A method of manufacturing high temperature-sound absorbers, comprising: providing a first casing shell (3,1); providing a second casing shell (3.2) or a direct hot gas-carrying member; providing means (7, 17) for acoustic and thermal insulation, comprising: providing an insulating and damping material; shaping of the insulating and damping material in small ball type geometric shapes, such as spherical or elliptical shapes, by shaping processes, for example forming into a ball and / or foaming up, such that ball-shaped means are provided; wherein the insulating and damping material is fiber-shaped and comprises a textile fiber, a silica glass fiber, a ceramic fiber; or a mixture of several of these fibers and wherein the insulating and damping material is at least partially formed of continuous fiber; wherein the continuous fiber is powertex®, advantex®, a commercially available ECR fiber or a standard E-glass fiber; wherein the ball-shaped means are spherical and comprise two types of ball-shaped means, having two different radii, respectively, wherein the ratio of the two radii is constant and in particular the ratio of the radii is about 2.415; connecting the first casing shell (3.1) with the second casing shell (3.2)or with the direct hot gas-carrying member such that a gap is formed between them, which is at least partially enclosed by the shell elements (3.1, 3.2); introducing the means (7, 17) for acoustic and thermal insulation into the gap between the first and the second casing shell (3.1, 3.2); activating the means (7,17) for acoustic and thermal insulation in the gap; wherein the activation of the means (7, 17) for acoustic and thermal insulation after installing the high-temperature sound absorber in a vehicle is performed during a first test drive, or a first test run of an engine in the vehicle. providing a first casing shell (3,1); providing a second casing shell (3.2) or a direct hot gas-carrying member; providing means (7, 17) for acoustic and thermal insulation, comprising: providing an insulating and damping material; shaping of the insulating and damping material in small ball type geometric shapes, such as spherical or elliptical shapes, by shaping processes, for example forming into a ball and / or foaming up, such that ball-shaped means are provided; wherein the insulating and damping material is fiber-shaped and comprises a textile fiber, a silica glass fiber, a ceramic fiber; or a mixture of several of these fibers and wherein the insulating and damping material is at least partially formed of continuous fiber; wherein the continuous fiber is powertex®, advantex®, a commercially available ECR fiber or a standard E-glass fiber; wherein the ball-shaped means are spherical and comprise two types of ball-shaped means, having two different radii, respectively, wherein the ratio of the two radii is constant and in particular the ratio of the radii is about 2.415; providing an insulating and damping material; shaping of the insulating and damping material in small ball type geometric shapes, such as spherical or elliptical shapes, by shaping processes, for example forming into a ball and / or foaming up, such that ball-shaped means are provided; wherein the insulating and damping material is fiber-shaped and comprises a textile fiber, a silica glass fiber, a ceramic fiber; or a mixture of several of these fibers and wherein the insulating and damping material is at least partially formed of continuous fiber; wherein the continuous fiber is powertex®, advantex®, a commercially available ECR fiber or a standard E-glass fiber; wherein the ball-shaped means are spherical and comprise two types of ball-shaped means, having two different radii, respectively, wherein the ratio of the two radii is constant and in particular the ratio of the radii is about 2.415; connecting the first casing shell (3.1) with the second casing shell (3.2)or with the direct hot gas-carrying member such that a gap is formed between them, which is at least partially enclosed by the shell elements (3.1, 3.2); introducing the means (7, 17) for acoustic and thermal insulation into the gap between the first and the second casing shell (3.1, 3.2); activating the means (7,17) for acoustic and thermal insulation in the gap; wherein the activation of the means (7, 17) for acoustic and thermal insulation after installing the high-temperature sound absorber in a vehicle is performed during a first test drive, or a first test run of an engine in the vehicle.