Digital Drive

Upsamplers, DACs, jitter, shakes and analogue withdrawals, this is it.

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RE: Just a thought ...

Posted by Charles Hansen on June 12, 2017 at 12:00:03:
>> I prefer nos as it sounds more natural than oversampling <<

I would suggest that it all boils down to the particular oversampling (interpolation) filter used. A decade ago there were many DACs introduced with NOS (filterless) designs. I was curious and when Ayre developed the ability to create custom digital filters, the first test we tried was NOS. This replaced a combination of an external 4x "upsampling" filter feeding the 8x "oversampling" filter built into the DAC chip.

There were significant improvements in many areas - the midrange in particular was very pure and natural, but the frequency extremes seemed to be not quite up to the performance level of the broad midrange band (~200Hz to ~5kHz). I then went down a rabbit hole of various interpolation rates (4x, 8x, and 16x), window functions (Kaiser, Taylor, Gaussian, etc.), multiple parameters affecting the shape of the rolloff curve, and finally various dithering algorithms.

In the end I felt that we had improved upon all of the sonic advantages of NOS without losing anything. But I would agree that in general NOS (filterless) is an overall improvement over the typical filters built into DAC chips. YMMV.

As always, strictly my personal opinions and not necessarily those of my employer or Pee-Wee Herman.