Soulnote Audio Philosophy (Part 8,9,10)

Oct 27, 2023Jeff Wells
Soulnote Audio Philosophy (Part 8,9,10)

SOULNOTE Chief Designer Kato Speaks
Design Philosophy Series - Part 8

Dynamic performance is more acutely perceived by our hearing than static performance. This heightened sensitivity likely evolved from primitive survival needs and has been encoded into our DNA since ancient times. To illustrate this, consider the following:

We can distinctly spot moving prey. The hawk, for example, possesses eyesight that's notably sharper for moving objects than for stationary ones. Similarly, humans can effortlessly identify moving objects. Thus, waving one's hand in a crowd makes them more noticeable. It's also easier to find Wally when he's on the move. The principle is simple: moving objects are more detectable. This principle likely extends to our auditory senses. A sudden sharp sound or any dynamic noise, like discerning the direction of a noise source, would have been crucial for our ancestors when hunting.

To defend against threats, in ancient times, humans were often vulnerable to attacks during the night due to limited visibility. It's believed that a heightened sense of hearing was vital for detecting enemy movements. Those who could perceive the footsteps and direction of potential threats, and subsequently flee, were the ones who survived. This could be why the human ear is sensitive to sudden, dynamic sounds, the kinds that signal danger. Conversely, constant sounds pose less threat, and thus we don't need to be as attuned to them.

Humans typically can't detect sounds above 20 kHz. However, that's mainly for continuous sounds like sine waves, which aren't seen as threatening. If the range above 20 kHz is eliminated because sine waves aren't detectable, then while static performance might improve, dynamic performance suffers. This results in sounds that feel inauthentic because we don't perceive them as immediate threats.

Equipment designed with a focus on static performance, like low-pass filters (LPFs), can inadvertently compromise sound quality. Many might not realize this, even some engineers. Over-reliance on numbers and metrics might lead them to believe that reduced noise equates to better sound. This mindset, prioritizing static over dynamic performance, could be termed as the "curse of Fourier."

Digital calculations further complicate sound. Operations like oversampling digital filters and digital phase-locked loops might not be intrinsically flawed, but they can obscure the real essence of sound. SOULNOTE's digital tools allow users to toggle between NOS and FIR modes to discern the impact of digital processing. The takeaway is that the essence of digital sound isn't the issue; the problem arises when we neglect the characteristics of human hearing.

Soulnote Audio

SOULNOTE Chief Designer Kato's
Design Philosophy Series - Part 9

The construction of a device's chassis impacts its sound quality. In past discussions, we've explored the distinction between Static and Dynamic performance. Now, we delve into a longstanding query among audiophiles: "How does a device's enclosure influence its sound?" This is another aspect of Dynamic performance, only discernible by actual listening.

SOULNOTE products showcase features like unfixed panels and lightweight cables, which contrast the heavy and rigid design prevalent in high-end products. But why?

The enclosure's effect on sound seems more significant than that of the electrical components. For instance, during the development phase, it's not uncommon to consider an open-top panel for efficiency. Yet, the refined sound can be drastically altered as soon as the top panel is sealed, resulting in a more confined auditory experience.

Vibrations seem to be the culprit behind these changes in sound quality. While measures have been adopted to counteract vibrations, such as anti-vibration rubber and weights, the results are mixed. I've often found that sound quality diminishes with these solutions. The ideal would be to entirely eliminate vibrations, but that's nearly impossible. Different materials used for dampening vibrations have their unique frequency characteristics, which can inadvertently colour the sound. Therefore, allowing these vibrations to be light and free might be more beneficial.

In the subsequent article, I'll delve deeper into another crucial aspect of vibrations: resonance.

Soulnote Audio

SOULNOTE Chief Designer Kato's
Design Philosophy Series - Part 10

Physical damping (vibration isolation) can obscure the waveform on the time axis. While I've previously discussed the potential influence of vibration isolation materials on sound, it's essential to consider the time delay aspect. Overlapping delayed signals can dampen the sound's clarity.

SOULNOTE's RSC series speaker cables are thin, lightweight, and designed to resist dampening. They're most effective when suspended in the air.

One overlooked damping material is air. When confined, air becomes viscous, similar to rubber. When equipment is sealed, the trapped air inside can act as a damping agent, potentially altering sound quality.

SOULNOTE's top cover is designed not to trap air, and it's anchored with spikes. This design ensures the air within remains unconfined, preserving the sound's integrity.

Audio racks have also evolved, moving away from encased designs to open structures for better sound quality. SOULNOTE products, which prioritize unconfined internal air, benefit from open audio racks.

In the following article, I'll delve into resonance and its potential impact on sound.