An Investigation into Stereo Microphone Techniques and their Applications
My Dissertation
My Dissertation
Abstract
There are a number of methods for creating a stereo recording, this report investigates and compares how a number of different stereo microphone techniques can be used to create a complete stereo field.
The report includes research from a number of sources examining how the human hearing system is able to identify the location of a sound source; through time and level differencesbetween the two ears and the unique interaction of the waves with the listener's head and torso.
A range of coincident, near coincident and spaced pair techniques were researched tocompare how they captured and encoded the time and level differences caused by differentsound source locations.Test recordings were conducted to confirm the spatial cues produced by the various arraysmatched the predictions made by formulae, using trigonometry to calculate the differencein path length. It was confirmed that, by varying the spacing and angles between microphones, the width and spacing of the stereo image could be adjusted to suit the recording.
These tests also highlighted the shadowing, image distortion and difficulty inpositioning the various techniques that occurs when too many microphones are setupsimultaneously. Five stereo arrays were selected to create the final small ensemblerecordings, each producing satisfactory, yet varied results confirming the researchsuggestion that no one microphone technique will be suitable for every situation. Therecordings were subject to a small scale listening test, which concluded that; for this ensemble and recording environment, the Blumlein array produced the most pleasingrecording with a wide stereo spread stretching from ear to ear and providing accurateimagery for each of the 4 performers
