About The Pico Speaker Grounding Blocks

The pico speaker grounding block is another very important variation on the theme. With this component we provide a mechanical ground for the tops of loudspeaker cabinets. We have actually produced versions of the speaker pico for several years, and then we used to call it an acoustic absorption module. But ‘acoustic absorption module’ or ‘grounding block’ are really the same in this context – it’s again all about taking vibration away and breaking it down.

We all know that most conventional loudspeakers are, in essence, a set of drivers bolted into a box. The driver motors convert an electrical signal into the motion of a diaphragm or cone, and this energy is imparted into the air. The cone has to push against the air, the air creates a load. And because of this there is always an equal force pushing back against the magnet – the voice coil gets propelled forward and the magnet gets propelled backwards, only the magnet is not free to move (much). Imagine this process now going on at audio frequencies, a force vibrating the cone back and forth, and also the same vibration fed into the magnet, because there is always that equal and opposite force present. So we have the same vibrational energy in the magnet assembly as there is coming off the cone, (but 180 degrees out of phase).

Where does that vibration go? Well, because the driver is bolted into the cabinet, the vibration goes into the cabinet. There will be some losses at this boundary between the driver frame and the cabinet, but if we assume the bolts are done up tight, then most of the vibration passes through into the cabinet. Now, this is a good thing! We don’t want to leave that vibration in the motor because it’s vibrating the magnet – and if the magnet is vibrating, then the voice coil is not pushing against a static field, but a vibrating one and this modulates the sound. And we know this to be true as we all occasionally tighten the screws holding the drivers in, and instantly hear the improvement in the sound.

So we know that the motor vibration passes into the cabinet. Now, the cabinet material will conduct this energy around the whole box, so it can pass into the motors of other drivers or back around again into the originating driver, but delayed. So even though the drivers are bolted in tightly, we are still always losing some performance because of the vibrational energy within the cabinet getting back into the driver motors. Indeed, what would be even better would be to allow the cabinet to drain the vibration out of the driver very efficiently, in one direction only, but not to let any get back in again.

The next thing that we know can be effective is to use good spikes or couplers on the bottom of your speakers, and try to drain some if this vibration into the floor. And if done correctly this often brings an instant improvement in performance too. But this can be problematic because you may not have a solid concrete floor, or you don’t want to put spikes into a lovely hardwood floor.

But look, and you can see whats coming here, we can use a Vertex AQ acoustic labyrinth sat on top of the cabinet to drain out some of that vibration. And if we use wooden feet on that Vertex device, we will reasonably match the acoustic impedance to the cabinet, and when the vibration gets into the labyrinth, rather than it just bouncing back down into the cabinet again, we can break it down in the labyrinth. The labyrinth has so many different acoustic paths that all the audio frequencies that pass into it are randomised and summed together, to end up with a net zero – that’s the principle of destructive interference (checkout interference (wave propagation) on wikipedia).

Use And Sound Quality

So the Pico Speaker Grounding Blocks (supplied in pairs) comprise a Vertex AQ acoustic labyrinth in an extruded aluminium box with hardwood feet. You simply place one on the top of each speaker cabinet and they provide an effective acoustic drainage route to lower vibration in the cabinet. And now we have explained all the principles, hopefully you can see how this will be an instant benefit to sound quality.

And a considerable improvement is what you get. Much like when you tighten up the mounting screws, but more so. You get improved clarity, definition and detail, imaging gets better as does tonality which sounds more natural and believable. The benefits also become more worthwhile if you like playing complex music or you like playing quite loudly – this is where the vibration pollution in the drivers can get worse, and the picos add considerable listening headroom without your speakers becoming harsh and muddled sounding.