Review: Emergence AS8 Pro S

It’s mid-morning at AudioTechnology HQ, and Joe Hayes rocks up with his latest invention in tow. He surveys the office’s mid-century bay windows, hardwood floor, timber desks, adjoining bass-trap of a kitchen and says, “This’ll be perfect” as he starts to pull out his sub-sat studio monitor system. Hardly perfect; the office’s only redeeming acoustic treatment is a bookshelf of old magazines, and the desk clutter I like to call ‘random diffusion’. Any other studio monitor manufacturer would laugh, cry, or promptly do a 180 and get back in their hire car. It’s definitely not a serious monitoring environment, and to be clear, we don’t use it as one. But to Hayes, it was just another emulation of a home studio’s crappy acoustics, and he could hardly care less.

See, Hayes isn’t worried about your room. His monitor placement guide doesn’t come with a preamble on room acoustics or diagrams pointing out angles of incidence. He’s got a whole different way of thinking about studio monitors and diffusion; a relationship he’s been patenting since the ’90s. 

The general gist is this: rather than adjust the acoustics of your space to try and flatten out its frequency response at your listening position, why not just get rid of the room’s acoustic altogether?

SPATIAL VERSION ONE

We’ve reviewed Hayes’ inventions before. One of our mainstay reviewers, Brad Watts, still has an early pair of Spatial One nearfields. Hayes’ new iteration under the Acoustic3D company name is called the Emergence AS8 Pro S, which I’m not convinced is a better name than Spatial One.

It’s a sub and satellite combo, with conspicuously Independence Day spacecraft-looking speakers. As you can probably tell, just by looking at it, that is indeed an angled quadratic residue diffusor leering over each satellite’s driver. But it’s not just any quadratic residue diffusor, it’s a correctly tuned one, according to Hayes. What he means is, Schroeder’s original concept treated sound as if it had a planar wavefront, but sound radiates from a source with a spherical wavefront, like a ripple in a 3D pond. By Hayes’ calculations, your back wall diffusor would have to be at least 6m away from a source to have the desired effect. So putting a QRD right at the speaker’s mouth without doing something to account for this curved wavefront would be ineffective. On this design, he’s compensated accordingly to diffuse across a quoted range of 1.4-20kHz.

So why diffuse at the source? Well, it’s a good question and one that requires a re-think about how our ears work.

RIDING THE WAVELET

I was re-introduced to the story of Daniel Kish not long ago, the blind man who can ride a bike by echolocating with clicking noises. Well, it’s really his gimmick to entice morning shows into booking him to talk about what he really cares about. Kish’s crusade is to stop institutions telling blind people they can’t see. That’s right. He says blind people can see, if only we’d change our expectations surrounding blindness. And it turns out, he’s right. When blind people train themselves to echolocate, the part of the brain they retrain is the primary visual cortex. It lights up like a Christmas tree as they ping out a car, tree, recording console, whatever. They see, just with a different methodology. After all, what we interpret as eyesight or vision is really only our visual perception of what’s going on around us based on processing the information contained in visible light.

Hayes sees acoustics in a similar way. As much as he hates statistics, he reckons acoustics is all about stats. “Perception is the probability of what’s going on,” he says. And with normal studio monitors we create a perception problem. First, there’s the recorded acoustic, which is a sound source plus a bunch of statistical properties, including the number of reflections per second that might influence the general tonal quality of the reverb. “When you put that into your listening room,” says Hayes, “which has a whole new bunch of statistics itself, you end up with two sets of stats that the brain just can’t really work out.” So, to solve this mash-up of acoustic statistics, we try to adjust the response of our listening environment rather than ‘fix it at the source’. Hmm, where have we heard that before?

Hayes has spent the last 20 years trying to prove why flattening the listening environment is a bad idea.

But back to this idea of perception and how we hear. When Hayes finished university, he says the hardest thing he had to do was unlearn much of his acoustics training. In 1984, Jean Morlet modified physicist Dennis Gabor’s work to come up with the Morlet wavelet and later on proposed it could be useful for analysing music. When Hayes came across Morlet’s work it was all pretty recent, but it helped inspire his invention’s first iteration in 1990. A Fourier transform, one of the more common acoustic measurements, receives signals in a window of time and gives you a picture of what happened in that window. So, you might have had 10kHz appear at some point, you just don’t know when. Morlet wavelets can be scaled to tell you precisely when 10kHz occurred in that window of time. “Finding out when a flautist plays a C sharp is the kind of thing you can do with a Morlet wavelet,” said Hayes. “You can set up the scale of a Morlet wavelet, so when you put a signal through, it only stands up when the flute plays a C sharp. They de-compose the signal to when that condition is met, then suddenly turn on, no matter how much signal-to-noise there is. And they have a nice property in that they’re perfectly time-aligned. So there might be latency, but the standing up and down of events is perfectly time-aligned.”

And Hayes sees this as a key to understanding how our brains perceive sound. Cochlear implants work on a similar principle, it recognises that a certain frequency is happening at a certain time, and transmits a jolt of electricity into the basilar membrane. Because when you think about it, our basilar membranes are set up to decode sound in a similar way. Got a low frequency coming through? Well, it’s only being picked up by the hairs right down at the skinny end of your cochlear spiral. Likewise, high frequencies are being decoded right at the throat of the horn. Hayes has a suspicion that the parts of the ear you can see, the pinna, is the wavelet encoder, which gives you the directionality as well the frequency. It explains why cochlear implants aren’t useful for spatial cues. But that’s just little more than a strong hunch at this stage.