Monday, November 14, 2011

034 KQED


1 comment:

Dr. Forrester said...

Pink Floyd
KQED TV Studios
San Francisco, CA
April 30, 1970

Audio Lineage: 1" or 2" station master > 3/4" U-Matic sub-master > DVCAM > WAVE (48kHz/24 Bit)
Running Time: Approx. 60 mins


We decided to create a CD from the audio of our KQED DVD release because we felt that, after much research, an audio upgrade was warranted. We only recently revisited our original source after several FM (or VPro) recordings surfaced on Yeeshkul.

Some notes from MOB:
We had 2 sources to choose from: one source from a U-Matic TV station master, the other source from a mysterious FM broadcast. The FM source was said to be in stereo, but a quick analysis clearly shows there is absolutely no stereo separation on the instruments. Further analysis of the FM source reveals that the fake stereo effect is mainly due to multiple analog generations and fluctuations in the tape channels stretching. The fact is that the original recording was done in mono, and that there's no evidence of any true stereo mix of that performance. The FM source has also the typical alterations from FM processing (levelling and limiting), and is riddled with pops and crackles, not even mentioning a 1.7% deviation from the real speed.

On the other hand, the U-Matic source has the original mono recording with a very stable and correct speed, along with excellent spectral characteristics (as you could expect from a station master). A close comparison between the 2 sources shows some evidence of the "pureness" (in terms of sound fidelity) of the U-Matic tape compared with the multiple analog gens of the other source. It is not easy to describe it with words, let's just say that if you listen to the cymbals sound during some quiet parts, you hear "dziing" on the U-Matic source, while it's "tching" on the FM source… ;-)

Therefore, the remastering work was performed on the U-Matic source. It consisted in the following main activities: adjust the levels and EQ in order to bring clarity to the raw recording, get rid of the annoying low frequency hum that is present most of the time, and manually clean all the little imperfections of the raw transfer (mainly pops and drop-outs).

It has to be noted that, while Atom Heart Mother, Cymbaline, Green Is The Colour and Careful With That Axe Eugene were rather well recorded by the KQED sound engineers, it was much more difficult to get a good sound for Grantchester Meadows and Set The Controls For The Heart Of The Sun. These two tracks seem to have been captured differently by the KQED engineers and there were some bad sounding sections difficult to correct or improve (on every source we heard, these two songs are always with inferior sound quality than the four others). A possible explanation could be the specific instruments settings: acoustic guitars and vocals for Grantchester Meadows, and a lot of middle frequencies (gong, toms, lack of bass) for Set The Controls. Too bad KQED staff was not able to do a better job when recording and mixing these two tracks. (Ed: Perhaps these to tracks were recorded 1st and then adjustments/corrections were made?).

Discussions on the topic can be found on the following Yeeshkul threads:

The raw, unprocessed 48kHz / 24 Bit file can be found here"

Until I hear something of better quality, I'll consider this to be the definitive version of this broadcast.
Thanks to Diego for the new 48kHz/24 Bit transfer, MOB for remastering the audio, and Big Ed for quality control.
Produced by Harvested Records

RonToon (October 2008)