Seminar: Mixing and timbral character

Online conversation with Gary Bromham (London), Bernt Isak Wærstad (Oslo), Øyvind Brandtsegg (San Diego), Trond Engum and Andreas Bergsland (Trondheim). Gyrid N. Kaldestad, Oslo, was also invited but unable to participate.

The meeting revolves around the issues “mixing and timbral character” as related to the crossadaptive project. As there are many aspects of the project that touches upon these issues, we have kept the agenda quite open as of yet, but asking each participant to bring one problem/question/issue.

Mixing, masking

In Oslo they worked with the analysis parameters spectral crest and flux, aiming to use these to create a spectral “ducking” effect, where the actions of one instrument could selectively affect separate frequency bands of the other instrument. Gary is also interested in these kinds of techniques for mixing, to work with masking (allowing and/or avoiding masking). One could think if it as a multiband sidechaining with dynamic bands, like a de-esser, but adaptive to whichever frequency band currently needs modification. These techniques are related both to previous work on adaptive mixing (for example at QMUL) and also partially solved by recent commecial plugins, like Izotope Neutron.
However interesting these techniques are, the main focus of our current project is more on the performative application of adaptive and crossadaptive effects. That said, it could be fruitful using these techniques, not to solve old problems, but to find new working methods in the studio as well. In the scope of the project, this kind of creative studio work can be aimed at familiarizing ourselves with the crossadaptive methods in a controlled and repeatable setting. Bernt also brought up the issue of recording the analysis signals, using them perhaps as source material for creative automation, editing the recorded automation as one might see fit. This could be an effective way of familiarization with the analyzer output as well, as it invites taking a closer look at the details of the output of the different analysis methods. Recording the automation data is straightforward in any DAW, since the analyzer output comes into the DAW as external MIDI or OSC data. The project does not need to develop any custom tools to allow recording and editing of these signals, but it might be a very useful path of exploration in terms of working methods. I’d say yes please, go for it.

Working with composed material, post production

Trond had recently done a crossadaptive session with classical musicians, playing composed material. It seems that this, even though done “live” has much in common with applying crossadaptive techniques in post production or in mixing. This is because the interactive element is much less apparent. The composition is a set piece, so any changes to the instrumental timbre will not change what is played, but rather can influence the nuances of interpretation. Thus, it is much more a one-way process instead of a dialectic between material and performance. Experts on interpretation of composed music will perhaps cringe at this description, saying there is indeed a dialogue between interpretation and composition. While this is true, the degree to which the performed events can be changed is lesser within a set composition. In recent sessions, Trond felt that the adaptive effects would exist in a paralell world, outside of the composition’s aesthetic, something unrelated added on top. The same can be said about using adaptive and crossadaptive techniques in a mixing stage of a production, where all tracks are previously recorded and thus in a sense can be regarded as a set (non-changeable) source. With regards to applying analysis and modulation to recorded material, one could also mention that the Oslo sessions used recordings of the (instruments in the session) to explore the analysis dimensions. This was done as an initial exploratory phase of the session. The aim was finding features that already exist in the performer’s output, rather than imposing new dimensions of expression that the performer will need to adapt to.

On repeatability and pushing the system

The analysis-modulator response to an acoustic input is not always explicitly controllable. This is due to the nature of some of the analysis methods, technical weaknesses that introduce “flicker” or noise in the analyzer output. Even though these deviations are not inherently random, they are complex and sometimes chaotic. In spite of these technical weaknesses, we notice that our performers often will thrive. Musicians will often “go with the flow” and create on the spot, the interplay being energized by small surprises and tensions, both in the material and in the interactions. This will sometimes allow the use of analysis dimensions/methods that have spurious noise/flicker, still resulting in a consistent and coherent musical output, due to the performer’s experience in responding to a rich environment of sometimes contradicting signals. This touches one of the core aspects of our project, intervention into the traditional modes of interplay and musical communication. It also touches upon the transparency of the technology, how much should the performer be aware of the details of the signal chain? Sometimes rationalization makes us play safe. A fruitful scenario would be aiming for analysis-modulator mappings that create tension, something that intentionally disturbs and refreshes. The current status of our research leaves us with a seemingly unlimited amount of combinations and mappings, a rich field of possibilities, yet to be charted. The options are still so many that any attempt at conclusions about how it works or how to use it seems futile. Exploration in many directions is needed. This is not aimless exploration, but rather searching without knowing what can be found.

Listening, observing

Andreas mentions is is hard to pinpoint single issues in this rich field. As observer it can be hard to decode what is happening in the live setting. During sessions, it is sometimes a complex task following the exact details of the analysis and modulation. Then, when listening to the recorded tracks again later, it is easier to appreciate the musicality of the output. Perhaps not all details of the signal chain are cleanly defined and stringent in all aspects, but the resulting human interaction creates a lively musical output. As with other kinds of music making, it is easy to get caught up in detail at time of creation. Trying to listen more in a holistic manner, taking in the combined result, is a skill not to be forgotten also in our explorations.

Adaptive vs cross-adaptive

One way of working towards a better understanding of the signal interactions involved in our analyzer-modulator system is to do adaptive modulation rather than cross-adaptive. This brings a much more immediate mode of control to the performer, exploring how the extracted features can be utilized to change his or her own sound. It seems several of us have been eager to explore these techniques, but putting it off since it did not align with the primary stated goals of crossadaptivity and interaction. Now, looking at the complexity of the full crossadaptive situation, it is fair to say that exploration of adaptive techniques can serve as a very valid manner of getting in touch with the musical potential of feature-based modulation of any signal. In it’s own right, it can also be a powerful method of sonic control for a single performer, as an alternative to a large array of physical controllers (pedals, faders, switches). As mentioned earlier in this session, working with composed material or set mixes can be a challenge to the crossadaptive methods. Exploring adaptive techniques might be more fruitful in those settings. Working with adaptive effects also brings the attention to other possibilities of control for a single musician over his or her own sound. Some of the recent explorations of convolution with Jordan Morton shows the use of voice controlled crossadaptivity as applied to a musician’s own sound. In this case, the dual instrument of voice and bass operated by a single performer allows similar interactions between instruments, but bypassing the interaction between different people, thus simplifying the equation somewhat. This also brings our attention to using voice as a modulator for effects for instrumentalists not using voice as part of their primary musical output. Although this has been explored by several others (e.g. Jordi Janner, Stefano Fasciani, and also the recent Madrona Labs “Virta” synth) it is a valid and interesting aspect, integral to our project.

 

Convolution experiments with Jordan Morton

Jordan Morton is a bassist and singer, she regularly performs using both instruments combined. This provides an opportunity to explore how the liveconvolver can work when both the IR and the live input are generated by the same musician. We did a session at UCSD on February 22nd. Here are some reflections and audio excerpts from that session.

General reflections

As compared with playing with live processing, Jordan felt it was more “up to her” to make sensible use of the convolution instrument. With live processing being controlled by another musician, there is also a creative input from another source. In general, electronic additions to the instrument can sometimes add unexpected but desirable aspects to the performance. With live convolution where she is providing both signals, there is a triple (or quadruple) challenge: She needs to decide what to play on the bass, what to sing, explore how those two signals work together when convolved, and finally make it all work as a combined musical statement. It appears this is all manageable, but she’s not getting much help from the outside. In some ways, working with convolution could be compared to looping and overdubs, except the convolution is not static. One can overlay phrases and segments by recording them as IR’s, while shaping their spectral and temporal contour with the triggering sound (the one being convolved with the IR).
Jordan felt it easier to play bass through the vocal IR than the other way around. She tend to lead with the bass when playing acoustic on bass + vocals. The vocals are more an additional timbre added to complete harmonies etc with the bass providing the ground. Maybe the instrument playing through the IR has the opportunity of more actively shaping the musical outcome, while the IR record source is more a “provider” of an environment for the other to actively explore?
In some ways it can seem easier to manage the roles roles (of IR provider and convolution source) as one person than splitting the incentive among two performers. The roles becomes more separated when they are split between different performers than when one person has both roles and then switches between them. When having both roles, it can be easier to explore the nuances of each role. Possible to test out musical incentives by doing this here and then this there, instead of relying on the other person to immediately understand (for example to *keep* the IR, or to *replace* it *now*).

Technical issues

We explored transient triggered IR recording, but had a significant acoustic bleed from bass into the vocal microphone, which made clean transient trigging a bit difficult. A reliable transient triggered recording would be very convenient, as it would allow the performer to “just play”. We tried using manual triggering, controlled by Oeyvind. This works reliably but involves some guesswork as to what is intended to be recorded. As mentioned earlier (e.g. in the first Olso session), we could wish for a foot pedal trigger or other controller directly operated by the performer. Hey it’s easy to do, let’s just add one for next time.
We also explored continuous IR updates based on a metronome trigger. This allows periodic IR updates, in a seemingly streaming fashion. Jordan asked for an indication of the metronomic tempo for the updates, which is perfectly reasonable and would be a good idea to do (although had not been implemented yet). One distinct difference noted when using periodic IR updates is that the IR is always replaced. Thus, it is not possible to “linger” on an IR and explore the character of some interesting part of it. One could simulate such exploration by continuously re-recording similar sounds, but it might be more fruitful to have the ability to “hold” the IR, preventing updates while exploring one particular IR. This hold trigger could reasonably also be placed on a footswitch or other accessible control for the performer.

Audio excerpts

 jordan1

Take 1: Vocal IR, recording triggered by transient detection.

 

 jordan2

Take 2: Vocal IR, manually triggered recording 

 

 jordan3

Take 3: Vocal IR, periodic automatic trigger of IR recording.

 

 jordan4

Take 4: Vocal IR, periodic automatic trigger of IR recording (same setup as for take 3)

 

 jordan5

Take 5: Bass IR, transient triggered recording. Transient triggering worked much cleaner on the bass since there was less signal bleed from voice to bass than vice versa.