3. Architectural acoustics - an aspect often underestimated

There can be no doubt: the choir and the recording space cannot be thought of as separate entities. You are not very likely to embark on your recording career with a mass choir and open air recording, in which architectural acoustics does not matter, of course. Quite the opposite, the influence of architectural acoustics is very significant; it forms an union of sound with the choir. Furthermore, you should pay attention to the question whether there is an audience present at the recording or not. A medium-sized modern church with rather low ceilings, filled to capacity, features very different reverberation times than the same space did that afternoon, when you did the soundcheck while it was empty! This immediately influences the ideal positioning of the main recording microphones, since the reduced reverberation time leads to a reduced reverberation radius, which has proven a useful factor in calculating the distance at which the mic should be placed from the sound source.

This is calculated as the relation of space volume to reverberation time and is expressed in meters. This is how you can calculate the reverberation radius yourself:

Expressed in words, the formula means this: The reverb radius expressed in meters is the square root of the space volume divided by the reverb time multiplied by 0.57. You must place your main mics within this radius, otherwise reflected sound will have too great an influence and the recording will end up sounding 'washed-out'.

A further influence on architectural acoustics are 'psycho-acoustic' factors. Less experienced choir members require a certain architectural sound in order to be better able to control their pitch. A rehearsal room with good acoustics is ideal in this respect, of course. This means a medium-long reverberation time, wood panelling rather than curtains, and no reverberant walls (glass, concrete, etc.). This would allow us to kill two birds with one stone: the choir performs in a setting the members are used to and thus feel comfortable in (which facilitates a good performance), and the room is useful and not too indifferent, it may even feature a small control room. If we cannot avail ourselves of such a room, or if we are not welcomed into this room by the musicians, then a medium-sized church is usually a good option for acceptable recordings.

But be mindful of devices such as air conditioning or heating, which make very bothersome low-frequency humming noises, and traffic noise, of course, which may render your recording unusable.