An auralisation method for real time subjective testing of modal parameters.

Subjective testing is necessary when attempting to determine the human response to audio quality. Small rooms, such as recording studio control rooms themselves have an effect upon the quality of the perceived audio reproduction. Of particular interest is the low frequency region where resonances, or ‘room modes’, occur. It is necessary to test a number of modal parameters individually and be able to alter them instantly during testing in response to listener perception. An auralisation method has been developed which is used to compare musical samples within modelled rooms. Methods are discussed in the context of providing a practical system, where real time testing is feasible. The formation of the room’s transfer function is discussed, as are a number of issues relating to the generation of audio samples. This work is then placed in context with a brief explanation of how the system is to be used in a real subjective test.

[1]  Jont B. Allen,et al.  Image method for efficiently simulating small‐room acoustics , 1976 .

[2]  R. Walker,et al.  Optimum Dimension Ratios for Small Rooms , 1996 .

[3]  Trevor J. Cox,et al.  Room sizing and optimization at low frequencies , 2004 .

[4]  Bruno Fazenda,et al.  Optimal modal spacing and density for critical listening , 2008 .

[5]  Todd Welti,et al.  Low-Frequency Optimization Using Multiple Subwoofers , 2006 .

[6]  C. L. S. Gilford.  The Acoustic Design of Talks Studios and Listening Rooms , 1959 .

[7]  Bruno Fazenda,et al.  Perception of Modal Distribution Metrics in Critical Listening Spaces—Dependence on Room Aspect Ratios , 2005 .

[8]  Matti Karjalainen,et al.  Perception of Temporal Decay of Low-frequency Room Modes , 2004 .

[9]  M. Schroeder.  The ‘‘Schroeder frequency’’ revisited , 1996 .

[10]  Andrew Goldberg,et al.  Measuring the Threshold of Audibility of Temporal Decays , 2006 .

[11]  Floyd E. Toole,et al.  Loudspeakers and Rooms for Sound Reproduction-A Scientific Review , 2006 .

[12]  A. Santillán.  Spatially extended sound equalization in rectangular rooms. , 2001, The Journal of the Acoustical Society of America.

[13]  Jan Abildgaard Pedersen.  Adjusting a loudspeaker to its acoustic environment: The ABC system , 2004 .

[14]  Roland Bücklein,et al.  The Audibility of Frequency Response Irregularities , 1981 .

[15]  Matti Karjalainen,et al.  Modal Equalization of Loudspeaker-Room Responses at Low Frequencies , 2003 .

[16]  R. Conrad,et al.  Acoustic confusions in immediate memory. , 1964 .

[17]  Sean Olive,et al.  The Detection Thresholds of Resonances at Low Frequencies , 1997 .

[18]  P. Morse.  Vibration and Sound , 1949, Nature.

[19]  Bruno Fazenda,et al.  Thresholds of detection for changes to the Q-factor of low frequency modes in listening environments , 2007 .

[20]  O. Bonello.  Corrections to "A New Criterion for the Distribution of Normal Room Modes" , 1981 .

[21]  F. Alton Everest,et al.  Master handbook of acoustics , 1981 .

[22]  R. H. Bolt,et al.  Normal frequency Spacing Statistics , 1947 .