**4. Interior acoustical design criterion**

Interior acoustical design is a relatively new profession, yet the acoustics was one of the human concerns throughout history. By primitiveness, humans from the prehistorical dates, automatically, used their instinct to adjust their interaction fields in a way to reach the best paths of sound communications.

Lindsay's wheel of acoustics shows the selective area of the architectural interior design, but the related fields that share in some range their outcomes and make benefits to the interiors are many (highlighted in the wheel (**Figure 1**)).

Interior acoustical design is a field where mixes of discipline contribute to the sound excellence for the benefits of the users. Interior acoustical design involves the basics of physics as science relates the reflection, absorption data, the sound formula regarding the reverberation time, the physical measurements of the materials based on the coefficient of absorption (alpha ᾱ), the space volume, and the sound frequencies. All these inputs enabled the creation of the new interior acoustical wheel (**Figure 15**) [12].

Interior acoustical design implicates in parallel the artistic perception of the material selection, the material patterning, and the material color schemes. Therefore, the interior acoustical design is deliberated, as science and art, through the following points:


**131**

**Figure 17.**

*Alpha chart to standard frequencies.*

**Figure 16.**

*Reflection position formulas [13].*

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

diffusers.

appropriate acoustical interior design.

designer could refer to them when needed.

parallel surfaces, the unproportioned spaces, and the circular plan's to reach an

• The interior acoustical design—or **room acoustics**—depends on the quality of

• The interior acoustical material classifications are reflectors, absorbers, and

• **Reflectors** are hard solid materials, where the designer can use simple formulas to determine their position (**Figure 16**), where "A" is the projected ray of sound, "B" is the reflected ray of the sound, and "C" is the direct ray of the sound.

• **Absorbers** are soft porous materials, where the coefficient of absorption alpha (ᾱ) specifies their level of absorption. The material is absorber if ᾱ = 0.6–1

(**Figure 17**). Absorbers are composite materials (sandwich panels).

• **Diffusers** are hard solid materials full of curves or hard edges (angles).

• Isolation materials are within the architect responsibility, yet the interior

• The **sound system** is designed by the electrical engineers, yet it is part of the acoustical interior layout upon strict guideline of uses. The three functional parameters of the electrical sound systems are recording the events, listening

the **material properties** and their **positions** in the interior.

**Figure 15.** *Interior acoustical design wheel.*

*Acoustics of Materials*

the following points:

official international languages. These booths should be enough in sizes to host, in each, two translators—each takes speech for 10 min. The visual field of these booths

Interior acoustical design is a relatively new profession, yet the acoustics was one of the human concerns throughout history. By primitiveness, humans from the prehistorical dates, automatically, used their instinct to adjust their interaction

Lindsay's wheel of acoustics shows the selective area of the architectural interior

Interior acoustical design is a field where mixes of discipline contribute to the sound excellence for the benefits of the users. Interior acoustical design involves the basics of physics as science relates the reflection, absorption data, the sound formula regarding the reverberation time, the physical measurements of the materials based on the coefficient of absorption (alpha ᾱ), the space volume, and the sound frequencies. All these inputs enabled the creation of the new interior acoustical wheel (**Figure 15**) [12]. Interior acoustical design implicates in parallel the artistic perception of the material selection, the material patterning, and the material color schemes. Therefore, the interior acoustical design is deliberated, as science and art, through

• The **classification of functional interior** permits the selection of the design paths regarding materiality schemes that support the interior function in favor of the users. The five different space functionality classifications are speech intelligibility, quiet interior, music enhancements, privacy needs, and public announcements.

• The **soundscape** plays a major role in the psychology scheme of the space as

• The interior acoustical space needs hard efforts to prevent the weakness of the **architectural layout** from the architectural perceptions, the domes, the

much it affects the users in unconscious ways.

design, but the related fields that share in some range their outcomes and make

benefits to the interiors are many (highlighted in the wheel (**Figure 1**)).

in the space must be clear to the main panel of discussion on the stage.

fields in a way to reach the best paths of sound communications.

**4. Interior acoustical design criterion**

**130**

**Figure 15.**

*Interior acoustical design wheel.*

parallel surfaces, the unproportioned spaces, and the circular plan's to reach an appropriate acoustical interior design.


### **Figure 16.**

*Reflection position formulas [13].*


#### **Figure 17.**

*Alpha chart to standard frequencies.*

**Figure 18.**

*Sound level chart to the normal daily life, where the hearing damages are indicated.*


#### **Figure 19.**

*Reverberation time (RT) measured in seconds for specific functions.*

to recorded materials, and simultaneous translation. The sound system should follow the rigor layout for the benefits of the output sounds.

