Noise control

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woodman

New member
I finally got the CV1800 running. Maybe related to the alcove I have it installed in (see Steve's cyclone install in gallery), but standing at my TS ( which is about 7 feet away) it registers 98 dB without the muffler. I'd sure like to get this lower, and have read the suggestions on Bill's site.

My question is if anyone has any results to share with thier sound and vibration dampening efforts? I noticed that the plastic on the blower housing vibrates quite a bit, and am considering the Dynamat Extreme sheets on the blower housing, filter transition and upper cyclone area. I don't feel to much vibration on the motor mount, so it seems like the stock bolts and rubber hose are doing an OK job. Also considering upgrading them, if necessary.

Any pros/cons and any thoughts are greatly appreciated.

Many thanks,
Steve
 
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Steve,
The first question I have is what scale did you measure the db levels? They seem very high. You should be using the A scale as it is the one that is representative of human hearing.....not the C scale. I had a problem with my measurements at first because I was using the C scale. I didn't realize it till I took a reading in my Dodge Caravan and got 90 db. That was with the van going down a paved street at 15 MPH.

Ok, now to your problem. The noise is coming from the blower. I don't believe you can deaden it very much by covering the housing. It will help some, but not as much as putting a sound deadening material in the alcove. You can line the walls with carpet or sound deadening foam (all foams are not created equal, so you need to use a type that is specifically for sound proofing). Closing off the front of the blower with a sound proof panel will also help a lot. That panel needs to extend down a couple of feet below the blower.....ideally you should close off the entire front side, but something is better than nothing.
Please keep us posted on this.

Ed
 
Ed, My bad....I had the meter set to C....so I'll have to re-test later today. Thanks for pointing that out.

The folks at Dynamat did a good job convincing me that if I can curtail the vibrations, that I would be able to cut down on the noise. Which is what got me thinking about placing a couple layers of it over the plastic blower housing.

I'll provide updates to this thread as I progress.
 
Steve, another thing that could be causing extra problems is having the unit "coupled" to the wall. Any vibrations from the unit will go to the wall which will act like a big speaker and increase the volume of noise. I have my unit isolated on a separate mount, and the unit is no louder than my contractor saw. I do exhaust outside which helps with the noise also. If you didn't use anytype of isolators on the mounting brackets to the wall, though it would be a hassle to do it now, they might help a little. Jim.
 
Jim, I think you're right about the wall acting like a speaker. More like an amplifier I would say since it's enclosed by the three walls. It's not the best installation scenario, but it's what I have to work with...

I'm going to try every little bit that may help with the noise since I have a very small shop to work in, so I won't rule out changing the mounting method...especially since I plan to take most of it apart to install the Dynamat. For ~$40 bucks, I think it's worth a shot to place it around the blower housing.

I'm curious...Is there alot of vibration on your plastic blower housing? I'd like rule out whether I have a unique issue, or not. It vibrates the most near the exhuast transition, which would make sense from what I've read on Bill's site. I.e. Each time an impeller wing passes the transition, it'll generate noise/vibration.

Also, I didn't caulk around the dado track that the plastic slips into the MDF blower housing top and bottem. Is that recommended?

I agree with Ed, that installing sound absorbing material on the walls will be a big help along with an enclosure.

BTW, I rechecked the dB with the scale set to A....98 without the muffler. Once I begin reassembling it all, I'll report back the readings with the muffler attached.

Thanks for the responses, and I'll keep you posted.

Steve
 
My Clear Vue is not enclosed, and it is attached to the wooden wall frame of my shop using the mounting kit provided with the cyclone and a support bracket that follows the basic recommended plan. Since my wall framing is exposed, I put a sheet of 3/4 plywood on the wall to span the distance from the frame members, and I put fiberglass insulation between the plywood and sheet metal walls of my shop.

Unlike Jim, I do not vent outside. I don't feel any particular vibration in the sheet metal walls of my shop. I've never measured the noise with a meter, but I can tell you that although the cyclone is loud, it is not as loud as some of my tools. It is slightly louder than my table saw (a Delta Unisaw). As noises go, it is not annoying. It is not as loud, nor nearly as annoying as my shop vacuum.

I always wear hearing protection, even when doing relatively low-noise woodworking, so my noise concerns are mostly that I don't annoy the neighbors.

I'm betting that you are right about the walls acting like speakers. The unit itself just isn't normally as loud as you report. I did caulk the dado track on the blower unit and outlet transition.

Fiberglass insulation is a pretty good sound insulator too. It works best on mid- to high-frequency noise. I'll bet the Dynamat is better at lower frequency noise, but they might complement one another. (This is just speculation, not a recommendation, since I have no experience with Dynamat.)

I look forward to hearing how it goes.
 
woodman said:
Jim, I think you're right about the wall acting like a speaker. More like an amplifier I would say since it's enclosed by the three walls. It's not the best installation scenario, but it's what I have to work with...

I'm going to try every little bit that may help with the noise since I have a very small shop to work in, so I won't rule out changing the mounting method...especially since I plan to take most of it apart to install the Dynamat. For ~$40 bucks, I think it's worth a shot to place it around the blower housing.

I'm curious...Is there alot of vibration on your plastic blower housing? I'd like rule out whether I have a unique issue, or not. It vibrates the most near the exhuast transition, which would make sense from what I've read on Bill's site. I.e. Each time an impeller wing passes the transition, it'll generate noise/vibration.

Also, I didn't caulk around the dado track that the plastic slips into the MDF blower housing top and bottem. Is that recommended?

I agree with Ed, that installing sound absorbing material on the walls will be a big help along with an enclosure.

BTW, I rechecked the dB with the scale set to A....98 without the muffler. Once I begin reassembling it all, I'll report back the readings with the muffler attached.

Thanks for the responses, and I'll keep you posted.

Steve
Click to expand...


I'll have to check the vibration part. Not that I recall noticing before, but I haven't put my hand on it while it was running. I built a "tree" that mine mounts to. It is kept away from the closet walls using some of the black styrofoam that Ed packed my cyclone in for shipping. I also have several pieces under the tree to de-couple it from the floor. My exhaust goes to an 8-6-6 wye, and then I used flex hose from there to the outlet vents so that it is also de-coupled from the wall. I think it isolated the cyclone very well. Pictures of my set up are under Coolmeadow Creations Fort Worth on the Gallery.
I did caulk mine from the outside, after it was assembled. That way it seals the joint, but doesn't glue it together so I can get it apart if need be.
I have fiberglass insulation on the wall behind the cyclone with plastic vapor barrier up, then open fiberglass insulation on the side walls and the tree behind the cyclone body. One of these days I'll get around to building a door for the closet which should also help some. Jim.
 
Thanks for the feedback, guys.

Yup, my old craftsman shop vac and a few other tools are quite loud, too, but not a problem with ear protection. The flip side is that the tools are on periodically as I cut/fit/cut/fit/cut/fit:) That goes one longer depending on the type of day I'm having:) Throughout all this, though, the cyclone should be running. I read that it should not be power cycled more the 6-7 times per hour for fear of overheating the primary windings...correct me here if I'm wrong. It'd also be nice to have it scrub the air while I'm not using the tools.

The neighbors are also a concern...dare I admit what the zoning board thinks my 'storage shed' is? ;)

Either way, I'm sure with some enginuity, I'll get the sound down to a good comfort level.
 
Photo's of muffler

Photo's of muffler

I also have just received my new ClearVue and was wondering how to keep the noise levels down. I seem to remember a few months ago, there were pictures posted in the photo gallery of someone making a muffler - what ever happened to these pictures? Ed - could we get you to re-post please?

Regards,

Reid
 
Nevermind - I found the pictures - don't know how I missed them. Have others out there built this muffler and if so, how effective has it been?

Reid
 
I have a 3 to 4 dB loss with my muffler. I essentially built the same one you see, but instead of the egg-crate like foam, I used two layers of McMaster-Carr part# 5692T13. There may well be a better foam solution out there, but I decided that I wouldn't be able to tell the difference between them, so I settled on it.

I will admit that I've dug myself into a hole with my choice installation location, but am determined to lower the volume as much as I can. I'll share my findings as I go along.

I just saw Nako's soundproofing installation in the gallery...WOW! I can't wait to hear some details on that! Great inspiration.
 
Muffler

Muffler

Just registered in but I'm definately interested in the pictures of the muffler if anyone would share them with an ole Ky boy...
 
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Hi woodman,

I hope my post is helpful to you for your project. Since your query on my gallery, I posted more pictures and comments. I believe you are correct to first put your attention to the blower assembly and as Ed had suggested to me much earlier on in my install, I found that most of the noise originates there. When I started thinking about noise reduction, I visited quite a few web-sites looking for sound reduction theory and material info. I also looked at Dynamat as a solution since it is used so widely for auto and industrial applications. I worried a little bit about adhesive and PETG compatibility, but didn't research that much further. Also, the cost factor got me wondering about alternatives to some of these commercial products.

Most of the info I got from web browsing research indicated that acoustic foam was effective as a sound absorber, but we also need a heavier and denser material to act as a sound barrier for this to be effective. Hence my use of foam around the blower unit and cyclone cylinder wrapped with closed cell 1/2" vinyl material. The foam was from a retail guy and the "barrier" material was previously an anti fatigue mat. I glued the foam to the mat, wrapped the combo in place, synched it with nylon strap from a cheap ratchet clamp I found on sale at a big box store and put some duct tape to hold the strap in place. That combo got some very noticeable results in sound reduction.

In my experience, the second largest source of noise is carried along in the air current in the exhaust from the blower. Thus the muffler many have made. I made a modified version of the muffler using a flex hose wrapped in foam and fibreglass insulation. I did it this instead of lining the inside with foam because I'm just too lazy to take it apart at some later date to clean it out. I probably sacrificed some noise reduction as a result. They say that life is full of compromises and so there goes your proof. I should mention that I also made a second similar muffler enclosed inside my filter box (it worked pretty good too) and I will post some pictures about that aspect of my project sometime very soon.

I wish I had of taken more pictures of the blower and cylinder enclosure to show more of the acoustic materials, but no doubt there are many ways to achieve these same or better results. In any case, I used a combination of fibreglass acoustic insulation wrapped in plastic bails to prevent any chance of floating debris from the insulation. Also, it's just a whole lot easier to install these bats into tight spaces this way. I used acoustic foam inside the enclosure that was glued to a 1/2" sound absorbing board that is made of paper fibers that goes by the trade name of Homasote. I attached the sound board to the 3/4" MDF enclosure with a few drywall screws.

By my subjective evaluation, I got pretty good results - I can hear the music from my shop stereo while the cyclone does its two stage thing and scrubs the air in my shop cleaner than ever. I plan to get some objective measures with a sound level meter sometime soon and will report these results in another post in this forum. I'll also post more pictures of my filter box on the gallery very soon.

My last thoughts for this post are that while I am pretty happy with my outcomes, I have no doubt that more research and engineering could yield better results, I just ran out of time for now. Also, of course it's buyer beware (I'm still slightly skeptical about the "Acoustic Foam" I bought), but for certain some commercial acoustic products have an economy and efficiency if you consider DIY time for research, engineering and sourcing materials. I just couldn't resist and I don't care what Sigmund Freud would say about that. Finally, I have no regrets about building the damn thing. After all, in my world any time in the shop is quality time. And the means justify the ends since I plan to use my lungs and ear drums for quite some time.
 
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Nako, Thanks for the reply. Well, I wrapped two layers of dynamat around the plastic blower housing, two on the filter transition and one of the cylinder part of the cyclone. I also installed neoprene vibration isolation hangers in place of the default setup included with the kit. This, along with the muffler and filters attached, I'm now down to 88 dB. Which is quite an improvement for me! The dynamat really dampened the vibration of the blower housing and filter transition and there is barely any perceptable vibration on the wooden frame wall mount.

I still plan to enclose the upper part of the cyclone to block the sound even more. I'll post the results afterward.
 
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Hey Woodman,

Thanks for the info from your dynamat application. How far from your cyclone are you taking your db readings?

I installed the cleanout to my filter box last night and was pleasantly surprised to find that I got another small decrease in noise. Standing at my table saw, 10' from the cyclone, my readings are 78 db with the blast gate open and 80 closed (the impeller makes a bit more higher pitch sound possibly due to the different type of turbulence in the impeller housing).

I'll take a few more pictures and post on my gallery in a day or two. In the meanwhile, take a look at the acoustic ceiling tile I put on the walls around my cyclone. I don't have any readings before and after since I just recently aquired the sound level meter, but this did make a definite small improvement in audible noise levels. This was relatively inexpensive since I had some tile left over from a basement room project, but you might also want to look into engineered acoustic foam products that would probably give even better results.
 
What if you were to enclose the alcove and make it a closet?

How tall did the 1800 end up installed that way?
 
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Nako, I was about 8 feet away, which is right in front of my TS.

Scott, I'm going to box in the upper portion of the cyclone, with an access door, instead of fully enclosing the alcove like a closet. That -would- be an easier solution to build though.

Since I want the clean air circulated back into the shop, I'd have to have a return air grill in the wall if it were fully enclosed to the floor. I think this would allow noise to come through and pretty much defeat a lot of the noise blocking properties of the full wall which needs to be air tight. If I think I'm having a heat problem with the motor, I can pop a ventilation grill into the ceiling directly above the motor, which would vent into the attic. It's doubtful that I or my neighbors would be bothered by whatever noise leakage occurs there.

I'm not sure what you mean by your second question?
 
Ya know, after sleeping on this, I'm beginning to seriously consider just closing up the whole alcove with a door. It'd be much easier, and I'm not sure whether a small opening at the bottem (8in diameter circle) will be such a problem that it would outweigh the effort in building the horizontal section below the cyclone that would have to account for the muffler and cyclone cylinder....
 
Hey Woodman,

You could get good noise reduction by enclosing the alcove by using acoustic insulation inside your partition wall. Also, lining the interior walls with some acoustic ceiling tiles would also help to reduce reverberation noise that would try to echo through your partition wall. As for the vent back into the shop, you could do a staggered baffle to reduce the noise transmission. Attached is a link with a small sample of a machine enclosure with baffle vent.

http://www.acousticalsurfaces.com/acoustic_enclosure/noisy_machine.htm?d=44
 
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