Grateful Dead February 21, 1971 Capitol Theatre, Port Chester, NY gd71-02-21.sbd.orf.98034.sbeok.flac16 SBD -> Dobly A Reel -> Dolby A decode -> DAT -> Sound Forge NR -> CD-R --Set 1-- 101 - Cold Rain & Snow 102 - Me & Bobby McGee 103 - Loser 104 - Easy Wind 105 - Playing in the Band 106 - Bertha 107 - Me & My Uncle 108 - Ripple (take 1) 109 - Ripple 110 - Next Time You See Me 111 - Sugar Magnolia 112 - Greatest Story Ever Told -> 113 - Johnny B. Goode --Set 2-- 201 - China Cat Sunflower -> I Know You Rider 202 - Bird Song 203 - Cumberland Blues 204 - I'm a King Bee 205 - Beat It on Down the Line 206 - Wharf Rat 207 - Truckin' 208 - Casey Jones 209 - Good Lovin' 210 - Uncle John's Band 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 the-sound-you-hear-after-you-slam-your-head-against-a-concrete-wall 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 ------------------------------------ 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 ________________________________________________________________________ Tagging notes: I altered the Orf tagging. Show information is embedded within the header of each flac file. It will display on any player capable of directly playing flac files. If converted to wav during processing, all tags will be stripped, however audio data will remain unaffected. If you must transcode to a lossy format, do so directly Flac > Lossy. Use ffp to validate audio integrity. Md5 values will change if tagging is altered. B. Proctor 6-08-09