Kinoull Aisle, field recording 1/4/15
After picking up the keys and some vital site information from David and Andrew at the Heritage trust offices in Perth, Paul and I made our way to Kinoull Aisle to conduct some field recordings. Kinoull Aisle has had a church on the site since the mid 14th century. The Aisle contains a large carved stone monument to the 1st Earl of Kinoull and measures approximately 4.5m by 5.5m with an approximate height of 6.5m. Upon entering the Aisle Paul and I immediately assessed the quality of the reverb, the height helping to create a rich but smooth reverb. A lot of the potential problem resonant frequencies were diffused quite effectively by the recessed shuttered windows and door and the monument itself.
The purpose of our field recording trip was to record a historic location's reverb in Perth to be used in a presentation and performance in June 2015 Perth Archaeology Festival. The opportunity to record at Kinoull Aisle would afford Paul the chance to further research the methods of DIY ethics and practice and my own field of research, archaeoacoustics and the collecting of the reverberant chacteristics in a series of digital data including audio recording.
As part of our field work analysis I had suggested to Paul that he bring his guitar which, recorded live on location would make a good comparison with the digitally processed reverbs gathered on site. My intention was to try recording Hi Fi quality reverb files using reference class equipment whilst also gathering Lo Fi recordings with 2 different portable recorders. Metadata in the form of visual spectrograms and numerical decay time over frequency tables were also taken, these achieved thanks to an iPad mini and 2 freely available apps. In keeping with this DIY ethic the Lo Fi recordings could have also been achieved utilising mobile technology and easily available mobile phone or tablet microphones.
Photographic recordings from the site are also an essential element of the practice of recording impulse responses these help contextualise the recording environment. Many photographs were taken on site both inside and out of the Aisle, along with video footage.
The Lo Fi portable recorders of choice were a Marantz PM661 and an Alesis Palmtrack, unfortunately upon uploading files from the Palmtrack later the same day they proved to be corrupt, a new HD card formatting error. In order to successfully capture the reverb characteristic of a space eventually an impulse response recording is required. This is essentially a short loud burst of broadband sound introduced into the space, clapping your heads is effective if limited containing very little low and high frequencies to be useful. A sound of a controlled explosion is what is ideally required, a balloon being burst or similarly a starters pistol being fired, both providing a useful amount of broadband energy. Due to the public nature of many of the historic sites sampled to date the starters pistol method was ruled out for obvious ethical issues. Successful recordings of the balloon burst were made with the Marantz recorder.
The Marantz was also left running in order to capture Paul's live improv playing acoustic guitar. Inspired by the environment Paul improvised an on the spot performance for 8 minutes or so.
Summary of equipment used:
For sine sweep recording - Apple MacBook running Impulse Utility software, MM1 reference microphone, Bose Soundlink mini loudspeaker unit, Presonus USB interface.
Impulse response recording - balloon burst, Alesis Palmtrack and Marantz PMD661 portable audio recorders.
Post production - Apple's Logic Pro Space Designer convolution reverb software.
All audio recorded and processed at 48KHz 24bit.
The rambling thoughts and musings of an audio engineer/sound designer turned archaeoacoustician