The Quarter Tone Concert Flute

invented by Eva Kingma with the collaboration of Bickford Brannen

By Stefan Keller

– What is so special about the quarter-tone flute?

– Do I have to relearn everything to play this instrument?

– What are the advantages of this instrument?

The quarter tone flute, invented by Eva Kingma, developed and built in collaboration with Bickford Brannen & Brannen Brothers, is THE invention in the field of “extended fingering & sound possibilities” of a concert flute with open keys.

Suitable for all flute players

First of all: Anyone can play a quarter-tone flute right away, because you don’t feel anything of the extraordinary additional possibilities when playing “normally”. 

I find this to be the most convincing point when it comes to this instrument, which immediately raises many questions when mentioned in the flutist’s circle: I don’t want to retrain, or, isn’t it very complicated, or, what’s the point? To reassure anyone who is interested: the quarter-tone concert flute, built by Brannen Brothers, is a great “classical instrument”, with either silver or gold tubing. On it, as usual and without any special previous knowledge, I can immediately play the entire flute literature, from baroque, classical & romantic to completely modern literature, without any problems. A supple instrument with all the tonal and mechanical advantages that apply in principle to all Brannen Cooper flutes.

In addition, there are the countless new fingering possibilities offered by the Kingma system. An extension with undreamt-of advantages that are a great gift for the modern musician.

C sharp trill “for free”

For technical reasons, the quarter-tone flute is always equipped with G-offset and has a c-sharp trill “built in” as standard. This c-sharp trill alone justifies the extra charge for a quarter-tone flute, as it makes a number of passages in the baroque and classical-romantic flute repertoire much easier. Starting with the c-c sharp and b-c sharp trills in the first and second octave, elegantly solved with this additional key, then continuing with the g-a trill in the third octave, as well as in many ornaments in baroque music, this key alone is very useful.

So if you buy a quarter-tone flute, you can continue to play normally at first and explore the new possibilities at your leisure and slowly incorporate them into your playing. The already explained c-sharp trill becomes familiar quite quickly and one likes to use it everywhere where it is a great help.

On the website of Brannen Brothers you can find a very helpful compilation of the possibilities of the cis-trill:

The Kingma System – “Key on Key”

“Key on Key” c – sharp – Thump – g – sharp

The additional “Key on Keys”, the special feature of this flute, invented by Eva Kingma, brought to serial production by Bickford Brannen and built by Brannen Brothers in Boston, allow the player to open all keys of the flute, which were always closed until now, half as well as all other ring keys. Thanks to these additional five “ring keys” with “Key on Key System” (Kingma Keys), there are innumerable possibilities to influence the sound, to correct the intonation and the extraordinary possibility to play a continuous quarter tone scale in very good sound quality. Only at the tone d1 an additional tone hole is needed to raise the d1 & d2 by a quarter tone. Multiphonics can now be shifted effortlessly chromatically. A huge advantage for contemporary classical music, for sound effects or for cool jazz licks!

extra hole for “d1 & d2 – up”
extra hole for “d1 & d2 – up”

The various new possibilities as well as the quarter tone fingering chart can be easily found on the Brannen Brothers website with the following link:


The Quartertone Flute – Scale
The Quartertone Flute – Partials

Alto, Bass & Double Bass Flute with Kingma System

Eva Kingma is happy to install this system on her own alto, bass and double bass flutes, either in a reduced version or in the full version. I was allowed to play the alto transverse flute with this fantastic system several times, a wonderful experience.

Link to the Eva Kingma website ->

Quarter tone flute combined with Glissando Headjoint by Robert Dick

To take the whole thing to the extreme in terms of tonal possibilities, I recommend mounting a glissando flute headjoint by Robert Dick on the Brannen-Cooper quarter-tone flute with “Kingma System”, and the absolutely most versatile flute is in your hands: Quarter tone transverse flute with continuous quarter tone scale, c sharp – trill key, multiphonics are chromatically shiftable as well as glissando of up to a major third are possible, a dream of a super flexible good sounding modern transverse flute!

Now it is up to the player to use all these fantastic possibilities musically!

Lets start!


This article is neither sponsored by Brannen Brothers nor by Eva Kingma …

I have been playing a Brannen Brothers Kingma – System flute with enthusiasm for over 25 years!

Stefan Keller | | |

Stefan Keller is an active flutist who plays a wide range of musical styles and instruments. This is reflected in his diverse projects and invitations to international flute festivals as a specialist for low flutes, improvisation and loops. His own compositions and practice books for flute complete his activities. He organizes since over 20 years the flute event  FLAUTANDO in Boswil, Switzerland. 

The classically trained flutist explores sound worlds with his flutes, known as FLUTE TRENDS by Stefan Keller.

As a musician and composer, as well as sound designer and „sound – image – designer“ of baroque – classical – avant – garde – jazz and improvised music, Keller has found his own language. He has been honored several times by the Aargauer Kuratorium for his innovative artistic work and attended further education at the „Cité Internationale des Arts“ in Paris and at the Aargauer Atelier in Berlin. His unique musical projects such as „under water“, „Sound – Castle – Hallwyl“, „Concert in the factory hall“, „carpentry“ as well as the collaboration with visual artists have made him known in Europe and Japan.

Keller plays Alto and Bass flute, Contrabass flute as well as Subcontrabass flute, Gemshoerner, Kalimba and various Bamboo flutes, acoustic and with electronics.

As a musician and composer, Keller moves in the area of ​​baroque – classical – avant-garde – jazz and improvised music.

As an looper, he has been working with the latest live sampling techniques for 25 years. He uses a specially developed surround – loop software, which offers unbelievable sound possibilities.