New Post: Seting WaveOut buffersize directly to a number of samples

You don't always get the chance to specify the exact size of sound-card buffers. My solution to this which you can see in the WPF demo I think was the SampleAggregator, which buffered up audio and when it got say 4096 samples, it calculated the FFT and raised an event. This makes it irrelevant what size the buffers are.