January 18, 2013, by Bruce Swedien
Excerpted from the excellent “Make Mine Music” by Bruce Swedien, available from musicdispatch.com.
It’s my opinion that after all is said and done, psychoacoustics is really why we are interested in recording music in the first place.
Psychoacoustics can be defined simply as the psychological study of hearing. The true aim of psychoacoustic research is to find out how our hearing works.
In other words, to discover how sounds entering the ear are processed by the ear and the brain in order to give the listener useful information about the world outside. I’ve never felt that psychoacoustics is concerned with how sounds produce a particular emotional or cognitive response. That is another matter entirely.
To me, the three most fascinating areas of psychoacoustic analysis are:
—How does the human ear separate sounds occurring simultaneously (e.g., two musical instruments playing at once)?
—How do we localize sounds in space?
—How does the human ear determine the pitch of, say, a sound source or, more important, a musical instrument?
Psychoacoustics is not about sonic mind control. (I must confess that I was a little disappointed when I first learned that fact!)
Determining the abilities and limitations of human hearing is invaluable to us involved in the production of music recordings. Any resource that produces sound for the purpose of human listening should \ take into account what the listener’s ears are going to do with that sound, if we are going to take that resource to its utmost potential.
I have always been a very curious person. I have always had to know why things are the way they are, especially when it comes to the recording of music.
Sound is so important to us in so many different areas that it has always been fascinating to me to think about why we perceive sounds the way that we do. I have heard it said that the purpose of the ears is to point the eyes.
Knowing that, I think it is safe to say that the primary use of our sense of hearing is to localize sound sources. Keep these thoughts in mind the next time you are doing a mix.
Sound as a stimulus is the arena of the physicist. Sound as a sensation is in the arena of the psychologist. We, as professional music recording people fall somewhere in between these two areas of
In actuality, to be truly successful in music recording, we may have to be a little bit of both. So, what I hope to accomplish is to help you discover, with the help of the little bit of the psychologist that I think is present in all of us, your own “sonic personality.”
A Card-Carrying Record-Buying Junkie
I think the first step on the road to developing our own “sonic personality” is to find a benchmark for our mind’s ear that has as its basic component true “reality” in sound. From that stark, uncolored point we can then add a new viewpoint for the listener that we can call truly our own.
Many recording engineers and producers spend a lot of their time listening to and trying to learn their craft from records. In my opinion, this is a serious mistake and is precisely the reason why there are so few engineers and producers in the industry today, who have a truly unique sonic character to their work.
A certain amount of information can be gained by listening to other people’s records, but my problem with this approach is that one’s own “audio personality” is short-circuited.
Bruce Swedien at work (click to enlarge)
In other words, if you try to learn about music mixing by listening to records, in actuality what is happening is that you are hearing the music, or sonic image of the music, with someone else’s “audio personality” already imposed on the sonic image.
I do believe that it is true that we must listen to records to keep up with sonic styles and trends.
Personally speaking, I am a bona-fide, card-carrying record-buying junkie. When I hear a record on the radio or in a club that has interesting music or an interesting sonic hook, I am off to the record store in a minute and buying a copy for myself.
However, to have an “audio personality” that is truly your own, you must start your personal sonic development with a knowledge of natural, acoustical sounds.
Let’s Talk About Acoustical Support
To take that line of thought a step further, I think I should say that I feel that the best way to develop your ears’ “benchmark” is to hear good acoustical music in a fine acoustical setting. How many of you get out to hear live music on a regular basis? It’s very important!
Let’s talk about acoustical support as it relates to music. All music is conceived to be heard with some sort of acoustical support. This does not necessarily mean long concert-hall-type reverberation. It can mean very short, closely-spaced early reflections and minimal reverb content. Both of those components constitute acoustical support.
Once we know what music sounds like in a natural setting with good-quality acoustical support, we can then take that “audio benchmark,” and through our work, give our sonic images our own distinctly personal touch.
An engineer’s or producer’s listening ability does not descend on him in a single flash of inspiration. It is built up by countless, individual listening experiences. So let’s make a real effort to hear the music and sound with as open a mind as possible.
One of our most important abilities as a professional listener is judging balance. So let’s consider balance as the first thing to listen for today. The balance of an orchestra’s instruments in classical music is the sole responsibility of the conductor.
In our work of recording music, that responsibility is transferred to us. It doesn’t matter whether the orchestra is acoustical instruments or the orchestra is represented by a synthesizer. We must be able to judge balance.
Over a long period of time, if we have the native ability, we will develop a seemingly uncanny sense of hearing nuances of balance and sound that would pass unnoticed by the inexperienced.
This ability seems to be acquired almost by osmosis through thousands of seemingly insignificant listening experiences. This random approach is effective and vital.
The antithesis of balance is imbalance. When you are at a concert listening to good music in a good acoustical situation, listen for any imbalances that might be there. Think about your spontaneous reactions later.
When you are at a concert, ask for very good seats. That way, you should be able to judge balance and many other elements with a certain amount of accuracy. Listen for spectral balance. In other words, how well balanced is the frequency spectrum of the orchestra in that specific acoustic setting?
See how your ears and psyche react to the overall volume level of the orchestra, particularly at fff (extremely loud) dynamic levels. How does the orchestra sound at ppp (extremely quiet) dynamic levels?
Make sure that you have a good working knowledge of the different levels of musical dynamics and learn how they are expressed in musical terms. This will help you later on when you discuss these very important values with the musicians and composers that you will be working with.
Here are some important aspects of sonic values to listen for when you are listening to good music in a good acoustical situation:
—Listen for early reflections in the acoustical support of the hall. Listen for the reverb quality of that specific room.
—Listen for reverb spectrum.
—Listen for the amount of reverb that you perceive in relation to the direct sound of the orchestra – in other words, reverb balance.
Let’s Talk A Bit About Reverberation And Echo
Most of the time, we are unaware of how much of the sound that we hear comes from reflections from environmental surfaces.
Even when we are outdoors, a significant amount of sonic energy is reflected back to the ears by the ground and nearby structures – even by surrounding vegetation.
We only begin to notice these reflections when the time delay is more than about 30 milliseconds to 50 milliseconds, in which case we become consciously aware of them as individual sounds and call them echoes.
Special rooms called anechoic chambers are built as research rooms to absorb reflected sound energy. In a test situation staged in an anechoic chamber, only the directly radiated sound energy reaches the ears.
Upon entering an anechoic chamber for the first time, most people are astonished by how much softer and duller any sound source sounds. If reflected sound is so common in an ordinary acoustic environment, I’ve always wondered why these reflections don’t interfere with our ability to localize sound sources.
I guess it’s because our binaural hearing sense can quickly adapt to a new acoustic environment. I do know that our hearing system uses only partially understood mechanisms to suppress the effects of reflections and reverberation.
The fact that we localize sound sources on the basis of which signals reach our ears first is known as the precedence effect. This is not to say that we are unaware of the reflections that follow. Actually, we subconsciously use the subsequent reflections to estimate range, or the distance we are from the sound source. In my opinion, a music producer/engineer is no better than his tools.
Our main tools are, of course, a good pair of ears and the wonderful brain to which the ears are connected. If the hearing is faulty, only faulty judgments can result. Please try to remember that good hearing is a rare and wonderful gift.
How Do We Achieve Depth, Or That Third Dimension, In A Stereo Image?
The feeling of depth perception in a recording is the result of a combination of values, including the ratio of direct to reverberant sound. The intensity of a sound source relative to others in the same field, and even EQ, especially in the presence area of about 1.5 kHz to, say, 5 kHz.
Probably the most important factor in creating a feeling of depth is the change in the ratio of direct to reverberant sound. As reverberant energy becomes more prominent, the source appears to move back.
The absence of early reflections in a sound source makes it seem much closer. As you change the quality of early reflections in a soundfield, they greatly affect the depth of field. These reflections are generally less than 40 milliseconds.
When they are longer than that, the ear can pick them out as individual reflections, but below 40 milliseconds they tend to smear into one sound. Early reflections in a sound source must be part of the sound-field of the original recording to be effective. There are virtually no effects devices that seriously address this important issue!
Thinking out and carefully designing a sound-field yields big benefits. Careful thought and intent will make your work memorable and separate you from the also-rans.
That is also why intelligent use of pre-delay with reverb devices can give a tremendous feeling of depth of field. By increasing the length of the pre-delay of a reverb device (to make sure the reverb itself does not cover the early reflections), your recording will have a unique sonic character that is truly your own.
The Attack Wall
Here’s something about “tube traps” that you may find interesting. I am very excited about a new and intriguing recording-room acoustical treatment.
In essence, this new theory creates a reflection-free listening zone for music recording and mixing. The concept was perfected by my friend Arthur Noxon of Acoustic Sciences Corporation.
The “attack wall” at Westviking Studio. (click to enlarge)
It’s called the “attack wall.” It is a free-standing wall that surrounds the monitor speakers. (I think we could call this speaker position “midfield” monitoring.) It acoustically loads the monitor speakers, and causes them to play as if there actually mounted into a wall. This gives the monitor speakers increased acoustic efficiency.
With an array of studio traps behind the listening space, the “attack wall” makes a 100 percent acoustically “dead” space. This creates a reflection-free zone for music mixing and recording.
I have found that with the “attack wall,” no monitor EQ is necessary.
With good monitor speakers, you hear smooth, linear sound. The low end is exceptionally clean and articulate. One of the additional advantages of the “attack wall” is its portability. It can be moved from place to place with a great deal of predictability and reliability.
In my next article, I’ll be discussing speakers, amplifiers, control room volume levels and much more.
Click to enlarge book cover
This is an excerpt from Bruce Swedien’s Make Mine Music. To acquire a copy of this book, click over to www.musicdispatch.com. NOTE: ProSoundWeb readers can enter promotional code NY9 when checking out to receive an additional 20% off the retail price plus free shipping (offer valid to U.S. residents, applies only to media mail shipping, additional charges may apply for expedited mailing services).