This suggests that some form of source-specific distance processing might be worth investigating, particularly in terms of customizing the degree of amplitude attenuation and the number and pattern of early reflections for different types of instruments and sounds. While the results are pretty good for certain instruments (the guitar for example), other instruments are still perhaps perceived as sounding a little too close. Here, the spot mics were processed using an implementation of Gerzon’s Distance Panpot created by one of our students in the MMT programme in Trinity College, Eoghan Tyrrel, and you can read more about his work here. This method uses a fixed pattern of early reflections as the primary means of altering the perceived distance, which makes it highly efficient and also allows for a certain amount of customization of the distance processing for different types of sounds. For this video, the instrument spot mic recordings were processed using a method suggested by Peter Craven, and one of the primary inventors of Ambisonics, Michael Gerzon. The precise way in which we synthetically alter the perceived distance of these close, spot-mic recordings remains an under-explored topic, particularly in the context of 360 video and VR, and this is an area which we are currently investigating. In general, this has been one of the biggest differences I’ve encountered when preparing a mix for a 360 video when compared to a traditional audio-only mix. This is particularly important if you are not mixing directly to picture or solely viewing the video on a desktop display, as in those scenarios, it is all too easy to underestimate the auditory distance required when viewing the content on a VR headset. The recording presented here is based around a CoreSound TetraMic, and multiple monophonic spot (AKG 414s) and room microphones (AKG C314s, and Sennheiser TLMs) arranged in a circle of 1m radius and at 90 degree intervals, as shown below.Īs always with this type of production, it is critically important that additional processing is applied to the instrument spot mics so that the perceived distance of the audio broadly matches the visible distance of the performers in the video. The title of A Round, Around reflects this approach and the spatial arrangement of players, and the use of rotations and other spatial effects created by passing musical material between consecutive instruments, as can be seen in the score excerpt below. The compositional aesthetic here follows a more traditional contrapuntal approach in the form of a modified round, a form of strict canon in which each part performs the same melody but starting at different times. This performance actually took place in June of last year but as the recordings were used as part of our Ambisonic Microphone study (discussed in the last blog post here), we decided to complete that research before releasing the video of the performance. The piece consists of an acoustic quartet (guitar, cello, flute and saxophone) arranged symmetrically around the central recording position in the debating chamber of Trinity College Dublin. Many, many thanks to Kate Ellis, Nick Roth, and Lina Andonovska for their fine performances. The second work composed specifically for the Trinity 360 project has now been released on YouTube and spatial audio should now be supported on most browsers and mobile devices (including iOS).
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