Testing, or putting yer money where yer cake hole’s at!

I put the exhaust hoses into the baffles and measured the noise from 1 meters away for 30 seconds. I then repeated the measurement after I removed the exhaust hoses. I am using the Noise Exposure app from the Swedish Work Environment Authority. The app is not updated for my iPhone SE 2020, so the exact decibel readout might not be dead accurate. The app is however adjusted for the iPhone 8, 8 plus and X so I think it is pretty spot on. My findings are also pretty much in line with the findings in the forum thread by the user Moonsafari69.

Regardless, using the same phone and the same app I can do a comparison. I also did several measurements to verify that the app returned the same value ±.3 dB. Which it did. This should indicate that the measurements are at least comparable.

The readings shows a 9dB reduction! That’s huge! The 3 dB rule tells us that the sound pressure level has dropped by a factor of ~10!

What does this mean? It means that I can speak in a normal voice. I can listen to music. I don’t have to use ear protectors while the DC unit is running. The sound pressure level is reduced, but more important: the perceived noise is completely different. The jet engine like squeal is muffled down, and the sound of air blasting out from the exhaust ports are gone. I suspect making an insulated enclosure would reduce the noise even more. This might be unnecessary though, as the noise from the inlet of any connected tool will still be loud (plus the noise from the tools). If you have a central vacuum system in your home, you know that vacuuming is a noisy business just from the sound of the air being sucked into the nozzle.

And relax – an enclosure won’t make the unit overheat. Up to 108 litres of air is rushing through the system every second. My own findings, and those of Moonsafari69, shows that the air from the CamVac does not get any hotter.

The performance does not seem to be affected in any way, and if so the negative effect is negligible.

But enough yappin’ – let’s hear it. Here is a quick video with ONE motor at a time to give you an idea. I start the DC remotely, and at first you hear a single motor without anything connected to the exhaust. I then reach in and switch the motor off, then I start the other motor which is connected to the noise baffle.

With the concept verified, I completed the enclosure and gave the thing two coats of white paint. And yes, a lot has happened in my shop during the time I’ve worked on this, but let us not focus too much on that. I spent 1.5 years from start to finish due to “life events“. As you might imagine, finishing this was a rather big milestone for me.

I made a small “roof” over the exhaust side, to which I glued a piece of foam panel. Just to reduce the noise further and to make it more difficult for stuff to fall into the baffle. I made a French cleat wall mount to hang it above the CamVac and dressed up the front with a small piece of wood. It makes the thing look like a pipe organ pipe!

I also made a hose holder from some plywood scrap, which is screwed to the sides of the baffle. The hoses extend into the foam lined pipes.

With the baffle mounted to the wall, the distance between the CamVac and the noise baffle is rather short. I therefore cut the hoses a bit long and looped them from the baffle to the CamVac. That worked great. The hoses have a connector that fits perfectly into the exhaust ports, which makes it really easy to disconnect them when it is time to empty the CamVac.

And here is the final result:

This noise baffle really did change things to the better. With the baffle connected, there is more noise coming from the business end of the suction hose than what you hear from the DC unit, especially if you stand a few meters away.

If you have a CamVac unit, do this. If you are in the market for a dust collector, I do recommend the CamVac units above all else. The built-in filtration down to 0.5 microns and the ability to hook it up to a simple noise baffle makes it a really tough product to beat. A shop vac does not have the 4” (100mm) port you need for bigger machines, nor do they have the power you need for bigger machines (great for sanders and small diameter dust port applications though).

And here is an idea for you: since the vacuum based dust collector works just as well (if not even better) with smaller diameter hoses and pipes, you can use central vacuum cleaner system parts for the machines who does not require or have big dust ports! The wall ports has built-in blast gates – really a neat solution, I think. Quiet dust collection? Used to be a brush and a pan. Now you have options!

On the next page, we’ll look at my dust collector duct system.