• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
  1. 1
  2. 2
  3. 3
  4. 4
  5. 5
  6. 6
  7. 7
  8. 8
  9. 9
  10. 10
  11. 11
  • Level: GCSE
  • Subject: Maths
  • Word count: 3003

Acoustics Assignment

Extracts from this document...


Acoustics Assignment Assignment Brief To choose a room and analyse the construction materials and subsequent surface areas of that room, and using the given formula, show an understanding in the calculations involved in solving absorption coefficients, reverb times and standing waves of any given space. Introducing Acoustics Before any formula can be applied, or calculations analysed, a firm understanding must be grasped of the main components involved in this assignment, namely: Standing waves Nodes / Anti-nodes Fundamental frequency Reverberation time Absorption Absorption coefficients Frequency Wallace Sabine Let us consider each heading Standing Waves The modes of vibration associated with resonance in extended objects like strings and air columns have characteristic patterns called standing waves. These standing wave modes arise from the combination of reflection and interference such that the reflected waves interfere constructively with the incident waves. An important part of the condition for this constructive interference is the fact that the waves change phase upon reflection from a fixed end. Because the observed wave pattern is characterised by points, which appear to be standing still, the pattern is often called a 'standing wave pattern.' Nodes / Anti-nodes One characteristic of every standing wave pattern is that there are points along the medium, which appear to be standing still. These points, sometimes described as points of no displacement, are referred to as nodes. There are other points along the medium, which undergo vibrations between a large positive and a large negative displacement. These are the points which undergo the maximum displacement during each vibrational cycle of the standing wave. ...read more.


0.7 0.8 0.6 0.4 Acoustic tile, suspended 0.5 0.7 0.6 0.7 0.7 0.5 Brick 0.03 0.03 0.03 0.04 0.05 0.07 Brick and plaster 0.41 0.45 0.48 0.56 0.58 0.60 Carpet, 3mm pile height 0.05 0.05 0.1 0.2 0.3 0.4 Chair, small fabric 1.5 3.5 4 4.5 4.75 4.5 Concrete block, painted 0.1 0.05 0.06 0.07 0.1 0.1 Concrete block, unpainted 0.4 0.4 0.3 0.3 0.4 0.3 Concrete, poured 0.01 0.01 0.02 0.02 0.02 0.03 Door, wooden 0.17 0.21 0.26 0.29 0.31 0.34 Draperies, medium velour 0.07 0.3 0.5 0.7 0.7 0.6 Glass 4mm 0.20 0.22 0.28 0.34 0.34 0.29 Gypsum wallboard, 1/2" on studs 0.3 0.1 0.05 0.04 0.07 0.1 Heavy carpet on concrete 0.02 0.06 0.15 0.4 0.6 0.6 Heavy carpet on felt backing 0.1 0.3 0.4 0.5 0.6 0.7 Heavy plate glass 0.2 0.06 0.04 0.03 0.02 0.02 Ordinary plaster, on lath 0.2 0.15 0.1 0.05 0.04 0.05 Ordinary window glass 0.3 0.2 0.2 0.1 0.07 0.04 Platform floor, wooden 0.4 0.3 0.2 0.2 0.15 0.1 Plywood sheet, 1/4" on studs 0.6 0.3 0.1 0.1 0.1 0.1 Person, adult 2.5 3.5 4.2 4.6 5 5 Recliner, leather 3 3.75 3.5 3 2.5 2 Stud wall 0.25 0.32 0.34 0.47 0.39 0.50 Timber floor 0.18 0.25 0.37 0.39 0.45 0.45 Upholstered seating, unoccupied 0.2 0.4 0.6 0.7 0.6 0.6 Upholstered seating, occupied 0.4 0.6 0.8 0.9 0.9 0.9 Vinyl tile on concrete 0.02 0.03 0.03 0.03 0.03 0.02 Wooden seating, unoccupied 0.02 0.03 0.03 0.06 0.06 0.05 Wooden pews, occupied 0.4 0.4 0.7 0.7 0.8 0.7 The Spare Room 2.74 cm 2.70 cm 3.07 cm 1.91 cm Door 1.72 cm Window .81 cm .79 cm Consider a room with floor (and ceiling) ...read more.


= 0.177944381 Tr = 0.17 seconds Analysis of results After carefully analysing the room's absorption coefficients and reverb times, the conclusion was that the room, due to the absorbing properties of the walls, ceiling and floor, suffered from a reduced reverberation time. This causes the sound within the room to appear dull, flat and without much bass. Corrective procedures To enhance the deficient bass, and add a warmer, richer element to the sound of the room, thick velvet curtains could be added to the windows. This would absorb the higher frequencies and reflect the lower end of the scale. The timber floor could be covered with a luxuriously deep pile carpet, again this would soak up the higher frequencies and reflect the lower ones. Acoustic wall coverings, designed for use on most vertical surfaces, could also be considered. These products are predominantly made of man-made polyester and olefin fibres, and are tested for a special sound attenuation rating known as a Noise Reduction Coefficient (NCR) rating. This rating indicates the amount of sound absorbed into the wall. The higher the number, the more noise absorption at the specified frequency; in this case, we would be looking to absorb the high end and reflect the bass. The ceiling could be covered with acoustically reflective tiles, specially designed to reflect a particular frequency whilst absorbing unwanted ones. Furniture also plays an important part in the room's overall acoustics. Bearing in mind the sound field will not be perfectly diffused; it would be advantageous to uniformly place seating, rather than placing items randomly throughout the room. ?? ?? ?? ?? 11 2 Lee Foster Lee Foster ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Fencing Problem section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Fencing Problem essays

  1. Impacts of tourism Positive and Negative effects in Castleton

    Point 5 Point 5 is situated in the very centre of the roads and tourist shops in the the village. There was no litter in this section of the town because there are many bins situated in the area. The area is very noisy because of it being one of

  2. Investigation of Open Ended Tubes.

    It was a hard lesson in how concentrated some of these formulae are. Herons formula, in the terms of a, b and c, is a whole page of numbers. I abandoned my efforts as I foresaw no good coming from them.

  1. Geography Investigation: Residential Areas

    to continue living there and what type of housing they live in. It is useless if I compare every single street I have surveyed on this hypothesis, so I will just compare the three streets on the outskirts, The Beaches, Vivaldi Close and Cumberland Avenue respectively; then the three streets

  2. Maths Coursework - Cables: For this assignment I have been requested to study a ...

    the same rules: We can spot from the diagram beneath that the thread length = We already know the values of (x) and (y) because they have not changed, so we only have to substitute the values into the equation: To conclude this part of my assignment I have worked out the thread lengths for several other 'square' sizes.

  1. What affect does the surface area of a beet have on the rate of ...

    Contrast the solutions formed and note the solution with the highest rate of anthocyanin therefore indicating the highest rate of pigment leakage (i.e look at the solutions formed and note the "redness" of each solution by placing a white sheet of paper to aid you in telling the difference in colors)

  2. Estate agents - It is essential that my current furniture fits into the house ...

    I shall put it down to a typing error and make it the same width as downstairs. Bathroom ~ above kitchen hence same width. Area of the rooms Kitchen ~ 12.5cm x 6.17cm = 77.125 ~ these are the dimensions from the scale plan This must now be multiplied by

  1. Investigate the affects of the surface area: volume ratio on the cooling of an ...

    This is achieved because the emperor has a low surface area : volume ratio which means it retains heat more efficiently. The fairy needs to lose heat as it lives in a hot climate. It achieves this by having a high surface area : volume ratio which means it loses heat more efficiently.

  2. HL type 1 portfolio on the koch snowflake

    gets multiplied by units and the graph slopes gently." This statement generalizes the behavior of the graph. To verify the generalization we derive the conjecture from the table's values. Therefore, with reference to the graph, we are now convinced that the generalization applies consistently to the table's values for.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work