18 July 2008

Foot wrapped in tonearm cables and inserted in mouth - film at 11

I made a recording of a 2-LP set before ever listening to it, and after mucho processing, I listened and discovered that it was corrupted by large amounts of ground noise. Bleh. I had to throw them out and re-record.

After much searching I discovered that the power supply from my Dell laptop was the culprit. Moving the turntable cables away from the PS relieved the noise. Moving them back increased it. Wrapping the cable around the power supply amplified the noise tremendously.

The noise consisted of peaks about 30db above the noise floor at 60hz and 180hz, many peaks in the 20db range from 200-10khz, and a huge mass of +20db harmonics centered at about 13khz and 18khz. Not subtle at all.

This throws a major wrench into my whole way of thinking about balanced turntable connections. I was under the impression that a well-shielded balanced cable is fairly immune to EMI of this nature; clearly I'm mistaken.

Microphone and pro audio connections have the same issues; I'll need to research how sensitive they are supposed to be to this sort of thing before I consider making cabling/equipment changes.

11 July 2008

Recording sample: Einstein on the Beach

Here is a 30-second sample of my current recording process. It's the first 30 seconds of side 3 of the CBS Masterworks pressing of "Einstein On The Beach", encoded with lossyWAV --portable in FLAC.

I bought the boxed set at Amoeba Records in SF for $9, and it's easily some of the best pressed and maintained vinyl I have ever laid eyes upon. (The music is excellent too.)

Note the hiss before the violin begins - that is the 0404 USB's mic preamp noise I was talking about. It is fairly prominent in silent passages, but is difficult to identify while most music is playing, and is also pretty hard to spot with noisy vinyl. So it's fairly important to get this fixed, as far as vinyl upgrades are concerned. Besides that, I think the sound quality is excellent.