To build new and rethink existing interfaces for producing and working creatively with electronic music, we are engaged in an ongoing conversation with professional musicians. With regard to getting suggestions on musical material and progression by the machine on, e.g., samples, loops, rhythmic patterns, or musical structure, we nd evidence that the notion of an algorithmic recommendation system should be extended through the use of artistic obstruction. We propose the concept of \strangeness" as an addition to recommendation systems to allow the adjustment of the degree of desired otherness in the suggestions made. This marks an important di erence to existing consumer-centred recommendation approaches, going even beyond the notion of serendipity.
The majority of today's electronic music is created from pre-recorded or
livegenerated sound material. This process often combines sound loops and samples
with synthesized and processed elements. For supporting the creator in the
process of nding suited sound material to express musical ideas, content-based
audio recommendation and retrieval techniques can be applied, e.g., [
From 16 open-ended interviews with young electronic musicians and producers conducted in the context of the Red Bull Music Academy 2014, a number of ideas have emerged with regard to systems for collaboration, intelligent and intuitive organisation of personal sound collections, and intelligent composition support. In this paper we highlight one particular idea that emerged in the context of discussing the usefulness of automatic suggestions on musical material and progression by the machine, e.g., samples, loops, rhythmic patterns, or musical structure, namely the desire to extend algorithmic recommendation systems with the concept of artistic obstruction. We present exemplary quotes from the 1 http://giantsteps-project.eu interviews as evidence and contextualise the ndings with respect to artistic practise and recommender systems research. Finally, we propose the concept of \strangeness" as an addition to recommendation systems to allow the adjustment of the degree of desired otherness in the suggestions made. This request for the creative domain marks an important di erence to existing consumer-centred music recommendation approaches but might also inspire new developments in mainstream recommendation systems. 2
In relation to supportive and recommendation systems, i.e., to the question \how do we want the computer to `help' us in our creative work process?", beside issues of artistic control and the fear of making predictable sounds, it becomes apparent that the desired features of recommenders in a creative context go beyond the query-by-example-centred paradigm of nding similar items and even also beyond the goal of serendipitous suggestions.
\Part of making music is about being lost a little bit and accidentally stumbling upon stu that you didn't think would work." USER07 This rst quote highlights a key element of much creative work, the element of the accidental, sometimes caused by the positive and negative e ects of malfunctioning of sound-editing software. It shows that serendipity is highly important to support creative work.
\It could be something like Google image search for example. [...] So if I set it to 100% precise I want it to nd exactly what I am searching for and probably I will not nd anything, but maybe if I instruct him for 15% and I input a beat or a musical phrase and it searches my samples for that, that could be interesting." USER03
Starting from an established retrieval scenario, the artist expresses the preference that the di erence between the query and the results is an explicit factor that can be controlled.
\What I would probably rather want it would do is make it complex in a way that I appreciate, like I would be more interested in something that made me sound like the opposite of me ... but within the boundaries of what I like, because that's useful. Cause I can't do that on my own, it's like having a band mate basically. [...] I am happy for it to make suggestions, especially if I can ignore them, but for it to just make suggestions that I would have never come up with, but would wish that I had come up with." USER07 \I'd like it to do the opposite actually, because the point is to get a possibility, I mean I can already make it sound like me, it's easy." USER01
These statements bear again the notion of controlled di erence, including the idea of complete opposition. Instead of wanting the machine to propose a common or well understood solution, the artists would like it to perform the role of \the other", providing an alternative or divergent view on a piece of music. So the desired functionality of the machine is to provide an alter-ego of sorts, which provides the artist with opposite suggestions, that still reside within the artist's idea of his own personal style. Note that this is in contrast to many contentbased recommendation use cases and systems that try to mimic and predict the behaviour of the user.
\The listening from outside the room is such a good one, turning around and the stereo just ipped, in terms of squinting, I often do this thing of listening through, I work on a track for half an hour through like horri c lters, so like the EQ feels all fucked up and putting it through a gramophone, and then just switching it o ..." USER16
Here a user lists a number of artistic strategies of \obstruction" he is already using to assess the quality of a piece, by changing the perception of the freshly edited music through changes in acoustics and hardware to render the piece \strange". 3
The idea of making things di erent and \strange" is a well-known cornerstone in
modern art strategies. The technique is known as \defamiliarisation" as de ned
by Shklovsky [
This need for opposition goes far beyond the commonly known and often
addressed needs for diversity, novelty, and serendipity in recommendation system
research, which has identi ed purely similarity-based recommendation as a
shortcoming that leads to decreased user satisfaction and monotony [
The common theme of this research is that diversity should not signi cantly
harm the accuracy of the approaches, i.e., items need to be relevant [
However, the aspect of recommending the opposite has not received much attention, potentially caused by a lack or insu ciency of technical de nitions of terms such as \unexpectedness", \serendipity", or \utility" (which is often de ned through economic factors rather than a real value for the user | not to speak of creative output) as well as the non-trivial notion of \the other", which rst requires de ning the full space of possible actions. While proximity of data items can be de ned rather intuitively based on a similarity metric (e.g., the nearest neighbours), remoteness is a less applicable concept. Particularly in highdimensional data spaces, similarity-based rankings become somewhat meaningless at higher ranks, as many points can have comparable distances (however, in di erent directions, making them mutually dissimilar, thus inconsistent).
In the context of experimental music creation, Collins has addressed the
question of opposition in the \Contrary Motion" system [
Inspired by both the input from our expert users and the inherent di culty in creating e ective search algorithms, and picking up the idea of controlled di erence to the point of complete otherness in the context of electronic music production, we propose to include \strangeness" as a controllable parameter, e.g., through a dedicated dial or slider.
The concept of \strangeness" is related to concepts like serendipity and
diversity [
In terms of user interaction, this concept could, for instance, extend a
recommender system such that it allows the artist to query the machine based on
existing musical material, but instead of returning just similar sound les, it
facilitates setting the level of \strangeness" the artist would like for the results.
Using the same or a comparable algorithm as one would have traditionally used
for a recommendation of a similar le, the system hence lets the artist set an
explicit level of otherness, allowing to preserve artistic control between variation
and opposition. By re-introducing the art strategy of defamiliarisation we hope
to propose an interface for working creatively with music without creating a
system of sameness and consensus. We are aware that this leads to new questions
regarding (semantic) descriptions of similarity spaces and personalised and
contextual de nitions of \the other", which need further investigation to become
applicable. Another consideration that needs to be made, when factoring in the
ndings of this paper, is that the degree of opposition and strangeness desired
depends on the preferences and the working style of the music maker. Taking
personality traits into account is a growing topic in recommendation [
Beyond our use case, we also see controlled \strangeness" as a potential extension for other, non-creative domains. As commercial recommenders have become a ubiquitous (and seldom inspirational) commodity, opposition to the user might be a way to make them exciting again and provoke interaction. 5
This work is supported by the European Union 7th Framework Programme FP7/2007-2013 through the GiantSteps project (grant agreement no. 610591).