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Miles Davis: So What

Audio Theory 2: Listening blog 2

Popularly known as one the greatest jazz records, Miles Davis’s ‘Kind of Blue’ features a spacious mix which captures both the intimacy of the music and maintains a timeless character. The record was produced by Irving Townsend at Columbia 30th Street Studios in New York and released in 1959. Though recorded with only three channels, the sound is cohesive, natural, and clear, no doubt adding to its popularity.

Davis’s first track ‘So What’ features six instruments with the alto sax and drums on the right, tenor sax and piano on the left, and double bass and trumpet squarely in the centre. The use of multitrack mono and no stereo microphone techniques produces the defined placement of instruments in the mix (Marks 2006, para. 12), which compliments its sparse musical arrangement and highlights each individual instrument. That being said, there is an amount of bleed on each side due to the close proximity in which the instruments were recorded. On the album and gear review blog Vinyl Haven, the writer notes that when recording musicians in close proximity, the microphones are placed closer to the instruments and their sensitivity is reduced to prevent bleed, however increases the chance of mic overload (Veyenyl, 2016 para. 3). This resulted in a “sizzle-like distortion issue” (Veyenyl, 2016 para. 4) in ‘So What’ on the saxophone, however unlike the blog writer, I don’t personally find this to be a problem. The bleed from all the microphones also helps glue the panned instruments together so there is a sense of clarity and intimacy without total separation.

Davis conversing with pianist Bill Evans outside the recording area which is set up with baffles to reduce reflections (Veyenyl 2016)

Additionally, the soft and delicate nature of this performance allows Townsend to take advantage of the natural bleed and room sound. This produces a timeless quality as the sound is less tied to technological features of the era. The only extra reverb added to the mix was produced by playing the recording through a speaker in Columbia’s basement concrete echo chamber and capturing it with an omnidirectional microphone. John Marks writes in his blog that only the centre track was sent to the echo chamber, however the existing leakage “helps account for the recording's naturally ambient sound” (Marks 2006, para. 13).

The Neumann M49 with remote potentiometer for variable polar patterns (Tape Op 2021).

Seven Neumann M49 microphones were used to record ‘So What’: two on the drum kit for overhead and snare, and one for each of the other instruments. The M49 is a large diaphragm condenser microphone with a dual diaphragm design which allows it to be switched between cardioid, omnidirectional, and figure-8 patterns. Two capsules are placed back-to-back inside the microphone with one having a fixed bias of 60Vdc and the other having a variable range of 0Vdc to 120Vdc. Unlike other dual-diaphragm microphones where the second capsule is disconnected in cardioid mode, both capsules in the M49 are always polarised. When in cardioid mode, the polarisation voltage of the second capsule is 0Vdc (Recording Hacks, 2019 para.3). The variable voltage is adjusted by a potentiometer located on the power supply, allowing the engineer to adjust the polar pattern from the control room. According to London Jazz Collector (2016, para 19), “the resulting sound features a consistent smoothness that is highlighted by excellent lows and highs that can cut perfectly across recordings.”

Through application of minimal techniques that utilise the acoustics of natural spaces, Townsend’s recording of Kind of Blue is a beautifully produced album that sounds clear and spacious yet intimate, much like listening to a live performance.


London Jazz Collector 2016, ‘Microphones and Missiles: The Legendary Neumann U47 Microphone’, London Jazz Collector, web log post, September 23, viewed 16 July 2021,

Marks, J 2006, ‘The Fifth Element #34’, Stereophile, viewed 16 July 2021,

Recording Hacks 2019, Neumann M49, viewed 16 July 2021,

Tape Op 2014, ‘Restoring a vintage Neumann M49 Microphone: Vintage King Restoration Series, Part 2’, Tape Op, viewed 16 July 2021,

Veyenyl, 2016, ‘Miles Davis’ Kind of Blue: The Good, The Bad, and The Awesome’, Vinyl Haven, web log post, December 17, viewed 16 July,


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