amplification and resonance.pdf

AMPLIFICATION AND RESONANCE SP-SHS 221 1ST SEMESTER | A.Y. 2024-2025 | PROF. Larissa Adique, RSLP...

AMPLIFICATION AND RESONANCE SP-SHS 221 1ST SEMESTER | A.Y. 2024-2025 | PROF. Larissa Adique, RSLP SYMPATHETIC VIBRATION AMPLIFICATION AND DAMPING A phenomenon in which a certain object vibrates without AMPLIFICATION a direct contact to the source object of vibration. The vibrations produced are the same frequency, or a According to Dabrowski (2020), harmonic multiple of that frequency. Amplification acts as a bridge, helping a child keep pace Occurs when the sound wave produced by an object with the standard development of children with normal strikes another object which also vibrates at the same hearing. frequency of the sound wave produced. Suitable amplification quickly delivers the sound input, Common examples are tuning forks with the same which helps activate neural connections in the brain and in frequency and walls vibrating when a movie or music is the hearing system. playing in the speakers Technologies that allow neural stimulation of the hearing Sympathetic vibration happens because of air as a system are also labeled as amplification. Some of its medium for the sound waves. Although the source and the examples are cochlear implants, hearing aids, and hearing receiver of the vibration may have no direct physical assistive technologies (HAT), which are all considered contact with each other, the air around and between them forms of amplification. makes them connected and allows sound waves to travel. ○ Differences between cochlear implants, hearing aids, and hearing assistive technologies (HAT) according to ASHA: SOUNDING BOARD RESONANCE SOUNDING BOARD Hearing Aid Cochlear Implant Hearing Assistive technologies (HAT) A device or surface used to amplify a sound, mostly used in musical instruments or even architecture in order to Hearing aids are A cochlear implant These are advanced intensify acoustic properties. devices that can be is done surgically in devices that people put in or behind one or both ears can help a person For example, a guitar. The strings alone produce a weak the ear that helps for people who hear at home, sound and when the strings vibrate together, it transfers with different types have severe school, work. their energy towards the sounding board that leads for it of hearing loss. hearing loss. to vibrate over a larger surface area. Thus amplifying the sound and making it louder and richer. DAMPING According to Raphael et al. (1980), Metaphorically, it also refers to a person or group that will The decline in the amplitude of displacement over time is listen to you and sometimes give you advice or feedback. called damping. As stated by Gelfand and Calandruccio (2022), RESONANCE Damping is the process in which vibrations die off over In music, resonance happens when an instrument vibrates time as a result of resistance or friction. in response to sound waves of a certain frequency. The reduction in oscillations because of friction can be seen by the decreasing displacement of the curve after In instruments, resonance is observed in the body of the some time. This curve represents a waveform, which is a instrument where frequencies cause it to vibrate more graph that displays displacement as it changes over time. that leads to a louder and sustained sound. According to our last lecture on Basic Acoustics: Damping reduces the changes in air pressure. When it comes to amplification and resonance, sounding board and Intensity lowers when dampened. resonance work together to enhance sound or architectural Materials that are soft and porous and with rough edges acoustics. absorb more sound energy, than materials that are hard or The sounding board amplifies the sound that is produced dense/smooth. by the source such as strings. Once it is amplified, that amplification is enhanced by resonance creating a powerful amplification effect. SP-SHS 221 Amplification and Resonance BY: Group 2 1  AMPLIFICATION AND RESONANCE SP-SHS 221 1ST SEMESTER | A.Y. 2024-2025 | PROF. Larissa Adique, RSLP - Resonant Cavity: is an enclosed area in which waves or The Sound board acts as the medium that captures and oscillations reflect off the walls repeatedly. Resonance reflects the vibrations. Meanwhile, resonance amplifies occurs when only waves that match the natural the sound waves that match the natural frequency of the frequencies of the cavity are amplified. This is used to board. manage or amplify the strength of electromagnetic waves at the resonant frequency. For example, once a guitar is plucked, the strings vibrate and transfer their energy towards the body. And if the Types of Waves: frequency of the vibration matches the resonant Soundwaves frequency, the body will resonate and will lead to - In the field of acoustics, a hollow space such as amplifying the sound. that found in a musical instrument or a room has the ability to vibrate with sound waves at CAVITY RESONANCE specific frequencies, resulting in the amplification of those sounds, as seen in the body of a guitar or violin. RESONANCE - A phenomenon that occurs when sound waves are Electromagnetic waves amplified upon reaching a certain frequency. - In the field of optics and radio frequency - In the context of SLP, Resonance is the modification of engineering, electromagnetic waves have the sound from the vocal cords. ability to resonate inside a cavity, such as in - “Resonance involves forced vibration in which an object or lasers or microwave cavities. container of air is set into vibration by the action of another vibration” (Ferrand, 2001). Applications of Cavity Resonance in SLP: Our noses and mouths are cavities which functions in CAVITY resonating sounds in our daily lives. - Refers to a hollow or enclosed space where waves, such as Since SLP’s treat various speech and language disorders, soundwaves, can reflect, dampen, refract/defract, they can help with cases that relate to resonance in interfere, and possibly resonate. patients that have problems in producing vibrations using - The walls of the cavity, like those in a room, restrict the their nose, mouth, or pharynx. waves and establish the requirements for resonance. Examples of Cavity: EFFECTS OF LENGTH AND SHAPE OF CAVITY A classroom A huge hall The speed of a sound and length of cavity modifies resonant The body of the guitar frequencies. Shell of the drums Nasal Cavity LONGER CAVITY VS. SHORTER CAVITY Oral Cavity Longer cavities will reduce the speed of sound waves to travel which will result in a lower pitch (there are slower CAVITY RESONANCE vibrations) and frequency. - Cavity resonance occurs when a sound or electromagnetic ○ Ex. Bassoon is a woodwind instrument that wave resonates inside an enclosed space, or cavity, at produces a low pitch sound when played due to specific natural frequencies of the cavity. The dimensions, its long tube and double reed. The bent shape of shape, and material properties of the cavity dictate these the instrument and such obstructions lessen the natural frequencies. speed of the air traveling as it still needs to go - Resonant Frequencies: represents the specific points at down the tube, make a u-turn to exit out the which objects or systems vibrate with the highest top. amplitude. SP-SHS 221 Amplification and Resonance BY: Group 2 2  AMPLIFICATION AND RESONANCE SP-SHS 221 1ST SEMESTER | A.Y. 2024-2025 | PROF. Larissa Adique, RSLP Shorter cavities allow sound waves to travel faster which How Odd-Quarter Wavelength Creates Resonance produce higher pitch and frequency. ○ Ex. A Flute has a smaller structure and a shorter When a sound wave travels through a medium and encounters a length of cavity which provides easier access for boundary, such as the end of a tube or a closed end in an acoustic air to travel that produces a high pitch and resonator, it reflects back. The reflected wave interacts with frequency. incoming waves. If the length of the medium (like a tube or cavity) is Differences in shape an odd multiple of one-quarter of the sound’s wavelength (e.g., 1/4, Sound in cavities with a three-dimensional structure reflects back 3/4, 5/4), the reflected and incoming waves can combine in a and forth within the cavity’s boundaries. In a cylindrical cavity, the specific way that amplifies the sound, creating resonance. tone is more clear and consistent despite the limited movement of sound waves since it can only bounce or circulate around the space Imagine you’re pushing someone on a swing. If you push them at of the cylinder. just the right time, they go higher and higher with each push. This is Ex. The guitar’s body acts as its own amplifier since its because you’re pushing in rhythm with the swing’s natural motion. hollow chambers intensify or amplify the sound made by But if you push at the wrong time, like when the swing is coming the strings. back toward you, it doesn’t go as high, and you might even slow it Fundamental: the lowest resonant frequency down. Overtones: the highest resonant frequencies The odd-quarter wavelength works in a similar way with sound Cavities that have an opening on both ends (open-pipe resonator) waves. In certain situations, when sound waves reflect off a surface such as flutes have fundamental frequencies that are more intense (like a wall or a panel), they can interact with new sound waves in a compared to tubes with a closure at the end (closed-pipe way that either amplifies or cancels out the sound. resonators). This concept is prevalent at the two acoustic resonators that are of Different instruments with the same notes sound different because, greatest interest to us, which are the vocal tract and the ear canal. although the fundamental frequencies are identical, the intensity of both of these structures are air-filled tubes, and their resonance overtones differ. This allows instruments to have distinct and unique characteristics can be modeled on the basis of their similarity to any sounds that allows us to differentiate them from one another. (Ex. uniformly shaped tube that is open at one end and closed at the Guitar vs Ukulele) other. (The vocal folds are considered to form the closed end of the Similar to the distinctions of human voices, our ability to speak vocal tract, and the eardrum closes off the ear canal). The air within depends on the “shape of cavity formed by the throat and mouth such a tub vibrates at frequencies that depend on the length of the and position of the tongue to adjust the fundamental and tube. The wavelength of the lowest resonant frequency in the tube combination of overtones.” (Urone & Hinrichs, 2020). is four times the length of the tube. To put it another way, only a THE ODD-QUARTER WAVELENGTH quarter of the wave can fit into the tube at any one pass. Vocal Tract The Role of Odd-Quarter Wavelength The vocal tract, when it resonates at its fundamental frequency, Resonance is a phenomenon where a system naturally oscillates at follows the odd-quarter wavelength rule. This means that the length higher amplitudes at specific frequencies, known as the system's of the vocal tract determines the specific frequencies that resonate. resonant frequencies. The odd-wavelength rule applies to tubes or For example, if the vocal tract is 17 cm long, the fundamental cavities that are closed at one end and open at the other. This is frequency will have a wavelength of about 68 cm (4 times the length common in many musical instruments (like trombones) and in the of the tube). human body (such as the vocal tract and ear canal). SP-SHS 221 Amplification and Resonance BY: Group 2 3  AMPLIFICATION AND RESONANCE SP-SHS 221 1ST SEMESTER | A.Y. 2024-2025 | PROF. Larissa Adique, RSLP This resonance affects the pitch (how high or low a sound is) and REFERENCES timbre (the quality or color of the sound) of the voice. By adjusting the shape and length of the vocal tract (e.g., through changing mouth shape or tongue position), a person can alter the resonant frequencies and thus produce different sounds. Ear canal The ear canal acts as a tube that can resonate with sound waves. When sound waves enter the ear canal, they create vibrations in the air inside it. The fundamental frequency at which the ear canal resonates follows the odd-quarter wavelength rule. This means that the wavelength of the lowest resonant frequency that fits into the ear canal is four times the length of the canal. The ear canal’s resonant frequencies enhance certain sounds while dampening others. This resonance can make specific frequency ranges more prominent, affecting how well you hear different sounds. The resonance of the ear canal helps improve sensitivity to frequencies around 3,000 to 4,000 Hz, which is crucial for understanding speech. SP-SHS 221 Amplification and Resonance BY: Group 2 4