Alexander U. Case

The vocal microphone: Technology and practice

Evolving technologies for converting acoustic pressure into an electrical signal have driven changes in the performance practice and sound of pop singers.

Multichannel soundscape recording techniques.

Several goals motivate the recording a soundscape: measurement, archiving, mitigation, preservation, design, modeling, education, marketing, and entertainment. Salient properties of a soundscape are similarly broad: levels versus frequency and time, their averages and associated statistics, discrete sound source identities, distance, localization, size, spaciousness, envelopment, and additional subjective sound qualities, sometimes subtle. While traditional noise metrics are based on single microphone measurements, a soundscape is better captured, quantified, and studied using multi‐microphone techniques. Multichannel recording techniques for large‐scale soundscapes, borrowed from the multitrack recording practices of concert halls and recording studios, are defined and compared. The resulting data and audio files are evaluated for their ability to satisfy the needs of owners, designers, and end‐users of a soundscape.

Soundscape versus noise—From the sound recording to the public space

The enemy of desired sounds is unwanted sonic competition. The positive elements of an interior soundscape need to be rid of noisy rivals. Solutions in the built environment might be inspired by approaches taken in the creation of sound recordings. Of course, noise is minimized where possible, but remaining noise must be dealt with. Masking the noise, taking care that the noise does not mask the soundscape, embracing the noise, and creating an environment of heightened awareness can improve the listener’s comfort and sense of pleasure when immersed in a soundscape clouded by noise.

Even weirder than the real thing—Gated reverb history and aesthetics

Sound presented via loudspeaker may take advantage of signal processing to create sounds not possible in an all-acoustic production chain. Breaking free of the acoustic constraints for music-making in the concert hall to take advantage of an analog, digital and electro-acoustic production chain has been a major attraction for many popular recording artists. New aesthetics evolved. Among the most absurd sonic concoctions to come from this, gated reverb is part discovery, and part invention, motivated by misunderstandings, and driven by plain old rock and roll rebellion. This paper tours the development of gated reverb, with audio illustrations, and makes the case for its continued use today.

The highly exaggerated attributes of the pop vocal in sound recordings

The voice in sound recordings must generally reign supreme over the rest of the multitrack arrangement. The loudspeaker mediates its interaction with the architecture. The entire upstream production chain anticipates the challenge. Recording space, microphone choice, and signal processing are carefully coordinated to maximize the audibility of multiple attributes the voice — intelligibility, emotion, musicality, and tonal quality. The highly manipulated approach to speech for sound recording can shed light on approaches taken in the built environment for the talker/listener interface.

Architectural acoustics—Hear here

The discipline of Architectural Acoustics consistently produces more than 100 papers across six or more special sessions, at each meeting of the ASA. Student paper awards, student design competitions, and Knudsen lectures augment these activities. Joint sessions, particularly with noise, musical acoustics, psychological and physiological acoustics, and signal processing in acoustics, add more still to the architectural acoustics goings-on at every ASA conference. The sphere of influence is not limited to ASA alone, as TCAA members participate in the Green Construction Code of the International Code Council, Society of Motion Picture and Television Engineers Study Group: Movie Theater Sound System Measurement and Adjustment Techniques, Classroom Acoustics Standards, the American Institute of Architects Continuing Education System, and more. This busy committee also produces a steady stream of publications documenting recent work and deciphering standards for key stakeholders. Anyone with an interest in the...

Recording studios—Optimized, contrived, and augmented spaces

Multitrack production occurs around the globe in spaces from large to small. Their acoustic capability ranges from thoughtfully designed purpose-built spaces for recording to unmodified, re-purposed residential rooms, with everything in between. Yet recordings built entirely within a laptop-and-headphones production space have no problem sitting in shuffled playlists next to work from high end, world-class studios. Acoustic features—or lack thereof—are variously leveraged and overcome through recording craft and signal processing to adapt almost any production space to the sonic needs of the recording artist.

A series of special sessions on architectural acoustics and audio

Along with his love of concert halls, opera houses, and pipe organs that are often considered the top of the architectural acoustics food chain, Dick Campbell always shared his enthusiasm for smaller rooms, loudspeakers, computers, signal processing, and all forms of media. Daring to incorporate MIDI-driven, synthesized sounds produced through loudspeakers into the pit orchestra, Dick knew how to rabble rouse—and inspire. One legacy of his politely provocative thinking is a series of 11 special sessions—so far—started with him at the 1999 Columbus meeting, and continued to this day by the authors. The thread of related special sessions had its most recent iteration at the Fall 2014 meeting in Indianapolis, “Architectural acoustics and audio—Rooms, systems, and techniques for adapting, enhancing, and fictionalizing acoustic traits”, with 22 papers covering a wide range of ideas and concepts. A tour of these sessions’ past topics and authors reveals a rich body of work that might otherwise have been overloo...

Electric guitar—From measurement arrays to recording studio microphones

A joint research effort by the audio recording programs at the University of Massachusetts Lowell and New York University has made use of a 32-microphone measurement array in the quantification and visualization of the spectral radiation of musical instruments. Work to date has focused on electric guitar and piano. The measured directivities of the guitar amplifiers offer rich insight for the recording engineer. Traditional microphone selection and placement strategies formed over decades, before such data existed, are found to have merit. The data also shed light on those potentially unattractive microphone locations to be avoided. The measurements, taken with high spatial resolution, reveal a process for microphone placement as much as providing a window into showing exactly where to place them. Measurements of the acoustic radiation from electric guitar amplifiers reveal a spatial complexity that many recording engineers anticipate, and add valuable further insight.

Equalization and compression—Friends or foes?

These two essential signal processors have overlapping capabilities. Tuning a sound system for any function requires complementary interaction between equalization and compression. The timbral impact of compression is indirect, and can be counterintuitive. A deeper understanding of compression parameters, particularly attack and release, clarifies the connection between compression and tone and makes coordination with equalization more productive.