a slide show presentation by David Moulton at Parsons Expo2001(Note: Due to time limitations, we have reproduced this show as text rather than as slides.)
The Loudspeaker
As Musical Instrument
By David Moulton
Parsons Audio Expo 2001
November 14, 2001
We’ll Consider:
• The Nature of Loudspeakers
• The Nature of Musical Instruments
• The Nature of Musical Transcriptions
• Live vs. Recorded Musical Experiences
• What’s Idiomatic for Loudspeakers
• My Current Projects, and how they bear on these issues.
Ways We Can Think of A Loudspeaker
• As a Reproducer
• As a Mimic
• As a Reinforcer
• As a Unique “Sound Source Without Its Own Sound Quality”
Loudspeaker As Reproducer
• A traditional view: the loudspeaker, along with its drive mechanism, “reproduces” a previous sonic event.
• Questions of “accuracy” and “realism” arise.
• Implies the existence of a previous “sonic event” (not always true)
Loudspeaker As Mimic
• A Synthesist’s or Producer’s view.
• The loudspeaker “mimics” the sounds of other sound sources: a flute, a snare drum, a rock band, an orchestra, etc.
• Again questions of accuracy and realism exist, as do distinctions between “natural” sound sources and “artificial” sound sources (i.e. the loudspeaker).
Loudspeaker As Reinforcer
• A Promoter's View (heh, heh! - $$$)
• The loudspeaker “makes other instruments sound louder”.
• Implies that loudspeakers “change” other instruments, not replace them. An essential viewpoint in sound reinforcement, theater, live performance.
Loudspeaker As Unique “Sound Source Without Its Own Sound Quality”
• A “Zen” view
• We can all imagine the sound of a tuba, but,
• what is the sound of a loudspeaker?
A Loudspeaker, Physically
• Is a device that can create any reasonable sonic spectrum,
• with any reasonable temporal envelope,
• at any reasonable loudness,
• in at least one direction,
• in a free field.
• The loudspeaker is a “universal sound generator.”
In Addition, An Array of Loudspeakers, Physically
• A phase-locked array of loudspeakers can:
• represent any reasonable space within another smaller space,
• reasonably represent the position of any sound source within that virtual space, and
• reasonably envelope the listener within that virtual space
• The phase-locked array of loudspeakers is a “universal sound environment generator.”
A Universal Sound Generator
• It is this “universal sound generator” quality that makes the loudspeaker hard to characterize, as well as extremely useful.
• If it can make “any” sound, what sound is most “characteristic” of a loudspeaker?
• How do we distinguish a loudspeaker from a bassoon, for instance?
Some Comments About Accuracy
• There is a commonly held view that “accuracy” (which is actually defined as “the absence of error”) is desirable, and that more accurate is better.
• From this viewpoint, it follows that there is a strong positive correlation between “beautiful” and ‘accurate.”
Accuracy, cont.
• If this is really true, then as loudspeaker playback of music becomes more accurate, it should also become more beautiful.
• This isn’t necessarily true, of course.
• In fact, current recording practice doesn’t maintain standards of absolute accuracy, or even much relative accuracy.
Accuracy, cont.
• So, while there may be considerable overlap between the qualities of “accuracy” and “beauty,” particularly at the low resolution ends of their particular ranges,
• accuracy and beauty tend to diverge as resolution increases.
Accuracy vs. Beauty
• In our recording practice AND in our loudspeaker design practice, when faced with the divergence between beauty and accuracy,
• we generally choose to pursue beauty, for very good artistic, aesthetic and professional reasons.
About Musical Instruments, for a minute
Music Instruments come in families
• These “families” are usually based on the nature of the vibrating element
• Strings – a vibrating string
• Winds – a vibrating column of air
• Percussion – vibrating solids and membranes
• There are, of course, many compound versions of the above
Musical Instruments, continued
• Some instrument families are based on how they are operated
• Keyboards, for instance, are actuated by an array of keys used to excite discrete frequencies, regardless of how the vibration is accomplished.
• Percussion instruments, are instruments that are “struck,” regardless of what such “striking” causes to happen.
A little more about musical instruments
• At the very least, musical instruments have a vibrating element, which physically creates the excitation of the air,
• and
• some sort of drive mechanism, which is the source and modality of energy to operate the vibrating element.
About keyboard instruments
• The Western keyboard is an offshoot of the development of music notation - the 12-step chromatic keyboard surfaced in the 14th century.
• This chromatic keyboard, used with organs, harpsichords, claviers, fortepianos and, of course, the modern piano, has been the “workhorse” of Western musicians from 1400 to 1970.
More about keyboards
• The “player” keyboard, originating in the 16th century, automatically “plays” the keyboard instead of a human performer.
• This technology peaked in the early 20th century, with very “accurate” and “expressive” player pianos “reproducing” the performances of great artists.
Even more about keyboards
• Interestingly, it was the emergence of the electrical loudspeaker, in conjunction with radio broadcasting and the mass market record industry in the late 1920s and 1930s, that drove the player piano into commercial obscurity.
Even more about keyboards
• However, keyboards remain the musicians’ work tool of choice for studying, arranging, composing and playing back in rehearsal, even today, due to their flexibility and comparatively low cost.
So what is a musical instrument, really?
• A musical instrument is a device “capable of producing music.” (American Heritage Dictionary)
So what is music?
• Music is “the art of arranging sounds in time so as to produce a continuous, unified, and evocative composition, as through melody, harmony, rhythm and timbre.” (American Heritage Dictionary)
How Does the Loudspeaker Fit Into All Of This?
First off, in light of these definitions:
• A loudspeaker certainly qualifies as a musical instrument.
• The loudspeaker is sometimes referred to as “electroacoustic” (a nice bit of jargon) because its drive mechanism is electrical.
• Nonetheless, the loudspeaker employs a vibrating membrane, not unlike the tympani, the snare drum, or (God Help Us!) the tambourine.
Loudspeakers, historically
• Evolved as part of the transition from acoustic to electrical recording in the 1920s.
• Originally used to reproduce voice in movies?
• Evolved (a) for reinforcement and public address, and (b) for reproduction of radio and phonograph records (voice and music).
Loudspeakers, historically
• Power limitations and reinforcement needs for sound pressure level required high-efficiency horn designs that
• traded bandwidth and dispersion for
• high sound pressure level in limited frequency bands in narrow sound fields
Loudspeakers, historically
• Beginning with “hi-fi” in the 1950s, loudspeakers began to evolve into devices using less efficient direct radiators and sealed enclosures to yield greater bandwidth and less distortion at lower levels for domestic use.
Loudspeakers, historically
• Also in the 1950s, we began to use loudspeakers in phase-locked arrays, for the transmission of stereophony.
• Phase-locked arrays permit the transmission of “spatial” or “environmental” information as well as instrumental reproduction or mimicry.
Loudspeakers in Instruments
• Meanwhile, “electronic” instruments evolved, including “electronic organs,” the theremin, and of course the “electric” guitar.
• All of these devices use loudspeakers as the sound-producing vibrating element.
Loudspeakers and Keyboards
• Finally, we have a “merging” of the loudspeaker and keyboard families of instruments, with the development of the modern electric organ, electric piano and “synthesizer.”
Loudspeakers and Keyboards
• Now, the “keyboard” (as the drive mechanism) and the “loudspeaker” (as the vibrating element) coexist in the same musical instrument.
Pause . . .
Take a deep breath . . .
• Plunge Ahead!
The Aesthetics of Loudspeaker Music
• Loudspeaker As Reproducer
– We desire to experience the equivalent of a “musical event” such as a concert or club performance. We wish to experience the sensation of “being there” (or that “they are here”).
– In short, we have expectations that are related to our expectations for experiencing “live” music.
• Loudspeaker as Musical Source
– We desire to experience “exactly” the sensation we would have listening to the “source” instrument(s).
– We would like the loudspeaker(s) and our room to “disappear,” and to have only the sensation of “musical performers” and “their space.”
Loudspeaker Music As Music Genre (this is important!)
• Popular Music
– We desire to experience “the song,” and we accept without any qualms that what we are listening to comes from loudspeakers only and is NOT a live performance.
– We enjoy the “entertainment effect” of music produced for loudspeaker playback.
Loudspeaker Music As Music Genre (this, too, is important!)
• “Classical” Music
– We desire to experience music as a private entertainment, a la the Esterhazys, but without the expense and complication of resident composer and performers.
– We enjoy the “perceived quality” of the recorded performance, performance acoustics and sonic artifacts, as well as the perceived quality of our surroundings.
Thinking in these terms about recordings for loudspeakers
Recording As Transcription
• To “transcribe” means:
– (a) “To adapt or arrange a [musical] composition for a voice or an instrument other than the original.”
– (b) “To record for [playback] at a later date.”
• (American Heritage Dictionary)
Recording As Transcription, cont.
• Both definitions apply to loudspeakers, but we tend to ignore the first.
• Nonetheless, it is reasonable and correct to view recordings as “an arrangement of music for an instrument other than the original.”
Recording As Transcription, cont.
• When transcribing, we need to consider both the nature of the original AND the transcribed instrument.
Recording As Transcription, cont.
• The best transcriptions
– illuminate qualities of the original that might not have been obvious
– add qualities that were not available in the original
– maintaining the essential musical identity and “gestalt” of the original.
• Cf. Ravel and Tomita, in re Mossourgsky
Recording As Transcription, cont.
• Such considerations are perfectly true for recordings (i.e. musical transcriptions for loudspeakers), as well as for more traditional transcriptions.
• We are “adapting” music to loudspeakers from its original form.
• From this view, “loudspeaker as reproducer” is not an appropriate perspective.
This Raises Some Questions About Loudspeakers
• What sorts of musical qualities are most idiomatic for loudspeakers (and the recording process)?
• What sorts of musical qualities are least idiomatic (i.e. don’t sound very good) for loudspeakers?
More questions
• What is the social and aesthetic experience of “listening to loudspeakers,” in comparison to “listening to live players?”
• What qualities of loudspeakers enhance the “loudspeaker listening” experience?
• It is in the consideration of these questions that we can find some insight into the nature of “loudspeaker music,” as a distinct instrumental genre of music, as distinct, perhaps, as “piano music,” or “orchestral music,” or “choral music,” and distinct from issues of musical style.
Live Music:
• is public and usually in crowded venues
• is highly social and ritualized
• has a strong emotional interaction between listeners and performers
• is mostly limited by human capabilities for performance (except for reinforcement)
• is a one-time event not under the listener’s control.
Loudspeaker music:
• is generally private
• is casual, ubiquitous and often extremely intimate
• has no interaction between listeners and performers
• is not constrained by human performance limitations
• can be played on demand, restarted, repeated exactly ad infinitum - becomes internalized
Loudspeaker music is generally private
• We do the bulk of our listening to loudspeakers in private spaces.
• We do NOT, as a rule, gather in public social groups to listen to loudspeakers (excluding dance clubs and aerobics classes!)
Loudspeaker music is casual, ubiquitous and often extremely intimate
• We often use loudspeaker music in our homes and cars as a kind of “sonic perfume.”
• Further, we regularly use loudspeaker music as a very strong “mood enhancer” for love-making, dining, meditation and other private ceremonies and activities, including “serious listening.”
Loudspeaker music has no interaction between listeners and performers
• Due to the “machine” nature of the loudspeaker drive mechanism, the performance does not vary as a function of our listening response.
• Further, in production, we “polish” performances to “idealize” them into “best possible”performances that lack “live blemishes.”
Loudspeaker music is not constrained by human performance limitations
• Loudspeakers can play indefinitely, at any reasonable level (subject to system design limits).
• Loudspeakers can play higher, lower, louder, softer, faster and slower than any other instruments.
Loudspeaker music is under the control of the listener.
• Loudspeakers can be played on demand, restarted, repeated exactly ad infinitum - the performance becomes internalized, and given “recordings” obtain mythic status.
• Listeners often “memorize” recordings (something that almost never happens with live performance).
• Listeners can and do “program” listening events, or sequences of recordings.
Exposure to Loudspeaker vs. Live Music
• It is reasonable to estimate conservatively that 99.9% of all music experienced today is loudspeaker music.
• This means that loudspeaker music has almost entirely displaced “non-loudspeaker music.”
From Live to Loudspeaker
• This displacement has happened essentially without notice – our preoccupation with “loudspeaker as reproducer” has tended to mask this change in instrumental usage.
• We now “listen to loudspeaker music” as our primary, often only, musical activity.
Loudspeaker vs. Live Music Exposure, cont.
• Further, much (most?) “live” music is produced, promoted and presented for the express purpose of encouraging the loudspeaker music equivalents of that live music (i.e. “touring to sell the record”).
Some Shop Talk
What Kinds of Musical Gestures Work Well For Loudspeakers, and What Kinds of Gestures Don’t?
What Is Idiomatic for single loudspeakers (mono)?
Works well in mono
– Simple sound sources
– Simple acoustics
– Simple doublings
– Single miking techniques (i.e. “acoustic mixing”)
– Consonant music
– Music with clear upper spectrum definition
– Music with moderate crest factors.
– “Dry” sounds
Doesn’t work so well in mono
– Complex sources (i.e. many sound sources in a space)
– Complex acoustics
– Complex textures, doublings, polyphony
– Complex mic arrays in a common space, especially with cross-talk
– Dissonant music
– Music lacking upper spectrum, or with rich mid and upper-bass harmonic content.
– Music with extreme crest factors (very high or very low).
– “Wet” sounds
Works Well in Stereo and Multichannel
– Simple arrays of instruments
– Use of time-domain localization
– “Phantom LF” vs. “Discrete HF”
– Spectral Management
– Spatial Distribution
– Simple stereo/mc Ambience
– Simple stereo/mc Reverberance
– “Acoustic mixing” via minimalist stereo and multichannel miking
Doesn’t Work So Well in Stereo and Multichannel
– Complex arrays of instruments in blend
– Use of amplitude cues for precise localization
– Complex stereophony/blends of multiple stereo and mono recordings from a single space
– Complex ambiences and reverberance, particularly with excessive mid and LF content.
The “Compatibility” Problem
Many desirable techniques for stereophony are quite undesirable for mono.
The problems can be characterized as:
• Changes in level
• Changes in timbre
• Changes in reverberance.
• These changes occur due to destructive interference in summation to mono. Time and amplitude difference cues become timbral cues and interference patterns when summed in the drive mechanism for loudspeakers.
• Therefore, such practices are often suppressed, even though they are idiomatic.
• This is simply in anticipation of the multiple possible modes of playback.
My Current Projects
And how they relate to all of this
Studio Monitors
• Issues:
– The Amplitude/Power Response Anomaly
– Listening Back vs. Listening Ahead
– The Interaction with (Which?) Rooms
– Accommodating Various Playback Modalities
“Museum-Grade” Loudspeakers
for Sausalito Audio Works
• “Cultured” Loudspeakers:
– Loudspeakers that are appropriate for the playback of music in concert and recital halls, museums, galleries, etc, as well as private homes.
– Such speakers must have great performance, superb room interface, and “fine quality” appearance.
• In this view we recognize that:
– the loudspeaker is NOT a generic Black Box, but a singular and distinctive musical instrument (think of “Loudspeaker as Steinway”).
– sound quality comes PRIMARILY from the loudspeaker - selecting a loudspeaker becomes THE primary musical quality decision.
Multichannel Music for “Museum-Grade” Loudspeakers
• Music As Sculpture
• Music As “Source And Space” simultaneously
• Music that uses the entire “audio window”
A Gift Of Sound
Sound Sculptures by David Moulton
January 9 to February 10, 2002
Boston Sculptors at Chapel Gallery
Chestnut St., Newton, MA
That’s All, Folks!
• Thanks for Listening
• – Dave
Want more info?
Wanna talk?
• Websites:
– Moultonlabs.com
– SAWonline.com
• Email:
– davemoulton@charter.net
• Phone:
– 978-448-6828
