CMU School of Drama


Wednesday, October 16, 2019

Working In Tandem: Combining Near And Far Field Measurements

ProSoundWeb: One approach to overcoming the inaccuracy of quasi-anechoic techniques at low frequencies involves combining them with near field measurements. Keele [1] demonstrated that the far field frequency response of a loudspeaker at low frequencies can be estimated by measurements in the near field.

1 comment:

Elliot Queale said...

This is a fascinating article that goes to show just how complicated acoustics can get, even when we try to eliminate as many external factors as possible. Frequency and phase plots are crucial in understanding how well a speaker or microphone will behave in a room. Even though some people may think that these measurements are worthless in the "real world" where there are infinitely many other factors, it is still vital to understand the ideal behavior. For example, the comb filtering situation is much easier to understand in this case and well represented in figures 4 & 5. When we begin to understand this theory, it isn't very difficult to relate that back to issues with baffle diffraction which causes both destructive and constructive interference in the same way hard-walled reflection affects sound. It is this type of pure analysis that I love applying to the real world and in many ways helps to 'see' what the sound might do given a specific configuration.