Heard a really great All Things Considered story last night about technology that can remove "wow and flutter" from old analog recordings. It works with reel to reel tape, phonograph records, and even a soundtrack on film. They played some examples that showed how remarkably well it worked. Stuff that was unlistenable sounded pretty good.
Imagine what this can do for old audio of all kinds -- old 78s, old master tapes, old movies. Wow. Listen here: http://www.npr.org/templates/story/story.php?storyId=7489316.
Using Digital Tools to Repair Analog Audio
All Things Considered, February 19, 2007 · Robert Siegel talks to Jamie Howarth about the next step in audio restoration: ridding analog-era sound of its inevitable speed variations by writing software that virtually recreates the original device on which a recording was made from the existing tape.
The sound is then digitally fed back through that machine to correct the errors due to azimuth, capstan bumps, tension in reels, etc. To say the least, it's a complex algorithm.