The Three Sirens A self learning robotic rock band More detailed information about the robots can be found at the creator's website at: www.baginsky.de
	Originally, three robots formed the band The Three Sirens, those were Aglaopheme (slide guitar), Peisinoe (bass) und Thelxiepeia (drum). By now, a few other artificial intelligences have joined the group: Aciilyzer (Vocals), LynxArm (Percussion) and some "off the shelf" electronic instruments. The Three Sirens are not conventional musical instruments but autonomous, self learning robot musicians. They are not controlled by humans. Artificial neural networks control every aspect of the robot's activities. This means that the authorship for their music does not belong to any living being (no predefined material or musical knowledge is available to the system), all musical material is generated by self organizing learning processes in an improvising manner.
	Aglaopheme, the guitar player
	Aglaopheme's body is both, a robot with framework, actuators and position sensors and a musical instrument (slide guitar) with six strings, machine heads and a guitar pickup. Six solenoids are used to either dampen and release or to pluck the strings. A short piece of cable tie serves as a very durable plectrum that is moved across the strings by a linear motor to pick selected strings. The entire plectrum-drive assembly can be pulled away from the strings by a solenoid to allow the plectrum to drive to the desired strings without hitting any others. A dc motor drives a sledge up and down the guitar neck. This sledge carries the slide and a small solenoid that pushes the slide against the strings if necessary. The sledge also carries a small video camera. Two more video cameras are attached to the machine. One is located at the lower end of the guitar neck. The other one is mounted on top of a leg-solenoid. Two big solenoids serve as legs to the robot. They can push up the entire framework in two different directions and thereby make the robot rock. This rocking motion also moves the whaa-whaa pedal up and down.
	The other Members of the Band
	Peisinoe, the bass player is a system very similar to the slide guitar robot. It is only much more simple in that it only has one string and therefore only one neural network to control it. In order to vary the pitch, the robot uses one strong solenoid to adjust the tension of the string. The machine has two mechanisms to cause vibration of the string: a motorized bow and a slapping device. Aciilyzer, the voice of The Three Sirens is still somewhat bodyless. Again, there is a neural network that takes audio spectrum data as sensorial input and that is in control of an sound generating device. But in case of this band-member the visual appearance of the machine is very boring.
	The sound generating device is a database filled with vocal sound samples of phonemes. Recordings of my own voice were used to set up the phoneme collection. The neural network is trained by allowing it to explore the outputs of the database. In a later state of learning the vocal sounds fed into the network are mixed with, or even replaced by, audio signals from the other members of the band. Intermixing the sounds of the different instruments makes the individual systems responsive to each other. In other words: they hear each other.
	The percussionists in the band are operated differently from the melodically instruments. The rhythm machines are basically just hooked up to the system update frequency. If for example the band plays at 100 bpm, and the guitar- and the bass-system perform a learning cycle every quarter note (roughly 6 analysis per second), the bass drum would make a kick once per measure. All percussion devices can be programmed to act with different repetition rates within this basic quarter note structure. Thelxiepeia, the drum was build around an existing rototom, a drum that was fashionable in the seventies. On this drum the player could change the pitch during playing by turning it. I motorised the rotational activity and added a mechanic drumstick. LynxArm is a small five axis robot arm kit that I bought during a robotic exhibition in Vienna. After assembling the kit I changed one mechanic function and attached a small camera to what originally was the gripper. I also attached some sound pickups to the framework. The robot now knows two modes of operation. It either follows directly the spectrum analysis of the guitar sounds or knocks the camera against a small wooden board at system update tempo divided by four.