The most important acoustical quality for a concert venue is reverberation time.
This is the length of time a sound continues audibly in the space, and it is also the quality that is easiest to measure or calculate.
A great sounding room has a balanced reverberation time- not so long that you hear echoes, but not so short that it sounds like you’re outside or in a recording booth.
The ideal reverberation time varies with the size of the venue and the type of music. Classical music sounds best with longer reverberation, around two seconds, while amplified rock music with words that need to be intelligible needs much shorter reverberation time, often less than one second.
The next most important quality of a concert venue is diffusion. The scattering of reflected sound waves is why the room needs some sound reflecting surfaces and some absorptive ones, and no huge flat parallel walls. Diffusion scatters the reflected sound waves in different direction so that there is no unpleasant effects such as focusing, dead spots, or flutter echo.
There are other important qualities for great acoustics in a concert venue, but those two would go a long way toward achieving good.
Our acoustical consultant or engineer could help determine the right reverberation time for your space, how to balance acoustical intimacy, clarity, and diffusion, and of course make sure background noise is kept to the appropriate minimum.