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A DISCUSSION OF SOUND MUFFLING
Absorbers reduce sound waves and convert them into heat energy. Use absorbers in areas that have hard, reflective surfaces. The average amount of sound absorbed by a material is represented by the Noise Reduction Coefficient (NRC) . The higher the NRC value, the more efficiently the material absorbs sound. A material with an NRC of 1 is the most sound-absorbing material you can get. NRC is calculated during testing in an acoustical laboratory.
Barriers reduce sound by blocking sound wave transmission and reflecting sound waves back to the source. Use barriers in passageways to reduce sound transmission to surrounding areas or to divide an open area. A barrier's ability to reflect sound back toward the source is represented by the Sound Transmission Loss (STL) . The STL is the difference between the sound level striking the barrier and the level of sound transmitted through the material. So the higher the STL, the better the barrier performs.
Absorber/barrier combinations give you the advantage of two noise-control products. Sound waves pass through the absorber where they are converted into heat energy. Any sound waves that then hit the barrier reenter the absorber which converts those remaining sound waves into heat energy.
Dampers reduce sound caused by vibrating surfaces. The damper material flexes slightly to convert vibration into heat energy so noise is deadened. A damper's ability to reduce vibration is represented by the Damping Loss Factor (DLF) . The higher the DLF, the more the damping material reduces vibration and sound.
Absorbers are best for musical instruments because vibrations that bounce back into the instrument will cause echoes. We carry only absorbers. We can supply vibrating surface sound absorbers if you feel they will perform better for your application.
Fiberglass Sound Absorbing Sheet
Feb. 9, 2007-- Customer report
We have a customer who lives in New York City and was close to
being evicted, along with his beloved Steinway, from his Manhattan
apartment. He reports that the muting into the room, and hence through
the walls, is close to total. He said the size of the fiberglass pieces were
perfect for stuffing into the holes under the grand between the massive
wood braces. He ordered four, and you may need up to six if you have
a grand that is six feet long or longer. We are pioneering sound control
with pianos in sensitive apartment situations, and we are convinced
we are onto something.
Ideal for absorbing sound waves in enclosures such as speakers, motors, cabinets,
and doors. Sheet comes wrapped in a clear plastic bag.
Temperature range is 32° to 350° F. Color is yellow.
NCR- .60 -- This is a high level of muffling and could be used under grand pianos in
apartments to block sound UNDER the piano. Two or three pieces would be required.
The sheets may be removed from the plastic bag to get the best results. This means that
these mats must not be used where children and pets can get into them where they could
be exposed from under the piano to crawling children and animals. If you have any doubt
about safety, wrap the sheets in plastic, like a garbage bag. The fiberglass is bonded and not
loose, but children and pets could pick at it and possibly endanger themselves. Handle the sheets
with latex gloves, though I have tried to handle the sheets roughly myself, and none of the fiber
glass came loose. It is not like the fluffy fiberglass used to insulate walls in homes. It is compressed.
The ideal places to use these fiberglass sheets is inside an upright, behind an upright, under
an upright, or in the cavities in the underside of a grand piano. Keep them out of sight and
away from little hands and paws.
For an example of MSDS safety instructions with fiberglass sheets, see:
Dow Corning's page on a similar product.
Of course, this is for working all day with home insulation material.
Some customers combine this sheet with the Decorative Fabric at the bottom of this
page, and the sound control with the ambient effect are very pleasing. This would be
very useful where a large voiced upright is in a small room with bare walls and a tile
floor, such as in a music director's office or in small practice rooms. Students often hold
back their "attack" when playing in small practice rooms, with the results that they sound
timid during a performance in a music hall. This solution would allow forte playing without
the student being blasted out of the room.
Remove the plastic bag the sheets are in when shipped. This is important so that the sound
will be absorbed completely.
Sheet Size 36" x 36" by 1 inch thick
Part Number -- SM6001
Price -- $ 12.50 per sheet
Fiberglass Sound Absorbing Quilts with Vinyl Barrier
"Often used in harsh environments where oil, grease, dirt, moisture, and other chemicals
and solvents are present, these quilts are made of a fiberglass absorber and vinyl barrier."
Quilts have hook and loop along vertical edges to fasten to other curtains. We are robbing
another area of commercial activity for this product, as you can see from the description.
Meet ASTM E-84 standards for flame and smoke.
Temperature range is -20° to +180° F. Color is metallic gray.
Vinyl-barrier back quilts are 48" wide stitched to a 54" wide reinforced water-resistant
Vinyl-barrier core quilts have a vinyl barrier that's lock-stitched between two 48" wide
layers of fiberglass.
They are double-faced for two-sided exposure and have all bound edges.
4-ft. long, 1 inch thick, curtains have five 9/16" ID grommets-- .
NCR- .70 -- [1.05 is maximum sound muffling]
8-ft. long, 2 inches thinl, curtains have five 5/8" ID grommets.
NCR- .85 -- [1.05 is maximum sound muffling]
These mats are also hung on walls to stop noise, but this would only be acceptable in a studio
or sound room where you have a piano. It would be impossible in a home parlor.
Vinyl-barrier core quilts-- 4 foot by 48 inches
Fits ideally behind a spinet of console Piano
BUT, only if the opening behind the piano can be
completely covered. May require a cord to hang
using the eyelets so that it covers the whole opening.
Part Number - SM6005 Price - $ 314.00
Vinyl-barrier core quilts-- 8 foot by 48 inches
Part Number - SM6006 Price - $ 445.00
Sound Absorbing "Egg Crate" Type Flexible Foam
crate foam has convoluted egg-shaped peaks and
valleys that provide increased sound absorption at higher
frequencies over flat surface foams. Temperature range is
-40 degrees to +225 degrees F. Foam can be cut with a knife.
An electric carving knife would also work well. Color is dark natural. Polyester-based polyurethane foam is strong
and maintains its shape better than generic foam. This foam
is specially formulated to absorb sound and is not the same
as packing material foam or bed foam.
27 " sheets meet UL UL-94 Rating (self-extinguishing as
to fire hazard)
3 inches to tops of peaks
NRC sound absorbing rating of 0.85. 1.05 is the best
available rating in sound control standards.
Part Number - GR5T494 Price - $ 147.50 each
Order two sheets for grand pianos up to 6 feet, and three sheets for larger grands.
Order two sheets for all upright pianos. See instructions below
I must emphasize something-- this is a specially made acoustic product and, though it looks like
ordinary egg crate foam, it is NOT. Thus, it seems pricey I suspect. But then, so is eviction :-)
This product ships from our office in Michigan.
Two sheets of foam are packed in a 30" x 17" x 16" carton,9 pounds weight
For approximate shipping cost, here are two extreme points:
East Coast- FedEx 3 day-- $ 36.00 for one carton of two foam sheets
East Coast-Priority Mail 2 -3 day - $69.00 for one carton of two foam sheets
US West Coast- FedEx 4 day-- $ 48.00 for one carton of two foam sheets
US West Coast- Priority Mail 3 day-- $87.00 for one carton of two foam sheets
To estimate your postage use our ZIP code, 49858 and your ZIP code, using the carton dimensions and weight above at the US Post Office page for postage: http://postcalc.usps.gov/
Be sure to click on "Large Parcel"
If caster cups have been added to the order, this will not be accurate of course, but close.
This product is not ready to use. We have included it for those who are willing to do some fitting
tricks. Two pieces of this foam should be enough to do a grand piano under 6 feet long. You will
measure the cavities under the piano made by the large wood beams. You may want to make a
pattern or rubbing. You will then cut pieces of foam slightly larger than the cavities created
between the massive wood braces under the piano, and you will push the pieces of foam up into
Be sure to push the foam in so that the flat surface is DOWN and as near level as possible.
Do not push the form up until it actually touches the sound board. It will not damage the sound
board, but it will over dampen the sound. Be sure to plan the pieces to minimize waste so you can
do all of the cavities with two pieces. Some pianos may require three pieces.
For extreme damping of sound, push pieces of foam all the way in against the under side of the
sound board. The resulting sound will be seriously deformed, but it may allow you to play in the
middle of the night in an apartment without being evicted :-)
This could be done very effectively with an upright piano also. In fact, two sheets can be
fitted between the upright piano and the wall to effectively drown sound greatly. Do not use in
an outside wall on an old home. Moisture build up could occur. Be sure the peaks of foam are
pointing TOWARD the back of the piano NOT toward the wall. The peaks of the convolutions of
the foam should just be touching the back of the piano, not being crushed or deformed at all.
Set one sheet on top of the other.
To avoid the top sheet sticking up in the air above the piano, cut the top sheet with sheers or an
electric carving knife horizontally so it stops just at the top edge of the piano.
A third sheet of foam can be cut to fit inside the lower part of the upright piano, inside the cabinet,
but not touching the strings. This will mute sound that wants to escape through the front of the piano.
To get more natural sound out of the upright piano when neighbors are not present, lift the top of
the piano open. The excess foam from cutting the top of the top sheet off may also be placed in the
bottom of the piano to stop some sound. Be sure it does not interfere with the pedal works.
SOUND STUDIOS AND HOME THEATERS
This foam is used in studios to muffle sound through walls. This strong lightweight material mounts to
most surfaces with foam adhesive, mounting pin assemblies, or nails. It may also be hung as baffles
and resists oils, alkali, and mild acids.
We can supply a cubical which you can assemble in a room and totally enclose an upright piano or
a small grand piano.
We can supply other wall mounted acoustic products-- SEND MAIL
WORK SHOPS AND SECURITY ISSUES
Whether you want to be quieter as you run noisy machines, or if you want to have a very private area in
which to conduct discussions, these foam sheets are great for wall mounting. Send us the square feet
you need to cover, and we will send you a quote for quantity. We can also provide adhesive.
DO YOU HAVE A MONSTER?
If you have a sound issue involving a piano, send mail to the link above, and we will research it for you.
We now have a good number of resources to use in problem solving.
CASTER CUPS-- Downward Sound Blocking
Blocking the sound coming from the piano is only part of the task of controlling your impact on your neighbors. The materials above will deal with the horizontal sounds that penetrate the walls of your apartment. They will also mute the sound directed at the floor from the under side of the piano. The last trick is to stop sound from penetrating the floor due to your piano's direct contact with the floor.
Here are the physics of sound going down--
The piano has a sound board which amplifies the sound of the strings when they are struck. This sound board sends much of the sound into the air, but it is anchored all the way around its edge into the wood of the cabinet of the piano. Wood carries sound very well, so the cabinet carries the sound it receives into the whole cabinet and down the legs of the piano. The casters, being metal, carry sound very well, and, if you have caster cups, they too carry sound well since they are made of a solid material.
The plot thickens--
The floor, if it is hard, especially if it is a wood floor, acts as another sound board to whatever sound reaches it, and the floor drives that sound on downward into the living area below. Thus, "Hey, could you folks up there please play that piano quieter?"
Some caster cups have a layer of thin felt under them to protect the floor. This felt deflects, or collapses, and the thin compressed felt then transfers sound quite well after all. Even a carpeted floor can transmit sound because carpet is not designed to stop sound, and the more is collapses, the more sound it transmits.
What is needed is acoustically designed material between the bottom of the caster cup and the floor. We have searched many sources and studied the principles of sound blocking. The two choices we offer, the virgin wool disk, and the polyurethane pad, both are made of special acoustic and vibration control materials. They are made to utilize the factor of deflection, that is, they load themselves, so that they develop a maximum sound absorbing quality. This means the sound that travels down the legs of your piano is stopped in the pads and turned into minute amounts of heat.
I trust this is not giving you nasty flash backs of physics class in High School :-)
We believe we are the first business to offer these products, in these researched combinations, to piano customers in apartments and condominiums worldwide. Other applications present themselves. School practice rooms, college dorm rooms may need these products, and we are VERY interested in making friends in Hong Kong, Tokyo, Amsterdam, and Singapore.
Here are the two choices we offer, and both are equally good choices:
Large Caster Cups and Wool Disk
This combo uses a 5-1/2 inch plastic cup.
Inside diameter is 1-1/2 inches and self-centers the caster. See below for wide barrel shaped wheels.
The cup can be ordered in Black, Brown, or White.
The wheel in the photo is small. Larger two inch diameter brass wheels will fit also.
The disk is made of 95% virgin wool and is off white, or natural, and it is void of dye. "Virgin wool" means the wool is not recycled, which further means there is no residue of chemicals or contaminants in the wool. Sound and vibration absorption is excellent. The large cups we offer MUST be used with the disk to benefit fully from the sound blocking qualities of the wool disk. The disk is 6 inches in diameter and will extend beyond the edge of the caster cup about 1/4 inch, which gives an eye pleasing border to the combo.
Because of the pure content of this real wool it is rather expensive. We have learned that most markets avoid it. But, real wool is an exceptional sound absorber. It is commonly the only sound deadening material used in all quality pianos. The reason we do not look for dyed wool is that it might easily bleed into the finish of your floor. By the way, these pads are popular with those who hand polish fine telescope lenses.
The caster cup and disk together will raise the piano about 3/4 inch higher than the caster alone, which means you will need to deal with that rise at the pedals. If this is a problem, a heel support can be improvised easily.
Wool Disk- SM6007
Caster Cup- SH839E
Give BOTH Part Numbers when you order please
PRICE: $ 110
For a set of three for a Grand Piano
For a Square Grand (needing a fourth combo), and for Uprights, add $ 38.00
For those who already have at least five inch caster cups:
Wool disk: $ 24.95 each
CUP CHOICE ONE WITH THE WOOL DISK
This Lucite cup has a 2-3/4 inch inside diameter to receive large
brass barrel shaped caster wheels on high end pianos.
Black, Brown, and Clear-- Cup is 4-1/2 inches diameter.
Add $ 6.00 ($ 8 for uprights) for the Lucite Cups
OPTIONAL CUP CHOICE TWO WITH THE WOOL DISK
Black, Walnut, Mahogany, White, Ivory, or Unfinished,
5-1/2 inches outside diameter, 3-3/8 inches inside diameter
Made of stained hard rock maple
Add $70 ($ 95 for uprights) for the wood cup
A sound absorbing trick is at the end of this discussion.
fabrics are hard synthetic monofilament and natural fibers so that sound is not
distorted as it passes through them. The fabric will keep its stiff shape well to prevent
sagging. The fabric is fade resistant, dust resistant, and meets fire regulations. Upholstery
tacks may be used to install the fabric. If Acoustic Mufflers and devices above have been
added to the piano, some fitting will be needed to add the fabric in a pleasing way.
fabric will improve the appearance of uprights which face the audience in churches
and performance areas. It will also prevent object and toys from falling into the back of
the piano and causing rattles and buzzes.
you wish to apply the fabric with glue, any glue which will work with glass will
Swatches can be sent at your request.
All fabric is 72 inches wide.
Choose the fabric you want, and use the Part Number under the photo when ordering.
SHB-6000 - Black and rich in color. A natural for use with Ebony finishes or to contrast.
SHB-6002 - DISCONTINUED
SHB-6003 - Oak and white woven together for a fine blend in decorative fabric. Light in tone.
SHB-6004 - Elegant warm brown fabric, especially good match for Walnut and Mahogany finishes.
SHB-6005 - No Longer available.
SHC-4216 - No longer available
Price -- $ 109.00 per linear yard [ by 72" wide ]
SOUND ABSORBING TRICK
Add some of this material to the back of an upright. Start installing at the bottom, and when
you are about six inches from the massive solid upper wood section, stop. Buy a couple
large bags of packing pop corn from an office supply. Pour the pop corn into the cavity you
have created with the backing material. Play the piano during the process to see how much
damping you want. Once you have the effect desired, finish installing the backing material.
If you want more sound for a gathering of sing along time, remove the lower board of the
piano in the front just above the pedals, or lift the top open.
DO NOT USE BIODEGRADABLE POP CORN. Moisture will be absorbed by it and
make a horrible mess of you piano over a period of time.
ORDER BY PHONE WITH CREDIT CARD
CALL TOLL FREE: (800) 338-8863
If there is no answer, please leave a message- we do answer our voicemail