Sample code in README gives weird squealing

[novalis]

The sample code in the README, on Linux with ALSA, doesn't seem to work for me (even after fixing #1 and #2).

First, frequency_hz isn't defined. But let's set it to the Versailles-approved A above Middle C: 435 hz.

This gives a weird sound. It does seem to have some relation to the frequency value, but it's weirdly noisy: bug.zip