Stereophile's Test CD 2 Tracks 3-4
 Acoustic Drum Solo (DDD) 3:37
Russ Henry (Yamaha drums)
 Acoustic guitar solo (DDD) 3:07
Gavin Lurssen (steel-strung Martin D-28 guitar)
Recording Venue: David Manley Recording Studio, Chino, CA
Recording Date: November 9, 1991
Recording Engineers: Robert Harley, David Manley
Microphones: Manley Gold Reference Stereo in crossed, coincident figure-8 configuration
Recorder: Manley Analogue to Digital Converter, Panasonic 3700 DAT
Robert Harley writes that when the idea of making a second Stereophile Test CD was proposed, he "jumped at the chance to record some fresh tracks. The plan was to record acoustic instruments in a fairly live studio with a single pair of microphones and a very pure and simple signal path. No artificial reverberation, no 'accent' mikes, no signal processing, no equalization, and no compression. In short, I wanted to capture the natural sound of the instruments in the room without electronic 'enhancement'—the engineer as transcriber rather than creator. The session would also give me the opportunity to describe and photograph the performers' and microphones' positions in the room, giving Test CD listeners a visual perspective of the sounds they were hearing.
"There was no better place to do this than David Manley's recently built recording studio a few miles from the Vacuum Tube Logic factory in Chino, California. Everything about the studio was ideal for this project, from the room's acoustic design to the recording signal path. The recording room, which is 29' wide, 38' long, and has a 12' ceiling that peaks at 17', was designed by David for making purist recordings. The room is very live as recording studios go, with wood walls and ceiling. The four side walls form low-frequency slat absorbers (60% of their area) to control the low-frequency reverberation time. Solid construction and double-doors provide acoustic isolation.
"Although the room is superb, what really sets this studio apart is the microphones and signal path. Every piece of electronics in the signal chain is tubed and designed by David—microphones, mixer, monitoring electronics, and analog tape machine electronics. The microphone used in these two recordings was the Manley Gold Reference Stereo (tracks recorded with the mono version, the Gold Reference, weren't included on the Test CD). Both types were built from scratch—including having the 3µm diaphragms sputtered with gold. The dual-capsule stereo microphone was used in its figure-8 pattern, in a Blumlein (crossed figure-8) configuration. Inside the stereo microphone are eight triode tubes (in four envelopes), which amplify the microphone level signal to line level. The microphone preamp is thus in the microphone. This technique not only obviates the need for a transformer in the microphone, but also eliminates the usual practice of sending tiny microphone-level signals (a few millivolts) down long cables to the microphone preamp, usually found in the recording console. The microphones are mounted in upside-down microphone stands and hung on beams suspended from the ceiling. The entire beam assembly can be raised and lowered by a pulley system. This arrangement keeps cables off the floor and prevents footfalls and other structure-borne vibration from getting in the mikes.
"David's recording console is very different from those found in today's recording studios. Modern consoles are usually the size of a pool table and covered by many hundreds of buttons and knobs—with many hundreds of corresponding components underneath. These often include dozens of op-amps (5532s are very popular), cheap capacitors, carbon resistors, and yards of pcb traces—all powered by supplies with poor isolation and regulation. By contrast, David's console is a small rectangular box the size of a preamp with 10 knobs to adjust the levels of up to 10 microphones, two master level controls, and monitoring level adjustments. The all-tube circuit is based on the VTL Ultimate Preamplifier and uses the new (and very expensive) MIT capacitors.
"The mixer's stereo output drives the Manley Reference A/D converter (which in turn drives two DAT machines) and the input of a vintage Studer C37 ½" analog tape machine retrofitted with David's custom tubed record and playback electronics. Also on hand is a Mitsubishi X-86 HS open-reel digital 2-track. The 'HS' stands for high sampling rate (96kHz), and the machine has 20-bit A/D converters, 20-bit storage, and 20-bit D/A converters. We chose not to use the Mitsubishi for this session: besides having to throw away the four extra bits of resolution when making a 16-bit CD master tape, we would have had to sample-rate-convert from 96kHz to the CD's 44.1kHz, a major sonic compromise. When making the CD master tape, we used the DAT masters as the source.
"The electronics, tape machines, and monitoring system are in a motor home parked next to the studio. Large windows in each permit visual interaction between the musicians and engineer. This motor home arrangement has advantages: greater acoustic isolation between the recording room and control room, and easy transportation of these special electronics to a concert hall for on-site recording. All the recording electronics are powered by 240VAC instead of 110V.
"David has installed a mastering room next door and is now rebuilding several Scully lathes. These lathes, with their new custom air-bearing turntables and modified cutting heads, would be almost unrecognizable to their designers. Having a mastering room next to the studio provides a terrific opportunity: cutting direct-to-disc records. The entire facility was built to keep purist recording alive and to make LPs and CDs for release on VTL's ViTaL label.
"I was particularly eager to record drums using purist techniques. Nearly all my experience as a recording engineer has been in multi-track studios where the drums are close-miked (using as many as a dozen microphones), equalized, gated, reverb'd, and spatially positioned with the recording console's pan pots (footnote 2). I had previously recorded drums with as few as three or four mikes (stereo overhead pair with individual mikes on the kick drum or kick and snare drums), but never by themselves in a live room with just two mikes.
"When I listened to the drums before putting up any microphones, I was encouraged; this was one of the best-sounding kits I'd heard. Drummer Russ Henry had spent the previous week installing new heads and tuning the studio's house Yamaha kit. No matter how good the room, microphones, electronics, or recording techniques, the secret to getting good drum sounds is to use good-sounding drums.
"After some experimentation with microphone placement (and lots of experimentation with placement of the drums in the room), the crossed figure-eight pair ended up 2½" above, and slightly forward of, the drummer's head. The stereo mike was behind the drums rather than in front of them to achieve a better ratio of drums to cymbals. We recorded several takes with varying levels of the spaced omnidirectional microphones mixed in, but, after auditioning the tapes in Santa Fe, JA and I both preferred the greater image specificity and dynamics heard from the crossed figure-eights alone, despite the slightly reduced sense of space.
"Old habits die hard; I was briefly tempted to put another microphone on the kick drum to get more punch and impact. I quickly came to my senses; this project was about capturing the natural sound of the instrument in a real room, not creating artificial hype. What you hear is what actually existed in the room. Incidentally, this track should be played back at as high a level as you can manage—live drums are very loud. This drum track is a good test of a system's dynamic range, LF extension, image specificity, and ability to differentiate pitch. The various toms should each have a distinct pitch and appear at individual points in space rather than sounding homogeneous.
"The guitar recording was made with the single Manley Gold Reference Stereo microphone (in crossed figure-8 pattern) about 8' from guitarist Gavin Lurssen, who sat in the middle of the studio. Again, the Blumlein technique was chosen over the pair of spaced omnis; image specificity and the impression of the instrument existing independently inside the room was far more realistic with the crossed figure-8 configuration. The Martin D-28 guitar should be surrounded by the acoustic, with the room 'lit up' by sharp transient attacks, especially when Gavin hits the strings hard. The guitar had a very wide dynamic range, a quality the recording seems to have captured."
Footnote 2: I was at a session in which the output from each drum microphone triggered preset electronic drum sounds from banks of drum machines. To prevent the sound of one real drum mistakenly triggering the wrong electronic drums, noise gates were put on each microphone. Getting all this to work—including finding the right threshold for each gate—was a 20-hour ordeal. Do you think anyone was in the mood for making music after that?—Robert Harley