[grc] [Stubblefield] Using a digital stream as STL to LPFM transmitter site

[Paul Bame]

A few other things to think about... 

CD-format audio (44.1k samples/sec, stereo, linear 16-bit PCM), which is
overkill for radio's 15kHz bandwidth, can be pushed through a 2 megabit
pipe. Unless you're stuck with DSL, entry-level cable and fiber internet
is plenty for that. 

Which means it is more realistic than it used to be when I first set up
streaming a long time ago, to use uncompressed audio, which you might
even call "direct". 

Which means the delay can be tiny. Compression algorithms add delay, and
usually additional delay through buffering too. 

I think the Barix boxes have a "direct" sort of capability. 

However a tiny audio delay means that small network delays turn into
audible dropouts. And there can be some surprising sources of delays,
like for example some network cards and drivers re-negotiate the network
link speed once in a while which can cause a delay. 

And if you're going across 2 ISPs, those variables are going to add up,
and to keep a reliable-sounding signal, a larger amount of
buffering/delay will be required to paste over network hiccups and
variations which you wouldn't even notice if just surfing the web. 

And a delayed audio signal can work just fine for almost everything. 20
or 30 seconds of delay/buffer can smooth over a lot of network problems
and for all but the most particular of people and automated recorders,
show start/end times and announcements of time-of-day and station IDs,
are close enough even without pre-compensating for the delay. 

Delays are hell for phone-in if the caller doesn't know to mute their
radio!