What is Sonic Shimmer? This week ASC President and TubeTrap Inventor, Art Noxon, PE shares his knowledge on the subject.
Let’s ask ourselves, What is Sonic Shimmer? When it comes to measurement or assessment tools in acoustics, we have a problem when the tools we have do not agree with subjective interpretations. In this case we need a shimmer meter to better study and understand concert hall acoustics and guitar pedal sound, because in both venues, the concept of shimmering sound is a valued commodity.
Vocal shimmer is measured in speech analysis testing (Praat speech analyzer from Phonetic Sciences). During a long or held tone, the voice signature is actually a sequence of very short tone bursts. The variation in the loudness of these tone bursts during a held sound is called shimmer. Using reverb circuits, shimmer is created by introducing lots of early reflections in contrast to late reflections and long reverb (Sound on Sound, Advance Reverberation Series, Oct 2001). Shimmer in musical composition is created when tones of various instruments playing the same note are slightly out of tune, which created a beating kind of sound, a tone whose amplitude rapidly varies.
There is reported to be a substantial component of what appears to be a random energy experience a fluctuation in the low frequency range associated in true, physical reverb spaces. It is referred to as an acoustic shimmer. There is interest in an electronic reverb shimmer effect but I’m not sure how it is or isn’t the same as acoustical hall shimmer. See ValhallaShimmer which is pretty close to what I’m talking about. Except I’m a little concerned about modulation rate adjustments. However, such an experience is not measured or explained. I have developed a conceptual perspective on this perception. It goes like this:
If you make a bass tone for a short duration, say 1 second, you have a huge expanding bass wavefront which reflects off of various large surfaces in a variety of different locations, then what returns to a seat in the audience is a series of intersection bass wavetrains, each arriving at different time delays and coming from different directions. This creates a phase add and cancel type of experience at the listening position, but because of the duration time, the number of different delays, strengths and directions, the phase add/cancel effect at the listening position becomes very complicated…
Finish reading Art’s thoughts on Sonic Shimmer here.