Decca tree

Decca tree
Name	Decca tree
Type	microphone array
Invented	1950s
Inventor	Decca Records
Primary use	orchestral recording, film scoring
Notable users	Ernest Ansermet, John Culshaw, Geoffrey Tozer

Decca tree is a three-microphone stereo recording technique developed for large ensemble capture and film soundtrack production. It emerged in the 1950s for use by Decca Records engineers and has since been adopted by orchestras, studios, and soundtrack mixers worldwide. The configuration emphasizes spatial imaging, depth, and a coherent center, and has influenced microphone practice in Abbey Road Studios, Capitol Studios, and broadcast venues.

History

The technique was developed in the postwar period by engineers at Decca Records working alongside producers at EMI rivals to improve orchestral recording for labels such as RCA Victor and Deutsche Grammophon. Its early proponents included producers and engineers involved with sessions at Kingsway Hall, Wigmore Hall, and Royal Albert Hall, where engineers experimented with configurations used earlier by Leslie Bricusse-era studios and film score pioneers at MGM Studios. The method was promoted in the 1950s and 1960s by figures associated with Philips Records, Columbia Records (US), and broadcast organizations like the BBC and RAI who sought an alternative to spaced pair and coincident arrays used at Carnegie Hall and Vienna State Opera. Over decades, it informed practices at landmark facilities such as Metropolitan Opera House sessions and influenced engineers working with conductors like Herbert von Karajan, Leonard Bernstein, and Igor Stravinsky.

Design and technical description

The array uses three matched microphones arranged in a triangular layout mounted on a central bar to form a stable stereo image for large ensembles recorded in concert halls like Royal Festival Hall or studios such as AIR Studios. The design balances directional pickup patterns, microphone polar responses, and spacing to capture the soundstage from front-center to left and right sections of an orchestra seated in venues like Teatro alla Scala and Philharmonie de Paris. Technical parameters reference microphone characteristics found in models used at Capitol Studios and by manufacturers such as Neumann, Sennheiser, and AKG. The frequency response, transient behavior, and self-noise figures are critical when matching capsules for use in environments including Berlin Philharmonie and Sydney Opera House. Electrical considerations—preamplifier gain staging and phase coherence—are addressed with consoles from companies like Neve, SSL, and API used in studios like Trident Studios.

Microphone placement and variations

Standard placement mounts the three microphones on a boom above the conductor’s head, with left and right units spaced roughly 1–2 meters apart and the center microphone delayed or vertically displaced to control imaging in spaces such as La Scala or Royal Albert Hall. Variants developed for film scoring rooms at 20th Century Fox Studios and location recording at BBC Maida Vale Studios include using omnidirectional, cardioid, or wide cardioid microphones from manufacturers like RCA, Telefunken, and Sony to adapt to reverberation times in halls like Cadogan Hall and Concertgebouw. Techniques such as the "Expanded Tree" and "Stereo-Plus" add outriggers or spot microphones used by engineers at Abbey Road Studios or on location during festivals like Glastonbury Festival, integrating with room mics and close mics for flexibility during mixing at facilities including Metropolis Studios.

Applications and usage in recording

The array is widely used for symphonic recording sessions for labels such as Deutsche Grammophon and film soundtrack sessions for studios like Warner Bros. and Universal Pictures. Orchestras including London Symphony Orchestra, Berlin Philharmonic, and New York Philharmonic have been recorded using the approach to preserve ensemble balance and ambient cues for releases on labels like Sony Classical and Philips Classics. The method also appears in live broadcast workflows for organizations such as BBC Proms, sports arenas like Wembley Stadium for fanfare capture, and in contemporary classical projects engineered at studios like Air Lyndhurst Hall.

Advantages and limitations

Advantages include a robust center image, consistent ensemble balance across releases for labels like RCA Red Seal, and adaptability across venues from Concertgebouw to studio spaces such as Olympic Studios. Limitations arise from the need for careful mic matching, possible phase issues when combining with spot mics in mixes for producers at Chappell & Co., and variable performance in very dry or very reverberant venues such as St Martin-in-the-Fields or Notre-Dame de Paris. The approach requires experienced engineers familiar with consoles from Neve or SSL and microphones from Neumann or Sennheiser to manage tonal coloration and depth in releases marketed by distributors such as Decca Records and EMI Classics.

Notable recordings and practitioners

Notable practitioners who advanced the method include engineers and producers associated with Decca Records, staff at Abbey Road Studios, and freelance engineers who recorded orchestras like London Philharmonic Orchestra and Chicago Symphony Orchestra. Significant recordings employing the technique can be found in the catalogs of Decca Records, EMI Classics, and soundtracks from 20th Century Fox, Warner Bros., and Disney productions scored by composers recorded with orchestras such as the Royal Philharmonic Orchestra. Prominent conductors and producers who have overseen sessions using the array include Herbert von Karajan, Leonard Bernstein, and contemporary soundtrack mixers associated with Hans Zimmer and John Williams.

Category:Audio recording techniques