"Eeyore" wrote in
message
Ian Bell wrote:
Arny Krueger wrote:
Standards for audio were a lot lower in the 50s, if you
didn't ever notice when you listened to a lot of
recordings from that time. There are some exceptional
recordings that still sound good, but in general, it
was not a good time for quality sound reproduction.
I would not say they were a lot lower. The flat
bandwidth extended only from 50Hz to 15KHz
i.e. totally crap.
but elsewhere the specs were close to today's.
********.
An RCA
broadcast console achieved a 68dB S/N ratio with a
-60dBm input signal which implies an equivalent input
noise of -128dBm
Cite ? A weighted by any chance ?
Here you go, Graham. As usual the tubies can't deliver what a few searches
with google turned up almost immediately:
http://sujan.hallikainen.org/Broadca.../index.php/RCA
Click on the manual for the RCA BC 7A. However, being stereo, this was not
a product of the 50s but rather one of the late 1960s.
The actual spec on page 4 of the PDF is 68 dB below +18 dbm. IOW, only 50
dB below 0 dB. As bad as that is, I would suspect 50-15 KHz (- 3 dB)
weighting. The corresponding spec for a modern console would be about
twice that, IOW over 100 dB. (!!!!!!!!!!!!!!!!!!).
Moving on to component chassic specs, such as those on page 15 (Figure 11)
we see the sad truth - noise level was -47 dBm, with THD speced at 1% over
a restricted frequency range. A modern component would have noise about -90
dBm, with THD no worse than 0.02%.
As usual, we're getting a humongous load of BS dropped on us. :-(