Audibility of "typical" Digital Filters in a Hi-Fi Playback
Reply #255 – 2014-11-17 18:33:54
You need to demonstrate using the paper and data within, how it was that people heard noise modulation and not effect of filtering/dither. Since noise modulation is the effect of using that incorrect dither, I don't know how to answer that self-contradictory question. I thought xnor had already explained the other part pretty well. Many signals are sufficiently self-dithering for this to be academic, but with carefully chosen samples and sufficient gain you can demonstrate that the choice of dither can be audible. None of this is news to anyone. I post the relevant data on this in my response to Arny. Please show using the gain in their setup how noise modulation was easily audible. This is what I meant when I said to back your statements using the report. You can't critique it in absentia. Alternatively, there is only one track in this test. It should be easy then to demonstrate how dither noise modulation caused a major flaw and was readily audible. Or else it would not be a major flaw, right? For now, these are the subjective observations we have from the paper from the test subjects:It was reported that filtering gave "softer edges" to the instruments, and "softer leading edges" to musi- cal features with abrupt onsets or changes. Echoes, when audible, were identied as being affected the most clearly by the ltering. It was felt that some of the louder passages of the recording were less ag- gressive after filtering, and that the inner voices (sec- ond violin and viola) had "a nasal quality". Over- all, the filtered recording gave a "smaller and flatter auditory image", and specically the physical space around the quartet seemed smaller. Listeners described that quantization gave a "rough- ness" or "edginess" to the tone of the instruments, and that quantization had a significant impact on decay, particularly after homophonic chords, where "decay was sustained louder for longer and then died suddenly". This could be an effect of quantization distortion; it is interesting that this was audible even in a 24-bit system, and is consistent with the hy- potheses of Stuart [29] that 16 bits are not sucient for inaudible quantization. Would you say these are consistent with audible effects of noise modulation? Edit: fixed the OCR problems in cut and paste of the quote above.