What kind of door for cyclone closet?

[Bob Johnson]

I'm getting ready to build a closet around the cyclone to try to quiet things down some. I guess that a prehung steel exterior door with weather stripping would be the best choice, but that gets a bit expensive. On the other end of the scale, a cheap interior hollow core interior door - would this do enough to be worthwhile? Or would just hanging a blanket over the hole be better?

What have you guys that have built cyclone closets used?

Bob

[Jamie Buxton]

Basic physics says that adding mass to a wall helps it reflect sound. Reflecting sound back into your enclosure means that less escapes. Hanging a blanket in the doorway will have almost no effect. If you don't want to buy an exterior door, you could use your cheap hollow-core door, but then put a layer of sheetrock or two on the inside. The rock provides the mass to reflect the sound. Sound leaks through cracks, so weatherstripping the door would help.

Of course, making the door very resistant to sound won't help very much if the rest of your closet is transparent to sound -- like it has holes in it, or if it is just made of thin plywood.

[Alan Tolchinsky]

Hi Bob, You need some way for the air to get out of the closet so I would use a louvered door for this. Or use a solid one and provide another means to relieve the pressure from the blower exhaust. Unless you're set up is different from what I'm thinking.

[Frank Pellow]

I have almost finished building the closet around my cyclone but still have one side (the one with the door) to go. I have built venilation into the walls, so don't need to do so for the door.

My door will be home-made with a 2" rigid foam insulatin interior in a (real) 2"x2" frame (including cross bracing) and covered with a thin (5mm) layer of plywood on both sides.

[Jim Becker]

I used a plain surface, pre-hung insulated steel door for mine. It was not all that expensive at the 'Depot. The interior of the door is foam-filled which provides at least a little bit of dampening. And when you combine it with a good closet design, it's effective. I barely hear my compressor when it's running and the cyclone's noise level is very low. (The real noise comes from the blast gates/hoods at this point!)

[JayStPeter]

I used solid core doors to the closet and shop entry. They are very effective in sound reduction. I had to order them at a building supply place, but the cost wasn't outrageous. I got the cheapest model. I think mine are luann skin with a chip board core. Very heavy.

Jay

[Bob Johnson]

Frank, thats a good idea to build my own door from 2" rigid insulation. Does anyone have any idea on how putting 2" rigid insulation in the walls would compare to using 3 1/2" fiber-glass batts in a 2x4 wall for noise control? Or perhaps just make wall panels like Frank's door, make it easy to remove if needed for service but still have a door to empty the chip barrel. Very interesting.......

[Mark Duksta]

Bob,

There are two major variables that must be addressed to make a room sound proof. It must be air tight, and the structure must not convey vibration. The best way to make a room sound proof is to build a room within a room where the inner room is physically apart from the outer room. This would take care of the vibration transmission. Add mass by adding extra sheetrock and make it air tight. This is usually not practical. There is a product that you can use to float a sheetrock wall on the existing sheet rock wall. I believe is call a Z channel.

Anyway, what I'm trying to say is add mass to the walls, and door (not foam), and make the closet air tight. In my shop I lined the stud faces with rubber, and then double sheet rocked the walls. I believe you can extend the return air filter so that it dumps the filtered air back into the room. By moving the filter away from the sound source you may be able to reduce the sound and get air back into the room. Check with the manufacturer.

Mark

[Frank Pellow]

Bob,
...
Anyway, what I'm trying to say is add mass to the walls, and door (not foam), and make the closet air tight. In my shop I lined the stud faces with rubber, and then double sheet rocked the walls. I believe you can extend the return air filter so that it dumps the filtered air back into the room. By moving the filter away from the sound source you may be able to reduce the sound and get air back into the room.
...
Mark
I guess that this would have been possible but I never thought of it and it is now too late for me. My filter is in the closet, so my closet cannot be air tight.

[Steve Cox]

My whole closet is lined with "soundboard", some really nasty stuff (to cut at least). It works like a champ. I installed a pre-hung hollow core door on the closet and glued a sheet of the soundboard to the inside. Weatherstripping around the edges and the bottom and it works very well.

[Jim Becker]

I did the walls of my DC (and compressor) closet with 2x4 studs, R13 insulation, Drywall on the outside and 1/4" pegboard on the inside with the rough side facing the interior of the room. The air return is ducted between some ceiling joists with a reverse turn/baffle about 36" out from the wall and the actual return back towards the closet....no direct path for sound transmission. The big IR compressor is nearly inaudible when running and the DC makes noise only slightly above "normal" sound levels in the shop. Only when a blast gate is open does the sound level increase and even then, only the hoods on the J/P require me to don hearing protection as they amplify the sound level of the machine for some reason.

[Bob Johnson]

My whole closet is lined with "soundboard", some really nasty stuff (to cut at least). It works like a champ. I installed a pre-hung hollow core door on the closet and glued a sheet of the soundboard to the inside. Weatherstripping around the edges and the bottom and it works very well.

Steve, what is "soundboard" and where do you get it? I have never heard of it before.

Bob

[JayStPeter]

My air return is actually the space under the door. My closet cuts the sound significantly, but as mentioned by Jim, there's lots of noise once a gate is open. I was planning on sealing the door (like I did my main shop door) and putting in a baffled air return. But, I feel like it's a waste of time given the noise levels when gates are open anyway. If I had my compressor in there it might be a different story.
The rest of my basement shop is "sound proofed". Drywall and good old fiberglass insulation are excellent and affordable sound dampeners. Staggered stud walls and resilient channel are also affordable ways to isolate vibration. My shop works well using those methods.

Jay

[Bob Johnson]

I did the walls of my DC (and compressor) closet with 2x4 studs, R13 insulation, Drywall on the outside and 1/4" pegboard on the inside with the rough side facing the interior of the room....

Jim,

Do you think that the holes in the pegboard are an important part of the sound reduction? Some of the tempered hardboard I have seen at Lowes or Home Depot has a rough side, no holes might be better as indicated by some of the previous comments. There might be so little difference that price could be the deciding factor between the two.

Bob

[Mark Duksta]

Steve, what is "soundboard" and where do you get it? I have never heard of it before.

Bob

Bob,

Soundboard is also called Homosote. You'll have to call around to find it. Most drywall and some building specialty suppliers will have it.

Mark

[Mark Duksta]

Bob,

Check out: http://www.soundproofing101.com. There's some good info there. Also http://www.soundproofing.org.

No affiliation.

Mark

[Steve Cox]

The "soundboard" I used is not Homasote. I am familiar with the product and it would work but the stuff I used is a brown, rough feeling, sheet from Home Depot. I picked it up in the insulation section. When I built the closet I built a return air baffle up top and lined the baffle with the stuff. I also lined the closet walls, floor and ceiling. The other critical step for the closet was to use lots of spray foam before I put the outside sheathing on to spray around all the seams and gaps (and possible gaps) to make sure there were no holes in the closet other than the baffle. The dust collector is not as l would like mostly because of air movement but the compressor is just a very dull hammering sound when running.

[JayStPeter]

Jim,

Do you think that the holes in the pegboard are an important part of the sound reduction? Some of the tempered hardboard I have seen at Lowes or Home Depot has a rough side, no holes might be better as indicated by some of the previous comments. There might be so little difference that price could be the deciding factor between the two.

Bob

I did the same as Jim in my DC closet. I used pegboard so I could hang stuff even though is contrary to good sound proofing. Drywall would be much better. On one of the soundproofing sites mentioned above (I think) there is a table comparing different materials and their sound transmission. Homasote is a little better than drywall. But, it doesn't provide a great finished surface. Pegboard wouldn't do too well. One of the principles of soundproofing is sealing. One of the techniques used is double layers of thin drywall rather than one layer of thicker drywall. The reason is that the seams can be offset and relieve a potential transmission path through the tape seam. Hundreds of 1/4" holes are definitely contrary to soundproofing, no matter which side is out. Hardboard based paneling also fared poorly compared to drywall if I remember correctly.
All that said, drywall, insulation and pegboard do a decent job cutting down sound (though I'm certain that removing the pegboard wouldn't make as big a difference as removing either of the others). I went further in my main shop so that my planer and router wouldn't bother others in the house.

Jay

[Jim Becker]

Do you think that the holes in the pegboard are an important part of the sound reduction? Some of the tempered hardboard I have seen at Lowes or Home Depot has a rough side, no holes might be better as indicated by some of the previous comments. There might be so little difference that price could be the deciding factor between the two.Yes, the holes were important as they further break up the high frequency sound waves and allow the insulation in the core of the wall to act as a bass trap. The drywall layer on the outside under the beaded panelling serves to stop sound. There are many ways to skin this coon...this works for me to the degree I wanted it to. A double, isolated wall would be better, but was not justified for my shop in a free-standing building. BTW, I used homasote in my previous cyclone closet and it was find, although the new one is more effective, IMHO.

[JayStPeter]

Yes, the holes were important as they further break up the high frequency sound waves and allow the insulation in the core of the wall to act as a bass trap. The drywall layer on the outside under the beaded panelling serves to stop sound. There are many ways to skin this coon...this works for me to the degree I wanted it to. A double, isolated wall would be better, but was not justified for my shop in a free-standing building. BTW, I used homasote in my previous cyclone closet and it was find, although the new one is more effective, IMHO.

Jim,

It's unusual for me to disagree with you. But, in this case I do. There seems to be lots of confusion of "listening room" or "quiet room" concepts with "sound transmission". Many sites and texts about soundproofing are written by those who deal with things like music studios. They have to deal with both concepts and often don't properly separate the two. My take after all my research is that the rough side out and holes concept would apply to breaking up the reflected waves within the closet to make it a better listening room. Sound transmission through the wall is a totally different thing. The only thing that helps with low bass frequencies is isolation. You need to isolate your inside wall from the outside. Once the bass frequencies hit your studs you're outer drywall is a big subwoofer. :eek: That said, the thin floppy pegboard probably doesn't aid in transmitting the vibrations to the studs like a piece of ply would.
I don't want to completely write off listening room concepts though. To avoid sound transmission, sound can either be reflected back into the room or absorbed. Breaking up the reflections before they have a chance to try again is a good idea. Right now, the inside of my shop is rather loud as I concentrated entirely on sound transmission. Nice and quiet outside though.

Jay

[Jim Becker]

Well, all I know is that it works to my expectations and the sound level is "really low" as visitors' eyebrows raising attest to! BTW, that peg board isn't very thin and floppy...it's the 1/4" thick stuff stapled to 2x materail 16" on center. Most of the noise transmission (mid-range, not low or high) seems to be on the wall that supports the stairway...it hasn't been "treated" the same way as it was already in place. But you are right, it's really interesting standing in that room 'cause the old ears immediately notice the complete lack of reflection!!!

In an ideal world, I'd do it differently, but I wanted quick and inexpensive.

[JayStPeter]

In an ideal world, I'd do it differently, but I wanted quick and inexpensive.

Jim, I think you did it right. The results are what matter. Quick and inexpensive is very significant. I wouldn't do it any different if I was to do it again. Those pegboard interior walls are priced right, easy to hang, and useful.
In an ideal world, we wouldn't need noisy DCs ;)

My feeling is that the DC noise isn't really that difficult to control. When I shoved the insulation between the joists in the ceiling, I couldn't hear it upstairs anymore. Far different from an angry benchtop planer ripping at some Ash.

Jay

[Jim Becker]

Aside from the wall construction, I think the one thing that really helps with the noise mitigation is the folded return air duct that I did between two joists near the top of the wall...there is no "straight path" for air/noise to flow back to the shop. An illustration of that is shown here:

http://www.sawmillcreek.org/attachment.php?attachmentid=14660&stc=1

[Bob Johnson]

Thanks to everyone for their comments. At this point I'm going to regroup and restart my planning for the cyclone closet. A neighbor down the street has a used metal clad exterior door (free), so I'll probably use that. I've got to digest all the information for wall construction I've received.

I should have posted pictures before, but I guess the pic police have been enagaged elsewhere. My filter is separated from the cyclone by about 15 feet of insulated flex duct so I don't have the air exiting situation most of the rest of you guys have. My filter collects the dust on the outside of the filters which is opposite of most other designs.

Bob

[greg kurtock]

How come I never hear of anybody using plain old acoustic ceiling tiles stapled to the wall? It's very similar if not identical to homosote, if you ask me.

Building soundproofing for the DC/compressor area is still pretty far down my list.

Greg