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What is a Decca Tree? – A Truly Unique Recording Method!

Do you love listening to choirs and orchestral music? The recorded performances often sound amazing don’t they? The production quality of these recordings can make you feel as if you are present in the concert hall itself, enjoying the show. Curious to know how this effect is created? Then you need to find out what is a Decca Tree!

Recording big concert bands, choirs, and orchestras, can be quite the challenge for many sound engineers, even for the more experienced ones. Hence, I think it is important for budding audio practitioners to at least have a basic understanding of one of the most important recording techniques that is used in such situations!

Decca Tree – A Unique Technique

The Decca Tree is a spaced microphone array often used for orchestral recordings. Its design is similar to a stereo A–B recording method, but with a “center fill”. The first commercial use of the decca tree was in 1954 by Arthur Haddy and Roy Wallace. Improvements were then made by engineer Kenneth Wilkinson, and his team at Decca Records, in order to provide a stronger stereo image.

Decca Array

The Decca Tree arrangement (without the centre microphone) / Photo by Polselekah / CC BY-SA 3.0

Here are the topics that we’ll be discussing:

  • Setup requirements
  • Microphones used
  • Common applications

Setup Requirements

The Decca Tree requires three omnidirectional microphones to be arranged in a “T” pattern, and two more “outrigger” mics placed further to the left and right. The stem of the “T” faces the orchestra, with the centre mic placed 2.5 feet out and the ones on the crossbar are placed about 5 feet apart. Former Decca engineer John Pellowe had this to say about the specifics of the setup:

Decca Tree Dimensions

The dimensions may vary depending on the situation / Photo by Polselekah / CC BY-SA 3.0

“…it was a very controversial method of recording, because when you have that many spaced omnidirectional microphones you lose a lot of the directional cues, which is absolutely right, the way that we would deal with that was we would pan the left and right tree half left and half right, and the outrigger mics we would pan hard left and right and we would paint an artificial stereo image…”

According to John’s description, the Decca Tree is usually about 3.2 metres high, with the centre microphone positioned roughly in line with the edge of the orchestra, pointing towards the centre of the strings section in front of the conductor. The two rear left and right mics (on the tree) would then be pointing towards the first violins and cellos (if that’s how the orchestra is arranged).

Decca Mic Positions

Not exactly Decca Tree, but has roughly similar microphone positions / Photo by Salfordsymphony / CC BY-SA 3.0

The two “outrigger” microphones would also be omnidirectional, and placed about twenty feet apart from each other, at the same height of 3.2 metres. They are often positioned about 5 feet away from the edge of the orchestra, looking down at the strings. Do also take note that the Decca Tree is fitted on a tall boom and suspended in the air, roughly above the conductor.

Microphones Used

The microphones used in a Decca Tree have an omnidirectional polar pattern. The Neumann M-50 small-diaphragm tube condenser model, is a popular choice. In reality, the Neumann M-50s are not truly omnidirectional at the higher frequences, but exhibit some high frequency lift and directionality which will improve the stereo imaging quality of the Decca Tree technique.

Neumann Condenser

The Neumann KM-56 / Photo by Andrew Pilling / CC BY-ND 2.0

Various other microphone methods such as X-Y, Mid/Side (M/S), or Blumlein positioning, have been used to replace the centre microphone. Other models such as the Neumann M49, Km 53, and KM 56 were also evaluated and utilised by the Decca team for early sessions. Later on, the Schoeps mk2S were used for live productions instead of the M-50, as it was more convenient.

Common Applications

It is well known that the Decca Tree is a stereo miking technique often used for large orchestras or choirs, but it can also be used to capture the “room sound” during recordings. For instance, when recording drums, its wide stereo image captures the nuances of the recording room better than most other techniques. However, in smaller rooms, the Decca Tree will not be as effective.

The Decca Tree can also be used for surround sound recordings. Ron Streicher, author of “The Decca Tree — It’s not just for stereo any more”, used a SoundField MK-V (four-element transducer) for the center, a pair of Schoeps MK21 sub-cardioid condensers for the left and right, and a pair of Schoeps MK41 hypercardioid condensers for the left and right surrounds.

That’s all I have to share with you folks today. Have you seen the Decca Tree being used in a live performance before? Or maybe you’ve seen a different technique?

Let me know your thoughts down below and share this article with your friends!

Farhan

When I'm not rocking out to great music, I'd prefer to be sleeping on a field on a windy day =)

6 Comments

  1. Wow that looks like a very cool microphone, I see that you mentioned it is used for orchestral recording, while it may not be as functional for outdoor recording, but would this work if I want to capture like nature noises and other things of that sort outside? Also does the recording tree gets sold alone or it all comes in a package?

    • Hi Bassam!

      The recording tree is something that you can put together on your own, using various parts from different mic stands. However, this is something that may require some “DIY” skills and creativity on your part. Or you could also just buy a complete set from various manufacturers. But they can easily cost you around $600 – $1000.

      As for the microphones, you’ll have to get them separately. Do keep in mind that you don’t necessarily need the most expensive of condenser microphones. You can just buy something that fits your budget for starters, and see how it works out for you.

      The Decca Tree isn’t normally used for outdoor recordings, but at the same time, there aren’t any hard rules as to how you can use this recording method (or any recording technique for that matter). So feel free to experiment and try different things!

      Thanks for your thoughts!

  2. Hi Farhan,

    I have never heard of a Decca tree. I am always game for a diy project and I think this may be useful to me in the future. My brother and I are sort of putting together a musical piece by piece from the ground up. My brother is more of the music expert though. Do you think a decca tree would be useful for recording some of the songs? We would have a small orchestra and a few singers.

    • Hi Alison!

      The Decca Tree would be great for your project. However, do keep in mind that the Decca Tree is designed to capture the “overall” sound of the orchestra, that is mixed with the “room sound”. Hence, you should also include several other microphones (apart from the ones on the Decca Tree) in order to “close-mic” certain instruments in your orchestra that may have solo parts. If you just rely on the Decca Tree alone, you will not be able to emphasize certain musical phrases from various instruments in the recording.

      Let me know how it goes if you do decide to give this recording method a shot. Thanks a lot for your comments!

  3. I’m more familiar with the basic mics in front of the musician style, but I can see how a Decca style arrangement can help an orchestra band. Before this site, I actually didn’t know about the Decca tree and now I will be looking for it when I go to my next concert.

    • Hey Nate!

      Glad to know you have learnt something new here. Do come back for more educational content!

      Thanks!

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