MusicCube: a physical experience with digital music

Abstract

Listening to digital music on a computer has led to a loss of part of the physical experience associated with earlier media formats such as CDs and LPs. This paper presents a series of steps and decisions that led to the design of MusicCube, a tangible user interface that allows users to control digitally stored music on a computer by means of gestures and positioning. Interaction with the MusicCube is enriched by offering feedback through multi-coloured light effects and clicking sounds together with computer-generated speech. Despite some ergonomic shortcomings, when comparing to the iPod, users appreciated the design and enjoyed using it.

1 Introduction

As with other forms of information music is more often stored on computers in digital format. Mp3 is a very popular compression format for storing digitised music and by which digital music is frequently referred to. Although Mp3 storage provides many interesting possibilities like creating play lists, it has also led to a loss of part of the physical experience associated with earlier music play formats such as CDs and LPs.

Digital music can be stored on various storage devices, but for reproduction in a home situation it is usually burned onto CD or controlled through a graphical user interface via a computer. By burning music on CD some of the advantages of digital music are lost, and on the other hand, playing music via the computer may not be ideal given that one may prefer to navigate through digital content comfortably while sitting on a couch instead of infront of a computer screen.

Although one could control digital music with a remote control, one could argue that they are typically control hardware at the low-feature level and are not designed to enhance the music listening experience.

2 Design vision

The purpose of this project was to create a tangible interface to control collections of digital music, away from the desktop. Trends in computing suggest that interaction is moving into the environment and that physical objects called tangible interfaces will constitute the next step in human computer interaction [2]. A tangible interface for music control should be easy to use and enrich or augment the experience of listening to digital music.

The virtual content of the interface should be clear, by means of a metaphor for example. As usage will be in a home situation, the object should be decorative and robust. The interface should allow carrying around and use of both hands for control, for which it should be wireless and not too large or heavy.

When people were asked to physically represent music, colour appeared to be an important way of expression, this was also found in literature as a phenomenon called coloured-hearing synethesia [4]. The design therefore should afford the possibility of applying different colours.

Because Mp3 collections are often large and thus not categorized, content-base music genre classification has been gaining importance [2]. This may affect the way people listen to music in the future, by genre or pre-defined play list instead of by album. Each device should support around three play lists, the amount that people actually listen to according to an informal study. However, to allow more play lists one could have various objects across the house, for which the device needs to be generic.

3 MusicCube

Through an iterative process of building prototypes and informally testing those with users, a concept resulted that was named MusicCube (Fig. 1). MusicCube is a cube-like object made of silicone rubber with a speaker-shaped aluminium button. The appearance resembles a loudspeaker as a reference to the virtual content, music. The shape and size of MusicCube were chosen to allow comfortable two-handed interaction (Fig. 2); the material makes it pleasurable to touch and provides additional protection to the internal electronic components. The shell is also interchangeable and can be changed in colour or shape allowing additional distinction when one has different MusicCubes. Multi-coloured LED lights and a soft clicking relay-activated sound provide visual and audio feedback during the interaction. Communication with the computer is wireless by means of radio, however, a standard such as Bluetooth should be considered in future work.

Fig. 1

MusicCube

3.1 Interaction

Dedicated software allows users to users create play lists by grouping different Mp3 files on a computer and assign them with appropriate colours. Four of these colours, and thereby four play lists, can be addressed to the four sides of MusicCube.

When MusicCube is off the lights are off. The lights slowly gain in intensity when the device is shaken together with an increasing rattle. This indicates that MusicCube is waking up. Once on, users can manage the basic controls for music reproduction. A play list can be selected by placing the colour side of the desired play list upwards. Rotating the speaker-shaped button allows scrolling through the songs in the play list. Music can be paused by pressing the button, as an act of metaphorically muting the music by covering the speaker. The volume mode is activated by briefly holding in the button. Shaking the cube activates shuffle mode and a randomly selected song is played. Placing the cube on a surface with the speaker-shaped button facing downwards also pauses the music because the speaker is covered as well. Pressing it while facing downwards it causes the device to fall asleep, indicated by a fading rattle and dimming lights (Fig. 2).

Fig. 2

Comfortable two-handed interaction

3.2 Feedback

Automatic text to speech generation, using a female voice, is used to provide feedback on play list name, song title, current function, and volume level. The colour lights are used to provide feedback on volume level, with higher intensity indicating higher volume (Fig. 3) and on current play list by a static light. A rotating effect between sidelights is given, with clockwise for fast-forward and counter-clockwise for reverse. Random sidelights are present in shuffle mode. While the music is playing, lights flashing in changing colours represent the current music rhythms. Non-speech click-like sounds are given for fast-forward, reverse, and volume steps.

Fig. 3

Interaction with MusicCube, from left to right play, change play list, pause, scroll or change volume, and shuffle

4 Discussion

An experiment that compared MusicCube to the iPod showed that users appreciated the hedonic qualities of MusicCube [1]. Although this was not a usability experiment, some conclusions can be drawn for improvements that will make MusicCube easier to use. The mode switch for volume control for example caused many problems to users and the light effects often produced confusion because it was unclear whether they represented feedback or visualisation of the music. Many users also discussed the omission of a screen, but if the recently launched iPod Shuffle is as successful as its predecessor it leaves them with little argument.

5 Conclusion

Despite some shortcomings that will be improved in future work, MusicCube is very well accepted. It is not just another remote control and people who used it considered it was decorative and exciting to use.

In the future artists and labels could offer a variety of rubber shells or specially designed colour sequences representing their music. This could perhaps return part of the physical experience to Mp3 whilst maintaining the advantages of digital music (Fig. 4).

Fig. 4

Changes in intensity of the lights indicate the level of volume ranging from mute on the left to maximum volume on the right

Fig. 5

Illustration to show the metaphoric representation of music by MusicCube through the evolution in physical music carriers, from left to right mechanical music box, LP, CD, and MusicCube