Abstract: A reduced volume drumhead has a layer of porous material and a ring of compressible material. The ring of compressible material is fixed to the underside of the layer of porous material in a substantially centered or coaxial position with the porous material stretched across a hoop in tension. The ring may be formed of a foam or similar material with compressibility and stretchability under tension and defines an open central area of the drumhead for striking. The ring may be formed of segments and thus include one or more circumferential breaks with spacing. The drumhead provides natural tonal characteristics and has a natural feel when struck.

Abstract: A drum includes a low volume drum head, a pellet chamber, and a magnetic choke. The pellet chamber is located beneath the low volume drum head. The pellet chamber is configured to hold a plurality of pellets, and the pellet chamber defines a plurality of apertures in a wall of the pellet chamber. The magnetic choke carries at least one magnet. The magnetic choke is configured to move relative to the pellet chamber so as to adjust a magnetic force imparted on the pellet chamber.

Abstract: The present invention comprises a drum with two playing surfaces on opposites ends of a hollow drum body. The drum is configured for the first drum head to produce a loud sound and the second head to produce a quiet sound, under the same full force drum strikes without compromising the feel and rebound of the drum heads. The drum may have a central base, a shell disposed on each side of the base, and a drum head stretched over each of the shell. The drum heads are attached to a shallow drum body with independent tensioning of the heads and sandwiched drum shells. The tensioning system is mounted to the central base. An optional snare system may be mounted to the base.

Abstract: A musical drumhead having a plurality of multifilament yarns joined to form an open weave mesh fabric wherein the surface of the multifilament yarns is uneven or undulating for enabling a strong bond with an applied coating, which, in turn, is provided to encapsulate the individual multifilament yarns. When struck by a hard object, the open weave mesh fabric absorbs vibrations resulting in a sound that simulates the sound properties of a modern day synthetic drumhead at substantially reduced sound levels. Integrating a plurality of soft fiber tufts into the surface (top and bottom) of the mesh fabric reduces the sound levels produced by the drumhead of the present invention even further.

Abstract: A sealant is provided for use on an aircraft or other vehicle. The sealant may be used with a gasket. The sealant is a perimeter seal that comprises a polyurea member. The polyurea member is a self-curing, two-component mix. It may cure to a hardness in the range of about 40 to 100 (Shore A). It may maintain an adequate peel strength to withstand multiple thermal and pressure cycling, and may have a working life, wherein it may be shaped, of less than about eleven minutes.

Abstract: Disclosed herein is a multi-layer drumhead with non-concentric inner layer. The drumhead in one form comprising: a flesh hoop; an inner layer of material affixed to the flesh hoop; an outer layer of material affixed to the inner layer adjacent the flesh hoop and not affixed to the inner layer; a plurality of surfaces defining cutouts in the inner layer. In one example the cutouts form a lateral dampening strip across the inner layer. The device in one example further comprising dampening materials removably positioned between the outer layer and the lateral dampening strip.

Abstract: A drum head having a striking feeling similar to an acoustic drum includes an inner head layer and a pair of outer head layers. The outside diameter of the inner head layer is smaller than the outside diameter of a flat part of the outer head layers and the inside diameter of the edge of the shell. The inner head layer is inside the connection part between the flat part and a cylindrical part of the outer head layers and the shell edge part. When tension is applied to the outer head layers, tension is prevented from being applied to the inner head layer.

Abstract: Disclosed is a novel “cajon” or box percussion instrument. A cuboid or rectangular shaped percussion instrument has six sides. It usually consists of five (5) panels of equal thickness with at least one panel of a thinner more flexible sixth panel which vibrates when percussed. One or more chambers and interior porting system are included in improve tonal quality. One or more external port openings, usually rectangular in shape, are formed in the unit to permit sound to emanate. Different external port geometries including shapes and sizes are contemplated. Encompassed in a single unit, the chamber delivers distinct independent tones. In some models, an interior resonating baffle and reflective block have been introduced to direct sound waves and air flow out of the exterior port opening creating a greater larger frequency range and greater amplification. In one example multiple independent chambers and interior porting system are included to improve the tonal quality.

Abstract: A bass drum 10 has a hollow cylindrical shell 11, a drumhead 12 mounted on an opening end of the shell 11 to form a striking surface, and a striking surface attachment 13 provided on the reverse side of the drumhead 12. The striking surface attachment 13 is formed of an elastic sheet. At least a part of an outer area of the striking surface attachment 13 is fixed to the drumhead 12 and a central area of the striking surface attachment 13 is not fixed to the drumhead 12. As a result, the bass drum 10 can generate a struck sound having both deep bass sound and clear attack.

Abstract: A drumhead and a method for coating a drumhead membrane comprising applying a coating having cross linkable polymeric material to the membrane and applying energy to cross link the polymeric material and thereby permanently adhere the material to the membrane as a play surface. The cross-linking not only hardens the coating to improve durability, but also improves the adhesion of the coating to the base film. Actinically cured coatings can completely harden in a matter of 3 to 5 seconds, with UV cured inks being especially desirable.

Abstract: An interchangeable drum head cover is disclosed which enables use of multiple advertisements, band identifiers or other visual indicia on a drum or like instrument. A drum head cover with a specific identifier, advertisement or other indicia printed thereon includes a flexible attachment means on its periphery that facilitates quick exchange of covers as needed. A pouch for storage of the cover can be formed as an attachment to the cover.

Abstract: A percussion instrument includes: a cylindrical shell portion having an open upper surface side; and a drumhead stretched to be installed on the upper surface side of the shell portion, wherein the drumhead includes: a membrane formed of a membranous material, having a struck head portion configured as a striking face to be struck by a performer and an outer periphery located on an outer circumferential side of the struck head portion; and an annular frame formed of a resin material and having the outer periphery of the membrane fixed thereto, and the drumhead is integrally formed by the membrane and the frame by injection molding.

Abstract: A drumhead and a method for coating a drumhead membrane comprising applying a coating having cross linkable polymeric material to the membrane and applying energy to cross link the polymeric material and thereby permanently adhere the material to the membrane as a play surface. The cross-linking not only hardens the coating to improve durability, but also improves the adhesion of the coating to the base film. Actinically cured coatings can completely harden in a matter of 3 to 5 seconds, with UV cured inks being especially desirable.

Abstract: A system and method for playing a multi-player music video game with a drum system video game controller is provided. In one embodiment, the invention relates to a method for providing a drum solo with a music based multi-player video game. In another embodiment, the invention relates to a system for providing analog input from one or more drum sensors used in game play associated with a music based multi-player video game. In yet another embodiment, the invention relates to a method for preventing interference between the one or more drum sensors. In one embodiment, the invention relates to a method for mapping digital information indicative of input to a video game controller in a first form to information in a second form, the second form conforming to a protocol for inputs to a video game console executing a music based multi-player video game.

Abstract: An acoustic drum 10 has a hollow cylindrical shell 11, a drumhead 12 mounted to an opening end of the shell 11 to form a striking surface, a striking surface attachment 13a provided on the entire surface of a useful movable portion of the front side of the drumhead 12, and a striking surface attachment 13b provided on the entire surface of a useful movable portion of the reverse side of the drumhead 12. Each of the striking surface attachments 13a and 13b is formed of a resin film, with respective outer areas of the striking surface attachments 13a and 13b being fixed to the drumhead 12. As a result, the acoustic drum 10 can reduce sound volume, while maintaining struck sounds having brightness and providing a player with favorable feeling of striking.

Abstract: A bass drum 10 has a hollow cylindrical shell 11, a drumhead 12 mounted on an opening end of the shell 11 to form a striking surface, and a striking surface attachment 13 provided on the reverse side of the drumhead 12. The striking surface attachment 13 is formed of an elastic sheet. At least a part of an outer area of the striking surface attachment 13 is fixed to the drumhead 12 and a central area of the striking surface attachment 13 is not fixed to the drumhead 12. As a result, the bass drum 10 can generate a struck sound having both deep bass sound and clear attack.

Abstract: The resonant drum head mounted speaker cone retrofit kit improves the sound of the drum on audio recordings and in live sound situations and changes the way the drum is miked in live and studio applications. The center of the resonant drumhead is cut out and a speaker cone assembly is attached thereon facing outwards. The speaker cone, which also vibrates from this pressure, now becomes the miked surface of the instrument. Using otherwise conventional miking techniques, a wider range of attack and tone characteristics can be obtained from the drumhead. Additionally, the use of varying speaker cone sizing, an audio foam dust cap, and cone composition options and differences in drum head tension, also contribute to define and tune the sound characteristics based on end user preference.

Abstract: The invention relates to a drumhead for volume-reduced and electronic drums, comprising an elastic mesh, fixed on a drumframe and elastic colloidal coatings integrally formed on the upper and lower surfaces of the elastic mesh. The colloidal coating covers at least a part of the surfaces of the elastic mesh. The elastic mesh uses one of polyester mesh, nylon mesh, cotton-fiber and mesh. Said elastic colloidal coating is round and located at the center of the drum, and has an area of 5%-100% of the entire drumhead surface. By injecting the colloid on the mesh according to the invention, the strength, elasticity and wear resistance of the elastic mesh body can be improved, and the lifetime of the drumhead can be extended up to five times. The invention reduces the sound of the drumstick by 20 dB.

Abstract: The resonant drum head mounted speaker cone retrofit kit improves the sound of the drum on audio recordings and in live sound situations and changes the way the drum is miked in live and studio applications. The center of the resonant drumhead is cut out and a speaker cone assembly is attached thereon facing outwards. The speaker cone, which also vibrates from this pressure, now becomes the miked surface of the instrument. Using otherwise conventional miking techniques, a wider range of attack and tone characteristics can be obtained from the drumhead. Additionally, use of optional speaker cone sizing, composition options and differences in tension also contribute to define and tune the sound characteristics based on end user preference.

Abstract: The present invention is a system for modifying the tonal output of a hand drum. The system includes the use of a tonal cover or membrane to change the sound emitted when the head of a hand drum is struck. Additional tuning pads are then added to further modify the sound of the drum. Tonal adjustment is affected by the number, thickness, material and tautness of the additional pads and tonal cover. A partial coverage of the drum head by a tonal cover may also be utilized.

Abstract: A silent drumhead, comprising: more than one layer of thin-film drumhead having a plurality of through-holes distributed throughout thereon; wherein the silent drumhead is formed by laminating the more than one layer of thin-film drumhead together; and wherein the more than one layer of thin-film drumhead are adhered together by means of an adhesive layer(s) therebetween. By using the plurality of through-holes to exhaust the air underneath the drumhead, vibrations generated when the drumhead is beaten are effectively reduced. This can mitigate the acoustic resonant effect of the drum shell to reduce the sound level when the drumhead is beaten. Furthermore, the thin-film drumheads that have been used in conventional drums can feed back the touch sense of beating in a totally realistic way to effectively overcome the shortcoming of conventional woven silent drumheads that they provide poor touch sense of beating.

Abstract: A hybrid drum as described combines the characteristics of both acoustic and electronic percussion apparatus enabling a musician to have a single instrument and have either acoustic or electronic output. A hybrid drum includes a multilayer drum head with a built-in FSR sensor such that the FSR drum head replaces the drum head of the acoustic drum and can be used to perform acoustically and or electronically. The FSR sensor is built into a double layer, double-head acoustic drum head, wherein one layer of the double head system has the FSR element printed on it, while the other layer of the double layer head has the inter-digiting conductive fingers printed on it and facing the FSR element. A conductive tail extends from one of the drum head layers and is operably connected to an electronic module secured to the drum shell.

Abstract: A drum head (1) for an electric drum (100), the drum head having a first side (11) and a second side (12), wherein the drum head (1) comprises chloroprene rubber and wherein a nylon fabric is provided on the first side (11) of the drum head (1).

Abstract: The resonant drum head mounted speaker cone retrofit kit improves the sound of the drum on audio recordings and in live sound situations and changes the way the drum is miked in live and studio applications. The center of the resonant drumhead is cut out and a speaker cone assembly is attached thereon facing outwards. The speaker cone, which also vibrates from this pressure, now becomes the miked surface of the instrument. Using otherwise conventional miking techniques, a wider range of attack and tone characteristics can be obtained from the drumhead. Additionally, use of optional speaker cone sizing, composition options and differences in tension also contribute to define and tune the sound characteristics based on end user preference.

Abstract: A shell for drum according to the present invention includes a laminated plywood-panel including a plurality of single-panels having different densities, the plurality of single-panels being jointed in decreasing order of density from a center portion in a thick direction of the laminated plywood-panel toward an outermost portion and an innermost portion, such that a single-panel having a highest density is arranged at the center portion, and single-panels having lowest densities are arranged at the outermost portion and the innermost portion.

Abstract: The percussion resonance system allows a drummer to produce additional, resonant acoustic effects beyond those produced by a conventional drum or other percussion instrument. In one embodiment, the percussion resonance system includes a substantially cylindrical sidewall having opposed upper and lower open ends, similar to the sidewall of a conventional drum, and batter and resonant heads respectively covering the upper and lower ends of the substantially cylindrical sidewall. A plurality of apertures are formed through either the batter head, the resonant head, or both, in order to produce additional acoustic effects caused by the air passing through the apertures as the heads vibrate. Air passing through the apertures increases the overall tonal qualities of the percussion instrument, and further aids in decreasing generation of unwanted vibrations, particularly in the form of ringing sounds or overtones.

Abstract: A musical drumhead having a top surface and bottom surface and a means attached to the drumhead for discharging an aromatic vapor. The musical drumhead is comprised of a membrane having means to vent the aromatic vapors through the top surface of the drumhead and disperse the vapors into the surrounding environment. Vent means comprises a plurality of vent holes in the drumhead membrane through which the vapors are discharged. The primary source of the vapors is a pad of porous material impregnated with an aroma producing liquid with a pleasing fragrance. The pad of porous material is attached in some conventional manner to the bottom surface of the drumhead immediately beneath the vent holes. The striking of the drumhead produces a vibration in the drumhead membrane which, in turn, excites the molecules in the air beneath and above the membrane.

Abstract: A drum fitted with drum heads features easy adjustment and variation of low-pitched sound. The drum head is formed with one or more openings to which surrounds made of material the same as or different than the drum head itself is attached for an independent and localized vibration area. Alternatively, the drum head is formed with a successively corrugated local area that offers localized deformation of the drum head. Either one of the constructions of the drum head provides the drum head with an independent and resiliently deformable local surface whereby when the drum is struck, the air contained inside the drum is pressurized to cause the vibration of the independent local surface, effectively increasing the vibration amplitude of the local surface on the drum head and thus extending the sound of the drum to a lower level.

Abstract: A percussion instrument may have a hoop member configured to hold down a head stretched across a first end of the shell by a plurality of adjustment devices that may be for operatively connecting the hoop member with a plurality of fixtures that may be arrangeable along at least two surfaces of the shell.

Abstract: A drum pad has a knitted material that is strechable and has a top surface to be beaten by a stick and a rear surface opposite to the top surface, a resin member that is strechable and thinner than the knitted material and that is capable of being thermally fused and bonded to the knitted material, and a rubber. The drum pad is formed of a first layer portion, a second layer portion, and a body portion. The first layer portion is formed in a region of the knitted material including the top surface thereof but not including the rear surface. The body portion is formed of the rubber. The second layer portion is formed in a remaining region of the knitted material other than the first layer portion and formed between the body portion and the first layer portion.

Abstract: An elongate drum augments sound through the use of varying cross-sectional shapes and dimensions, sound boards, and a cochlear-shaped horn.

Abstract: An enhanced low-noise drum tympan comprises at least two net bodies which are combined to a drum frame; the net bodies being combined by adhesive and being rolled as an integral body. The net bodies are selected from knitted fabrics nets, woven fabrics nets or the combination of knitted fabrics nets and woven fabrics nets. The knitted fabrics net is formed by only wide fabric strips or narrow fabric wires. The knitted fabrics net is formed by intersection of wide fabric strips and narrow fabric wires.

Abstract: The percussion resonance system allows a drummer to produce additional, resonant acoustic effects beyond those produced by a conventional drum or other percussion instrument. In one embodiment, the percussion resonance system includes a substantially cylindrical sidewall having opposed upper and lower open ends, similar to the sidewall of a conventional drum, and batter and resonant heads respectively covering the upper and lower ends of the substantially cylindrical sidewall. A plurality of apertures are formed through either the batter head, the resonant head, or both, in order to produce additional acoustic effects caused by the air passing through the apertures as the heads vibrate. Air passing through the apertures increases the overall tonal qualities of the percussion instrument, and further aids in decreasing generation of unwanted vibrations, particularly in the form of ringing sounds or overtones.

Abstract: An electronic drum 30 comprises a hollow body part 10 having an opening side, a drum head stretched over the opening side of the hollow body part 10 and having a stroked surface, an elastic cushion part 40 arranged to touch with a reverse side of the stroked surface of the drum head 30, a vibration absorber 43 that is arranged inside the body part 10 and absorbs a vibration transmitted from the body part 10, and a sensor 41 that is arranged in the vibration absorber 43 to touch with the elastic cushion part 40 and outputs a result of detecting a stroke on the drum head 30 transmitted by the elastic cushion part 40. The drum head 30 is made of a lamination of a plurality of elastic films and has a plurality of holes 30h pierced thorough all layers of the laminated films.

Abstract: An enhanced low-noise drum tympan comprises at least two net bodies which are combined to a drum frame; the net bodies being combined by adhesive and being rolled as an integral body. The net bodies are selected from knitted fabrics nets, woven fabrics nets or the combination of knitted fabrics nets and woven fabrics nets. The knitted fabrics net is formed by only wide fabric strips or narrow fabric wires. The knitted fabrics net is formed by intersection of wide fabric strips and narrow fabric wires.

Abstract: A drum pad has a knitted material that is strechable and has a top surface to be beaten by a stick and a rear surface opposite to the top surface, a resin member that is strechable and thinner than the knitted material and that is capable of being thermally fused and bonded to the knitted material, and a rubber. The drum pad is formed of a first layer portion, a second layer portion, and a body portion. The first layer portion is formed in a region of the knitted material including the top surface thereof but not including the rear surface, and is permeated with the melted resin member such that the resin member and the knitted material monolithically solidify with each other. The body portion is formed of the rubber.

Abstract: A shell for drum according to the present invention includes a laminated plywood-panel including a plurality of single-panels having different densities, the plurality of single-panels being jointed in decreasing order of density from a center portion in a thick direction of the laminated plywood-panel toward an outermost portion and an innermost portion, such that a single-panel having a highest density is arranged at the center portion, and single-panels having lowest densities are arranged at the outermost portion and the innermost portion.

Abstract: The resonant drum head mounted speaker cone apparatus improves the sound of the drum on audio recordings and in live sound situations and changes the way the drum is miked in live and studio applications. By integrating the resonant side drumhead with a speaker cone, when the drum is hit (on the batter head), the air pressure generated inside the drum moves the opposite resonant head. The center of the resonant drumhead is cut out and a speaker cone with the dust cap is glued to the inside thereof facing outwards. The speaker cone, which also vibrates from this pressure, now becomes the miked surface of the instrument as opposed to previously having to mike the drum from above the respective batter heads where it often interferes with the player. Using otherwise conventional miking techniques, a wider range of attack and tone characteristics can be obtained from the drumhead.

Abstract: A practice drumhead assembly including a mesh membrane held in substantially fixed relation to an acoustic membrane. The assembly preferably includes an annular tensioning ring for tensioning the mesh membrane, and an engagement member for substantially fixing the mesh membrane relative to the acoustic membrane. The tensioning ring includes a cylindrical rod with a turnbuckle that is rotated to increase the diameter of the tensioning ring.

Abstract: An electronic drum comprises a pad comprising a body portion made of a polymeric elastic material such as a rubber or a thermoplastic elastomer, and a surface layer portion which is bonded with the body portion so as to cover the body portion, the surface layer portion being made of a polymeric material having an elastic modulus of 0.5 to 20 GPa.

Abstract: An acoustic percussion instrument and percussion set containing the instrument. The instrument includes a hollow cylindrical shell having a first end and a second end and an inside cylindrical surface. A first substantially rigid plate having an outside surface and an inside surface is attached adjacent to the first end of the hollow cylindrical shell. A first resilient pad, that provides a percussion surface that does not require periodic adjustment, is attached adjacent to the outside surface of the first substantially rigid plate. A raised rim circumscribes the first resilient pad.

Abstract: An object of the present invention is to provide a percussion detecting apparatus, which is excellent in percussion feeling, and the percussion sounds of which are very small, in electronic percussion instrumental system. The percussion detecting apparatus is provided with a head prepared from a net-like raw material composed of a first net and a second net, the net-like raw material being obtained by such a manner that both the nets having been woven in accordance with plane weaving manner wherein the longitudinal and transverse fibers cross at right angles are laminated in such a way that the weave pattern directions thereof intersect obliquely with each other; and a head sensor which is in contact with the center position of the under side in the head and detects percussion with respect to the head as electric signal.

Abstract: A hybrid electric/acoustic percussion instrument and percussion set containing the instrument. The instrument includes a hollow cylindrical shell having a first end and a second end and an inside cylindrical surface. A first substantially rigid plate having an outside surface and an inside surface is attached to at least the first end of the hollow cylindrical shell. A first resilient pad is attached to the outside surface of the first substantially rigid plate. An electroacoustic transducer is attached to the inside cylindrical surface of the hollow cylindrical shell.

Abstract: A drumhead for use in a percussion instrument is composed of multiple (e.g., two or three) plies of synthetic resin films, which are laminated together and are brought into close contact with each other when stretched across the opening of a hollow cylinder of a drum, for example. At least one air evacuation hole is formed at the center of the backside synthetic resin film or in proximity to the center of the backside synthetic resin film. Therefore, when the drumhead is stretched outwardly along a diameter direction of the opening of the hollow cylinder of the drum, remaining air between the films can be reliably evacuated from the air evacuation hole towards the exterior of the drumhead. Thus, it is possible to reduce unwanted loss in transmission of vibration between the films of the drumhead when beaten; hence, it is possible to realize good sound quality in the drum.

Abstract: An object of the present invention is to provide a percussion detecting apparatus, which is excellent in percussion feeling, and the percussion sounds of which are very small, in electronic percussion instrumental system. The percussion detecting apparatus is provided with a head prepared from a net-like raw material composed of a first net and a second net, the net-like raw material being obtained by such a manner that both the nets having been woven in accordance with plane weaving manner wherein the longitudinal and transverse fibers cross at right angles are laminated in such a way that the weave pattern directions thereof intersect obliquely with each other; and a head sensor which is in contact with the center position of the under side in the head and detects percussion with respect to the head as electric signal.

Abstract: The present invention relates to a musician quality hand drum that may be produced in a simplified and economical manner. The hand drum is simplified in that it utilizes a ring interconnected within an open end of a simple tubular shell to allow a musical quality drumhead (e.g., an animal skin drumhead) to be interconnected in tension directly to the outside surface of the drum shell. In this regard, the need for an intricate, expensive drumhead fixation means and/or drumhead tensioners is eliminated, allowing for cost benefits to be realized.

Abstract: A drum includes a shell with two heads fixedly connected to two opposite ends of the shell by two counterhoops. Each head includes a base, a decoration layer on the base, a protection layer on the decorative layer and a durable layer on the protection layer. The durable layer has ridges extending therefrom so that the patterns on the decorative layer looks like flapping when the head is beat.

Abstract: A percussion instrument head is composed of a synthetic resin film (e.g., a PET film) having a prescribed thickness, which is subjected to chemical etching using a prescribed solution (e.g., an alkali solution), thus processing at least one surface thereof to be rough. Irregularities are formed in substantially uniform sizes and dimensions on the rough surface of the film, wherein hydrolysis processing advances firstly on the surface of the film, which are gradually dissolved or decomposed. Thus, it is possible to simulate the exterior appearance and flexibility of the conventional natural-leather head, and it is possible to produce sharp and articulated sounds having balanced pitches (or intervals) when playing the percussion instrument head composed of the synthetic resin film, which can simulate the property of sound of the conventional natural-leather head. After completion of chemical etching, the film is coated with an epoxy resin, for example.

Abstract: An object of the present invention is to provide a percussion detecting apparatus, which is excellent in percussion feeling, and the percussion sounds of which are very small, in electronic percussion instrumental system. The percussion detecting apparatus is provided with a head prepared from a net-like raw material composed of a first net and a second net, the net-like raw material being obtained by such a manner that both the nets having been woven in accordance with plane weaving manner wherein the longitudinal and transverse fibers cross at right angles are laminated in such a way that the weave pattern directions thereof intersect obliquely with each other; and a head sensor which is in contact with the center position of the under side in the head and detects percussion with respect to the head as electric signal.

Abstract: A practice drumhead assembly including a mesh membrane held in substantially fixed relation to an acoustic membrane. The assembly preferably includes an annular tensioning ring for tensioning the mesh membrane, and an engagement member for substantially fixing the mesh membrane relative to the acoustic membrane. The tensioning ring includes a cylindrical rod with a turnbuckle that is rotated to increase the diameter of the tensioning ring.