[linux-audio-dev] ignorance is bliss..

I have a really stupid problem here and thought maybe you guys could help me improve my understanding.. I have a tiny audio program. It consists of two threads. The first thread uses the xinelib for audio output and reads its input from a fifo. The second thread creates a sine wave, "converts" it into WAV/PCM16 format and sends it to the fifo. After it has sent the first WAV/PCM16 chunk it keeps on looping but only sends the PCM part of the sine wave without the WAVE header. Now my problem: the second thread (=sine thread) uses a buffer where it generates the sine data. Once that buffer is full it writes the whole buffer to the fifo. What I experience is that what I hear depends on the size of this buffer. When I set the buffer size to 44100 samples (which I think equals 1 second of sound) then I hear a proper sine wave at the right frequency. When I change it to 22050 still ok. But once I choose for intance 11025 or 16384 or 8192 or 4096 I get strange stuttering, clicks or a somewhat modulated sound. So I thought the problem is my sine generator and compared the output using different buffer sizes. But it's the same no matter what buffer size I use. I can post some code too if that helps and would be grateful for any help. Thanks mimo