PHY2010 - Physics for AET, Activity: Room/Hall Design

Materials:

RoomHallDesign.xlsspreadsheet in Microsoft Excel

The Task:

A client wants to build a rectangular auditorium, and has hired you to design and construct it.You need to have a reverberation time acceptable for the purposes of the room (i.e. long enough but not too long), over a range of frequencies, when people are in the room. …And you need to stay on budget!

Directions:

  1. You will work in groups of 3 or 4. Your group will be assigned what sort of room/hall to design based on drawing lots.
  2. Decide on roughly how many people you want your hall to hold, and determine a rough set of dimensions (L x W x H) for the hall. Make sure to leave adequate floor space for your audience – consider that each person will use about 6 ft2, and you’ll want room for a stage and aisles!
  3. Calculate the volume of the room (this is done automatically by the spreadsheet). By referring to Figure 8-4 on page 218 of the Berg & Stork Text, determine the “Ideal Reverb Time” for a room of your type given your volume.
  4. From the number of people, calculate your total operating budget using the table below. The spreadsheet will do this for you if you update the “income per person” field in cell D37.
  5. Decide the construction materials you will use to build the hall itself (concrete, glass, plasterboard), and determine the cost of the room --- including seats --- before adding any acoustical treatment.
  6. Done automatically by spreadsheet: Using the Sabine equation and the table of absorption coefficients in the textbook, determine the reverberation times in three frequency bands: 125Hz, 500Hz, 2000Hz.
  7. Now determine how you will treat the room to lower any reverberation times which are too long, in terms of materials and their areas, being careful to stay within your budget. You may need to change the size of walls, raise/lower the ceiling etc.
  8. Done automatically by spreadsheet: Calculate the reverberation times in each frequency band for the treated room. Your goal is to have the mid-to-high frequencies match the “Ideal Reverb Time,” with the low-frequency reverb time roughly 0.2 larger than this.
  9. As a summary, present all of this information, especially the ideal reverb time, the final reverberation times you calculated and the total cost of the hall.

Income (per seat): / Construction Costs:
Church: / $270
Lecture Hall / $270 / Volume Cost (per ft3): / $0.65
Chamber Music Hall / $300
Romantic Music Hall / $300 / Surface Costs (per ft2):
Concrete / $0.50
Glass / $4.00
Plasterboard/Plywood / $0.35
Carpet / $0.75
Curtains / $0.80
Acoustical Board / $1.25
Other items (each):
Upholstered Seat / $50.00
Pew, per person(church) / $10.00