seanadams;568666 Wrote: > > > Slow filter specifies -3dB at 18.2kHz whereas sharp is -6dB at 22kHz. > So in either case it's bat country and a well mastered 44.1KHz track > would have been rolled off properly in analog land before the ADC (to > prevent aliasing) so there should be nothing there. > > Same thing applies for 96KHz material, just double the cutoff > frequencies. Honestly I'm not sure what one should expect to hear in > either case and it would depend very much on the recording having any > content up there. > > I vaguely remember talking to AKM about this years ago but I just can't > remember what the deal was exactly. Certainly if they had told me slow > filter is awesome I would have used it.
This is a controversial subject because I don't think anybody really understands whats going on. After building a lot of DACs with different digital and analog filters and a lot of listening my current theory is that it has nothing to do with the ultrasonic content of the material but an aspect of the filter itself. Brick wall filters close to the audio band do SOMETHING to the music that detracts from its naturalness, usually manifesting as a closed in soundstage, less sense of space of the original recording venue and a subtle "smoothing over" of emotional expression of performers. There have been several proposals as to what is causing this but to date I don't think anybody really knows for sure. Personally I think its more than one thing, which makes tests trying to nail down one culprit inconclusive at best. There is a camp which says scrap the filter all together (the NOS guys) but that lets a lots of aliasing through, which can be very detrimental to the sound as well. I prefer an intermediate approach, considerably more filtering than nothing, but not as much as brick wall. To my ears this gives most of the advantages of NOS with no where near as much detrimental aspects. For me a least its a good compromise. Then there are those who will say that its the aliasing itself thats causing enhanced soundstaging, people may like it but its not "real". I've been in a situation that tends to dispel this view. I was present at a recording of a very good singing group in a good acoustical environment. The recording was made to a top notch reel to reel recorder. Later we listened to the recording on quite a good system. The sense of space around the performers was uncanny, it actually was pretty close to being there. Then the reel to reel was digitized to 24/176 and 24/88.2 and 16/44.1, files were produced in software. (I don't remember the software used) We then listened to the files on the same system as before using a high quality DAC with adjustable filters. The "normal" setup of this DAC used slow rolloff for high sample rates and brickwall for 44.1. The 24/176 was very close to the sound of the tape, the 24/88.2 was a little less involving, but not by much. The 16/44.1 was drastically different though. That wonderful recreation of the original space was gone, replaced by a very flat, closed in space. Switching to a slow rolloff for the 16/44.1 opened up things quite a bit, still not as good as the 24/176 or 24/88.2, but quite a bit better than the brickwall. The brickwall was doing something that was not good while trying to suppress all the aliasing. Anyway I think its great to give the users the option to listen and choose for themselves. John S. -- JohnSwenson ------------------------------------------------------------------------ JohnSwenson's Profile: http://forums.slimdevices.com/member.php?userid=5974 View this thread: http://forums.slimdevices.com/showthread.php?t=76763 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/mailman/listinfo/audiophiles
