Since the late 1970s, Graham Thirkell was the pre-eminent designer and builder of studios for recording and in radio and TV in Australia. His experience in the acoustical field was initially built on his agency for Tom Hidley, who had a global studio construction business, with over 180 studio projects world-wide at the time of this presentation. However, Graham quickly took a more scientific approach to studio design and construction and created a broader range of more specifically designed and customised studio and control room projects. By 1981, Graham had built thirty rooms, including fifteen or sixteen studios, with the remainder being for TV audio post production and radio stations. At the time of this recording, Graham’s experience was second only to Hidey, but with a much more diverse range of studio and control room design projects.
In an invited “Master Class” lecture on 8 September, 1981, Graham described the fundamentals of recording studio and control room design and construction. Using the examples of Paradise Studio in Sydney and AAV Studio 2 in Melbourne, he describes the need for isolated slabs and isolated walls built as “room within a room” construction and some of the problems encountered with this kind of construction. He also describes the kind of isolation required and achieved between these spaces; the role of controlling reverberation time; and the effect of room modes on recorded sound quality.
Moving from foundation construction of a facility and the characteristics of studios, he describes in some detail the design principles for control rooms: non parallel surfaces; strategic control of reverberation, and room modes; diffusion of sound within the space; provision of air conditioning and sight lines; and the design of traps to capture the energy from direct and reflected sound over the frequency range.
While most of the studios Graham describes are characterised by diffused uniform controlled reverberation, he also describes his modified design with a totally absorbing, time aligned, back wall, and he compares that approach with the Live End Dead End approach common at the time in the United States.
In response to audience questions, Graham describes: the construction of traps; double glazing to reduce noise in domestic homes; the audibility of standing waves and distortion; digital recording quality vs. analogue and the relationship between the reverberation time and monitoring for the dynamic range of digital and large format analogue equipment.
While Graham’s presentation was a snapshot of the understanding at the time, most of the principles that Graham describes are still at the foundation of modern acoustical thinking in studio and control room design.
A recording of this presentation was made with Graham’s permission on condition that it be used for the information and education of interested parties. It was made by the presentation host, Rodney Staples. Publication of this presentation acknowledges the contribution Graham made to the acoustical design of studios and control rooms in Australia and is of historical value in describing the “state of the art” in 1981.
This recording was made as an “aide memoire” for the students, and as a foundation for designing the course curriculum. It was made on cassette, and recorded in stereo. The room in which the recording was made was a large space designed as a TV studio. At the time of recording the room had very good control of low frequency resonances, but the high frequencies were largely uncontrolled in the space, which at times made the speaker hard to hear. After Graham’s presentation, and using techniques he described in this presentation, we were later able to modify the acoustics to better suit the room’s dual role as a recording studio as well as its TV functions. The presentation was to an audience of students who engaged in lively discussion as the presentation progressed.
The recording of this lecture comes in four parts, with a small continuity break between each.
Part 1 (42:40 minutes)
In Part 1 Graham describes Paradise studio in Sydney, which was a Hidley design built by Graham’s team. He continues by describing and the key principles of building rooms within rooms on isolated slabs. Graham begins a description of the effect of traps, which he continues in Part 2.
Listen to Part 1:
This audio file can be downloaded for offline listening at:
https://aesmelb2.s3.ap-southeast-2.amazonaws.com/Graham+Thirkell+Part+1+Studio+Acoustics.wav
Part 2 (39.44 minutes)
Graham continues In Part 2 to describe the use of “traps” to control “room modes” or resonances in spaces, and surface treatments to control reverberation times and diffusion in those spaces. He also describes the construction of AAV Studio 2, control room design and how this differs from the design of studio spaces, and the problems associated with monitor speakers. He describes the need to time-align drivers in monitors, and control reflections at the monitoring position. He discusses the question of distortion in compression drivers and how that problem was being overcome at the time.
Listen to Part 2:
This audio file can be downloaded for offline listening at:
https://aesmelb2.s3.ap-southeast-2.amazonaws.com/Graham+Thirkell+Part+2+Studio+Acoustics.wav
Part 3 (36:00)
Part 3 continues with a comparison between the Hidley design and Graham’s evolved time-aligned design. He describes the construction of “compression absorbers” designed to “remove” the back wall acoustically. This discussion leads to a comparison between the “time-aligned” approach versus the “Live End, Dead End” approach common at the time. He describes the use of Helmholtz resonators as alternative to traps in the confined acoustical spaces at 3XY’s new studios. In response to student questions, Graham discusses the need for low and consistent reverberation times in control rooms, the need for non-parallel glass and other surfaces, and the listening environment in domestic situations. Graham begins to describe the special acuity of experienced operators, continued in Part 4.
Listen to Part 3:
This audio file can be downloaded for offline listening at:
https://aesmelb2.s3.ap-southeast-2.amazonaws.com/Graham+Thirkell+Part+3+Studio+Acoustics.wav
Part 4 (34:29)
Discussion of the acuity of experienced operators continues in Part 4. This leads to discussion of the audibility of distortion, phase audibility, and studio isolation vs digital dynamic range. Discussion evolves to building on greenfield sites, recent changes to RT and monitoring quality expectations, Stephen Temmer mastering on copper with 1/2 inch two track tape mastering, and digital vs analogue recording, mobile facilities, the effect of spill into microphones, audibility of narrow frequency aberrations, and the audibility of standing waves.
Listen to Part 4:
This audio file can be downloaded for offline listening at:
https://aesmelb2.s3.ap-southeast-2.amazonaws.com/Graham+Thirkell+Part+4+Studio+Acoustics.wav
Copyright
Graham’s estate retains copyright in the material presented in this master class. The recording of this presentation was made with Graham’s permission on condition that it be used in education contexts to inform potential practitioners in the field of studio design. Copyright in the sound recording stays with the recording’s author, Rodney Staples © 1981. Copyright in the digital edition is with the author, Rodney Staples © 2025. The Audio Engineering Society Melbourne Section is granted limited license with the permission of Graham’s estate to include this recording on its web site for the education of members and interested parties.
Dr. Rodney Staples, MIEAust. C. P. Eng. (Ret.), Life Member SMPTE, Life Member AES.
Editor’s Note:
Due to limitations of the venue at the time, the quality of the recording is impaired. However, we feel that the historical nature of the recording and the ongoing relevance of much of the material presented by a master in the science of acoustics make it important to publish it for those interested in the field of acoustics, or in the career of Graham generally.
Peter Smerdon
12th November 2025