an espeak phenomena

[Linux for blind general discussion]

> I'm using speakup with espeak and espeakup, and over the past
> couple of weeks I've noticed an odd phenomena: on occasion,
> the speech sounds gravelly. If I continue to use speakup the
> gravelliness or roughness of the voice becomes worse and
> worse. But If I stop the speech and wait a few seconds, the
> speech smoothes out and I can use speakup extensively with no
> problems, at least until the problem recurs a few days later.

Are you using pulseaudio?
If so, there seem to be some cases especially with espeak where pulse's
adaptive latency algorithms get unstable and introduce some really
horrible crackle.
This can be particularly bad on HDMI audio out.