Amazing dB’s Sound Pressure Level: Sound Power Level:

Slides:

Advertisements

Similar presentations

Outdoors propagation free field (point source). The DAlambert equation The equation comes from the combination of the continuty equation for fluid motion.

Advertisements

Angelo Farina Dip. di Ingegneria Industriale - Università di Parma Parco Area delle Scienze 181/A, Parma – Italy

Living room acoustics You can use the heading from the model documentation for the title. © 2013 COMSOL. All rights reserved.

Sedan Interior Acoustics

SOUND PRESSURE, POWER AND LOUDNESS MUSICAL ACOUSTICS Science of Sound Chapter 6.

MUSIC 150 MUSICAL ACOUSTICS BRASS INSTRUMENTS REFERENCE: CHAPTER 11 IN SCIENCE OF SOUND CHAPTER 14 IN THE PHYSICS OF MUSICAL INSTRUMENTS.

PHYSICS OF SOUND PHYSICS OF SOUND HEARING CONSERVATION PROGRAM 1 28 Jan 2013.

SOUND ENERGY, INTENSITY AND POWER The acoustic power of a sound source is the amount of sound energy produced by a source per second. Acoustic power.

Auditorium Acoustics Chapter 23. Sound Propagation Free field sound pressure proportional to 1/r SPL drops 6 dB with every doubling of distance. Indoors.

BASIC CONCEPTS IN ARCHITECTURAL ACOUSTICS ENVIRONMENTAL CONTROL III

Sound How are sounds Classified? How are sounds produced? How are sounds different? How are sounds measured? How fast does sound move?

SOUND WAVES AND SOUND FIELDS Acoustics of Concert Halls and Rooms Principles of Sound and Vibration, Chapter 6 Science of Sound, Chapter 6.

EE2F1 Speech & Audio Technology Sept. 26, 2002 SLIDE 1 THE UNIVERSITY OF BIRMINGHAM ELECTRONIC, ELECTRICAL & COMPUTER ENGINEERING Digital Systems & Vision.

Experimental Equalization of a One-Dimensional Sound Field Using Energy Density and a Parametric Equalizer Micah Shepherd, Xi Chen, Timothy W. Leishman,

Auditorium acoustic (continued) 1. Sound sources Sound source can be characterized by power and directivity Directivity factor Q – ratio of sound intensity.

Earth’s Normal Modes. Fundamentals and Harmonics Remember, a guitar string can have a fundamental (lowest tone) and many harmonics (integer level multiples).

Kai Ming Li School of Mechanical Engineering Research in Environmental Acoustics Ray W. Herrick Laboratories.

ME 220 Measurements & Sensors Mechanical Measurements Applications

Intensity, Intensity Level, and Intensity Spectrum Level

Ch 16. Waves and Sound Transverse Wave Longitudinal Wave

Noise Control A Guide for Workers and Employers. Steps used to solve Noise Control Problems Define the problem Establish a noise reduction target Determine.

1 Sound Propagation in Different Environments What is Sound? Free Field Sound Field Rooms Sound in Motion.

Sound Chapter 17. Wave fronts In a flat region of space, spherical wave fronts are near planar.

BA , 1 Basic Concepts of Sound Contents: Definitions dB Conversion Sound Fields dB ± dB.

2. 6 Sound intensity Let us consider a harmonic sound wave moving in a pipe of cross-sectional area A at a wave speed v and frequency f. The wave induces.

Acoustical Properties of Materials Chapter 8. Mehta, Scarborough, and Armpriest : Building Construction: Principles, Materials, and Systems © 2008 Pearson.

SOUND Longitudinal Wave Travels through some medium Cannot travel through a vacuum How does vibrating drum produce sound? Skin moving up presses air.

Waves and Vibrations Chapter 14

1 Loudness and Pitch Be sure to complete the loudness and pitch interactive tutorial at … chophysics/pitch/loudnesspitch.html.

Dept. of Mech. Engineering University of Kentucky 1 Wave Motion – Some Basics Sound waves are pressure disturbances in fluids, such as air, caused by vibration,

Room Acoustics Bouncing Around October 27, Music and Other Sounds Come from a source. The source is not isolated, it is in an environment. The environment.

Sound Sound waves are –Longitudinal –Pressure Waves Infrasonic – less than 20 Hz Audible – between 20 and 20,000 Hz Ultrasonic – greater than 20,000 Hz.

Chapter 16 Waves and Sound The Nature of Waves 1.A wave is a traveling disturbance. 2.A wave carries energy from place to place.

Psychophysics of Intensity Amplitude = Loudness Amplitude = Pitch Scales of Intensity –Decibel (dB) Scales Logarithmic (x2 = 3 dB; x1 million = 60 dB)

ORE 654 Applications of Ocean Acoustics Lecture 6c Scattering 1 Bruce Howe Ocean and Resources Engineering School of Ocean and Earth Science and Technology.

BA , 1 Basic Frequency Analysis of Sound Contents: Frequency and Wavelength Frequency Analysis Perception of Sound.

Physics 101: Lecture 33 Sound

SOUND PRESSURE, POWER AND LOUDNESS MUSICAL ACOUSTICS Science of Sound Chapter 6.

EE Audio Signals and Systems Room Acoustics Kevin D. Donohue Electrical and Computer Engineering University of Kentucky.

Sound Pressure, Power, and Intensity Chapter 6. Sound Pressure/Power/Intensity All three terms describe physical sensations. All three are perceived on.

Dept. of Mech. Engineering University of Kentucky 1 Two Vacuums Shopvac Bosch.

Lanjutan…materi 3 Noise Measurement. 2 Dept. of Mech. Engineering University of Kentucky Equal Loudness Contours Sound level meters incorporate frequency.

The Speech Chain (Denes & Pinson, 1993)

SOUND PRESSURE, POWER AND LOUDNESS

ARCHITECTURAL ACOUSTICS

Physics Section 12.2 Apply the sound properties of intensity and resonance Intensity is the rate at which energy flows through a unit area perpendicular.

SPATIAL HEARING Ability to locate the direction of a sound. Ability to locate the direction of a sound. Localization: In free field Localization: In free.

What is the absolute power of a sound with an intensity of X dB IL? What is the absolute power corresponding to 20 dB IL? What is the absolute power corresponding.

Auditory demonstration : sound level and frequency Yang-Hann Kim.

EE599-2 Audio Signals and Systems

Date of download: 10/15/2017 Copyright © ASME. All rights reserved.

Two Vacuums Shopvac Bosch Dept. of Mech. Engineering 1

Design of Mufflers and Silencers

Properties of sound.

Auditorium acoustic (continued)

Sound Intensity & Resonance

Acoustics in Generator Applications Section A:

NOISE CONTROL TECHNIQUES (ENCLOSURES and ABSORPTION)

Sound How are sounds Classified? How are sounds produced?

VENTILATION NOISE.

Acoustic Reflection 2 (distance) = (velocity) (time) *

INTERACTION OF A SLOT-TONE WITH A PIPE

Low frequency radiation from a duct exhausting a hot gas

Outdoors propagation free field (point source)

QRTV for UN Regulation GRB 61.

CHARACTERISTICS OF SOUND

Sound Intensity and Loudness

Chapter 22B: Acoustics A PowerPoint Presentation by

Presentation transcript:

Amazing dB’s Sound Pressure Level: Sound Power Level: The main thing to remember is that 100 dB sound pressure level and 100 dB sound power level are completely different! To avoid confusion, use the reference values: 100 dB (re 20 Pa) sound pressure level 100 dB (re 1x10-12 W) sound power level Dept. of Mech. Engineering University of Kentucky 1

But they are related… S in m2 S = cross-sectional area (duct) (no reflections) (Spherical source) r (Hemi-spherical source) S = cross-sectional area (duct) r Dept. of Mech. Engineering University of Kentucky 2

An Example A source has a sound power level of 90 dB (re 10-12 W). What is the sound pressure level at a distance of 10 m in (a) a free field, (b) in a hemispherical free field, and (c) in a duct of cross-sectional area 1 m2? a. b. c. Dept. of Mech. Engineering University of Kentucky 3

Field Quantities How do we determine these? Numerical Acoustics p, u = sound pressure and particle velocity in the field. How do we determine these? Numerical Acoustics un = velocity of surface in normal direction – must be known Dept. of Mech. Engineering University of Kentucky 4

Two Vacuums Shopvac Bosch Dept. of Mech. Engineering 5 University of Kentucky 5

Bosch Vacuum Exhaust flows through foam Dept. of Mech. Engineering 6 University of Kentucky 6

Shopvac Vacuum Dept. of Mech. Engineering University of Kentucky 7

Sound Power Exhaust Deflected Upward Dept. of Mech. Engineering 8 University of Kentucky 8

Time and Frequency Domains Dept. of Mech. Engineering University of Kentucky 9

Sound Power Comparison – Bosch, All Sides Dept. of Mech. Engineering University of Kentucky 10

Sound Power Comparison – Narrow Band Dept. of Mech. Engineering University of Kentucky 11

Sound Power Comparison at Low Frequency Low Frequency Tone Dept. of Mech. Engineering University of Kentucky 12

Sound Power Comparison – 1/3 Octave Dept. of Mech. Engineering University of Kentucky 13

Sound Quality Bosch (original) Bosch (w/o foam) Shopvac Bosch (w/o 1st peak) Dept. of Mech. Engineering University of Kentucky 14

Sound Quality: Jury Test Note: Rate each vacuum on a scale from 1 to 10 where 1 is “very quiet” and 10 is “very loud.” Dept. of Mech. Engineering University of Kentucky 15

Foam Inside Bosch Vacuum Dept. of Mech. Engineering University of Kentucky 16

Sound Absorption Coefficient Dept. of Mech. Engineering University of Kentucky 17

Sound Absorption Coefficient of Foam Dept. of Mech. Engineering University of Kentucky 18

Sound Intensity (Shopvac) Dept. of Mech. Engineering University of Kentucky 19

Sound Intensity (Bosch) Dept. of Mech. Engineering University of Kentucky 20

Sound Intensity (Bosch) Dept. of Mech. Engineering University of Kentucky 21

Summary Absorption of foam in BOSCH significantly reduces sound power Sound exhaust is better directed on BOSCH Recommend altering design to reduce/shift first peak Dept. of Mech. Engineering University of Kentucky 22