Saturday, April 26, 2008

Finishing the Whiffenpoof Audio Restoration project

Well, the audio restoration project is completed. The Whiffenpoofs from 1973 wanted to create a CD to give to class members returning for a reunion. The group had long since lost the master tapes. Presumably, these were left on file at the studio in Wallingford, CT. Eventually, the studio figured they wouldn't hear from these guys and disposed of the archives. What was left to work from was a 33 1/3 LP record that had never been played. That seemed rather fortunate. How many people have a record they never played?


The original transfer took a little doing to get set up properly. There was some excess noise on side 1 on the left channel to worry about. This noise did not come from wear and tear, but rather from the original stamping process. After trying a couple of configurations, Eric found a way to record the LP that reduced the noise significantly and side 1 recorded very nicely.


As side 2 was transfering, we could hear a lot more noise over the monitors, and my heart began to sink. The layout of music for the 2 sides of the vinyl had put a lot of songs on the second side, and many of these songs carried more density of information overall then the songs on side 1. The result? A lot of data packed into tightly packed grooves. Worse still, the stamping process had done worse on this side, and there was a lot more noise in the left channel. The further we got into the transfer, the more the sound degraded. It was not awful, but it was far less optimal than we'd anticipated starting with a clean piece of virgin vinyl.


Clearly what we had was good enough for the singing group members to have as a memento, and was probably better than their well-worn copies from 1973. But to produce something of quality for the reunion class gift, we knew we had to go to the next level. We discussed with the University and got approval to remaster the audio.


Eric did some research, discussed the problem with other experts at the college where he teaches and located some fabulous software for restoring from vinyl. We took the raw transfer back into the studio, and tuned parameters on some of the most delicate songs to remove pops, hiss and crackle. The results were astounding! It was like sheer magic. This software could identify the chaff, remove it and put these more delicate songs back to a state so close to pristine, it was jaw-dropping. We ran the filters over the entire raw data and thought we were finished.


Then we spot-checked across the entire result. While the parameters we selected had worked like a dream on those delicate songs, the dense, rumbling pieces from side 2 where the grooves were jammed so tightly were not pretty. Although they were hiss, pop and crackle free, they were now distorted. Terms like "wow" and "flutter" come to mind. We found these pieces required special attention, a completely different set of parameters and some measure of compromise to find the right level where noise could be reduced measurably without distorting the vocal performance. We reduced thresholds on the filters by 50% and then another 50% and made several more passes over the data, giving us 4 versions the entire stream from which to select the best starting point for each song.


Then Eric worked by with each piece to fine-tune the compression and a light EQ, as well as removing some noises by hand to achieve a result that was unimaginable after the initial transfer. The master has been sent off for production and the result should be something worth adding to a collection of college a cappella recordings. The reunion group should be very happy, and we came in right on budget!


I hope to talk more about getting the artwork together as well as acquiring all the mechanical licenses, so we're nice and legal. I even got to speak with one of the composers, Fred Hellerman on the phone in the process! How cool is that?

~Bob