Abstract: In an appliance, such as a cyclonic vacuum cleaner, a motor is arranged to drive an impeller fan located in a motor and fan unit. The rotation of the impeller may cause nuisance tones to be generated. A silencing arrangement is provided to control such noise and includes a plurality of discrete passive silencers in the form of tube silencers arranged in a first set and a second set. The tube silencers have open end portions arranged to face the fan and the silencers of the first set are spaced from the silencers of the second set in both axial and radial directions. This combination gives the same effect as an array of closely spaced tube silencers—however, by spacing the silencers in two directions, fluid is allowed to flow freely.

Abstract: A linear acoustic liner for an aircraft includes a cellular core having a first surface and an opposed second surface. A substantially imperforate back skin covers the first surface, and a perforate face skin covers the second surface of the core. The perforate face skin includes an outer face skin layer having a first plurality of spaced openings, an inner face skin layer having a second plurality of spaced openings, and a porous layer disposed between the outer face skin layer and the inner face skin layer. Each of the first plurality of spaced openings are substantially aligned with one of the second plurality of spaced openings.

Abstract: An engine assembly, an acoustical liner and an associated fabrication method are provided to address fan blade flutter and fan noise control simultaneously within the same liner area. Fan blade flutter is therefore controlled without necessarily increasing the weight of the engine, impairing the structural integrity of the engine, or increasing the noise generated by the engine. The acoustical liner may have additional acoustical degrees of freedom which permit these seemingly competing concerns to be addressed in a complementary manner. The acoustical liner may include inner and outer barrels with the inner barrel having a perforated face sheet, a perforated back skin and a core disposed between the perforated face sheet and the back skin. The fluid communication between the core and the space between the inner and outer barrels provides additional acoustical degrees of freedom which may be utilized to reduce fan blade flutter while concurrently limiting fan blade noise.

Abstract: The invention includes a joint assembly for connecting first and second longitudinal edges of portions of an acoustic barrel or panel having an open cell core, a perforated inner skin, and an outer skin. The joint assembly includes at least one strip covering a plurality of openings in walls of cells along the first and second longitudinal edges. The strip is separate from the inner and outer skins. A plate includes a first portion connected to the outer skin proximate to the first longitudinal edge, and a second portion connected to the outer skin proximate to the second longitudinal edge.

Abstract: A duct 26 has circumferentially distributed features capable of scattering acoustic energy associated with fluid dynamic shocks 34 extending in a shock orientation direction D. Each feature is oriented, over at least a portion of its length, substantially perpendicular to the shock orientation direction. The features may be splices 42 used to connect segments of an acoustic liner 30, partitions 56 in a stability enhancing casing treatment 32, or other features capable of scattering acoustic energy associated with shocks.

Abstract: An inlet of an aircraft nacelle having an acoustic barrel configured to reduce engine fan flutter by attenuating various frequencies. The acoustic barrel may comprise an acoustic panel of a honeycomb configuration sandwiched between a first back sheet and a face sheet and extending from a forward bulkhead to an aft bulkhead of the inlet. The acoustic barrel may further comprise a deep liner section bonded to and sandwiched between the first back sheet and a second back sheet. The deep liner section may have a narrower width than the acoustic panel and may be located proximate the aft bulkhead. The sections of the first back sheet, the face sheet, and a septum of the acoustic panel may be perforated and may contain additional holes formed in portions aligned radially inward of the deep liner section.

Abstract: A turbofan gas turbine engine comprises a fan and an intake duct upstream of the fan. The fan comprises a fan rotor having a plurality of fan blades. The intake duct has a liner, the liner comprising an acoustic liner positioned upstream of the fan and a buzz-saw tone noise liner positioned upstream of the acoustic liner. The buzz-saw tone noise liner is positioned substantially at, or near, an upstream end of the intake duct. The intake duct has a lip and the buzz-saw tone noise liner is positioned at, or near, the lip.

Abstract: An acoustic treatment structure related to a leading edge onto which an aerodynamic stream flows, in particular at an air intake of an aircraft nacelle, includes—from the outside to the inside—at least one acoustically resistive substructure (30), at least one alveolar substructure including strips (32) of cells, arranged in a direction that is essentially perpendicular to the direction of flow of the aerodynamic stream, and at least one reflective layer (34). Each strip (32) includes a first part that insulates the strips from one another, called a support, with a U-shaped cross-section in the longitudinal direction, whose open surface that is opposite to the bottom of the U shape is flattened against the acoustically resistive substructure (30), and at least a second part, called partitioning, making it possible to partition the space that is delimited by the support and the acoustically resistive substructure (30) into cells.

Abstract: An intake silencer of a gas turbine capable of efficient noise reduction in which a high frequency sound-absorbing splitter group composed of a plurality of sound-absorbing splitters capable of reducing highfrequency component noise and a middle/low sound-absorbing splitter group composed of a plurality of sound-absorbing splitters capable of reducing middle/low frequency component noise are disposed separately in a gas flow direction. High frequency component noise is reduced by the high frequency sound-absorbing splitter group, and middle/low frequency component noise is reduced by the middle/low sound-absorbing splitter group.

Abstract: An aero-acoustic aviation engine inlet with a single air blowing slot or multiple air blowing slots flows air over one or more segments of inlet acoustic lining surfaces at speeds that are higher than the inlet mean air flow speed, for aggressive inlet noise abatement.

Abstract: An acoustic inner barrel for an aircraft engine nacelle inlet is constructed from a composite material and is formed as a single, 360-degree annular segment. The barrel includes an inner skin, an outer skin, a cellular core disposed between the inner skin and the outer skin, and at least one crack and delamination stopper extending radially from the inner skin to the outer skin.

Abstract: An acoustic panel for a fan casing of a gas turbine engine includes one or more Helmholtz resonators to absorb acoustic energy propagated upstream from the fan. By arranging that the periodic air flow out of the resonators has some axial momentum, by inclining the passages that exit from the necks of the resonators in a downstream direction, some of the energy in this air flow can be realised as a useful pressure rise in the direction of the air flow into the fan, rather than a pressure drop as in known acoustic panels.

Abstract: An acoustic, noise-attenuating panel for an aircraft engine nacelle inlet. The panel includes at least three layers: (a) a perforated film; (b) a sound attenuating core; and (c) a structural layer. The structural layer has through-holes adapted for receiving fasteners that are configured to engage structure of an engine nacelle. The structural layer is fabricated, at least at its ends, of a material sufficiently strong so that when fasteners are engaged in the through-holes in the layer's ends, the fasteners retain the acoustic panel in a nacelle inlet under conditions of use. Alternatively, or in addition, the structural layer ends may be reinforced at the through-holes with reinforcing strips.

Abstract: In order to provide noise suppression, bumps or undulations are provided on a nozzle surface in order to vary the convergent-divergent ratio between that surface and an opposed nozzle surface. By such an approach, a circumferential variation in the shock cell pattern is created and the flow is deflected so as to enhance turbulent mixing thereby suppressing noise.

Abstract: The invention relates to a method for making an acoustic absorption panel in particular for the nacelle of an aircraft engine, the panel being of the type comprising a cellular core covered on one side with a so-called outer air-permissive skin and on the other side with a so-called inner perforated skin, the cellular core being formed by the edge-to-edge junction of a plurality of blocks with a cellular core (B1, B2). The method comprises the following steps: a) before the edge-to-edge junction of blocks with a cellular core (B1, B2), opening the cells (A1, A2) located on the edges of the blocks to be joined; and b) edge-to-edge dry joining the blocks (B1, B2) so that the open cells (A1, A2) engage into one another.

Abstract: A coating for acoustic treatment relative to an aircraft's surface, in particular a leading edge such as an air intake of an aircraft nacelle, includes an acoustically resistive layer, at least one alveolar structure (30), and a reflective layer. The alveolar structure (30) includes a number of tubes that empty out, on the one hand, at a first imaginary surface (34), and, on the other hand, at a second imaginary surface (36). The alveolar structure (30) includes cut-outs or openings (38) made at the side walls of certain tubes that make it possible to link adjacent tubes so as to create a network of communicating tubes that isolate at least one tube or a group of non-communicating tubes, whereby at least one of the communicating tubes is connected to at least one hot gas intake (40).

Abstract: In an aspect, a method is provided for attenuating jet engine noise. Air velocity, adjacent to an inlet fan duct outer wall, is increased to a greater rate than typical velocity of an operational engine ambient inlet airflow, adjacent to the inlet fan duct outer wall. Boundary layer and associated turbulence is reduced or eliminated. Refraction and absorption of inlet sound into an acoustic liner is optimized. In an aspect, air velocity is increased by injecting air. In an aspect, air velocity is increased by exerting a suction force. In an aspect, a system is provided to attenuate jet engine noise. In an aspect, a fluid duct is provided opening to an inlet fan duct outer wall and to aft of a fan rotor.

Abstract: A sound increase apparatus includes a partition wall adapted to divide an engine room for defining a first engine room space that is located on a side of a dash panel and a second engine room space in which an engine is installed, and a first pressure fluctuation amplification unit inter-communicating an engine inlet pipe arranged in the second engine room space and the first engine room space. The first pressure fluctuation amplification unit amplifies a pressure fluctuation of a first frequency selected from a plurality of frequencies when pressure of air residing inside the engine inlet pipe fluctuates at the plurality of frequencies.

Abstract: A turbine engine resonator comprising a panel and a vessel. The panel is along a flow path within the engine and has an aperture. The vessel has a mounting flange secured to the panel. The flange has an aperture mated to the aperture of the panel. The vessel has a body secured to the mounting flange with an interior of the body in communication with the flange aperture. A first portion of the panel extends into the mounting flange aperture and may redirect a leakage flow, if any, to limit an effect of leakage upon resonator performance.

Abstract: A resonator for damping pressure waves or instabilities in a system supported by acoustic energy wherein the resonator adopts the use of counter-bored openings on the downstream side of the resonator within the flow path of the system. The resonator includes a first member and a second member where the second member includes a plurality of openings therethrough with each hole having a counter-bore on its upstream side. The first member has a size substantially smaller than the diameter of said flow path and a first plurality of openings therethrough. The openings are in fluid communication with the flow path. The second member has a size generally equal to the first member and a second plurality of openings therethrough, which openings are in fluid communication with the flow path.

Abstract: A device for simulating sound produced by certain equipment, for example a rotor-stator arrangement of a turbomachine, or for generation of opposing sound fields for active sound control, including active sound reduction and active sound amplification, comprises flow obstacles (2) provided in a flow duct (1) flown by a fluid at which vortices (5, 6) are shed at a certain frequency depending on the shape and size of the flow obstacles and the velocity of flow. The quantity and spatial arrangement of the flow obstacles is selected such that a periodically spatially and temporally changing pressure field for the excitation of a sound field (8) of a certain modal content is produced by the entirety of the vortices shed. This sound field reacts synchronizingly on the vortex shedding. The resonant circuit so formed, whose vortex shedding frequency is in the range of the resonant frequency of the sound field to be excited, is the sound source.

Abstract: An acoustic panel for integration in a nacelle of an aircraft engine assembly for absorbing noise generated by an engine or a fan assembly of the aircraft engine assembly. The acoustic panel comprises a generally annular section integrated into or attached to an inner wall of the inlet section, and a flange extending generally perpendicularly from the annular section. The flange attaches the acoustic panel to a bulkhead without requiring the use of fasteners extending through the annular section of the acoustic panel, thus eliminating any unwanted air passages through the annular section of the acoustic panel.

Abstract: An acoustic panel for a fan casing of a gas turbine engine includes one or more Helmholtz resonators to absorb acoustic energy propagated upstream from the fan. By arranging that the periodic air flow out of the resonators has some axial momentum, by inclining the passages that from the necks of the resonators in a downstream direction, some of the energy in this air flow can be realised as a useful pressure rise in the direction of the air flow into the fan, rather than a pressure drop as in known acoustic panels.

Abstract: Aspects of the invention are directed to a system for improving the damping performance of an acoustic resonator. According to aspects of the invention, a resonator, such as a Helmholtz resonator, can be attached to a surface of a combustor component in a turbine engine. The combustor component includes a region in which a plurality of passages extend through the thickness of the component. The resonator is attached to the component so as to enclose at least some of the passages. The passages are in fluid communication with a cavity defined between the component surface and the resonator. Resonator performance is a function of the length of the passages in the component. According to aspects of the invention, resonator performance can be improved by reducing the length of the passages in the component by reducing the thickness of the component in a region that includes the plurality of passages.

Abstract: The present invention provides support means for an acoustic liner in an APU exhaust system, where the acoustic liner has a tubular sidewall with an outer surface, a first longitudinal edge, a second longitudinal edge, and an axial gap formed between the first and the second longitudinal edges. The APU exhaust system includes an annular support disposed substantially symmetrically about a longitudinal axis and coupled to a portion of the acoustic liner and a linear support disposed at least partially in the acoustic liner axial gap.

Abstract: The present invention provides a composite muffler for use with an auxiliary power unit. The composite muffler comprises a composite outer can, an annular baffle, an acoustic liner, and a thermal barrier. The composite outer can is disposed substantially symmetrically about a longitudinal axis and has an inner peripheral surface defining a cavity. The annular baffle is disposed within the composite outer can cavity, has an opening formed therein, and extends radially outwardly from the opening toward the composite outer can inner peripheral surface. The acoustic liner extends through the annular baffle opening. The thermal barrier is coupled between the annular baffle and the outer can inner peripheral surface.

Abstract: An acoustic liner 20 includes a remote panel 26, a perforated proximate panel 22 transversely spaced from the remote panel and one or more partitions 32 spanning across the space between the panels. At least one baffle 44 cooperates with the partitions to define a resonator chamber 34b and an associated neck 56 for establishing communication between the resonator chamber and a fluid stream G flowing past the proximate panel.

Abstract: An acoustic, noise-attenuating panel for an aircraft engine nacelle inlet. The panel includes at least three layers: (a) a perforated film; (b) a sound attenuating core; and (c) a structural layer. The structural layer has through-holes adapted for receiving fasteners that are configured to engage structure of an engine nacelle. The structural layer is fabricated, at least at its ends, of a material sufficiently strong so that when fasteners are engaged in the through-holes in the layer's ends, the fasteners retain the acoustic panel in a nacelle inlet under conditions of use. Alternatively, or in addition, the structural layer ends may be reinforced at the through-holes with reinforcing strips.

Abstract: An acoustic panel for integration in a nacelle of an aircraft engine assembly for absorbing noise generated by an engine or a fan assembly of the aircraft engine assembly. The acoustic panel comprises a generally annular section integrated into or attached to an inner wall of the inlet section, and a flange extending generally perpendicularly from the annular section. The flange attaches the acoustic panel to a bulkhead without requiring the use of fasteners extending through the annular section of the acoustic panel, thus eliminating any unwanted air passages through the annular section of the acoustic panel.

Abstract: Methods and apparatus are provided for an exhaust duct having an externally replaceable acoustic liner. The exhaust duct includes a forward section that is configured to be axially coupled with a bulkhead collar on the aircraft, a body section that is coupled to the forward section and a stinger cap that includes the replaceable acoustic liner. The replaceable acoustic liner is configured to be slideably received by the body section.

Abstract: A cooled acoustic liner useful in a fluid handling duct includes a resonator chamber 52 with a neck 56, a face sheet 86, and a coolant plenum 80 residing between the face sheet and the chamber. Coolant bypasses the resonator chamber, rather than flowing through it, resulting in better acoustic admittance than in liners in which coolant flows through the resonator chamber and neck. In one embodiment, the liner also includes a graze shield 88. Openings 40, 38 penetrate both the face sheet and the shield to establish a relatively low face sheet porosity and a relatively high shield porosity. The shielded embodiment of the invention helps prevent a loss of acoustic admittance due to fluid grazing past the liner. Another embodiment that is not necessarily cooled, includes the resonator chamber, low porosity face sheet and high porosity shield, but no coolant plenum for bypassing coolant around the resonator chamber.

Abstract: Flow restrictors for aircraft inlet acoustic cores, and associated systems and methods are disclosed. A system in accordance with one embodiment of the invention includes an inlet flow surface having multiple openings, and an acoustic treatment positioned adjacent to the inlet flow surface. The acoustic treatment can have multiple cells in fluid communication with the openings in the inlet flow surface. A fluid collector passage can be positioned to collect liquid entering the acoustic treatment through the multiple openings, and can have an exit aperture through which the liquid drains. The fluid collector passage can include at least one flow restrictor positioned to at least restrict the flow of air from the exit aperture through the fluid collector passage to the multiple openings.

Abstract: A liner assembly for a fan case includes a noise attenuation layer covered by a face sheet. The face sheet includes openings to the underlying noise attenuation layer. The face sheet and noise attenuation layer include acoustically transparent joints. The noise attenuation layer includes a first side joined to a second side at a seam by an adhesive strip. The adhesive strip bonds the first side to the second side without filling any chambers. The face sheet includes a joint filled with an adhesive providing the desired uninterrupted surface within the fan case. Openings are formed through the joint and the adhesive to communicate with the underlying noise attenuation layer. The joint and seam become essentially transparent acoustically to improve noise attenuation performance.

Abstract: A liner assembly includes a plurality of aligned passages providing a large open area combined with openings much smaller than a length of the passages. The plurality of passages are disposed parallel with each other and include an opening transverse to incident sound waves. The passages are separated by walls and are blocked at an end distal from the openings. Sound waves incident on a face of the liner enter the passages and are dissipated by viscous losses. Sound energy is further dissipated as thermal energy to the walls of the passages. The long narrow passages provide the desired visco-thermal losses for sound energy in a broad frequency range.

Abstract: An acoustic liner 20 includes a remote panel 26, a proximate panel 28 transversely spaced from the remote panel and a resonator chamber 34b residing between the panels. Perforations 38 penetrate the proximate panel in registration with the resonator chamber 34b. A neck 56 with an inlet 58 recessed from the proximate panel establishes communication between the chamber and a fluid stream G flowing past the proximate panel. A bypass coolant passage 66 guides coolant through the perforations without guiding it through the resonator chamber.

Abstract: A liner assembly for an aircraft engine housing includes a noise attenuation structure that is covered by a face sheet. The face sheet covering the noise attenuation structure includes a surface having a plurality of circumferentially spaced apart acoustic energy absorption areas that are interspersed between a corresponding plurality of acoustic energy reflective areas. The acoustic energy reflective areas scatter higher order acoustic modes into a plurality of lower order modes. The difficult to attenuate lower order acoustic modes produced by the various acoustic energy cancel each other out to provide significant improvement in liner noise reduction efficiency.

Abstract: A duct liner assembly includes a noise attenuation layer for absorbing noise energy that is covered by a face sheet. The face sheet includes a seam that is covered by an acoustically active splice. The acoustically active splice includes a plurality of acoustic regions that provide for communication of noise energy to the noise attenuation layer to minimize creation of acoustically dead areas.

Abstract: A fan case assembly includes a noise attenuation layer that is covered by a face sheet. The face sheet includes a first plurality of openings. The noise attenuation layer includes a plurality of individual cells that are in communication with at least one of the first plurality of openings. Noise energy is communicated through the first plurality of openings into the individual cells and dissipated to reduce noise emissions. A seam in the face sheet is covered to protect the underlying noise attenuation layer from damage by a retainer. The retainer is bonded to the face sheet over the seam and includes a second plurality of holes that communicates noise energy through the retainer to the noise attenuation layer. Communication of noise energy through the retainer provides an acoustically active seam that aids in the dissipation of noise energy and thereby reduces the level of sound emitted from the engine.

Abstract: A fogging device (26) for introducing water and/or vapor into an intake air flow (10, 27) of a gas turbine (1–3) includes a sound-absorbing device (31, 35). This device may in particular be designed in the form of Venturi tubes (31), the water (29) being fed to the air flow (27) via nozzles (33) arranged at the narrowest location. In this way, the spraying of water for increasing the power output or for generally regulating the gas turbine can at the same time be combined with a silencer, and this in a comparatively simple construction.

Abstract: A silencer (25a) for the attenuation of noise occurring in an intake airstream (10, 27) of a gas turbine (1–3) includes a device or devices (31, 32, 33, 34) for the introduction of water and/or steam into the intake airstream (10, 27). These devices may be designed, in particular, in the form of Venturi tubes (31), the water (29) being supplied, in particular above the saturation limit, to the airstream (27) via nozzles (33) arranged at the narrowest point. In this way, the silencing can be combined at the same time with the introduction of water for increasing the power output or for the general regulation of the gas turbine, this being achieved with a comparatively simple design.

Abstract: The tunable resonator is coupled to the engine speed control such that the resonator is set to a different frequency range when the engine speed is changed. The frequency range is changed by opening and closing necks and/or changing the effective volume of the resonator.

Abstract: An assembly useful in reducing aircraft engine noise such as turbofan engine noise comprises: (a) a core portion comprising at least one entrance end and at least one exit end for the passage of acoustic energy therethrough; (b) a first member having an exterior face and an interior face, wherein the first member is adjacent to at least a part of the core portion, and the first member has a plurality of openings therein to permit the passage of acoustic energy therethrough; and (c) a second member having an exterior face and an interior face, wherein the interior face of the second member is adjacent to the core portion. The core portion may be a honeycomb acoustic structure, and the first member may be perforated to permit the passage of acoustic energy into and out of the conduit portion.

Abstract: An aircraft engine assembly is provided that is adapted to reduce noise produced by an engine included in the engine assembly. The engine assembly includes a nacelle having an inlet section and a main section that is houses the engine and fan assembly associated with the engine. The inlet section is coupled to the main section at a main bulkhead junction between the inlet section and the main section. A one piece annular acoustic panel is located within a recess in an internal wall of the nacelle. The annular acoustic panel extends from a forward portion of the inlet section to a forward portion of the main section such that the bulkhead is covered by the annular acoustic panel.

Abstract: An internal duct of an aircraft engine pod may include a fan and a tubular air intake having a first acoustic attenuation internal tubular piece. The first acoustic attenuation internal tubular piece is acoustically homogeneous, is of the resonator type, and has no internal assembly fish-plate. Additionally, the internal duct may include a tubular fan casing and a tubular transition part for connecting the air intake to the fan casing. An internal face of the tubular transition part is acoustically homogeneous also. Moreover, the internal face of the first acoustic attenuation internal tubular piece and the internal face of the tubular transition part are disposed in aerodynamic continuity.

Abstract: An acoustically resistive layer for an acoustic attenuation panel (22) forming a conduit in which there is an aerodynamic flow (18), adapted particularly for an aircraft turbo jet engine. The panel has at least one acoustically resistive layer (24), at least one porous structure (26) and a reflector (28) disposed opposite the incident wave. The acoustically resistive layer (24) is constituted by strips (30) disposed in the direction of the flow (18), interconnected by a plurality of splints (32) ensuring the absorption of force, particularly radially, the splints (32) having very small surfaces ensuring the continuity of the homogeneous character of the quantity of open surface of the acoustically resistive layer thus formed.

Abstract: An acoustic-structural LPC splitter assembly which comprises a structural acoustic splitter through which are arranged a plurality of bleed exhaust ports, the acoustic splitter having a first and second end, an inner and outer surface, a front joint for securing the first end, and a slip joint formed at an FEGV interface for securing the second end, wherein the structural acoustic splitter provides support sufficient to maintain concentricity of an LPC inner case.

Abstract: Tubular acoustic attenuation piece for an aircraft jet engine air intake. According to the invention, said tubular piece (1) is made up of shells (2) with a cellular core (5) assembled only by external fish plate strips (8), the facing edges (6) simply being edge faces of said shells (2) forming slots (9) between them.

Abstract: A Helmholtz resonator includes a chamber at least partially defining a cavity. The chamber has a neck which defines a passage that is in fluid communication with the cavity. The chamber and the neck produce a passive response to a sound wave produced by the internal combustion engine. The sound wave negatively effects engine performance. An active resonator is disposed within the chamber. The active resonator produces a forced response for supplementing the passive response and increasing the band width of the noise attenuating pressure wave. The Helmholtz resonator is in fluid communication with a portion of an air induction system that defines a passageway that carries the sound wave. A driver is connected to the active resonator, which is preferably a loud speaker, to drive the loud speaker and produce the forced response. The driver preferably utilizes a signal source, such as an engine speed signal, to synchronize the forced response with the engine speed.

Abstract: An HQ tube arrangement suitable for packaging within a vehicle may be designed by creating a mathematical model representing a tube arrangement having a first passageway and a second passageway fluidly connected to the first passageway at first and second junctions. The second passageway is divided by the junctions into first, second, and third passages. Lengths may be associated with each of the first passageway and the first, second, and third passages to produce a particular length combination. A filter parameter, which may be passed upon an average transmission loss for a particular frequency over a standard deviation, is calculated for the particular length combination. Other lengths may be associated with the tube arrangement to calculate other filter parameters for the other length combinations.

Abstract: The invention relates to a device (10) for the targeted sound transmission from an intake tract (1) of an internal combustion engine to the interior (21) of a motor vehicle. Said device comprises at least one hollow transmission conduit (12), which communicates on the input side with the intake tract (1) and to which at least one resonator chamber (13), which emits the sound to the motor vehicle interior (21), is connected. In order to achieve improved modulation of the sound that is emitted to the motor vehicle interior (21), the inventive device (10) has several resonator chambers (13) operating in parallel, at least two of which differ from one another-with respect to the tuning of their frequencies.