In Reply to: Sure, but it was mainly to John's comment ... posted by Slider on February 10, 2009 at 10:10:09:
Like I said, it seems to be a step in the right direction. I don't know how long those parts have been available, but it's not surprising that they are -- it seems that when the time is ripe for an idea that there is often a lot of parallel development from several sources.
Assuming those parts have been available for a while, I'm surprised that not more people are using them. The only other commercial product I know of that has a minimum-phase filter is the Meridian 808 Mk.II Signature CD player. It has an "apodizing" filter that is quite similar to the "apodizing" filter that is the "Measure" position of our new MP players. As far as I know, Meridian only offers the one filter choice and no other selections.
When we put the "Listen-Measure" filter selection switch on the back, it was for a reason. I *hate* user adjustments like that. To me, it is an admission from the manufacturer that says, "We couldn't figure out what sounded best, so we'll let you fiddle with it and see if there is something that you'll like." However, one of magazines blasted a Pioneer CD player with its slow roll-off "Legato Link" filter (similar to our old "Listen" filter) for not having ruler flat frequency response. So we a selector switch (but put it on the back!) just so the magazines (especially the German ones!) could measure and not have a heart attack because it was 2 dB down at 20 kHz. But it's called "Listen" for a reason -- that is what sounds best and that's what you should use when you are listening to the danged thing.
All of this nonsense is strictly due to the limitations of the CD format. At higher sample rates, the roll-off from a "slow roll-off" filter is strictly academic. It really doesn't matter if something is a few dB down at 48 kHz or 96 kHz. But that is one thing that has slowed down the pursuit for better sound -- all pro gear is largely sold on the basis of specs. So they all used brickwall filters to make sure that their gear would be dead flat to as high a frequency as possible.
As some of the posts in this thread point out, it's not clear that filters (record or playback) are even necessary at high sample rates. I think that a 192/24 system with no filters could sound absolutely stunning. But as far as I know, it hasn't even been tried. I think the main reason SACD sounds as good as it does is because there are no filters on the record side. The problem is that they have to use fairly steep filters on the playback side to keep the high frequency noise from overloading most electronics.
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Follow Ups
- RE: Sure, but it was mainly to John's comment ... - Charles Hansen 11:00:27 02/10/09 (13)
- Cambridge and Onkyo are using them - Slider 11:25:59 02/10/09 (12)
- RE: Cambridge and Onkyo are using them - Charles Hansen 14:05:28 02/10/09 (11)
- you may be right about the 8740 - Slider 20:46:14 02/10/09 (0)
- RE: Cambridge and Onkyo are using them - andy_c 16:17:00 02/10/09 (9)
- Thanks for the link - Charles Hansen 22:51:44 02/10/09 (8)
- Guys the filters are bypassed in the Wolfson - Gordon Rankin 07:45:23 02/11/09 (0)
- RE: Thanks for the link - andy_c 04:48:06 02/11/09 (0)
- RE: Thanks for the link - Todd Krieger 00:32:25 02/11/09 (5)
- Not What I Thought...... - Todd Krieger 01:35:51 02/11/09 (4)
- Like we said above, the Wolfson digital filter isn't used with the DacMagic - Slider 09:26:23 02/11/09 (3)
- Well, That Makes Sense...... - Todd Krieger 11:31:54 02/11/09 (2)
- Upsampling would be part of the DSP code - Slider 11:51:53 02/11/09 (1)
- RE: Upsampling would be part of the DSP code - Charles Hansen 12:38:47 02/11/09 (0)