Convention Paper
Measurement of Low Frequencies in Rooms
AES Convention 139 · Paper 9482 · October 2015
Abstract
When aligning and tuning sound systems in commercial cinemas and other rooms there are difficulties with setting an appropriate response for low frequencies and the LFE channel. Long standing practice has been to use pink noise and Real Time Analyzers, but this method is “time blind” and includes the reverberation of the room. A new method is outlined for measuring frequency response at low frequencies. This method uses microphones arranged in a low frequency end-fire array to create useful directivity to discriminate against sound waves from rear wall reflections and reverberation. It also operates in the time domain, processing the acoustic impulse response as it arrives at successive microphones–a shotgun microphone writ large.
