Well, 1.4MHz is not a DSD sampling rate, so presumably you're talking about a 1.4MHz PCM file, in WAV or some other format.
So you would need an output device, like a DAC, capable of accepting PCM at a 1.4MHz sample rate. Do you have one? There aren't very many.
If your output chain (the audio output device in your computer, plus whatever it is connected to, like a Receiver) won't support that rate, then MC has to resample it. Which is what you report it to be doing.
