Category: Sessions

Concert : Tape to zero festival, April 21 2016, Victoria Jazz, Nasjonal jazzscene Oslo

Participants: Maja S.K. Ratkje, Siv Øyunn Kjenbstad, Øyvind Brandtsegg

The objective, in the context of this research project, was live use of the “cross_shimmer” effect, testing musical applications and a recently developed feedback reduction mechanism.

Takes:
* Full concert, the cross adaptive effect is used in the first few minutes.

Recording available at: https://www.youtube.com/watch?v=NInAifyF1B8&feature=youtu.be&t=10767

Comments:

* The effect is still not feedback safe, so the contact mic percussion pad was used as an exciter instead of taking the signal from the drumset as intended.

* The spectral input is taken from Maja’s vocal

* The musical effect works as highlighting and prolongation of features/pitches from the vocal input.

*Subjective evaluation: This works quite well

* We would like to optimize the effect so that the analysis stage spends less CPU. It is  currently more CPU heavy than Hadron (1.5x)

* We would like to have a more reliable feedback prevention system, enabling the use of the effect with an open mike exciter.

Experimental session in the context of ensemble teaching at the jazz dept at NTNU, April 2016.

The objective was to test some simple interaction modes, starting with cross adaptive amplitude control. How will the musicians react to this kind of interaction? Even simple amplitude control over the other instrument is a quite drastic intervention. In addition we tested a cross adaptive resonator effect, where the resonators were tuned by one instrument and excited by the other.

Participants: Vilde Aakre Lie, Cecilie Grundt, Magnus Skaug, Christian Alexander Cuadra, Tore Hodneland, Ingrid Øygard Steinkopf, Julian Bjorå, Frederik Villmow, Vebjørn Mamen, Harald Relling Nielsen, Wilhelm Westerman, Aasmund Mathias Smidt, Øyvind Brandtsegg, Trond Engum, Andreas Bergsland, Gary Bromham

Takes, day 1:

Take 1: Cross_shimmer. Vocals/Sax(exciter)

Take 2: Cross_shimmer. Guitar/Drums(exciter)

Take 3: Cross_shimmer. Vocal/Vocal(exciter)

Take 4: Amplitude gating: Each instrument only has sound if the other one also plays simultaneously.
Vocals/Vocals

Take 5: Amplitude gating, as for track 4. There seems to be some amount of direct sound (not amplitude gated). Possibly as a result of leakage, routing, or mix decision (undocumented)
Guitar/Sax.

Take 6: Quartet: 2 Vocal, 2 Drums. We use amplitude gating, but the result is not very clear. Complex interaction between 4 performers, and also signal leak between performers.

Takes, day 2:

Take 1: Sax/Git: cross-adaptive amplitude gating

Take 2: Sax/Git: one more attempt with same setting.

Take 3: Pno/Dr. Amplitude gating, also controlling reverb send to try to enhance the audibility of the signal interaction.

Take 4: Bass/Git. Amplitude gating.

Take 5 : Cross_shimmer. Git/Pno( exciter). Interesting due to the way the piano triggers resonances, and also the filters of the shimmer effect creating an “old time rotten piano” kind of color which is kind of nice.

Take 6: Cross_shimmer. Pno(?)/Git(exciter). Interesting due to the way the guitar triggers piano resonances, and attins an almost voice-like quality. Sometimes the resonator and the exciter will have clearly overlapping spectral content, leading to slight imbalance in the output. Perhaps the (later implemented) feedback control mechanisms can also be applied to the exciter input, checking for spectral overlap and adjusting pre-eq accordingly.

Take 7: Cross_shimmer. Bass/Dr (exciter)

Take 8: Cross_shimmer. Sax/Dr (exciter)

Take 9: As above, but using lower Q and more source. The sound of the sax is undocumented, but I assume there is also a cross_shimmer effect on the sax (drums as resonator input, sax as exciter). So, two-way cross_shimmer. I (ØB) know I had this in the routing setup for the session, so it is highly likely that this is the effect.

Reflections/Comments:

Many of the comments are summed up from 2 days of working. More specific comments (done in retrospect) at the end of the document.

* Musicians: Unfamiliar situation. Want to work more to get into this method

* Direct acoustic sound is a problem. Less effect from processing

+ Possible to accentuate the other musicians playing/expression

* Can make one common instrument , making “sound-blobs” together (amplitude control so that the other musician has sound only when the first is playing, and v.v.)

* When there is a high degree of sound leak between instruments (e.g. between Piano and Drums), the cross-adaptive amplitude gating works more to the effect of opening the room than actually full mute of each other’s sound. This also relates to the amount of direct acoustic sound of course, so that it is impossible to fully mute the sound (for the performer playing the instrument).

+ These techniques may be used to build a musical form, enhancing structural elements.

+ Works well on speech/conversations, like accidentally captured fragments of conversations between the two performers.

* Musicians are seeking for roles in this context. The situation is very flexible (and undefined as of yet), so many roles are possible. Perhaps the quest for new kinds of musical roles is one core element in these investigations(?).

Cross adaptive shimmer effect:

+ Timbral shaping . “Very unique and strange sounds”. Fragile and crisp.

+ Common (collective/unifying) form concept. Follow each other. Collaboration

– Danger of peaking signal, especially on overlap(?)

– The shimmer effect sounds the same always. Make a variation with a huge number oof bands and low Q  (more like modal reverb)

– Two-way cross_shimmer was very undefined/unclear.  Perhaps the signal routing was not correct?

* Try to use these kind of techniques also for spectral inversion. E.g. instead of amplifying/resonating on the frequencies/partials from instrument 1, do try to make an inverse spectral shaper so that instrument 2 will only have energy in the frequency bands where instrument 1 does not.

Reflections when listening (a month later)

* The cross_shimmer effect allows for a softer kind of interaction, since the interaction is very easy to understand. Less surprises and uncertainties than with artificially/contrived mappings to any effects parameter.

* Cross_shimmer always sound “bell-like”. Try to use significantly less Q to enable a gentler kind of sonic imprint on the exciter sound.

* Cross_shimmer fix: Sometimes the resonator and the exciter will have clearly overlapping spectral content, leading to slight imbalance in the output. Perhaps the (later implemented) feedback control mechanisms can also be applied to the exciter input, checking for spectral overlap and adjusting pre-eq accordingly.

* Amplitude gating is very effective as a means of demonstrating this kind of interaction. But it can quite unnatural due to unmotivated volume changes on the affected instrument. Still, a good way to train interaction, easy for musicians to understand. A drawback is that the musician often will hear the acoustic sound of the instrument directly, so the gating is less prominent for the player than for the audience.

* Amplitude gating seems also to invite the performers *not to play* when the other player does not. Quite a natural mechanism. But it is indeed interesting when we can hear the sound being triggered by the other player, so we should perhaps invite them both to also play separately asa well as together.