HI: I have experienced the same problem with the deNoiser.
But if the noise is like low humming or high pitched sounds, u can use the Highpass or Lowpass effects to eliminate unwanted frequencies.
APP Help: – The Higphass effect removes frequencies below the specified Cutoff frequency and the Lowpass effect eliminates frequencies above the specified Cutoff frequency. –
U can also use the MultibandCompressor effect to have even more control of each band (Low-, Mid-, High- Frequensies).
Hope this helps, but I would also like to know how does the DeNoiser work.