In general there are a couple of principals that can make for a “good” sounding room or space, dependent on what a person is listening too. One general classifications can be:
- Contemporary Music – music listening can be enhanced by echo or reverberation to some degree. However often speakers need to have good bass response and the reverberation/echo should be consistent at all Frequencies.
- Classical Music – Long reverberation or echo can improve perceived sound quality to the extent that often speaker systems are not used, and the natural echo or reverberation of a hall or space is preferred, think of a Church or Classical Recital Hall.
- Speech – bass response is not important, high frequencies are critical. High frequencies help us determine critical vowel and consonants sounds. Limiting reverberation (echo) is also key to a good speech sound system.
Of course these are general rules and there are rarely spaces designed these days for one purpose in particular. So there always needs to be some balance and consideration to all the uses of a room/space.
However for business meeting rooms there is an Australian Standard, which sets a range for meeting rooms, 0.5-0.7s RT60 and less for rooms with Video Conferencing.
There are no general rules to determine if a room will meet these criteria or not. Typically to work out reverberation time or echo requires many variables including room volume, internal surface area and absorption efficiency (coefficient) of those surfaces.
However, the simplest reference when planning these types of rooms is that a typical residential lounge room has similar reverberation time standards to meeting room. I’ve often found by starting a meeting room finishes with an even balance of “hard” or “soft” surfaces gets the design pretty close to achieving the standard.
Soft finishes are typically things like:
- Ceiling tiles
- Pin board panels
- Perforated (Specialist) plasterboard
Hard finishes are typically things like:
- Glass & mirrors
- Concrete, blockwork or rendered masonry
- Timber (polished) finishes
By using more soft finish surface area of a room it’s still simple enough to achieve these design standards. In some instances specialist acoustic panels can be used to offset large areas of hard surfaces. However this solution is likely to be more expensive and be less reliable than evenly distributed acoustic absorption.
On the other hand, Video conferencing spaces are more critical in terms of voice replay and intelligibility. Specialist acoustic treatment is often required to achieve the high frequency quality that is needed for lots of voice communication. These rooms more often require careful acoustic, speaker and microphone planning and placement to achieve good results.
These more critical types of spaces normally require specialist engineering and advice to achieve good results, however the general outline above is still a good starting point.