Thursday, March 27, 2008

Dave Moulton: Golden Ears and Just-in-Time Spectral Management for Chamber Musicians

 Dave Moulton
M  astering [engineering recordings] is an art, not a science. It involves a lot of technical craft and control, plus practice.”
  —  Dave Moulton.
Your plane is delayed by bad weather, and you land in late afternoon at the airport of the city where your performance tonight is to occur. The taxi whisks you to the performance hall where you greet the presenter and observe the production people busily getting the stage ready. You have less than 2 hours before the performance begins. You should be focusing, centering, warming up, getting your game-face on. You should be taking deep breaths.

But wait! The house has a much taller ceiling than you thought it would have. The acoustic reflective panels on-stage are adjustable, but at the moment they seem to be in a perverse flat configuration that lets a lot of sound leak out into the wings. What was the last gig played in here anyway, some break-away faction from Cirque du Soleil? The whole acoustic ‘feel’ of the place is horrifically drier than your ensemble is used to. And there’s an odd acoustic ‘sweet spot’ slightly to the left of center-stage. What the hell! Where in this catastrophe of a venue is the best location for the harpsichord? Precisely where should the other ensemble members be placed, so that the solo passages of each will be heard and so that the balance of the group will have some hope of realizing your artistic vision?

Very few musicians receive any formal training in how to cope with this part of performance. As a result, it’s an incredibly stressful and agonizing thing for most ensembles and individual musicians. And yet it’s possible for you to systematically acquire skills that will help you make accurate acoustics decisions confidently and quickly. How do you train your ears to immediately recognize what you and your ensemble members need to do to deliver your best?

Golden Ears is one way—Dave Moulton’s CD-based audio ear-training course. It’s not perfect pitch or interval training. Instead, it aims to teach your ears to hear the frequencies, the signal processing, the compression, the left-right stereo imaging, the distortion, and the amplitudes in acoustic media. The course is self-paced and available as a set of eight audio CDs. To use it properly, you’ll need a set of good speakers or headphones. I use the Bose noise-cancelling headphones, to make sure that ambient noise around my house doesn’t confuse my ears when I’m practicing with the Golden Ears CDs.

 Moulton book
Moulton basically puts forty years of his recording studio, performance and teaching experience on these CDs. There are hundreds of exercises on the CDs that systematically take you through different dimensions of acoustic spectrum and timbre and electronic equalization (EQ) and processing of sound. While the main purpose of the course is to help recording engineers and producers to understand and be able to describe the elements that recorded tracks contain—their spectrum, dynamics, reverb and other audio qualities—with the goal of insightfully adjusting them in recording gigs or in post-production, the course is just as relevant for sound-reinforcement engineering in live performances and for classical musicians and presenters who work in traditional non-reinforced acoustic settings.

In a way, Moulton’s educational process is a little like a culinary course for chefs—helping them to quickly assess deficiencies in a dish, and equipping them with the ability to know instantly how to salvage a dish that suffers from imbalances in flavor.

Once you get a feel for the acoustic ‘ingredients’, you can take better control of the weird performance hall you find yourself in, take control of the hall’s sound-reinforcement control board, take charge with the presenter’s or the hall’s sound engineering staff, or take control and better utilize your own recording gear and approach the process of tracking, mixing and engineering with more confidence and less time consumed in trial-and-error. You can consistently ‘cook’ a better ‘dish’.

 Golden Ears audio course
How does the course work? There are four volumes, with two CDs per volume, each covering different components of the recording process. In Volume 2, after you’ve followed instructions for optimizing your listening set-up, you go through a series of A/B drills using excerpts of recorded music. The first recording (A) is the reference piece and the second (B) is a clone of the first with an applied amount of as-yet-undisclosed signal processing, frequency boost, delays, etc. Your task is to learn to identify the difference between the two recordings. To assist you, Moulton limits the number of options and groups them into six families of effects: amplitude change, distortion, compression, equalization, stereophony, time-delay, and reverberation. The drills are progressively more difficult. After you’ve completed your first pass through them, you can do the drills in random order to practice and improve your skills. The course materials are automatically randomized so you can’t identify any drill until it’s over. Golden Ears teaches you:

  • to recognize the effects of compression on a various music signals;
  • to identify fast and slow compressor attack and release times;
  • to correctly identify musically important EQ problems;
  • to recognize when loudness is the only difference between two signals;
  • to distinguish ranges of 1 - 10% and 10 - 30% Total Harmonic Distortion (THD) in recorded music or in sound reinforcement rigs used for live performances in larger chamber music venues;
  • to recognize abnormalities in stereo imaging (reverse image, mono summation, polarity reversal, pseudo-stereo, etc.) ;
  • to identify channel-to-channel time differences over a 1 to 50 msec range; and
  • to correctly recognize and manage gated and ungated reverb.
Moulton is a pro engineer and producer. He holds degrees from Bard College and The Juilliard School of Music. In the 1960s and 70s, he owned and operated his own commercial recording studio in New York. Previously at SUNY and the University of Massachusetts at Lowell, he was in the 1980s and early 1990s Chairman of the Music Production and Engineering Dept. at Berklee College of Music in Boston. He is now teaching privately and at the Museum of Fine Arts in Boston. He has worked as a studio designer and has designed playback room configurations for recording studios and wide-dispersion acoustic lens arrays for performance venues. In 2000 he (with Curt Wittig) received a Grammy nomination for the CD recording of music by George Crumb performed by the Philadelphia-based ensemble, Orchestra 2001. Dave wrote and produced Golden Ears in 1994, based on traditional music school ear-training techniques.

 Orchestra 2001 CD
The first two CDs each have a series of 14 EQ drills, each drill consisting of ten short bursts of sound with EQ applied and cancelled as you listen. First there is a warm-up for each drill, where Moulton describes what’s coming. Then the drill begins. For example, drillset_1/example_1 has ten seconds of pink noise, and for a few seconds an octave band centered around 500 Hz is boosted by 12 dB. Drillset_1/example_2 does the same thing to an octave centered around 63 Hz, and so on, until all of the octaves of the human hearing range from 31 Hz to 16 KHz have been covered—all ten octaves in random order. The manual is well-written. The comprehensiveness of the drills enables you to discover and make note of your own hearing deficits in a systematic way. If you do this with other members of your ensemble, you can identify certain aspects where one or another ensemble member has particular strengths. More likely, doing this together will confirm in an objective way which one of you is actually the most skillful and accurate acoustician (for purposes of reconnoitering with venue engineers and production people), rather than who merely has the strongest opinions and the most insistent expression of them.

After the pink noise drills, Moulton conducts more exercises involving applications of EQ, except this time they are done to musical excerpts. Next, there are more reps of EQ apps, this time with octaves being cut instead of boosted. Vol. 2 also has two CDs, this time with a wide variety of signal processing applied to a vast number of musical selections and styles. You can assess and practice your perceptions of things like amplitude changes, distortion, compression (including recognizing slow and quick attack and release times), some different examples of EQ, stereo/mono/pseudo-mono switching, time delays (including time differences over a 1 – 50 msec range), and reverbs. Vols. 3 and 4 extend the skillset into progressively more detailed and exotic effects that are important for performance and for recording/engineering.

Some effects are simple and easy to recognize, like a 3 dB amplitude boost. Yet, depending on the texture and timbre of the music, even something so simple as this may be difficult to hear. It may be even more difficult in high or low registers. Other effects are more obvious—clipping distortion, long reberbs, etc. But most are somewhere in the middling range of subtlety, like ‘left channel mids (1 KHz) boosted by 6 dB while right channel highs (10 KHz) cut by 6 dB.’ You can refine your ears to hear subtle EQ cuts and boosts within narrow intervals of a fourth or a fifth, and to readily hear multiple frequency bands at once. After 20 or so hours with these CDs, you’ll be able to quickly diagnose what’s going on acoustically in any performance venue and intelligently strategize what to do about it—to make the best of the situation you’re in.

In summary, all the hundreds of drills on these CDs train you to hear and to recognize problems in all these areas and across the whole span of registers—before you go on-stage or before you exit the recording studio. By revisiting the CDs before you travel to give a concert in an unfamiliar hall, or by revisiting the CDs a few days before you start a recording gig, you can refresh your familiarity and refresh your confidence to be able to quickly amend and improve the acoustics that will affect the music you make.

In effect, for those of us who are not recording engineers or conductors in our day-jobs, rehearsing our ears to recognize and thoughtfully manage these ‘macro’ acoustics effects is a very important yet under-recognized aspect of our art. The Moulton CDs are an efficient way to establish and maintain a mastery of this.

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