"Dave Plowman (News)" wrote in message
...
The last version of Dolby (pro) was SR, and quite superb.

Yes. SR was excellent.
I remember the first professional model, the 301.
It was a two channel unit in a 6U box with eight plug in cards, and psu.
So NR units for an Ampex 4 track (half inch tape), or a Studer J37
(four tracks on 1") which were "state of the art" in 1965,
filled a half rack. The first units were known as "Stretchers" because
they had the letters SN (Signal to Noise) with a double headed arrow
and the word Stretcher painted in small white silk-screen letters at the
top left of the front panel.

Ray Dolby set up Dolby Labs in 1965 in South London (Streatham IIRC)
They moved to LA in 1the late 70's but still had European HQ in
Soho Square London, and development at Wootton Bassett.

Dolby approached both EMI and Decca, the two major record
companies in the UK with regard to funding. EMI were working
on their own "Compander" at their Hayes facilities, with a project led
by Dr Percival. They were not interested in investment in a rival system.
As far as I know the "Compander" never became available commercially.

Decca promised technical assistance, and field evaluation, making stereo
recordings with two tape machines in parallel, one with and one without
Dolby NR. Decca was the first record company in the UK to buy Dolby
equipment. I recall many of the units had very low serial numbers.

One might get the impression that due to tape noise, recording pre Dolby was
of low technical quality. This is of course not the case. There are many
fine
classical recordings made in the 50s and 60s which are still highly
regarded.
In those days tape speeds of 30ips (76 cm/s) were commonly used for better
HF and lower noise. Some American record companies used the AME
recording curve.

For pop recordings it was common practice to record on four tracks
(Bass and Drums on one track) and the rest of the band across two
tracks, with one left for vocals. Studios with more than one 4 track
machine
recorded four tracks, and then "bounced" these (the technique known as 4 to
4)
to two tracks of a second machine mixing via the console, sometimes
adding new material from mics as they went. The build up of tape noise was a
critical factor, and so the advent of Dolby NR was a great technical
advance.
This 4 to 4 process demanded considerable skill, as each instrument in the
submix had to be at the level at which it will appear in the final mix.
There was no "undo"

Interesting to note that analogue multitrack (typically Studer A80-24 and
Dolby
SR) is still in demand for pop music recording. Tracks are then
transferred to a digital workstation for post and mixing.

It is easy for us, in this digital age, to be critical of earlier
techniques, which were
at the time of their introduction, ground breaking. Duke Ellington whose
first
recordings were made at the very end of the acoustical recording era,
announced
on hearing the playingback of an electrically recorded wax, made at Okeh
Studios
in 1929 that "recording techniques have now reached perfection"
so great was the improvement:-))

Iain