LSI University | Acoustic Measurement

It can be said that the most fundamental process regarding the reception and evaluation of sound is that of comparison. Any description of fidelity or the lack thereof must be in reference to something.

How long will it take sound to propagate from the shed to the nearby property line, where Mr. and Mrs. Public are hoping to enjoy a beautiful summer evening?

“I am going to equalize the room.” We’ve all heard that statement so many times that we scarcely think about what it literally means. We know that in practical terms it means adjusting an equalizer to suit your taste. It may be done with the latest high-technology analysis equipment, voodoo magic or simply tweaking away “until it sounds right.”

The point that it is difficult if not impossible to localize the sound source.

Equalization and other processing are no substitute for proper loudspeaker placement

Since the impedance of a loudspeaker is a frequency-dependent parameter, it must be measured at multiple frequencies to get a true picture of what the amplifier is “seeing” at its output terminals. While very sophisticated methods and instruments exist, you can get a pretty good idea about the impedance curve of a loudspeaker with a standard real-time analyzer.

Taking the guesswork out of seeing where your sound is going

In the last installment of this series we examined the goal of system equalization and introduced the concept of time as the third dimension in sound. In this portion we shall explore Smaart hardware and interconnect issues.

In this multi-part series we shall attempt to explain SIA Smaart Live concepts and implementation in a fashion easily digested by the beginner.

First, a definition from Merriam-Webster:
Linear: having or being a response or output that is directly proportional to the input.

If one could listen to only the direct sound of a loudspeaker, the world would be a very different place! Unfortunately, free field listening, where you have NO reflections, room modes or ambient noise, is hard to achieve in everyday life, so we listen to loudspeakers in real rooms. 

The most informative frequency domain plot, by far, is the Nyquist plot, Named after Harry Nyquist of Bell Telephone Laboratories, famed for his work on feedback circuit analysis, the Nyquist plot makes visual simultaneously the following viewpoints of the signal:

A look at new Ease 4.0
September 5, 2001 Mderated by Keith Clark

I recently had the opportunity to assist a local contractor in the final calibration of a line array system for a reverberant Catholic monastery.