I've been trying to locate a clean MP3 or AAC stream for this with no avail.
The PLS is....
https://www.npr.org/streams/aac/live1_aac.pls
.. which generates...
[playlist]
NumberOfEntries=1
File1=https://nprdmp-live01-aac.akacast.akamaistream.net/7/91/364917/v1/npr.akacast.akamaistream.net/nprdmp_live01_aac
Title1=NPR 24 Hour Program Stream
...and the embedded stream URL results in a redirect to...
https://edge11475.icecast.akadns.net/7/91/364917/v1/npr.akacast.akamaistream.net/nprdmp_live01_aac?akacasthops=1
....which generates an SSL certificate error.
Converting to http, keeps redirecting from URL to URL, incrementing the hop count, and eventually resulting in a 404.
The web audio player at...
https://www.npr.org/2016/04/05/472557877/npr-program-stream
...does things a bit different...
The player fetches...
https://nprsxsw-lh.akamaihd.net/i/prog24_1@348758/index_256_a-p.m3u8?sd=10&rebase=on
which generates something like:
#EXTM3U
#EXT-X-TARGETDURATION:10
#EXT-X-ALLOW-CACHE:YES
#EXT-X-VERSION:3
#EXT-X-MEDIA-SEQUENCE:156192163
#EXTINF:10.000,
https://nprsxsw-lh.akamaihd.net/i/prog24_1@348758/segment156192163_256_a-p.ts?sd=10&rebase=on
#EXTINF:10.000,
https://nprsxsw-lh.akamaihd.net/i/prog24_1@348758/segment156192164_256_a-p.ts?sd=10&rebase=on
#EXTINF:10.000,
https://nprsxsw-lh.akamaihd.net/i/prog24_1@348758/segment156192165_256_a-p.ts?sd=10&rebase=on
These are "MPEG Transport Streams", but I cannot seem to get anything but a 404, but in any case, I'm not sure whether the Chumby audio player can handle them.