Muffler for G0 440

[Kris Cook]

I am looking for input from those that have specific experience (Glenn Bradley - hope you see this). I have my DC fully functional and I have good pickup from all of my tools with the 2HP Grizzly unit. I bought but did not install the muffler for the G0 440 unit.

My neighbor, for whom I have great respect, and would never complain, has his bedroom fairly close to my garage - probably 25'-30'. I turned on the DC today and walked around to their side of my garage and the noise is fairly noticeable/obnoxious. I have refrained from running the DC after about 8:00 PM because of this. This is the time of day when I have a couple of hours to get some projects done so trying to figure out ways to deal with this.

I didn't install the muffler because I was worried about reduced performance, and as I recall, seems the noise reduction wasn't significant but I could be wrong. Given my predicament, I am willing to give it a shot but don't want to start cutting hoses if it doesn't provide significant benefit.

Thoughts on noise/performance reduction by installing the muffler?

[glenn bradley]

Hi Kris. When I first got the G0440 back 2008 I got the muffler with it. I ran the unit with and without the muffler. Without an instrument to check, the perceived difference was pretty minimal. The impact on performance was not noticeable if it exists. I will say that getting the muffler into the path in the standard filter configuration is a bear. I did install the muffler in my new configuration simply because I had it.

New Shop (449).jpg

I imagine the muffler is attenuating some frequencies and therefor some noise level. The bulk of the noise from a DC is air in motion. You can demonstrate this by running your DC with a few gates open and then closing them all to hear the difference. Like a shop vac or a router it is not so much the noise that disturbs as it is some frequencies of that noise.

You have done a little recon near your neighbor's wall area while the unit is on. Is it the low roar or the higher 'jet engine' sounds that concern you? The higher frequencies get reduced / scattered by passing through walls, fences, and botanical attenuators (bushes and trees) . The lower frequencies carry better and are probably less effected by the type of muffler we have. Both types of sounds could probably be reduced to the outside world via a sound blocking panel between the DC and outside wall. There are a few threads on here about different methods for soundproofing the shop.

I now vent outside (there is quite a distance between neighbors at the new shop) and had designed a rather good baffle as part of the original installation plans.

New Shop (187).jpg

As this phase of the project got closer I started some open conversation on a few forums. I soon realized that I was skipping the very first step one uses in any decision tree; what happens if I do nothing? I tried the exhaust with only the commercial muffler in the path. I added a long 90 degree elbow outside the shed and aimed the exhaust at the ground, at an angle . . . that is, not straight down. This got me to where I wanted to be and I am so glad I didn't over build and use a lot of time for a minimal return. My point is, maybe you want to get some direct input from your neighbor. You are a good person for being concerned about your noise levels but it may be a non-issue for the neighbor. I would ask before I went much further.

[lawrence dosson]

Kriss
i installed one on my 443 version of the same collector it helped a little with the high-pitched scream part of the noise
i see no difference in the way the collector works
on my version it was quite difficult to install i had to toss the instructions
Lawrence

[Jim Becker]

Mufflers on the exhaust side don't have major impact on performance...no worries. And make sure the business end of the exhaust is pointed at the ground to further reduce direct sound transmission.

[Kris Cook]

Thanks Glenn. It's definitely the higher pitched frequency that is carrying. Looking at the space available between the blower and the filter I can see the muffler would be difficult to install.

I will play with some other options as regards attenuation. The DC is on a floor stand and on the far side of the garage from the neighbor, so this adds another 15' or so to the distance stated.

I will also talk to my neighbor.

Every time I see your quote I think of "someone got excited had to call the state militia, gonna move" even though that's not the next line in the song.

Thank you Lawrence and Jim. Probably won't install the muffler at this point. DC is exhausting in the garage - standard configuration.

[Jim Becker]

I didn't understand you were exhausting inside. Perhaps you could consider a sound reducing enclosure....I did that at my old shop and it was amazing at how it knocked down the sound level to the point one could have a normal conversation in the shop with the DC running. A non-direct return path for the air helped keep the sound at bay, too.

[Kris Cook]

I didn't understand you were exhausting inside. Perhaps you could consider a sound reducing enclosure....I did that at my old shop and it was amazing at how it knocked down the sound level to the point one could have a normal conversation in the shop with the DC running. A non-direct return path for the air helped keep the sound at bay, too.

Thanks Jim. I read the thread with the baffle concept several times when I was planning my shop build. I have a couple of ideas I will try first and then I may look at something closer to the DC itself.

[Keegan Shields]

I thought I read somewhere that the type of impellers used in DC systems were very sensitive to exhaust restrictions… that’s why you get such a performance gain with a oversized filter or by venting outside.

[Jim Becker]

If you are actually restricting the exhaust, yea, it will be detrimental to performance. So anything you do to keep it at "free air" or better is going to be the way to go.

[Bill Dufour]

I thought the poor mans muffler was an, oversized diameter, length of flexible insulated heating duct.
Bill D

[Jim Becker]

Bill, in general, both the homemade and commercial mufflers for cyclones are essentially similar what you describe but "more constructed". They do not directly impact the air flow through them aside from maybe a little bit of friction because the the sound absorbing material used is not smooth like the pipe. I suppose you can use large diameter insulated flex duct like your describe, too.

[Keegan Shields]

All mufflers attached to an exhaust generate back pressure. And the better the sound reduction, the more restrictive they are. So it seems you need to find where the trade off point is for you. My 2hp system vents directly outside via a 6” pipe. Neighbors are close and have never even noticed.