Location
Location sound recording or mobile audio recording has its own set of rules and problems that set it apart from more conventional studio recording but fortunately it has one huge advantage over recording in a studio and that is size. Live concert recording is usually done in a large good sounding venue and no matter what they say, size does matter.
The whole point of location sound recording is to enable a large ensemble like a choir, orchestra or band to create a blend of the direct sound of the group with the natural ambience or acoustics of the venue.
With this in mind there are really 3 separate elements that all contribute to the finished sound of any mobile recording; the choice of venue, the preparation of the performers and the skill and equipment of the recording engineer.
The choice of location really is a critical factor in determining what the final recording will sound like. All venues large and small have their own unique acoustic properties that interact with the performance of the musicians and some concert halls become famous for their great sound whilst others achieve notoriety for theirs'.
However it's not to say that you have to rent a famous concert hall for a great location sound recording. Some very fine sounding recordings have been made in local chapels, old churches, village halls and even school halls.
Generally with a choir or orchestra you really need a space that will comfortably fit everyone in 4 or 5 times and that has a fairly high ceiling. This space then begins to work for the recording, blending voices and instruments into an overall sound so that no individual parts stick out.
Try to find a place that is not on a busy road as traffic noise is a real problem along with the occasional train or jet. Make sure that you can get facilities for a drink in rest periods and that there is adequate power. This last bit can be the most difficult in our modern and noisy world!