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With digital its all to do with the number of bits used to encode the sound we hear.
Quote from: nsbuk001 on 06/05/2010 15:48:15With digital its all to do with the number of bits used to encode the sound we hear.The upper frequency limit is dictated by the sampling rate alone and is not dependent upon the bit-depth of the sample.
One of the things I find astonishing is people still pay astronomical amounts for valve amplifiers and the like. Surely these days, a perfect 'map' of a valve's dynamic response can be made electronically - giving the warmth (or distortion) at a fraction of the cost.Maybe someone with a greater grasp of audio electronics than I can explain why valves (aka tubes) still can not be emulated. Or is it just an aesthetic discern?
I have a highly unscientific theory that they are paying more to satify their sense of smell than anything else. Valve (tube) equipment produces a very nostalgic aroma, and nostalgia is an extremely powerful emotion.
...in any case, high order digital filters used in the better systems are FIR filters and do not have phase distortion.
But how can you use a digital filter without first digitising the signal? As far as I understand, there's no way of avoiding an analogue filter before the sampler. However, one of the ways to reduce the phase incoherency produced by this initial filtering is to reduce the steepness of the filter slope, which increases the bandwidth (albeit attenuated at the upper end) in combination with a higher initial sampling frequency to handle the increased, but attenuated, higher bandwidth. Once that's been done you can then start to use digital filters and down-sample to a lower rate without affecting phase.
The main attraction of valve (thermionic tube) amplification over solid state amplifiers is believed to be due to the nature of the harmonic distortion they produce. Both types of amplifier produce harmonic distortion but valve amplifiers tend to produce predominantly even order harmonic distortion whereas solid state amplifiers tend to produce predominantly odd order harmonic distortion, and in listening tests it seems that people prefer the sound of even order harmonic distortion to odd order harmonic distortion.