Interactive real-time musical systems
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This thesis focuses on the development of automatic accompaniment systems.
We investigate previous systems and look at a range of approaches
that have been attempted for the problem of beat tracking. Most beat
trackers are intended for the purposes of music information retrieval where
a `black box' approach is tested on a wide variety of music genres. We
highlight some of the diffculties facing offline beat trackers and design a
new approach for the problem of real-time drum tracking, developing a
system, B-Keeper, which makes reasonable assumptions on the nature of
the signal and is provided with useful prior knowledge.
Having developed the system with offline studio recordings, we look to
test the system with human players. Existing offline evaluation methods
seem less suitable for a performance system, since we also wish to evaluate
the interaction between musician and machine. Although statistical data
may reveal quantifiable measurements of the system's predictions and behaviour,
we also want to test how well it functions within the context of a
live performance. To do so, we devise an evaluation strategy to contrast
a machine-controlled accompaniment with one controlled by a human.
We also present recent work on a real-time multiple pitch tracking,
which is then extended to provide automatic accompaniment for harmonic
instruments such as guitar. By aligning salient notes in the output from
a dual pitch tracking process, we make changes to the tempo of the
accompaniment in order to align it with a live stream. By demonstrating
the system's ability to align offline tracks, we can show that under
restricted initial conditions, the algorithm works well as an alignment tool.
Authors
Robertson, AndrewCollections
- Theses [3706]