Skip to main content
QTA Systems Loudspeaker Parts
QTA Systems

DIY Loudspeaker Components

You are Here -- home -- loudspeaker components -- sorbothane isolation

Use Sorbothane Damping to Reduce Vibration in Speaker Cabinets or Stands

Sorbothane Hemispheres for Damping Vibrations

Sorbothane hemispheres for vibration damping

   Sorbothane is a modern polyurethane rubber composite. It is a very good material for damping and absorbing unwanted vibration in sensitive audio equipment. With care, Sorbothane damping can be effectively applied to loudspeaker cabinets, speaker stands, CD players and amplifiers to reduce their level of mechanical vibration. These vibrational nuances when damped are often associated with providing a cleaner, clearer audio signal. Of course, not all problems associated with vibration can be solved in this way, but it is a good start.

      It is used in a wide variety of applications which require isolation from shock and vibration. These applications include medical footwear, sports footwear, vibration damping of heavy machinery, isolation of delicate scientific instruments from noisy environments, top-end Hi-Fi equipment such as CD players, amplifiers and for loudspeaker cabinet mountings / feet. As a mouldable material many different shapes and sizes of Sorbothane products are possible. However, the most used shape for diy audio applications revolves around using Sorbothane Hemispheres for damping loudspeaker vibration. Donut shapes and flat sheet are alternatives but less popular.

The Tech Bit. A Basic Explanation

      Sorbothane is a synthetic, human made, visco-elastic polymer known as an elastomer. Knowing what this means is not going to have much direct impact on your daily life, but . . . . . It's one, in a family of four differing types of polymers and it's known as an elastomer. As the term suggests, this class of materials have stretchable type physical characteristics. How they stretch depends upon their molecular chain composition and the molecular bonds that are formed as the long chains of molecules stick together.

      The unique properties of these materials, i.e. those of performing somewhat like a solid and also as a liquid, make it a superb performer for the damping and suppression of unwanted vibrations. In the final analysis, the energy absorbed as mechanical vibration is converted into internal heat and lost as re-radiated heat into the environment.

      Of course, modifications to the manufacturers Sorbothane recipe can be made to provide a hard or soft rubbery product and this hardness is measured in Duro. The material hardness also determines the amount of compression / weight loading that a particular hardness and shape will tolerate.

       Three values of hardness are generally available, 30, 50 and 70 Duro. Other values are possible but this spread in hardness covers most typical applications. For optimum energy dissipation / practicality hemispheres need to be compressed by some 20% to 30% of their free height. Some shapes, flat sheets and donuts do not compress equally when forces are applied and therefore the performance / energy dissipation is more variable and hence less than optimum unless carefully calibrated

Article - Sorbothane, Overview and Usage - How to use Sorbothane Hemispheres

      Note: This product, particularly the smaller items, look much like sweets, so it is important that they are kept away from children.


Sorbothane Damping for Loudspeakers and Speaker Stands

30 Duro Sorbothane Hemispheres. NON-ADHESIVE. Sold in Packs /4.
Order Code Spec Wt Range 1+ 6+
11M30D 11mm 30 Duro Hemi (55 - 140) Gms /1 2.58 /4 2.45 /4
19M30D 19mm 30 Duro Hemi (170 - 420)Gms /1 4.45 /4 4.23 /4
30M30D 30mm 30 Duro Hemi (350 - 850)Gms /1 8.21 /4 7.80 /4
40M30D 40mm 30 Duro Hemi (0.65 - 1.55)Kgms /1 11.57 /4 10.99 /4
50M30D 50mm 30 Duro Hemi (1.2 - 2.7)Kgms /1 17.41 /4 16.54 /4


* 50 Duro Sorbothane Hemispheres. NON-ADHESIVE. Sold in Packs /4.
Order Code Spec Wt Range 1+ 6+
11M50D 11mm 50 Duro Hemi (260 - 500)Gms /1 2.58 /4 2.45 /4
19M50D 19mm 50 Duro Hemi (550 - 1250)Gms /1 4.45 /4 4.23 /4
30M50D 30mm 50 Duro Hemi (1.6 - 3.7)Kgms /1 8.21 /4 7.80 /4
40M50D 40mm 50 Duro Hemi (3.1 - 7.4)Kgms /1 11.57 /4 10.99 /4
50M50D 50mm 50 Duro Hemi (5.8 - 12.6)Kgms /1 17.41 /4 16.54 /4


* 70 Duro Sorbothane Hemispheres. NON-ADHESIVE. Sold in Packs /4.
Order Code Spec Wt Range 1+ 6+
11M70D 11mm 70 Duro Hemi (0.75 - 1.7)Kgms /1 2.58 /4 2.45 /4
19M70D 19mm 70 Duro Hemi (1.4 - 3.15)Kgms /1 4.45 /4 4.23 /4
30M70D 30mm 70 Duro Hemi (4.0 - 9.0)Kgms /1 8.21 /4 7.80 /4
40M70D 40mm 70 Duro Hemi (5.7 - 12.5)Kgms /1 11.57 /4 10.99 /4

Anti Vibration Kits, Trial Sets of Hemispheres

   A selection of Sorbothane hemispheres of different sizes and hardness. These give the user the flexibility to trial different combinations / options of damping characteristics at an attractive price. 4 pieces each of the listed specifications equals one kit. The suggested 'Weight Range' covers four 'like' Hemispheres, 'equally', statically loaded.

* Sorbothane Kits, NON-ADHESIVE. DIY Assorted Specs. Sold 4 per Type. 12 OR 16 Pcs / kit
Order Code Spec Wt Range /4 1 Kit
SORBKT1 4 each of (11M30D, 19M30D, 30M30D) (0.22 - 3.4)Kgms 13.71 /1
SORBKT2 4 each of (11M50D, 19M30D, 30M30D, 40M30D) (0.68 - 6.2)Kgms 25.46 /1
SORBKT3 4 each of (11M50D, 19M50D, 40M30D) (1.04 - 6.2)Kgms 17.66 /1
SORBKT4 4 each of (19M50D, 19M70D, 30M30D, 30M50D) (1.4 - 14.8)Kgms 22.78 /1
SORBKT5 4 each of (19M70D, 30M50D, 40M50D) (5.6 - 29.6)Kgms 21.81 /1
SORBKT6 4 each of (30M50D, 40M50D, 40M70D) (6.4 - 50)Kgms 28.21 /1

The Use of Adhesive Tapes

      Sorbothane is a difficult material to find adhesives which will effectively stick to its surface. By default the Hemispheres are supplied without adhesive backing. As most applications use the product in a trapped / compressive mode there is minimal use for adhesive backed types. However, If you wish to use an adhesive backed item we can now supply two types of adhesive tape, (in strips), which, you can cut and apply as required.

      The first tape is an adhesive transfer tape by 3M type 3M200MP. This "only" transfers the adhesive film which is extremely thin. It is rather difficult to separate it from the adhesive backer, so patience is required. It only sticks well to smooth surfaces and not so well to rougher surfaces.

      The second tape is a 0.8mm thick, double sided, white polyethylene foam tape, otherwise known as PE tape. The foam backer is of the closed cell variety. It has a rubber adhesive which sticks well to most surfaces. As the tape is "under" the Hemispheres the edge will be barely visible. This tape is also supplied in strips and is easy to cut / apply. Take note that the complete under surface of the hemisphere needs to be covered with the strip, NOT partial coverage. The larger Hemispheres (30, 40, 50)mm diameter require two strips to be edge butted together to give full coverage.

Adhesive Transfer Tape for Hemispheres

* Adhesive Tape 3M200MP: Sold in Strips
Order Code Spec: (W * L) Strip Size Price /pk 1+ Price /pk 6+
ATAPE1 Suits 11M**D (12.7 * 55) Strip £0.17 /1 £0.16 /1
BTAPE2 Suits 19M**D (19.0 * 90) Strip £0.38 /1 £0.36 /1
CTAPE3 Suits 30M**D (34 * 140) Strip £0.80 /1 £0.76 /1
DTAPE4 Suits 40M**D (44 * 176) Strip £1.60 /1 £1.52 /1
ETAPE5 Suits 50M**D (54 * 216) Strip £2.14 /1 £2.03 /1

Adhesive Foam Tape for Hemispheres

* Adhesive Foam Tape: Sold in Strips
Order Code Spec: (W * L) Strip Size Price /pk 1+ Price /pk 6+
FOMTAPE1 Suits 11M**D (25 * 75)x 1 Strip £0.27 /1 £0.26 /1
FOMTAPE2 Suits 19M**D (25 * 150) x 1 Strip £0.55 /1 £0.52 /1
FOMTAPE3 Suits 30M**D (25 * 150) x 2 Strip £1.09 /1 £1.04 /1
FOMTAPE4 Suits 40M**D (25 * 150) x 3 Strip £1.64 /1 £1.56 /1
FOMTAPE5 Suits 50M**D (25 * 150) x 4 Strip £2.19 /1 £2.08 /1

Adhesive Transfer Tape for Hemisphere KITS

* Adhesive Tape 3M200MP for SORBOTHANE Kits: Sold in Strips
Order Code Spec: (W * L) Strip Size Price /pk 1+ Price /pk 6+
FTAPE6 Suits SORBKT1 ( *****) Strip £1.32 /1 £1.26 /1
GTAPE7 Suits SORBKT2  (*****) Strip £2.94 /1 £2.79 /1
HTAPE8 Suits SORBKT3  (*****) Strip £2.14 /1 £2.03 /1
JTAPE9 Suits SORBKT4  (*****) Strip £2.35 /1 £2.23 /1
KTAPE10 Suits SORBKT5  (*****) Strip £2.77 /1 £2.63 /1
LTAPE11 Suits SORBKT6  (*****) Strip £3.99 /1 £3.79 /1

Telephone: +44 (0) 1223-891091 Email:- Sales, and Support to Contacts.  Mod (26), January 12, 2022 Copyright © 2008: