[Elecraft] How to record Audio on K3

[David Woolley (E.L)]

Tom Hammond wrote:
> One item which has (i believe) been touched upon, but may not have
> been explained deeply enough is the SIZE of the resulting audio file
> if you use the default record settings often offered by many (most)
> audio recording softwares.

One really needs to know something about the nature of the specific 
problem before you start optimising the sound file settings.

In particular, whilst MP3 will be good for problems that are easily 
audible and can be diagnosed by ear, it will probably completely corrupt 
  PSK data.  If one ends up taking a spectrum, MP3 is also likely to 
distort it.

I admit that 44.1kHz is likely to be excessive, if the roofing filters 
are working.

> I've found that it's not necessary to use the highest fidelity recording
> parameters when recording SSB voice or CW... and possibly digital as well.
> 

SSB is generally lower quality than telephone voice, so telephone 
settings, i.e. 8kHz, mono, 8 bit mu- or A-law encoding would be enough 
for recording voice.  (GSM is possibly the most compact form for SSB 
voice (mobile phone quality), although you can get almost as compact 
with low bit rate MP3.  I'm not sure if GSM (or MP3) handle noisy voice 
very well. Standard bit rate MP3 will be larger than 8kHz mu-law.)  If 
the roofing filters are OK, 8kHz should be OK for all but AM and FM 
filters, although I might use 16 bit linear for raw recording of digital 
modes.

(Telephone quality may appear as something like G.711 (G.71x) in the 
list of codecs.)


-- 
David Woolley
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