You could try changing the frequency of the beep ( look for that information on the WWW, you need to write in the timer register). It could make the sound appear less noisy.
You could put a resistor on the speaker cable to lower the sound. Or you could put a real sound card and get fancy
Thank you for your reply.
but… i cannot found frequency of beep…OTZ…
I found that Beep(), sound(), but this function not support QNX6.x
And put a resistor…is too hard in my workspace