The optimization of modal spacing within small rooms

The reproduction of audio in small rooms is significantly affected by room modes – resonant frequencies set up as a result of the geometry of the room. These frequency specific modes combine to form a unique frequency response for that room. This frequency response becomes part of the overall reproduction system, and as such, a poor response can have a detrimental effect on the listener’s enjoyment of the audio. Researchers have, therefore, consistently looked at how these modes affect our perception, and in particular, attempted to optimize the distribution of the modal frequencies so as to reduce the negative effects. A study is presented which determines an optimal frequency spacing between two adjacent modes which relates to the optimal listening scenario. This result is then discussed in the context of an objective measure which predicts a similar spacing and some remarks on how these results can be incorporated into optimization techniques.