post feeds post comments feeds rss email feeds twitter updates

How I’m Soundproofing My Shop Part I

Woodshop tools link belt

Making simple changes to your machines will minimize the noise; I’ve found the things mentioned below make a big difference for little cost. It’s kind of a fun challenge too.

I’m particularly sensitive to shop noise because I had several neighbors near my shop.  Below me and next door to my apartment bedroom shop.

For the most part, I restricted my woodworking to when my neighbors weren’t home, either during lunch or when they went out somewhere.

I got creative with sound-attenuating strategies so if I made a few quick power-tool cuts, it wouldn’t be as bad.  I swore that when I built my ultimate shop, I’d incorporate quite insane soundproofing so that I could do whatever I wanted in complete freedom.

Soundproofing your woodshop is vital to maximizing your freedom.  Imagine if you could do woodworking anytime–late night or early morning without fear!

I’m also realizing that many of these strategies have other comfort and security benefits as well.

Simplify the Approach

I like to categorize things to simplify how I attack a problem; it’s drilled into any engineer’s skull over and over.  So, I can’t help but to do that with things like this.  I need to eliminate sound as a problem.  Both to my ears and to others’ ears.

To do that, I hafta do two things.  Control the sound source, and also control sound escape out of my shop.

Simply put, controlling the sound source means doing things to the machines themselves to limit how much sound they generate into the shop.  Controlling the sound escape means somehow blocking or absorbing the sound so it never leaves my shop walls or ceiling, a sound bubble.

It’s like creating two rings of defense.  If you do a perfect job at silencing the tools, you are done at that point.  Having to soundproof your envelope is necessary because your tools will still generate unacceptable noise, even after you reduce it using the methods outlined below.

Of course, you could switch to hand tools entirely, but that’s not gonna happen for most people.  I do use hand tools when they’re faster (swipe a chamfer, clean up a tenon, etc.).

Woodshop router table soundproofing

I like to go after the sound source first. The router table’s dust chamber is lined with two layers of soundboard. Closing this off with a door helps with dust collection too. The air intake is through the throat plate, which is how I want the air to flow.

Sound Source Control

To start, of course, we need to identify all the sources.  Just list them, then expand on each one with a mini-tasklist of things you’ll do.  Typically these are tools with a universal motor, but some tools that have an induction motor are loud enough to be worth treating.  My list looks like this:

          • Shop Vacuum
          • Jointer
          • Table Saw
          • Benchtop Planer
          • Dust Collector
          • Handheld Power Tools
          • Router Table

Each of these tools has a range of frequencies, and a noise level (measured in dB) associated with each frequency.

Some, like my shop vacuum, scream with a high pitched noise.  Some shake and rumble at low frequencies.  Some are louder in the mid-range.  Low vs. high frequency sounds have different strategies that are most effective.

Below, I’ll walk you through what I’ve done and will be doing to mitigate tool vibration from being transmitted to your shop structure, and how to use both sound absorbing and sound-reflecting strategies to limit the level of sound in your shop.

Jointer sound attenuation-woodshop

When I put my Delta 8” jointer together, I had rubber washers, adhesive-backed foam, and sound-dampening spray at the ready (I bought them while waiting for the jointer to be shipped). Here you can see that the cast iron jointer bed sits on the cabinet but is separated by a foam sheet.

Higher & Mid-Range Frequencies

When I put together my Jointer, I decided to line the cabinet with adhesive-backed sound-absorbing foam.  I also wanted to keep the sheet metal panels on the cabinet from vibrating and making noise, so I used rubber washers at many of the fasteners, being careful not to apply these washers where precision machined parts must fit together.

But certain parts like the cabinet don’t matter for machine performance, so that’s what I focused on.

For my router table, I lined the chamber surrounding the router with several layers of soundboard separated by dry beads of caulking and construction adhesive.

For my planer, I used sticky-back foam sheets to help absorb some of the noise.  I still have a ways to go on this machine.  High frequency noise seems to be the problem range here.

On other machines with metal cabinets, you can consider sound-dampening spray found in auto parts stores.  It’s basically a rubberized coating that dampens the vibrations transmitted to the sheet metal from the machine’s motor and cutterheads.

The goal of all this is to absorb as much of the sound as I can right at the source, either near the blades and cutters or the motor.

Remember that when the blades contact the wood, a lot of the noise is generated right there.  Sometimes, there’s not much you can do about that (some blades and bits perform better than others, though.  If you know of any that are exceptionally good, let me know in the comments below!!).

Now, you can’t really totally seal your tool motors in an airtight chamber, or they might overheat.  But you can use a baffle design to eliminate a line-of-sight path for sound to leave the tool cabinet.

The more surface area of absorbent material you put in there, the more sound will be absorbed.  Another reason to use zero-clearance throat plates for table saws and router tables is they help close off the path to the motor noise.

Jointer soundproofing for woodshop

Haven’t opened this for a long time, but thought I’d take a picture for the blog. I sprayed the whole inside of the cabinet with sound-deadening spray to keep some of the sheet metal vibrations down to a minimum. Last thing I want to do is create a speaker box for the motor.

Take a look at sound booths at recording studios and anechoic chambers for inspiration.  Often, the texture of the sound-lined walls is full of small bumps.  These are typically triangular, and at very acute angles.  This is to increase the surface area for the sound to be absorbed.  Also, any sound that hits these sloped surfaces and reflects off of them (the part that isn’t absorbed) reflect at an angle that leads it right into another part of the insulation, usually an adjacent pyramid.  So, the sound is trapped and the reflected waves keep getting progressively more absorbed.

You can do something similar; introduce sound-absorbent panel baffles at acute angles to each other inside your tool cabinets (keep in mind how dust will interact with these surfaces, i.e. don’t encourage accumulation).

Sometimes there are products specifically designed to reduce sound on power tools.  Shop vacuum mufflers are available; I have one and it works a bit (every bit helps), but it’s not a miracle cure.  You could design your own too.  Some people have built enclosures with baffles for the exit air, to eliminate the line-of-sight from the noise source.

Muffler-like duct silencers are also available to place your dust collection system, meant for centralized collectors.  These are expensive, but if sound is a big issue for you, maybe look into them.  If you can get one designed specifically for your collector’s frequency ranges, that’s the ideal way to go.

Most sound-absorbing insulation is good at mid-to-high frequency ranges. Lower frequencies, which I’ll discuss below, are harder to attenuate.

WoodChip Tip: When modifying your tools, make sure that what you’re doing won’t interfere with the tool’s operation, affect its accuracy, or void the warranty.  For me, I’m way past the warranty periods so I don’t really care about that, but I sure don’t want to use rubber washers in a location that’ll mess up whether something’s bolted straight or in a precision way!

 

Jointer soundproofing woodshop tools

Here’s one of the rubber washers I used to help block the path of vibrations.

 

Lower Frequencies and Vibration

Since my first shop was on the second floor, I had a really big interest in limiting the vibrations that were being transmitted to the floor sheathing and joists for my neighbor to enjoy.

Think of the sound or vibration as travelling a path through solid material, and when that ends, and hits the air, it’ll continue on to hit your ears.  If it ends at the floor, and vibrates the whole floor, you’ve just provided a nice amplifier.  However, if you can block this path, i.e. a sound-break, with an absorbent dampening material, you can make a big difference in the low-frequency noise emanating from your machines.  Adding mass to your flooring system will also help.  For my shop, I have concrete floors which are good for absorbing the vibration.

Lower frequencies tend to travel farther as well, so these are important to tackle.

I do several things to attack the low-end frequencies.  First, I try to dampen them at the source.  Secondly, I try to prevent them from being transmitted to the floor from the tool stand or cart.

To help reduce your machine vibrations, look into those red link belts to replace the stock belt that came with your tool.  I have one in my jointer and it’s awesome.  Balancing of the rotating parts is also important.

Now, for limiting the transmission to your floor, use vibration isolation between the parts of your overall tool station.  Also block the solid material path.  Where your tool sits on a mobile cart or base, use rubber/ neoprene vibration isolation pads.  If you want your machines mobile, use rubber-wheeled casters.  I go a step further and use a lot of rubber washers when assembling the tool cabinets, even rubber grommets at the caster plate attachment.  Those little sound waves really have a tough time in my shop.

Adding mass is another common way to keep vibration at bay; my SawStop cabinet saw is tremendously beefy, and has significantly less vibration than my old Delta benchsaw.  If you can afford to, get robust cast-iron versions of tools when you can.

Woodshop planer vibration isolation soundproofing

You can buy these pads online; I suggest using them to separate the benchtop tools from their tool cart or table top, and also between the larger machines and their mobile bases. If you don’t have a mobile base, make sure you have a support frame or rails spanning between each pad.

Basically, Do These Things

If you understand the things that must be done to curb machine noise and vibration, you’ll be able to apply them to both new and old tools.  I incorporate sound control into my shop design for each workstation, just as I include dust collection and electrical considerations.

Below are some quick things you can do when you don’t feel like running any more boards through the planer, or are sore from pulling a scraper:

        • Buy a bag of rubber washers and apply them to machine cabinet fasteners as long as it’s not a critical connection for precision alignment
        • Retrofit all of your tool stands to include rubber-wheeled casters, and look at using rubber grommets on the plate holes where you bolt them to the stand legs
        • Buy those square rubber vibration isolation blocks and use them to separate the tool from the mobile base or tool cart
        • Spray sound-dampening material on the insides of metal machine cabinets
        • Add sound insulation lining to machine cabinets, router table chambers
        • Use baffle-like sound shields made of sound-absorptive materials near motors and other noise sources without restricting heat dissipation for the motor. 
        • Add additional sound absorbing material (perhaps backed by sound reflecting material) directly behind noisy machines that are against the wall
        • Safety guards around blades and bits do help with both dust collection and noise isolation, so it’s not a bad idea to use them when you can, especially over the table saw blade.  Maybe make your own, and incorporate some sound-deadening strategies in addition to dust collection efficiency strategies.

Remember that a lot of little things will add up to a much quieter shop.  You’ll feel much more free knowing that you won’t get complaints about your late night or early morning dust-making activities.

Next time, I’ll walk through how I’m dealing with sound escape, which primarily means treating the shop’s envelope.  If you are working with unfinished walls, or are building your shop from scratch, you have an advantage.  You can incorporate a more extreme version of soundproofing strategies in your walls, ceilings, doors, windows, and floors.

Wooshop workstation casters

One of my design standards is to have every workstation mobile. Double-locking casters are a good way of doing that; another is to get a specialty caster that flips up and out of the way if you want. Either way, having a rubber wheel or a rubber pad will help prevent a lot of the vibration from transferring to the floor.

 

Dust Collector sound attenuation

This is at the dust collector; I put rubber washers between the fan mount and the metal cart.

 

Jointer vibration isolation pads

This is a scary look inside the jointer cabinet. The blue square is the rubber-foam vibration isolation block between the jointer cabinet and the mobile base. After doing all of these things, the jointer is barely audible while running. Can’t do much about when the blades contact wood, except treat the shop walls.

For more guidance in assembling your Woodshop Design, click on the Starting? Go Here! category and read those first.

Connect with me on Facebook, and follow me on Twitter for more ninja tips to Optimize Your Woodshop!

And, if you’re on Twitter, be sure to follow #woodchat every Wednesday night, at 6:00 pm, PST.

Gotta get more clamps,

 

 

Woodshop Design Outline (FREE)

 

 

Enter your name and email below to get your free copy of this organized and detailed checklist to jump-start your woodshop design today!

Also, you’ll get weekly WoodChip Tips, design ideas, free useful downloads, free mini-courses, and other cool stuff in The Other Side of Zero newsletter!



Visit Rockler.com - Woodworking Superstore!

Like what you're reading ?

RSS Digg Twitter StumbleUpon Delicious Technorati

8 Responses to “How I’m Soundproofing My Shop Part I”

  1. Dan Marin says:

    I REALLY enjoy your website and garner tidbits from every issue. I moved from a funky shaped shop with lots of angles but over the years I made it work.

    I recently moved to a home with a three car-garage. I walled off the third stall and am using your tips to help me refine my new rectangular space.

    Thanks and keep the tips coming…

    Dan

    • Bobby says:

      Well thanks Dan! Is your shop in the third stall or the 2-car portion? I had a 1-car garage shop for awhile and made it work. I wound up moving before I could take advantage of the vertical space clear some more floor. But I still kept an “open area” to do assemblies and things, and banned storage or machines from that space. That kept the flexibility and maneuverability we really need in a shop. Let me know what things you’re wanting to know and I’ll be glad to give my take on it!

  2. Smithy says:

    I’ve used automotive undercoating, or bed liner spray for sound deadening in cabs.
    (works great on metal sink basins)

    Low freqs are sometimes amplified by squared, even walls.
    Making the corners not quite 90° can keep them from getting louder
    (I used a pinknoise generator and a calibrated mic to find the hot spots)

    Not sure how well it would work in a shop application,
    but a lot of studios have a floating floor,
    with an underlay of homasote and neoprene donuts.

    reduces mechanical transmission

    to keep mechanical virations from reaching the room microphones.

    • Bobby says:

      Hmmm…this got me thinking about stealth concepts, i.e. 90 deg. panels in two or three dimensions reflect waves back to the source. Angle of incidence = angle of reflection, so if you shoot a beam at a 90 deg. corner, it reflects back to you. It’s probably similar with sound. My plan is to have floating ceiling clouds, so maybe angling them will both look good and help with sound echo too. Thanks for getting my neuron gears spinning!

  3. Hi Bobby, good article. Another tool in the arsenal is vibration damping foil, this sticks to sheets of metal to damp down any vibrations. I’ve only seen it demoed so not sure of how it performs in the workshop. http://solutions.3m.com/wps/portal/3M/en_US/3M-SpecialtyTapes/SpcltyTape/ProdInfo/Catalog/Damping-Foils/

    • Bobby says:

      This is so awesome; I’ll put these in the Resources page for people to use. I haven’t tried either of these, but I think I will. I’m always looking for things like this to optimize my shop stations. I’ll find the most “rattly” metal machine cabinet I have and see what happens. Thanks Andy!

  4. fong says:

    Saw this stuff on Cool Tools. Looks pretty impressive if you haven’t put up drywall yet. http://www.acoustiblok.com/

    • Wow, that is a cool product! Thanks for the link! I’ve watched nearly every episode of Cool Tools but don’t remember this one.

      Besides installing this material in critical walls/ doors, seems like we could add it to machine cabinets too.

Leave a Comment