[GLLUG] Audio Production

[Chris Bell]

On Fri 05 Dec, James Roberts wrote:
> 
> On 05/12/14 15:21, Chris Bell wrote:
> >     As an aside, I am told that professional sound studios often prefer older
> > sound hardware which uses germanium transistors which are low noise compared
> > with silicon.
> 
> With apologies, and without personal aspersions - that's an... 
> "interesting suggestion"... and I rather am of the opinion that it's a 
> pseudo-audiophool urban legend (as in, 'pull the other leg-end').
> 
   The information was supplied via a friend at Angelsound studios. I have
been asked for old sound cards and AT power supplies. No doubt they have
other equipment as well.

> That's speaking as a (once) professional recording studio designer (and 
> speaker, amp, preamp, multi-track, test equipment etc. designer), and 
> user of same - admittedly mostly of yore.
> 
> I grew up on germanium (which we sometimes called 'geranium' as in 
> 'flowers briefly') and one of the best things ever to happen to the 
> semiconductor industry was the replacement of noisy, smelly ('cos they'd 
> melted - again) and generally mayflower-like germanium devices with 
> quiet robust silicon ones - especially when the planar process arrived. 
> Old germanium devices as in early transistor equipment were dreadful - I 
> still have drawers full of them, against the unlikely chance I can ever 
> find a use for the junk.

   I started with valves, (even operating the incredibly insensitive
CPS-Emitron cameras still in use at Lime Grove at the time, then 3 inch and
4.5 inch Image Orthicons, Vidicons, Plumbicons, and CCD devices).
   General sound and vision maintenance was part of my job. Some of our
first semiconductors were used in reference pulse generators, which had to
be pulled out from their cases into the corridor to prevent them from
overheating. We often had serious overheating and reliability problems, with
the maximum amount of kit crammed into OB vehicles, and the change to
silicon was a great help. Much of the equipment required well over an hour
to get anywhere near stable, followed by realignment as required during
operation.
   The minimum noise depended on the input device and its configuration,
matching the input impedance to the output impedance of the source, so
different pre-amps were available to match each type of microphone in use,
including low impedance ribbon microphones, just about everything else was
set by feedback.

> 
> Please forgive me Chris for jumping on your comment, but I believe that 
> whoever issued it originally was deeply misinformed and probably bereft 
> of useful instrumentation.
> 
> There's a lot of it about.
> 
> An anecdote - it is Friday - once (in my 15 year studio career) I was 
> invited round with a colleague mix engineer by one of the Hi-Fi gurus, 
> who worked for a magazine that my newsagent insisted on calling 'Hi Fi 
> Nudes'.
> 
> He had a pair of 'valve' (wow - had hoped we'd got rid of those) 
> mono-bloc (sounds impressive - why not 'mono') Hi-Fi amplifiers one of 
> which he had modified by removing the main negative feedback loop and 
> adjusting the gains to compensate. This was a man who hated negative 
> feedback and blamed it for all ills that he (though not me) could detect 
> in almost anything.
> 
> I was known as a bit of a golden ears in the studio side, so he wanted 
> the opinion of myself and the other mix engineer as to the much improved 
> sound of the modified amp.
> 
> So he had one on the left, original, and one on the right, modified.
> 
> These were plugged in to a set of KEF speakers - very large ones we 
> called the 'kangaroo'. They were the first hifi speakers to correct for 
> speaker voice coil alignment  and were generally very good (but looked 
> like kangaroos).
> 
> So he turned it all on.
> 
> After a few seconds of peaceful silence, it warmed up.
> 
> A loud 100 Hz hum came out of the right speaker.
> 
> 'Ah - just wait while I put this on', he said, and went to his turntable 
> and started to play - Steely Dan, I think it was (superb studio 
> recording of the highest quality).
> 
> And out of the left speaker came Steely Dan. Out of the right speaker 
> came 100HZ hum with cross-modulated and possibly even ring-modulated 
> 'Steely Dalek' with about 30% distortion and nothing above about 6 kHz - 
> but lots of bass. Distorted, modulated bass.
> 
> 'There!' he said, pointing to the right. 'Doesn't that sound better?'.
> 
> I cancelled my subscription the same day.
> 
> Nothing that has happened since has raised my opinion of audiophiles.
> 
> MeJ
> 
   Most of the studios I worked in were "dead" by design because they were
not dedicated to orchestral use. They had about two feet of insulation in
all the walls. We even had a "dead" listening room for critical reviewing
and testing. There was an attempt to provide an artificial "live" effect in
two medium sized studios by feeding back individually delayed sound through
speakers mounted around the walls, but it only worked for one point in the
studio so it was no use for an orchestra and was scrapped.
   No need to comment about having to work in front of a huge bank of 1KW
speakers in Wembley Pool, where even ear defenders were of little use and
your whole body just vibrated.

-- 
Chris Bell www.chrisbell.org.uk
Microsoft sells you Windows ... Linux gives you the whole house.