Arny Krueger wrote:
"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.
If you check the my other posts you will see I cited the BC 6 series not
the one you chose and it was mono not stereo.
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. (!!!!!!!!!!!!!!!!!!).
********. Work out the actual output noise of a 'modern' console with
68dB and show me how you get it to be -100dBm
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. :-(
As usual you pick an example that suits your argument.
Cheers
Ian