FROM CONCERT HALL TO RADIO

RECORDINGS FROM THE ANECHOIC CHAMBER

Ever since the invention of the microphone there have been many philosophies as to the best way to record classical music. Ever-new principles and ideas have been debated at studio engineer conferences all over the globe.

As early as the 1930s the first “dummy heads” were developed to capture human hearing as accurately as possible. The guiding idea was to exactly replicate the human head, including the auricles and ear canals. Instead of ear drums, two microphones were installed in the plastic head to simulate the auditory faculty. Dummy head recordings create a very close approximation of human hearing, especially at high stereo resolution. However, optimum aural perception is only attained when the recordings are heard over headphones.

In the first music example you hear just such a dummy head recording. Here the dummy head was placed behind and above the head of the conductor, Mariss Jansons. Still, the vertical placement and sound depth are no quite authentic. Nor does the spatial effect exactly match what the conductor actually hears at the rostrum while conducting. For this reason dummy head recordings are used mainly for purposes of documentation and measurement rather than music recordings or radio broadcasts.

Why not simply place two microphones in Hercules Hall to capture the concert experience, as in the second music example? Unfortunately the two mikes would lack something essential: the human eye. Since our brains can combine the faculties of hearing and sight, the listener’s attention is automatically focused on the sound event. This means that people listening to music in a concert hall are also spectators: we hear an oboe solo more clearly and vividly when we watch the oboist playing it. Thus, a recording made with only two mikes in lieu of a listener will not produce the desired result. In this example, the oboe seems more distant.

That’s why we need much more for concert broadcasts than just a pair of mikes. Radio broadcasts of symphony concerts on Bavarian Radio’s classical programme use a main microphone to capture the overall impression and many additional microphones (so-called “spot mikes”) to enhance the clarity required by the score.

Here is an extract from Sergei Rachmaninoff’s Third Symphonic Dance, op. 45.