Sound Suppression Base for Venus

Sound suppression has been a big topic with some Venus 2000 fans. The basic problem is the power unit is not only heavy, but the power stroke is not even. It has a point, not unlike top dead center on an automobile compression, stroke where effort maximizes. Thus as the drive wheel rotates, the torque required is not even through 360 degrees.

As it hits this "bump in the road" on each turn of the crank, it can make a "whoomp" sound. Not overly loud, but obvious if under heavy load. If the diaphragm is set just right and the slack in the drive motor gear reduction is just right, and the load is light, Venus 2000 can be as quiet as just the whoosh, whoosh of the air in and out of the hose connectors. I do not want to imply that the Venus 2000 power unit carries on like an old rickety bedstead rhythmically slamming into the wall or someone whaling away on the floor with a rubber hammer. If it does, there is something wrong that needs correcting.

But in my experience the power unit tends to make some noise. Of course, I do not find this airborne noise a problem in my case, and just ignore it. But there is one thing I do mind and do take care of. Noise transmitted through contact with the building structure.

If you place the Venus 2000 power unit on a hard surface, that surface will act like the sounding board of a piano and amplify it. It will travel through walls and floors. While keeping any minor airborne sound in the privacy of your own bedroom is easy, this structure dwelling sound roams freely from room to room.

The solution to this conducted sound is to "acoustically disconnect" the Venus 2000 power unit from the building structure. This can be as simple as running the power unit on a thickly carpeted floor, where the carpet prevents it from contacting a hard surface directly to which it can transmit sound by direct conduction.

But my solution has been to create a wooden base for my Venus 2000 and float that base on two 1/2 inch layers of foam rubber, like used for padding in shipping delicate objects. I was able to find four extra long rubber feet to replace the short ones on the original unit. This allowed me to countersink four holes in the wood base to accommodate the feet. The holes were drilled with one of those big flat paddle drills, a 1 1/4 inch wood bit. Only about 1/4 inch deep was plenty. The extra long rubber feet drop into these four holes, locking the power unit in place on the wooden base.

Even this is overkill. Any piece of wood or really heavy cardboard will work without the holes. You just need something flat and solid  to support the feet and keep them from sinking deep into the foam. The holes or recesses for the feet are just something I had resources to do.

The reason I did not set it directly on the foam was that the feet would sink deeply into it and heavily compress the foam right under the feet and "defeat" the purpose. Also I wanted to keep the underside of the Venus 2000 power unit clear of contact with the foam padding so the power unit base could have air under it. This lead to the design with a hard layer floating on the foam. One can even be extra fancy and put a sheet of stiff cardboard between the two layers of the foam. It is known that such a structure, alternating layers of hard and soft material, are quite effective in preventing conduction of sound energy.

With the Venus 2000 acoustically disconnected from direct contact with a hard surface this way, it is much quieter and what sound remains does not transmit except through the air. You can prove this by placing the Venus 2000 on a hard topped dresser, turning it on, and then picking it up by the handle on the power unit. You should hear an immediate change as soon as you lift the power unit free of the dresser top.

Once I had the base plate, I also mounted a small round base fixture I had salvaged along with some aluminum support rod. This plus a special clamp created a little adjustable support arm that can support the receiver hose.

In my normal use, the Venus 2000 power unit sits on a dresser next to the bed on its padded base. This adjustable support arm helps keep the hose under control and makes sure the hose does not unduly pull on the receiver. I have found that in my normal use, this hose hanger arm is a quite worthwhile addition.

But the main function of the base is to sound isolate the Venus 2000 power unit from the rest of the world. The idea is simple. A hard surface for the Venus to sit on, like a section of 1/4 inch plywood, and that floated on some foam rubber or a pillow, instead of the Venus 2000 being set directly on the hard surface of the dresser which in turn sits in hard direct contact with the floor. Thus breaking up the path which would allow Venus 2000 sound to be amplified by the "back board" of the dresser top and transmitted through the structure of the building. The little adjustable hose support is just a bonus.

The ring on the support arm can also be used to hang the control head from a special little clip. The Venus 2000 control head has a nasty habit of wanting to be on the floor, and slithering off like a snake at every opportunity.

This second modification used a small clip such as used to close fancy coffee bags after opening. Because of a pronounced overbite, such clips get a great grip on bed sheets, for instance. Added to a few swivels and split rings, I found a combination that would slip over the controller's connector and wire. A bit of spiral split wrap like used for corralling wire bundles was used to bundle the stroke control hose and the controller wire next to the control unit head. The entire thing can now be secured to a pillow case, or a sheet or even hung from the ring on the little gantry. Result?

No more slithering away onto the floor at every opportunity. These clips are also found on fancy plastic nametags for attachment of the nametag to the shirt, a good reason to save your next nametag.

The Venus 2000 has a plastic base plate secured under the rubber feet. At one point I tried removing this to improve cooling. But I have not really found that the Venus 2000 heats up a lot, even with extended usage. What I did find was the plastic plate seals up some holes in the metal plate that is the real base of the Venus 2000 and does add to the noise suppression.

Personally, I find this solution to any noise the Venus 2000 makes in operation more than enough, and better than struggling with the diaphragm fit and other hardware in an effort to totally quiet the unit. The baseboard and foam layer trick should keep things quiet enough that no one will be tipped off to what you are up to in the privacy of your own bedroom, at least not by noise from the Venus 2000 power unit.

12/03