Bagpipes bought to Life Using JANET Lightpaths

5/10/08: The JANET Lightpath service was put to interesting and novel use at the recent e-Science all-hands meeting held in Edinburgh during September (http://www.allhands.org.uk)

A 1Gbit/s Lightpath connection was established between a music studio at the University of York, and a lecture theatre at the National e-Science Centre at the University of Edinburgh. This connection was used to support a high-quality studio recording session including a performance of bagpipe music before a live audience in Edinburgh, with the lightpath carrying the audio data from Edinburgh back to York to be recorded. Dr Rob Fletcher of the University of York co-ordinated the project, with his colleague Dr Ambrose Field controlling the recording and subsequent mixing and composing at the studio in York.

Five high-resolution microphones were lent to the project by the commercial partner DPA (http://www.dpamicrophones.com), and these were used to record both sound samples and complete pieces performed by the piper Alex Urquhart-Taylor (http://www.orscotland.com/band_alex.html). Two microphones were placed to capture the sound of the pipes’ drones from above, and the other three to pick up sound from the chanter and around the piper at waist height. The microphone signals were digitised and fed into a software package called Reaper (http://www.cockos.com/reaper), which has a capability to exchange and process digital audio information between multiple instances of itself distributed on a network. This feature was used during the recording session to interconnect two instances of the software, one in York and on in Edinburgh, to undertake the recording session.

The common perception is that audio data does not require much network capacity, but this project used studio recording standards with high sample rates and large bit depths (96kHz, 24bit audio for each of the five channels) taking it well beyond what most of us will be used to in a domestic environment with typical CD quality home hi-fi. Furthermore, the data was exchanged between the two sites in an even higher-resolution 64 bit format, giving sustained data rates of between 30 and 40 Mbit/s during the sessions. For comparison it is worth noting that this was purely uncompressed audio data, with no video content, and that these data rates are more than ten times those that are currently used for a typical videoconference over JANET.

The activities on the day were completed later in the afternoon at a surround-sound performance to the audience who had been present at the recording session. Following sound balancing and mixing, Ambrose Field played back his recordings of the piper’s performance pieces, and also an example of a first cut of an idea for a composed piece based on studio processing of the recorded material, and these were very well received by the audience.

The sustained high-quality of the data transfers with low latencies and no data loss show the potential for this kind of distributed real-time work with very successful recording and performance sessions. This in turn may lead to future collaborative work across JANET and international networks. Further information about this project, including links to the partners and people involved, can be found at the project web-site (http://www-users.york.ac.uk/~rpf1/AHM/AllHandsAudioDemo.htm)