Acoustics Definition and 130 Threads

  1. T

    How Does Conical Chamber Shape Affect Sound Amplification?

    Homework Statement This is a problem I've been pondering, and I simply need some recommendations for texts to read on the topic. Suppose you have an enclosed air chamber with an acoustic source on one end (http://beckerexhibits.wustl.edu/did/images1/hatpatent.jpg" ). How can one predict...
  2. T

    How Can You Predict Sound Amplification in a Conical Volume?

    Homework Statement This is a problem I've been pondering, and I simply need some recommendations for texts to read on the topic. Suppose you have an enclosed air chamber with an acoustic source on one end. How can one predict the amplification (most important), distortion, and...
  3. L

    Careers Combining Acoustics & Electrical Engineering

    I want to study acoustics but not sure what kind of work is out there. I would also like to be able to use my electrical engineering skills. What kinds of careers out there will involve use Electrical Engineering and Acoustics?
  4. B

    Acoustics: Sound Level Calculations

    Homework Statement Helicopter Noise Transmission [i]It is planned to introduce a regular helicopter service from a helipad at ground level in a hospital premises. There will be four arrivals and four departures per day but never more than one arrival and one departure in any hour. There is a...
  5. D

    What are some potential topics for an extended essay in acoustics research?

    Hi! I am in Grade 11 in high school, and we have this big project coming up which is called Extended essay. Basically, it is a research essay 3000-4000 words, and I chose to do mine in physics. The thing is I have trouble finalizing my topic. I decided to do something in acoustics, such as...
  6. R

    Acoustics of metal alloys question

    I design percussion instruments and I have been researching for some time now the acoustic properties of different common alloys such as phosphor bronze, brass, copper, nickel silver (german silver) and so on... Specifically I want to test the amplitude and frequency modes of each. This would...
  7. T

    Introductory acoustics & noise control tutorial

    Homework Statement A small reverberation chamber is constructed with concrete walls. Its internal dimensions are 2 x 2.5 x 3m. Calculate the final steady-state sound pressure level produced by a source of 7.5microwatts acoustic output. Assume the absorption coefficient of the concrete to be...
  8. M

    Musical Acoustics, Combining frequencies of two instruments

    Homework Statement A certain dog whistle operates at 21.5 kHz, while another (brand X) operates at an unknown frequency. If neither whistle can be heard by humans when played separately, but a shrill whine of frequency 5000 Hz occurs when they are played simultaneously, estimate the...
  9. M

    Why Do Beats Occur When Tuning String Instruments?

    Homework Statement String instrument (e.g. guitar) players can tune one string off of another - once you are happy with the tension (and resulting pitch) in one (lower) string, you put your finger down partway up the first string at the appropriate spot to make a higher pitch, one which...
  10. E

    Bessel functions, acoustics circular room

    Hi everybody ! Maybe this post should go under partial differential equations but I'm not sure... I have the following problem and I would like to know if someone could give me some hints or something to read related to this. I'm studying multiple reflections of acoustics waves in a...
  11. C

    Acoustics: Amplitude/frequency/area in regards to sound power

    I really don't understand this problem at all...my thoughts were that for: a) you triple the area, sound power would be greater b) you double the frequency, the period it takes for the sound power to generate is cut in half c) if you triple the amplitude, the output would be louder d) you...
  12. C

    How Does Changing Frequency and Amplitude Affect Sound Power Radiated?

    Acoustics Homework Question! Please HELP! We're doing some problems in my acoustics class...and I absolutely don't get this one! HELP PLEASE! For radiation from a sound board of area AREA, vibrating with amplitude A at frequency f we find power for P radiated: P=(2.8x10^5...
  13. S

    Acoustics simulation using comsol

    hello there I'm using comsol multiphysics acoustic module. so: 1) acoustic model / pressure acoustics / time harmonic analysis 2) draw a circle and do boundaries (F7) = radiation condition (p=0) so this boundary absorbs all the acoustic pressure... 3) then made a mark in the middle and...
  14. F

    Vibro Acoustics Senior Design Project

    Hello All, My partner and I are mechanical engineering technology students who are in search of a feasible senior design project related to acoustics. During the first semester we will be doing the theoretical parts then during the second semester we will be doing the hands-on...
  15. S

    How Does Distance Affect Sound Pressure Levels?

    Homework Statement An omidirectional source produces a free field sound pressure level of 77 dB at a radius of 1.6 m from the centre of the source. What free field sound pressure level in dB does it produce at a radius of 6 m from the centre of the sound source? Answer: 65.5 dB...
  16. N

    Wine glass acoustics - wavelength not what expected

    Hi, I have been conducting a lab experiment using a piece of latex glove to stimulate a tone from a wine glass that is rotating on a turntable. I used the equation \lambda=v/f (using an audio spectrometer setup to find f) to find the wavelength of the emitted tone. We expected the top...
  17. R

    Biophysics problem - Acoustics and Sound

    Hey guys, I need some help on this problem from my biophysics homework on the nature of acoustics and sound. Readers beware...lol Homework Statement If all the sound energy of a 5MHz US continuous emitter with an intensity of one watt per square centimeter is deposited into an isolated...
  18. Q

    Acoustics? (Yet Another IB Extended Essay Thread)

    Hi there, I'm sorry if this sounds incredibly vague, but I'm having difficulties narrowing down the research question for my Physics EE. I'm sure of the field I want to do it in: acoustics. The problem with most experiments involving applied acoustics (ideal room sound, etc.) is that, unless...
  19. H

    Why does the directivity of a loudspeaker change with frequency?

    Hi all! Can anyone explain me why the directivity of a loudspeaker varies with frequencies? It is observed that the speaker is omni-directional at low frequencies and becomes increasingly forward-directional towards higher frequencies. This is to due with the wavelength, but I have no clue on...
  20. B

    Basic info on the subject of acoustics

    Hello again, I am wondering where I might find some basic info on the subject of acoustics. I have some books that I plan on reading, but I was just wondering if anyone knows of any online sources. I have already done a search for acoustics here but not any luck :rolleyes: Anyways, I would...
  21. F

    Solving Problems in Theoretical Acoustics: Need Book Suggestions

    Does anyone happen to know of a book or other resource that has solved problems in theoretical acoustics? I am particularily interested in the basics like pressure fields from monopoles, dipoles and pulsating spheres in both the near and far fields. The book I currently own has plenty of...
  22. A

    Piano Tuner: Loosen or Further Tighten String?

    Suppose a piano tuner hears 2 beats per second when listening to the combined sound from her tuning fork and the piano note being tuned. After slightly tightening the string, she hears 1 beat per second. Should she loosen or shoud she further tighten the string? I believe the answer is to...
  23. C

    Acoustics like oceanograpy, architectural acoustics

    I gave my name for a compteition (though in my right mind I wouldnt) where we have to present a 10page report on any part of acoustics like oceanograpy, architectural acoustics, etc. I don't know what topic to chose. I want to do on echolocation but will it be enought to fill 10 pagss of A4...
  24. S

    Book on transducers in marine or underwater acoustics

    Hey I'm hoping there are some people involved in marine acoustics here :) I was hoping that someone here could maybe recommend some good books or sites that exaplain the use of transducers in Marine Acousitcs. I just need to have an idea of what sort of transducer I'm looking at. The carrier...
  25. S

    Acoustic Principles: Exercises & Solutions for Exam Preparation

    :shy: Any help will be apreciated. These are some pre-exam exercises that were given to my daughter I would like to be able to check the answers and help her with any difficulties. 1) A string, whose density is 0.01 kg/m, and whose length is of 60 cm is stretched with a tension of 576...
  26. T

    Solving Sound Reduction Index Problem: Air to Water

    I hate acoustics, but unfortunately I have to get through this subject. Most of the time I don't even know where to start with the problems, and this is one of those times. I'm sure there's some easy formula for it, but I just can't seem to find it. What is the normal incidence sound...
  27. Q

    Acoustics homework problem help

    Comment on this (1) What is the difference betweem plucking a guitar with a hard pick and plucking it with bare fingertips? What could be the reason behind this? (2) The bass strings in a grand piano are longer than the strings in the treble range. Why?
  28. J

    Help with Musical Acoustics Final: Sample Test Questions

    My final is in two days and I am clueless. My professor issued a series of sample test questions. Any help would be appreciated. Thanks. 1. What is a frequency spectrum? Why is a spectrum special if it contains only frequencies belonging to a harmonic series? 2. What is a natural mode? Why...
  29. J

    How Do Drumhead Strike Points and String Tension Affect Musical Acoustics?

    If anyone could help me out with these problems, it would be greatly appreciated. If one were to strike a drumhead simultaneously at two symmetrically located points, which modes will be strong and which would be absent from the vibration recipe? If the tension applied to a string is...
  30. J

    What Frequencies Arise from a 4 ms Waveform Cycle?

    A complex waveform repeats every 4 ms. What are the frequencies of its Fourier components? Thanks in advance.
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