MASTERING EQUIPMENT AND TECHNIQUE

THUNDER STUIDOS: Award winnding Mastering Studio

By: Don Christopher Kassay

In order to get the sound I want, I have a variety of options to choose from. The signal path is primarily equipment I purchased many years ago with a few custom improvements that I use to control the dynamics, spectral balance and ambient feel of the music. As stated, a lot of my equipment has been modified during the years and are now proprietary and support Mastering techniques not found in other Mastering Studios.

I do have and use the best digital software on the market today, such as Digidesign’s Pro Tools HD and Steinberg’s Cubase Studio 4 Professional, both rated as the cutting edge in digital mixing and mastering technology and are highly regarded in the analog and digital recording world.

1. The console is the core of any mastering facility. It defines the clarity of sound and the enhancements that can be made to the music. I have several consoles that I have the options to use in my studio from analog to digital, but the console that I used for Mastering is built with Class-A line amplifiers. Chassis cabling and interconnects that are made with specially manufactured solid silver wire, and the audio controls are stepped switches with gold plated contacts. Other components are chosen with similar regard for quality. This is the center of my ongoing years of experience and research efforts since it provides expansion bays for testing and comparing new circuits.

2. Compressors and limiters: These are the most powerful components available for shaping the sound of a song and obtaining the very best quality. Over time, I have used a variety of Mastering tools from studio units to gear specially built for Mastering.

3. Equalizers are the next choice for shaping sound. Certain EQs produce a resonant or sweet quality, the result of non-linearities that give a pleasing tonal color. For Basic and many Extended Mastering projects, I prefer the efficiency and excellent performance of parametric EQs from Sontec and other brand names specifically designed for top Mastering Studios. I can also select from vintage EQs that I purchased that were used in the film industry before modern designs became common that can still produce a great sound.

4. For Custom Mastering, I stay with the classic sound of fully passive devices followed by tube or solid-state gain stages depending on the required feel. These units are built like the console, with silver wiring and stepped controls. The spectrum can be shaped in ½ dB increments at frequencies from 10 Hz to 60 kHz. Bandwidths range from broad "air-band" and shelving curves down to surgically precise notches. Because of its flexibility, adjusting the Sontec equalizer can take an unusual amount of time but the end result is an open, non-electronic sound and exact control that cannot be found in even the most sophisticated parametric device. When time permits, I try to use some of its features for Extended mastering also.

The next step in enhancing a signal might involve image processing. This allows the width and other characteristics of a stereo image to be altered. I use the classic Blumlein Matrix, which offers precise control of the soundstage. A good Ambiance Enveloper is especially useful for synth-based tracks and recordings made in less than perfect environments. It can recover and in extreme cases, recreate the sense of depth often lost when recordings are processed too heavily. Many of my clients using Tascam, Alesis, Roland VS and other digital recorders have found that this processor will bring out the life in their tracks.

The quality of the final master depends on the excellence of the converters used. I have six (6) converters I keep on hand, and of the three (3) 24-bit samplers, the one I use most often is designed with fully programmable dithering that supports sample rates up to 96 kHz. It is directly coupled to the output of the Limiter processor, preserving the shortest possible path between the finished sound and the CD. I also have three (3) 16-bit processors that I use to convert back to 16-bit sampling at 44.1 Khz, which is the standard format for CDs. These converters are also couple to the output of the limiter processor.

For Custom Mastering, I use a number of tools that offers even more flexibility and performance that are effective for achieving hot levels with very low distortion. They essentially borrow headroom from frequency ranges that are not dominant at the moment, providing "room to breath" to the parts of the music that are contributing the most impact.

Another specialty module for the mastering console, is based on wide-bandwidth tubes from the 1920's, produces an adjustable super-fat sound on the final master. I call it the Analog Airbrush, after the graphics tool often used to enhance the highlights in a photo. It works like the legendary "Good" knob that was supposedly built into mixing consoles many years ago. ("That's good! I want more of that! Turn that knob up!") Dial in Smooth, Crunchy or Super Chunk, depending on your tastes. All kidding aside, some of the sounds connected with this early technology are amazing. They are also virtually unknown today since a few of the necessary parts have not been produced for over 60 years.

Along with the standard features - dynamic controllers, EQ, image processing and specialty designs, I can also select devices for effects, level and balance automation. I use them as needed, first to bring out the character of each track and then to relate the tracks together, producing the finished CD.

MONITORS: For a number of reasons, I have several monitor systems that I use. My main stereo environment uses a pair of large full-range electrostatics driven by custom solid-state power amps. These are time aligned and matched to a pair of M&K subs and the room (which is 26 ft. or 8m long), using FFT and real-time analysis. This setup is very flat in frequency response and exhibits Doppler distortion much lower than box speakers. These are my primary preference because they are higher in resolution at low to moderate listening levels than anything else I have tried. (The music has to sound good at low levels if it is going to sound good on many different systems.) Electrostatics can be a real bear to set up properly, but when you succeed, the resulting clarity can be staggering. It is possible to listen for hours without tiring. The secondary stereo monitor I use the most is the Mackie HR824. It is verifiably more accurate than most speakers at ten times its price, THX certified, with excellent bass for a small system. It is widely used in professional studios, so it is a common point of reference. I have other near field options also, driven by custom tube amps.

On many Mastering Projects, I spend more time using headphones than speakers. Stax Nova Electrostatic headphones with tube driven amps are great for resolving fine detail, noise and distortion problems. They are very useful for verifying how tracks will translate across different systems. I have found that Sennheiser HD-600's work well for this also.

I also have a calibrated 5.1/6.1 surround environment, for DVD-Audio, SACD, and other high-resolution multi-track formats. Surround sound is an emerging part of the business today and some of the panning and other aspects of current releases are pretty extreme to my ear. Decisions are made to show off the benefits of multiple channels since hardware companies are trying to promote their toys. Having lived through the 1970's Quad era, my own interest in surround Mastering is engaging the listener more completely rather than dazzling them with cool technology. The tools for authoring DVD's and other multi-channel formats are pretty crude. I hope that this situation will evolve quickly, bringing surround into financial range for a larger group of artists.

I also monitor music visually with peak and VU meters, modified real time spectrum analyzers, phase correlation meters, and a number of specialty tools that provide large amounts of information about what is happening inside the music. This enhances the process of making fine adjustments that otherwise could take a lot of time. The combination of speaker systems and instrumentation provides an analytical tool that is tough to beat.