Acoustics

Sound velocity c or velocity of sound should not be confused with sound particle velocity v, which is the velocity of the individual particles. More commonly the term refers to the speed of sound in air. The speed varies depending on atmospheric conditions; the most important factor is the temperatu

Some effects experienced by vehicles with open sunroofs when buffeting include: dizziness, temporary hearing reduction, discomfort, driver fatigue, and in extreme cases nausea. The importance of reducing interior noise levels inside the car cabin relies primarily in reducing driver fatigue and impro

The reduction can reach up to 20 dB for the best cases. But since good reduction can only be reached for low frequencies, the perception we have of the resulting sound is not necessarily as good as the theoretical reduction. This is due to psychoacoustics considerations, which will be discussed late

For example, the conception of air-conditioning ventilators requires a full understanding of this interaction. ## Noise emission of a Rotor-Stator mechanism A Rotor wake induces on the downstream Stator blades a fluctuating vane loading, which is directly linked to the noise emission. We consider a

Each technique has its advantages and disadvantages. ![Muffler type "Cherry bomb"]( Muffler type "Cherry bomb" (Image: Jleonar at English Wikibooks, Public domain) ## The absorber muffler The muffler is composed of a tube covered by sound absorbing material. The tube is perforated so that some part

**SONAR** (**so**und **n**avigation **a**nd **r**anging) is a technique that uses sound propagation under water to navigate or to detect other vessels. There are two kinds of sonar: active and passive. ## History The French physicist Paul Langevin, working with a Russian émigré electrical engineer,

Vibration is defined as the motion sensed by the body, mainly in 0.5 Hz - 50 Hz range. It is characterized by frequency, level and direction. Harshness is defined as rough, grating or discordant sensation. Sound quality is defined according to Oxford English Dictionary, "That distinctive Quality of

In a room, the reflections of the sound on the walls produce a wave which is propagated in the opposite direction and comes back to the source. In anechoic rooms, the walls are very absorbent in order to eliminate these reflections. The sound seems to die down rapidly. The materials used on the wall

The bad part of reflected sound occurs when the reflections amplify some notes, while cancelling out others, making the sound distorted. It can also affect tonal quality and create an echo-like effect. There are three types of reflected sound, pure reflection, absorption, and diffusion. Each reflect

Links on Physiology: - [Discover The Larynx]( ## Voice production Although the science behind sound production for a vocal fold is complex, it can be thought of as similar to a brass player's lips, or a whistle made out of grass. Basically, vocal folds (or lips or a pair of grass) make a constrictio

The guitar controls the length and tension of six differently weighted strings to cover a very wide range of frequencies. Second, there is the body of the guitar. The guitar body is very important for the lower frequencies of the guitar. The air mass just inside the sound hole oscillates, compressin

This is a bit surprising, however, since the marimba is a melodic instrument that needs to be in tune to sound good. So what gives? Why is the marimba never tuned? How would you even go about tuning a marimba?

For a detailed anatomy of the violin, please refer to [Atelierla Bussiere](   ## How does a violin make sound? ### General concept When a violinist bows a string, which ca

Whatever sounds right to you, is right. ## Types of microphones ### Dynamic microphones These are the most common general-purpose microphones. They do not require power to operate. If you have a microphone that is used for live performance, it is probably a dynamic mic.

The Magnet Motor Drive System is comprised of a front focusing plate, permanent magnet, back plate, and a pole piece. In figure 2, the assembled drive system is illustrated. In most cases, the back plate and the pole piece are built into one piece called the yoke. The yoke and the front focusing pla

A sealed or closed box baffle is the most basic but often the cleanest sounding sub-woofer box design. The sub-woofer box in its most simple form, serves to isolate the back of the speaker from the front, much like the theoretical infinite baffle. The sealed box provides simple construction and cont