Using the MPS-420 - One Engineer's Experience
By Alan Silver President, Connoisseur Society, Inc. New York, NY
Philips of Japan was the customer, Jazz pianist John Lewis the artist.
"In 1984 I was offered the opportunity to record the legendary jazz pianist, John Lewis, in the 24 Preludes and Fugues from J.S. Bach's Well Tempered Clavier, Book One. It was a large assignment intended to take five years with completion scheduled for 1989. Each prelude was to be recorded exactly as written on solo piano and each fugue was arranged by John Lewis for piano, bass, guitar and varied combinations of strings. In addition, an interlude of jazz improvisation, played by Lewis, was to be integrated seamlessly into each prelude and fugue.
The record company was Philips of Japan, and they wanted me to match the solo piano sound they had heard on one of my Connoisseur Society recordings recorded earlier in a New York church. They ordered me to spare no expense in hall rental, engineering, or any other part of the master production. I hired a renowned engineer, his Schoeps microphones, and Studer mixer, and used the same hall as before. Kiyoshi "Boxman" Koyama, a noted producer of jazz recordings and writer on jazz subjects, was sent from Japan to New York as executive producer for Philips.
Koyama and Lewis were satisfied, and four years of fascinating music making followed, utilizing three different top-rated mixing desks and two engineers. But at the end of 1988, as preparations were being made for the final group of sessions in 1989, the engineering staff for the last several sessions was not available, and I was asked by Koyama to hire someone else. But in the preceding two years my wife, Patricia A. Duciaume, had become my engineering partner for all new Connoisseur Society records, and we had a full complement of digital recording equipment of our own, including a prized Benchmark MPS-420 microphone mixer. So I approached Koyama with the idea of having the last sessions be an all Connoisseur Society team. Koyama was concerned that our equipment didn't include a famous name-brand mixing board with its dozens of faders, solo buttons, E.Q., and pan pots. Also, he pointed out, we were customarily using more than 4 microphones for these sessions, and panning was essential.
Pat and I countered with a guarantee that we would provide pan pots and up to 8 mic capability. Koyama agreed, and we faced the next hurdle of getting more than 4 microphones into and out of our 4 channel Benchmark mixer. We consulted with Benchmark president and chief engineer, Allen Burdick, who recommended using two MPS-420 mixers. He offered to design an interface so that the two mixers could be ganged together, providing a maximum of 8 in and 2 out. Additionally, Burdick designed new circuitry for adding pan pots to the mixers, with the promise that they would not degrade the excellent noise and distortion characteristics we had come to admire.
The December 1989 session finally arrived, and as we set up, Koyama looked somewhat apprehensively at the two slim but elegant Benchmark mixers now replacing the large mixing desks of earlier sessions. But he politely said nothing and we began our work. After the first few playbacks, Koyama moved over to my chair and said with a pleased look that the sound was definitely the best of all the sessions since we began in 1984. It was cleaner and more transparent. But since we were using the same type of microphones and digital recorders he wondered if the improvement could be coming from the Benchmark mixers. I assured him that was the case.
Koyama is a sensitive man and I wondered if he was as enthusiastic as he said. The question was answered a few months later when he invited Pat, me, and our Benchmark mixers to record John Lewis again, this time in a new project for Polygram, Paris."
While this application note is now somewhat dated, the MPS-400 and the MPS-420 microphone preamplifier systems are not. We recently received high praise from one of Canada's top mixing engineers who had purchased a very highly regarded competitive preamplifier system, only to return it in favor of the Benchmark MPS-400. These systems are regarded by those who own and use them as the finest available.
Also in Audio Application Notes
Interpolator Overload Distortion
Most digital playback devices include digital interpolators. These interpolators increase the sample rate of the incoming audio to improve the performance of the playback system. Interpolators are essential in oversampled sigma-delta D/A converters, and in sample rate converters. In general, interpolators have vastly improved the performance of audio D/A converters by eliminating the need for analog brick wall filters. Nevertheless, digital interpolators have brick wall digital filters that can produce unique distortion signatures when they are overloaded.
10% Distortion
An interpolator that performs wonderfully when tested with standard test tones, may overload severely when playing the inter-sample musical peaks that are captured on a typical CD. In our tests, we observed THD+N levels exceeding 10% while interpolator overloads were occurring. The highest levels were produced by devices that included ASRC sample rate converters.
Audiophile Snake Oil
The Audiophile Wild West
Audiophiles live in the wild west. $495 will buy an "audiophile fuse" to replace the $1 generic fuse that came in your audio amplifier. $10,000 will buy a set of "audiophile speaker cables" to replace the $20 wires you purchased at the local hardware store. We are told that these $10,000 cables can be improved if we add a set of $300 "cable elevators" to dampen vibrations. You didn't even know that you needed elevators! And let's not forget to budget at least $200 for each of the "isolation platforms" we will need under our electronic components. Furthermore, it seems that any so-called "audiophile power cord" that costs less than $100, does not belong in a high-end system. And, if cost is no object, there are premium versions of each that can be purchased by the most discerning customers. A top-of-the line power cord could run $5000. One magazine claims that "the majority of listeners were able to hear the difference between a $5 power cable and a $5,000 power cord". Can you hear the difference? If not, are you really an audiophile?
Making Sound with Plasma - Hill Plasmatronics Tweeter
At the 2023 AXPONA show in Chicago, I had the opportunity to see and hear the Hill Plasmatronics tweeter. I also had the great pleasure of meeting Dr. Alan Hill, the physicist who invented this unique device.
The plasma driver has no moving parts and no diaphragm. Sound is emitted directly from the thermal expansion and contraction of an electrically sustained plasma. The plasma is generated within a stream of helium gas. In the demonstration, there was a large helium tank on the floor with a sufficient supply for several hours of listening.
While a tank of helium, tubing, high voltage power supplies, and the smell of smoke may not be appropriate for every living room, this was absolutely the best thing I experienced at the show!
- John Siau