out the distortion and noise floor.
--
Tciao for Now!

John.