*3.1.2 Circular plan*

Circular plan is a challenge for the acoustical design perfection. Similar to some extent to the dome, straight surfaces of paneling would break the echo resulting from the circular perimeter. A mixture of balanced acoustical materiality scheme is the best solution, and the decision of the properties of the materials relates to the functional acoustical study of the specific interior [9].

#### *3.1.3 Parallel surfaces*

The interior surfaces should not have parallel surfaces, either as peripheral surfaces or as ceiling and flooring opposite to each other. The interior acoustical designer needs to break these parallelisms. The creation of acoustical interior treatments, diverse in quantities and properties, will solve this problem, although it is much expensive than having the spaces without such problems.

#### **3.2 Interior acoustical treatments**

The sound behavior in the interior spaces is the result of the interior treatments used. The quality and the properties of these materials share to some extent the success of the sound propagation within the space. The sound could be reflected, absorbed, diffused, or transmitted depending on the material physics (**Figure 9**). Materials used in the acoustical design are expensive as their majority are natural materials. Additionally, they need exclusive fire-resistant coating.

**127**

**Figure 11.**

**Figure 10.**

*comparison to the convex reflectors on the right.*

*foam), and different densities of foam.*

*Acoustics from Interior Designer Perspective DOI: http://dx.doi.org/10.5772/intechopen.84167*

Reflectors are hard solid materials that reflect the sound following the rule of reflection—angle of projection equals to angle of reflection but in the opposite side. Best reflectors are the ones made from natural hardwood with thickness limits of 5–15 cm (**Figure 10**). Oak, beech, mahogany, maple, walnut, and pine are all good selection. Ash wood is one of the best as it can easily bend which allows better coverage in favor of materiality limitations. Convex surfaces will scatter the sound waves allowing natural reinforcement for the unamplified voice without electrical

*Sound behavior in the enclosed spaces ((1) sound wave projected from the source, (2) sound wave reflected on* 

Opposite to the reflectors, absorbers are soft, porous materials (**Figure 11**). Used to name the foams with different densities and thicknesses, a sandwich panel composed from a finished layer of fabric or soft natural perforated or slotted wood (with different perforation percentages), and the inside might be one or more of the following materials: rock wool, glass wool, or foam, based on its absorption coefficient "alpha". Heavy curtains exceed its dimensions seven times the length to work as absorbers.

*Reflectors appearance in the interiors on the left and the difference of dimensions between the flat reflectors in* 

*From left, perforated and slotted softwood, sandwich panels (fabrics coverage with glass wool, rock wool, or* 

sound systems while reducing the material surfaces.

*the surface, (3) sound wave absorbed, and (4) sound wave transmitted).*

*3.2.1 Reflectors*

**Figure 9.**

*3.2.2 Absorbers*

*Acoustics from Interior Designer Perspective DOI: http://dx.doi.org/10.5772/intechopen.84167*

#### **Figure 9.**

*Acoustics of Materials*

the overall interior purposes.

**3.1 Interior acoustical layout**

als and as fire-resistant coatings [8].

additional different perception.

**3.2 Interior acoustical treatments**

functional acoustical study of the specific interior [9].

much expensive than having the spaces without such problems.

materials. Additionally, they need exclusive fire-resistant coating.

*3.1.2 Circular plan*

*3.1.3 Parallel surfaces*

*3.1.1 Domes*

ments that create the interior spaces in excellence [7].

the soundscape—contributes in the overall success of the interior functions. Slow music accelerates the blood circulation, therefore speeding up human functionality. On the other hand, the slow music depresses most of the time the human being. Soundscape, as a new psychological tool, bolsters in today interior design upgrading

The interior acoustical design is a combination of these three important ele-

The architectural design affects deeply in the interior sound behavior. While the sound behavior follows the architectural layout, the architectural shape could lead to a successful acoustic or a harmful one. The architecture should support the acoustical design to enhance the functionality rather than create problems that need extra solutions. Domes, circular plan, parallel surfaces, and unproportioned spaces lead to several acoustical problems for the interior spaces. Solving these problems will over cost the interior, as the acoustical treatments are expensive as raw materi-

Dome does reflect the sound to a specific point, creating a nonstop echo. Adding absorbers on the full surfaces of the dome will create a convenient sound layout for space. Suspending of a huge luminaire, designed for masking the echo, is a solution of cutting out the reflection but in condition to use an amount of absorbing materials within its design. Baffles are a different solution but, similar to the suspended luminaire, it will block the view of the dome and will create an

Circular plan is a challenge for the acoustical design perfection. Similar to some extent to the dome, straight surfaces of paneling would break the echo resulting from the circular perimeter. A mixture of balanced acoustical materiality scheme is the best solution, and the decision of the properties of the materials relates to the

The interior surfaces should not have parallel surfaces, either as peripheral surfaces or as ceiling and flooring opposite to each other. The interior acoustical designer needs to break these parallelisms. The creation of acoustical interior treatments, diverse in quantities and properties, will solve this problem, although it is

The sound behavior in the interior spaces is the result of the interior treatments used. The quality and the properties of these materials share to some extent the success of the sound propagation within the space. The sound could be reflected, absorbed, diffused, or transmitted depending on the material physics (**Figure 9**). Materials used in the acoustical design are expensive as their majority are natural

**126**

*Sound behavior in the enclosed spaces ((1) sound wave projected from the source, (2) sound wave reflected on the surface, (3) sound wave absorbed, and (4) sound wave transmitted).*

## *3.2.1 Reflectors*

Reflectors are hard solid materials that reflect the sound following the rule of reflection—angle of projection equals to angle of reflection but in the opposite side. Best reflectors are the ones made from natural hardwood with thickness limits of 5–15 cm (**Figure 10**). Oak, beech, mahogany, maple, walnut, and pine are all good selection. Ash wood is one of the best as it can easily bend which allows better coverage in favor of materiality limitations. Convex surfaces will scatter the sound waves allowing natural reinforcement for the unamplified voice without electrical sound systems while reducing the material surfaces.

### *3.2.2 Absorbers*

Opposite to the reflectors, absorbers are soft, porous materials (**Figure 11**). Used to name the foams with different densities and thicknesses, a sandwich panel composed from a finished layer of fabric or soft natural perforated or slotted wood (with different perforation percentages), and the inside might be one or more of the following materials: rock wool, glass wool, or foam, based on its absorption coefficient "alpha". Heavy curtains exceed its dimensions seven times the length to work as absorbers.

#### **Figure 10.**

*Reflectors appearance in the interiors on the left and the difference of dimensions between the flat reflectors in comparison to the convex reflectors on the right.*

#### **Figure 11.**

*From left, perforated and slotted softwood, sandwich panels (fabrics coverage with glass wool, rock wool, or foam), and different densities of foam.*
