If you have configured Snack to use the NIST/Sphere file format you have
to explicitly add this file format in your script using the
'package require snacksphere' command after 'package require snack'. 
This will make Snack automatically recognize this file format in addition 
to those already built-in, such as WAV, AU, and AIFF. 

See ../demos/tcl/SphereTest.tcl for an example on how to use the package.

Writing files in the Sphere file format is not supported yet.

There seems to be a problem with reading some long compressed
NIST/Sphere files. One solution is to use the program sph_convert
to convert these files to wav-format before using them.
The program is available from http://morph.ldc.upenn.edu/Using/