Serenade: the 1996 Santa Fe Chamber Music Festival CD Page 6
The downside of that is that instruments produce somewhat different tonal balances when you're above them than they do when you're in front of them. I think that is what people object to---that the instruments sound a little different tonally from what they used to when the mikes are high. But it's one of those things where there really is no right way of doing it.
Phillips: Do you think your sound this year will be substantially different from that of last year?
Atkinson: I've made a few changes. Last year I ran very long microphone cables all the way to the digital recorder in the back room. I used the Nagra recorder's built-in microphone preamplifiers and analog/digital converters (ADCs) for all four channels. This time [fig.2] I put a microphone preamp, a very low-noise, very transparent-sounding tube design from Fred Forssell on-stage as close as I could to the cardioid pair. The two-channel output of the mike preamp was immediately converted to digital using the Manley 20-bit ADC. (The Manley and the Forssell were housed in an Anvil case together with a rack-mount Power Wedge line conditioner.) I then ran the digital signal the long distance to the back room, where we had set up the recorder, reclocking it at the Nagra's channel-1/2 AES/EBU data input using a Sonic Frontiers UltraJitterbug. This way I hope I've got an even more transparent sound on the main cardioid pair. The omnis still ran analog all the way to the recorder, though the Nagra's channel-3/4 ADCs were slaved to the Manley to ensure synchronization between all four channels.
All the editing of the performance tapes was done with 24-bit resolution to preserve as much of the original quality as possible. But once Heiichiro Ohyama and I had assembled a master edit list for the CD, I had to decide how to reduce that 24-bit data to the 16 bits mandated by the Compact Disc Standard. Simply dumping the output of the Sonic Solutions hard disks to DAT or CD-R, thereby truncating each digital word from 24 to 16 bits, both reduced the sense of recorded space and added a feeling of "digititis." I therefore redithered the data to 16 bits when I prepared the master using the Meridian 518 Mastering Converter that we used for the Festival CD. This uses a Motorola DSP56002 digital signal processing chip to manipulate digital data in real time. The input and output data word lengths can be independently selected; pre-emphasis or gain can be added if the operator so wishes; and, most important, the 518 applies a choice of noise-shaping curves to the music data. By shifting quantizing noise up to the inaudible 20kHz region as it reduces the output word length, it preserves as much as possible of the original's resolution in the midrange. Using the Meridian's noise-shaping algorithm when we downloaded the 24-bit master to a 16-bit CD-R gave a noticeable improvement in air, space, and overall palpability.
Phillips: I find it fascinating that the key to preserving a spontaneous, ephemeral event is to be meticulous to the point of obsessiveness.