[bittorrent] gd1971-02-21

Automated Mailer noreply-bt.e at etree.org
Thu Mar 19 12:43:39 MDT 2009

Band:           Grateful Dead
Torrent Name:   gd1971-02-21
Uploaded by:    Orp
DB Link:        http://db.etree.org/shninfo_detail.php?shnid=112
Details:        http://bt.etree.org/details.php?id=523533

Contact the seeder at http://db.etree.org/Orp

If the link to this show does not work, it was probably removed for
being non-trade-friendly.

Description / text file:
Grateful Dead
February 21, 1971
Capitol Theatre, Port Chester, NY

SBD -> Dobly A Reel -> Dolby A decode -> DAT -> Sound Forge NR -> CD-R

The Sound Forge noise reduction was used to attenuate a very narrow
frequency band (in the vicinity of 8000 Hz) which was present as
interference on the original reels.  See my notes below for details.

Disc 1

Set 1
1. Cold Rain And Snow (7:24)
2. Me And Bobby McGee (8:18)
3. Loser (7:37)
4. Easy Wind (9:21)
5. Playing In The Band (5:46)
6. Bertha (6:17)
7. Me And My Uncle (4:57)
8. Ripple (take 1) (1:31)
9. Ripple (7:53)
10. Next Time You See Me (5:41)
11. Sugar Magnolia (7:33)

Disc 2

1. Greatest Story Ever Told > (4:43)
2. Johnny B. Goode
Set 2
3. China Cat Sunflower (11:36)
4. Bird Song (6:44)
5. Cumberland Blues (5:48)
6. King Bee (9:12)
7. Beat It On Down The Line (4:53)
8. Wharf Rat (11:02)

Disc 3

1. Truckin' (8:42)
2. Casey Jones (6:33)
3. Good Lovin' (16:55)
4. Uncle John's Band (7:36)

The original reels of the Port Chester run of '71 were audibly
tainted due to a cable problem. The result is a tone which hovers
around 8000 Hz with an amplitude of about +20 dB above the noise
floor. This translate to a very annoying pitch, especially during quiet
sections, which is in the old-tv-tube or lousy-hard-disk or maybe even
class of 'whine'. Because this interference is 'monochromatic' it's
easy to get rid of if you have the processing power and a quick
FFT algorithm. I used the filter-shaping capabilities of the Sonic
Foundry Noise Reduction Plugin to tailor a very narrow notch filter
which attenuated the interference without affecting the rest of the
signal. And it's all done in the digital domain. Huzzah!

As a side note, I actually ended up crafting many filters to process
these shows. The frequency of the interference actually drifted anywhere
from 7700 to 8100 Hz during a given show. This was probalby due to a
slightly wandering reel speed. It made my work harder but when I tried
a much wider filter I started to be able to hear the attenuation in the
music. The filters generally go like this:

25 dB     /- - - - - - - -\
         /                 \
        /                   \
0  dB  |                     |
       7830      7900      7970

The end result is no more annoying whine!

I also removed some of the nasty mic feedback in the 2/18/71 Bertha
using this type of filter.

Leigh Orf <orf at mailbag.com>

Update (3/19/09): This is a re-seed. I have re-encoded the files
using FLAC, and added tags. For some more discussion about the notch
filtering, please see http://orf5.com/badnr.html

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