From: Patent Tactics, George Brock-Nannestad
Göran Finnberg quoted:
> Richard Hess:
> > My biggest concern is gap-loss in normal pro-machine
> > repro heads. I think that's probably the limiting factor.
> Sorry no.
> The wavelength on the tape stays the same irrespective of the
> duplicating speed.
> So when duplicating at 64X the original speed by running the binloop
> master recorded at 3 3/4" speed at 240"/s then the replay gap in the
> loop bin master machine isn´t any better than around 2 µM.
> The losses occur in the inductance of the playback head at 2.5 mHy
> resonating with the loading capacitance.
----- I'll second that 100%. One example that I remember from my Uher days
was that if I reproduced at 15/16 ips a recording that I had spent the
"expensive and luxurious" 7˝ ips on I could hear a 10 kHz whistle. I never
measured the frequency, but it would correspond well with hearing the 80 kHz
erase and bias recording. The Uher Report 4000 was a 1964 vintage, and we
have later regarded a higher bias frequency as desirable.
----- David Lennick wrote:
One of these years I'm going to have to deal with thousands of tapes my dad
recorded off radio and TV between 1959 and 1996..much of it dross, but a lot
of it containing audio from programs that probably aren't archived anywhere
(variety, talk, interviews, panel shows) and I can assure you that he
recorded at the slowest speed possible on whatever machine he was using.
Much of it was on a Philips at 15/16 ips. Aaaaargh.
----- your dad would not need very much prompting to relive the orginal
event, so for him it was assisted memory. The same goes for a lot of field
recording - ideally it should be used by the fieldworker him/herself, and so
it does not absolutely need to be as high quality as if you are giving it to
someone else to transcribe.
----- the 15/16 ips capability at halftrack and triple-play tape was a very
economic approach in the 1960s.