can’t point this out of enough:
Signal Source (float, sine, 1khz freq, sample rate 8000) -> Throttle
-> Wav File Sink (sample rate 8000, 8 bit per sym).
Never, ever use a throttle block in a flowgraph where hardware dictates
the physical sampling rate.
Your GNU Radio companion should even have warned you about that, if your
GNU Radio version is rather recent:
Warning: This flow graph contains a throttle block and another
rate limiting block, e.g. a hardware source or sink. This is usually
undesired. Consider removing the throttle block.
If you’re not seeing aUaU… on the console, you’re lucky. Usually, you
would have built a system with two competing clocks. One is bound to
be a little slower than the other, and if it’s the throttle, your audio
sink would have no samples to play when it needs them.
I do, however, suspect that your sound system doesn’t support a 8kHz
sampling rate. Try 44.1kHz, as it’s supported by most systems.
If that doesn’t help: try explicitely setting the ALSA device to use;
“aplay -L” will usually list all available output devices.
Also, try going down with the amplitude a bit. Typically, 0.4 as
amplitude is enough to drive sound cards “loud”, and higher values often
result in clipping.
Best regards, and happy hacking,