You cant mix audio streams together without converting them to the same sample rate. In NAudio there are three ways of accessing a resampler:
- WaveFormatConversionStream - this uses the ACM resampler component under the hood. Note that you may have issues resampling IEEE float with this one.
- MediaFoundationResampler - this uses MediaFoundation. It allows you to adjust the resampling quality.
- WdlResamplingSampleProvider - this is brand new in the latest NAudio, and offers fully managed resampling.
As well as matching sample rates, you also need matching channel counts. NAudio has various ways to turn mono into stereo and vice versa.