Fate, I Defy You: The Robert Silverman Liszt CD Page 3
The Sonic Solutions software allows the time relationship between tracks to be adjusted. This facility was essential for this project, as the outputs of the omni microphone pair and the Sphere pair were not in time synchronization.
Once the four 20-bit Nagra tracks had been uploaded to the 6GB Sonic Solutions hard drive, the individual microphone signals were slid past each other until they were coincident in time. This was visible on the computer's display of the waveform, but it was audible as well: The time disparity between the nonsynchronized signals first produced an echo effect, then the distinctive sound of comb-filtering, which got higher and higher in frequency as the time delay got shorter and shorter.
THe hall added a luminous sense of reverberation to the sound of the 9' Steinway D.
The Sonic Solutions system allows all four tracks to be played back with independent control of level, polarity, and positioning within the L-R image. The resultant balance chosen is that which I felt best caught the optimal combination of soundstaging precision and tonal accuracy. The microphones were positioned so as to place the image of Robert Silverman almost at the inside of the left loudspeaker—you can occasionally hear his sharp intake of breath at a climax, or even his gentle baritone crooning! This means that the image of the piano should extend from just inside the left speaker all the way to the right loudspeaker position. Although this does mean that the piano is positioned a little right of center, this is what you would have heard in real life had you been sitting on the hall's center line.
Whereas the edited master residing on the computer hard disks preserved the full 20-bit resolution of the original tapes, the CD in your hand only carries 16-bit data. Simply dumping the output of the Sonic Solutions hard-disk editor to a DAT or CD-R truncates each digital word from 20 to 16 bits, the result being easily audible degradation. The sense of reverberant space surrounding the piano is reduced, and the instrument's midrange balance becomes more clangy. The Meridian 518 Mastering Converter, however, allows us to reduce the 20-bit data to 16-bit in such a way that much of the original signal resolution is preserved.
The Schoeps KFM6 Sphere stereo microphone on the Manley Starbird stand. The right-hand microphone capsule can be seen; the black dot on the front is a recessed red LED to make "sighting" the mike a relatively easy task.
The Meridian 518 was reviewed in the January '96 issue of Stereophile. Using a Motorola DSP56002 digital-signal processing chip to manipulate digital data, the 518 redithers the data with a choice of noise-shaping curves. By shifting quantizing noise up to the inaudible 20kHz region as it reduces the output word length from 20 bits to 16, the 518 preserves as much as possible of the original's resolution in the midrange. Note that this increase in effective resolution does not depend on the nature of the input signal. The source may have acoustic or electrical noise well above the 16-bit noisefloor, but the 518 can't distinguish noise from music: Everything in the source data is processed as though it were the wanted signal.
I used the Meridian's Shape D noise-shaping algorithm. The result, I believe, preserves on this CD as true a sound to the original as it is possible to get. But what was the original sound? While I was preparing the CD master, I talked to Robert Silverman about the American-made Steinway D piano we had used. This was a fabulous-sounding instrument, with live sound levels in the hall well exceeding 100dB at climaxes. I asked Robert if playing Liszt makes special demands on a piano—other than not falling apart under the pounding.