@gdhal
I did not read Archmago entire blog post but I agree with this “ideal filter is linear phase”! Always has been and always will be!
Archmago states:
“The key here is to remember that within a properly bandwidth limited signal where all the frequencies are below Nyquist, a linear phase FIR filter actually does not create ringing regardless of the impulse response appearance. As I have said in the previous weeks, any decent recording will follow this rule. And if it does, then the ideal filter to use is clearly a linear phase, sharp filter that can reconstruct all the frequencies in the audio data with essentially ideal temporal resolution.”
Different filters on DACs seems to be a popular thing right now - perhaps a mania. It sounds like “more” from a marketing perspective when in fact it is often less. Minimum phase filters for example are just plain WRONG! The MQA style anti-ringing minimum phase filters make no sense. For audio reproduction, it was established more than 30 years ago that linear phase is what you need. Linear phase preserves all the relationships between the multitude of frequencies that make up the sound - use any other type of filter and you ruin the timbre!!
Benchmark of course use Linear Phase only and they disable all of the other fancy distorting filters on the ESS 9028 chip. Furthermore they upsample to 211KHz so that the filter is tricked in to attenuating only around 105.5 KHz and above - way beyond Redbook audio band and therefore a gentle filter at a high corner frequency ensure no audible effect!! Meanwhile shameless marketing departments are offering the filter options on the newer chips to their user as a “feature” even though several of the filters are plain wrong and their implementation leaves a lot to be desired compared to the Benchmark approach (and also an approach used by Steve Audioengr in his own DAC design).
I did not read Archmago entire blog post but I agree with this “ideal filter is linear phase”! Always has been and always will be!
Archmago states:
“The key here is to remember that within a properly bandwidth limited signal where all the frequencies are below Nyquist, a linear phase FIR filter actually does not create ringing regardless of the impulse response appearance. As I have said in the previous weeks, any decent recording will follow this rule. And if it does, then the ideal filter to use is clearly a linear phase, sharp filter that can reconstruct all the frequencies in the audio data with essentially ideal temporal resolution.”
Different filters on DACs seems to be a popular thing right now - perhaps a mania. It sounds like “more” from a marketing perspective when in fact it is often less. Minimum phase filters for example are just plain WRONG! The MQA style anti-ringing minimum phase filters make no sense. For audio reproduction, it was established more than 30 years ago that linear phase is what you need. Linear phase preserves all the relationships between the multitude of frequencies that make up the sound - use any other type of filter and you ruin the timbre!!
Benchmark of course use Linear Phase only and they disable all of the other fancy distorting filters on the ESS 9028 chip. Furthermore they upsample to 211KHz so that the filter is tricked in to attenuating only around 105.5 KHz and above - way beyond Redbook audio band and therefore a gentle filter at a high corner frequency ensure no audible effect!! Meanwhile shameless marketing departments are offering the filter options on the newer chips to their user as a “feature” even though several of the filters are plain wrong and their implementation leaves a lot to be desired compared to the Benchmark approach (and also an approach used by Steve Audioengr in his own DAC design).