sample rates in audio

[Sivakatirswami]

Amazing... Stephen... I really don't know much about this... I mean I  
don't know theactually "audio physics" between bits and sampling  
rates. Of course sample rates seems obvious... how often the recorder  
is "trapping" for sound, but how that relates to 'bits" is  
mysterious... anyway... just going with what you said:

on recordSound
   set the recordsamplesize to 11
   set the recordrate  to 5
   set the recordformat to "wave"
   record sound file gAudioTestPath
end recordSound

I'm getting really decent quality at about 15 K per second or 900 K  
per minute

i.e. 11 seconds gives  us a 168 K file... I don't think it gets any  
better than that!  And you seem to have declared the bottom  
threshold... as anything less than a sample rate of 11 starts to  
break down noticeably... I guess  everyone has figured this out long  
ago...

Sivakatirswami





On May 15, 2006, at 6:10 AM, Stephen Barncard wrote:

> Actually you could halve that sample rate to 11 K and still have  
> good intelligibility. Using the Nyquest theorem, the highest  
> frequency you can record at a given sample rate is approximately  
> less than half its sample rate. AM broadcast stations cut off at  
> 5khz, which can be handled easily by the 11k sample rate.
>
> This is not 11 k bits per second, like in MP3s, but a full parallel  
> 16 bits at 11k and without compression, will have no artifacts,  
> just bandwidth reduction - i.e. less high end.
>
> sqb