Eigenmodes are room resonances that determine the low-frequency behaviour of any recording studio, hi-fi listening room or home cinema. Thus, their detection by listening tests and measurements is an almost indispensable basis for the selection and positioning of suitable countermeasures.
The detection of eigenmodes, also known as room resonances, through a professional modal analysis has a threefold effect on sound in a room:
Certainly, without the results of a detailed modal analysis, the effective reduction of room eigenmodes is impossible. In other words, crisp bass sounds in professional control rooms, hi-fi rooms and home cinemas can’t be achieved. However, it is possible to calculate the eigenmodes of a cuboid and perfectly sound-reflecting room, but the actual conditions usually differ significantly vastly from the theory. There are several reasons for this:
In conclusion, every successful acoustic planning starts with the modal analysis of a room to determine the dominant eigenmodes under real conditions. This important step creates the basis for all further planning steps. Only if we understand the low-frequency behaviour of a room, we can develop targeted and successful corrective measures.
The detection of room resonances, which we also perform for highly professional control rooms, includes detailed measurements. We carefully measure the geometry and analyse the existing components in relation to their vibration behaviour. Consequently, this results in a detailed overview of the orientation and characteristics of a room’s resonances. After that, all results of the modal analysis are documented in a final report.
The modal analysis includes
We prepare modal analyses both in the shell and in the existing building.
When looking at the following waterfall representations, in which only the microphone position changes, it becomes clear why pure measurement data without extensive details about the room have little informative value: