| Title: | Welcome to the CD Notes Conference |
| Notice: | Welcome to COOKIE |
| Moderator: | COOKIE::ROLLOW |
| Created: | Mon Feb 17 1986 |
| Last Modified: | Fri Mar 03 1989 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 1517 |
| Total number of notes: | 13349 |
A recent ad in one of the digital audio mag's, on the back cover
I believe, had and ad for Yamaha's CDX-910U, which sports a "feature"
called Hi-Bit, which allows you to SWITCH OFF the analog filters!
The ad goes on to explain that this allows "crystal-clear" sound.
From all the discussion on filtering here, I'd say that the quality
of the filtering, and how it's done, is critical ... such that going
with NO filter seems like a BAD thing! Is this marketing hype or
are there times when using NO filter would provide for better sound?
My intuition says that w/o the filter, the high end would be too
much, too "cutting". Comments? Anyone heard one of these?
-Jim
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 1476.1 | My vote: it's hype | RETORT::RON | Tue Jan 17 1989 10:15 | 25 | |
The analog filter's job is to remove the switching artifacts, which occur at sampling frequency harmonics. When the player 'oversamples' at X8, the lowest frequency component is around 350 KHz. A correctly designed filter would be way over the audible range, anyway - that's one of the biggest selling point for higher and higher 'oversampling' rates. At X8 'oversampling', even with a bonafide filter out of the way, the analog circuitry itself (plus the cables, the preamp and the power amp) acts as a low pass filter. Switching out the specific filter is hype, because, regardless of what's built into the player, the filtering action is still there. Depending on your system, a 350 KHz component in the signal could be real bad if you have a rectifying junction somewhere (added noise) or if a section somewhere does have good RF response (overload, leading to distortion). Besides, who says filtering sounds bad? Listen to the Yamaha CDX-910U with 'high bit' ON and OFF through a good system and see if you can tell the difference. -- Ron | |||||
| 1476.2 | DEMING::AUGUSTINE | We Will Survive | Tue Jan 17 1989 10:59 | 5 | |
I wonder if that is for direct digital output to an externl
D to A filter?
jeff
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| 1476.3 | HARLEY::DAVE | it's tee time !!! | Tue Jan 17 1989 11:41 | 5 | |
I have a cdx 910 u and it sounds pretty good. have not switched
the filters on/off to check out the difference.
Dave
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| 1476.4 | No Filter in Digital Output | USRCV1::THOMPSONP | Paul Thompson, Rochester, NY | Thu Jan 19 1989 15:10 | 7 |
Re .2
The direct digital output is before any of the oversampling circuitry
or filters. If you choose to use the direct digital output, all
of the oversampling or extra bits in the world won't make a difference
because you have bypassed them.
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