AUDIO_SCALEDOWN
val = AUDIO_SCALEDOWN(val * ch_volume[ch], 8);
*d++ = AUDIO_SCALEDOWN(s[0], 1) + AUDIO_SCALEDOWN(s[1], 1);
*m = AUDIO_SCALEDOWN(*m * mixer->volume, 8);
*d++ = AUDIO_SCALEDOWN(v * track->volume, 8)
*d++ += AUDIO_SCALEDOWN(v * track->volume, 8);
buf[i] = AUDIO_SCALEDOWN(sinewave[j] * (int)volume, 16);