SOULNOTE Kato’s Design Philosophy Part 10.

SOULNOTE Chief designer Kato continues his essay series with the topic physical damping (vibration isolation) and how it affects sound. 

Physical damping (vibration isolation) blurs the waveform on the time axis.

In the previous issue, I wrote about the possibility that vibration isolation by rubber or weights may be putting habits on the sound. For simplicity, I wrote about the frequency response of the vibration isolation material, but to be precise, it is the delay on the time axis. I feel it is reasonable to think that the overlap of delayed signals blurs the rise of sound and reduces the sensitivity of human hearing. Thick, heavy cables enhance bass! Many people say. That is only because the rise of the sound is blurred and only the low frequencies are noticeable in comparison. Isn’t it much more unscientific to think that cables amplify sound?
SOULNOTE’s RSC series speaker cables are single wires with foamed Teflon coating. It is very thin, lightweight, and resistant to being damped. This is even more effective when it is floated in the air with a single point grounding cable insulator.

Invisible damping material ruins the sound.

It is air. When sealed, air is a hard and viscous substance, like rubber. Air suspension supports cars and trucks. In other words, restrained air is very hard. It just doesn’t feel that way because we are usually exposed to unrestrained, free air.

When the top cover is tightened, the air is restrained.

Now, in my previous talk, I wrote about an example of sound damping, losing a sense of openness and atrophy as soon as the top cover is tightened. This does not seem to be an electrical shielding effect, since the tendency is the same even if the top cover material is made of wood, for example. But we are forgetting the presence of trapped air. When air is trapped, it becomes as hard as rubber and damps the board and all the components on the board. Lots of small holes are not going to be effective in releasing air. This is because air has a strong viscosity. And air, like rubber, holds back fast movement more forcefully.

SOULNOTE’s top cover does not restrain air.

The top cover of SOULNOTE is not fixed; it is placed on the body by three spikes. Of course, they are hooked to prevent them from coming off. If it were easy to come off, we would not be able to sell it as a product. As a result, it has the effect of loosening the air restraints inside. I thought about how I could provide you with the sound with the top cover open. After much thought and trial and error, I finally succeeded in creating that top cover that rattles when you push on it. Of course, it would be better if the top cover were somewhat lighter, but this would cause another problem: resonance. We solved this problem by joining two types of boards at three points to form a composite material top panel, and at the same time succeeded in releasing the air inside. This effect can be confirmed by experimenting with placing weights on the top cover. When weight is placed on the top cover, the sound instantly loses its openness and becomes boring and ordinary high-end audio sound.

About audio racks

These days, audio racks surrounded by boards like a bookcase are becoming less common, and racks with four pillars supporting the boards are the norm. I think this is because of the better sound. In fact, the sound is good. There are also racks with holes in the boards. The manufacturer explains this as to adjust the vibration mode of the board, but I think it is another effect.
SOULNOTE’s RAR series audio racks also have holes in the boards. The reason for this is to escape the effects of air damps. When audio equipment is enclosed by boards, it instantly sounds cramped. On the other hand, if the audio rack is open, the sound will be liberated and the sound field will be expanded. SOULNOTE products, which release the air inside the product, require an open audio rack.
In the next article, I will write about resonance, a mechanical element that kills sound along with damping.