On Wed, 2008-06-11 at 12:52 +0100, Andy Farnell wrote:
I'm really looking forward to giving this the 'ear test'.
Maybe I'm growing old but differerences in interpolation methods are very subtle to my perception. What would be the hard case to test it? It would be when the signal is greatly transposed, right?
Remember when I tested your stab at sinc interpolation Charles, I honestly couldn't hear an big difference, there was one, but hard to define.
yo, i recorded a snare drum sound (from the netpd-patch bon-minidrm) into a table and made a comparison, while playing the sample at different speeds. i chose the snare, because it has lots of noise in the high frequencies and i assume, this will probably rather make any interpolation effects audible. when playing at 0.05x original speed, the differences between [tabread4~] and [tabread4c~] are not so subtle anymore. [tabread4~] sounds almost 'gameboyish' compared to [tabread4c~].
without any scientific approach and without any judgement about which of those two methods gives the result, that comes closer to the imaginary function of the original soundfile, it's becoming obvious, that cubic interpolation sounds more what one would expect from an audio interpolation algorithm (i.e. less audible artefacts). the difference is not only clearly visible, but also audible, especially when transposing very low downwards. i couldn't hear any difference, when transposing upwards, though.
roman
Telefonate ohne weitere Kosten vom PC zum PC: http://messenger.yahoo.de