Circa 1970 tape machines: low-speed modes

[John_BS]

I've just managed to recover some old recordings from a tiny tape (3 inch?) which contains thin (double-play?) tape. I can only replay down to 3.75ips and there was some "chipmunk" stuff so I recorded the entire content to a digital recorder at 48kHz sampling, then re-sampled to recover the content. Much of it was recorded at 15/16th ips!! How common was this speed?? Perhaps Dictaphone applications?

John

[dazzlevision]

Originally Posted by John_BS

I've just managed to recover some old recordings from a tiny tape (3 inch?) which contains thin (double-play?) tape. I can only replay down to 3.75ips and there was some "chipmunk" stuff so I recorded the entire content to a digital recorder at 48kHz sampling, then re-sampled to recover the content. Much of it was recorded at 15/16th ips!! How common was this speed?? Perhaps Dictaphone applications?

John

Philips included this speed on some of their more expensive domestic tape recorders in the 1960s, such as the EL3556: https://www.vintage-radio.net/forum/...d.php?t=148287

[Edward Huggins]

I seem to remember a version of the Brenell deck with the 15/16 ips speed option. Brenell gave a very impressive demostration of Piano music recorded at this speed and (even better) at 1 7/8 ips at one of the very early Hi Fi Shows at the Russell Hotel in Russell Suqare, London.
THINKS: I wonder how many of you remember those early Shows?

[TIMTAPE]

7.5/3.75/1.875 were probably the most common domestic speeds but some domestic and professional machines carried the slower speed. I know Philips, Uher, Akai, Sony and Revox made models with this speed, as did Nagra.

Because of its lower sound quality it was a tradeoff mainly used for either the smaller machines where recording time was limited, or on large reels for super long recording times. A standard format for logging radio broadcasts to satisfy legal requirements was 15/16ips on 10.5" reels of 1/4" tapes. With LP tape that gave a comfortable 12 hours per reel.

It was also used on cassettes and the US Library of Congress developed it as a Talking Book standard using 4 tracks to give over 6 hours of programme on one Compact Cassette. The earlier British Clarke and Smith Talking Book tape cartridge (1/4" tape) also ran at 15/16 ips, giving over 13 hours on 6 tracks. That was often enough to contain narration of a complete novel.

It's also the same tape speed used on standard VHS cassettes, allowing a little over 3 hours. When it was set up properly it could give quite reasonable fidelity especially as VHS cassettes used Chrome type tape.

[DMcMahon]

I believe 15/16 ips was the normal/default tape speed on most dictation machines and as stated above was sometimes the fourth (slowest) tape speed on some of the better reel to reel machines.

[TIMTAPE]

Originally Posted by DMcMahon

I believe 15/16 ips was the normal/default tape speed on most dictation machines..

Maybe on some but many Grundig and Philips dictation machines (1/4" and cassette width tape) were rim drive so as the take up reel filled up, tape speed increased. The capstan and pinch rollerless rim drive was simpler and more rugged, so more suited to constant starts, stops, rewinds etc in a dictation environment.

[red16v]

Originally Posted by TIMTAPE

7.5/3.75/1.875 were probably the most common domestic speeds but some domestic and professional machines carried the slower speed. I know Philips, Uher, Akai, Sony and Revox made models with this speed, as did Nagra.

Because of its lower sound quality it was a tradeoff mainly used for either the smaller machines where recording time was limited, or on large reels for super long recording times. A standard format for logging radio broadcasts to satisfy legal requirements was 15/16ips on 10.5" reels of 1/4" tapes. With LP tape that gave a comfortable 12 hours per reel.

It was also used on cassettes and the US Library of Congress developed it as a Talking Book standard using 4 tracks to give over 6 hours of programme on one Compact Cassette. The earlier British Clarke and Smith Talking Book tape cartridge (1/4" tape) also ran at 15/16 ips, giving over 13 hours on 6 tracks. That was often enough to contain narration of a complete novel.

It's also the same tape speed used on standard VHS cassettes, allowing a little over 3 hours. When it was set up properly it could give quite reasonable fidelity especially as VHS cassettes used Chrome type tape.

My bold. Yes, at the UK tv station I worked at we used that combination. The tapes were rotated through the system on a monthly basis. Remembering to change them in the early evening was the difficult bit!

[Ted Kendall]

15/16 was available on the Akai X-4 and X-5 and the Uher 4000 portables, to name but three.

[hillmanie]

Originally Posted by Edward Huggins

I seem to remember a version of the Brenell deck with the 15/16 ips speed option. Brenell gave a very impressive demostration of Piano music recorded at this speed and (even better) at 1 7/8 ips at one of the very early Hi Fi Shows at the Russell Hotel in Russell Suqare, London.
THINKS: I wonder how many of you remember those early Shows?

That is amazing. I recorded much piano music in 'the old days' and could detect distinct wow and flutter at any speed less than 7.5 ips. An informed person explained the the piano was the most difficult to record clearly as it contains the most harmonics of the notes due to the way the strings are constructed, ie overwound or something. I'm sure there's some folks out there who can confirm or correct. It would have saved slim pockets a lot if the 1-7/8 speed sufficed.
Re HiFi Show, yes I recall them , started 1960s or earlier? Unfortunately I was too far out of London and never made it to one
TT

[Ted Kendall]

The problem with pianos is that the string, having once been struck, vibrates at constant frequency, so any wobble is detected immediately. Conversely, wow correction software, such as Cedar Respeed, finds it easier to straighten pianos out than almost anything else.

[hillmanie]

Originally Posted by Ted Kendall

The Conversely, wow correction software, such as Cedar Respeed, finds it easier to straighten pianos out than almost anything else.

Alas, @ >$4300 I don't expect it in my Xmas Stocking
Thanks
TT

[Welsh Anorak]

Revox supplied a special order low speed version of the A77 especially for logging in a radio studio. We still log in our studio, but this time it's at a low bit rate on a computer (running XP!) and a 320GB hard disc drive will easily hold six months of constant output.

[emeritus]

Re #4, interesting observation on the 15/16 ips speed of standard VHS. Quite a few Christmas days ago, the BBC broadcast the complete reading of the first Harry Potter book by Stephen Fry, which I recorded on my then top of the range Panasonic S-VHS recorder, which had a seperate audio input with volume control and audio level meter, on the long play setting on a 5 hour tape.This would have given a linear speed of 15/32 ips. I normally only used the hi-fi stereo audio track for playback, but it did also record in linear mono. I still have the cassette but unfortunately the VCR is no longer working so I can't try out what 15/32 ips analogue audio sounds like.

[AC/HL]

I seem to remember seeing call logging equipment in comms rooms using VHS tape. Not my field, but I always took a superficial interest in all the other gear I came across. Racal possibly?

If they had started at 32 inches per second rather than 30 it would be much easier on the arithmetic.

[TIMTAPE]

Originally Posted by AC/HL

I seem to remember seeing call logging equipment in comms rooms using VHS tape. Not my field, but I always took a superficial interest in all the other gear I came across. Racal possibly?

I suspect logging audio only onto long play (LP) VHS was common. I have some such tapes from a radio station. All recorded in HiFi but the linear track is also there. At best the LP linear is good for 4 to 5 kHz. At LP speed the HiFi tracks can be unreliable. Sometimes a slight tweaking of the tape guide height helps with the switching noises and the machine and tape need to be in top condition.

[red16v]

Originally Posted by AC/HL

I seem to remember seeing call logging equipment in comms rooms using VHS tape. Not my field, but I always took a superficial interest in all the other gear I came across. Racal possibly?

Our open reel to reel machines were eventually replaced by a Racal Logging system. Rather than open reels, the Racal system used cassettes - about 25/50% bigger than a standard physical VHS cassette if I recall. Usefully the machine had 'end of cassette coming up' warnings that could be remoted to the operational control room which made life easier. (Station output on one track, transmission talkback plus TIM on the other).

[barrymagrec]

Originally Posted by merlinmaxwell

If they had started at 32 inches per second rather than 30 it would be much easier on the arithmetic.

Indeed, but 30ips (76.2cm/s) was conveniently close to the old German standard speed of 77cm/s. Early EMI BTR1 tape machines ran at 77cm/s.

No idea where 77cm/s came from.....

[barretter]

Originally Posted by red16v

Our open reel to reel machines were eventually replaced by a Racal Logging system. Rather than open reels, the Racal system used cassettes - about 25/50% bigger than a standard physical VHS cassette if I recall. Usefully the machine had 'end of cassette coming up' warnings that could be remoted to the operational control room which made life easier. (Station output on one track, transmission talkback plus TIM on the other).

The Racal 4DS Storage instrumentation tape recorder had 7 speeds doubling from 15/16 ips up to 60ips

[Ted Kendall]

Originally Posted by barrymagrec

Indeed, but 30ips (76.2cm/s) was conveniently close to the old German standard speed of 77cm/s. Early EMI BTR1 tape machines ran at 77cm/s.

No idea where 77cm/s came from.....

The DC biased Magnetophon ran at 1m/s. When AC bias was introduced, the speed could be reduced to 77cm/s as the bandwidth, s/n ratio and distortion were all substantially improved. It also meant that a 1km length of tape would give twenty minutes' continuous recording. Before AC bias, experiments were in hand to record two simultaneous tracks at differing levels with level-dependent switching on playback to improve the s/n ratio. The redundant head from this development enabled the consruction of the first stereo tape machines by RRG.