Here’s another easy assignment. All you have to upload for the assignment are two tables with a few measurements you’ve made. Here’s what we’re looking for in those table though. The tables I’ve made for you are at the bottom.
Download a sound level meter app and spectrum analyzer if you don’t already have one. You don’t have to use any of the ones listed below. These are just a few to consider depending on your circumstances. Here are a few to consider:
Google:
Advanced spectrum analyzer Pro https://play.google.com/store/apps/details?id=com.vuche.asap&hl=en_US (Links to an external site.),
Spectrum analyzer and sound level meter in 1 https://play.google.com/store/apps/details?id=com.bolshakovdenis.soundanalyzer&hl=en_US (Links to an external site.)
A simple sound level meter https://play.google.com/store/apps/details?id=kr.sira.sound&hl=en_US (Links to an external site.)
Google chrome extension
https://chrome.google.com/webstore/detail/sound-meter-noise-decibel/fhamlklnpkhdfepaipljcngncafnlbfa?hl=en-US (Links to an external site.)
PC, Mac, Linux (Friture). Don’t know much about it but it’s free and has a simple enough spectrum analyzer. http://friture.org/index.html (Links to an external site.)
Apple:
NIOSH sound measurement app :https://apps.apple.com/us/app/niosh-sound-level-meter/id1096545820 (Links to an external site.)
Simple free spectrum analyzer https://apps.apple.com/ru/app/fftwave/id1080227446?l=en (Links to an external site.)
Measure the level of various sounds around your house, neighborhood, or workplace and make a table
Describe the thing you measured how it was measured (examples: piano rock song at 5 ft, at 10 ft, microwave ding at 2 ft, at 4 ft, toilet flush or sink drip at 4 ft, 8 ft, a child whistling from 100 ft, 400 ft, etc.). Try to isolate just that one thing you are measuring by reducing as much background noise as possible. Measure at least 5 things at two levels or distances for a total of 10 LEVEL measurements. If the tool you use gives you the option, choose C-weighted for the level measurements. We’ll talk near the end of the course about what A-weighting does (spoiler: it mimics the human ear response/filter). For now, just know that A-weighting is kind of like filtering the sound through someone’s ear before measuring it, whereas C-weighting is unfiltered.
I know it is hard to reduce other noise. That’s okay. I know the level is going to fluctuate a lot as you make these measurements. You may have to make a best judgement call. If it fluctuates a bunch but seems to be hovering around a certain level then just put that certain level down. Try to make these measurements on a broadband stimulus (something that would produce a complex wave), or not a pure tone.
Additionally, for part 2 measure the frequency of 3 items using the spectrum analyzer (examples: a musical instrument playing a note, the hum of the lights in the basement, the seat belt reminder tone, the fundamental frequency of the first note of your favorite song, the sound of the hand signal at the crosswalk/traffic light, the whistle of your spouse’s or room-mate’s nose when they snore) and make a table. Try to make it something tonal that you measure so you can pick out a single tone. White noise spectrum, remember, is equal level per frequency so it won’t have any one particular frequency that jumps out or gives it a pitch. Try to measure sounds that are tonal or have a pitch for this part. Find and use 3 distinct sounds/frequencies.
Calculate the wavelength for the lowest frequency you’ve measured for those three sounds. If there are multiple peaks on the spectrum, use the fundamental or lowest frequency. Again, it might fluctuate a little so you may have to pick the frequency that it seems to hover around.
Please don’t use the same or very similar frequency as the one listed in the example.
For what you’ll turn in – Make 2 tables, not a wooden table but a spreadsheet table, of the things you measured. I’ve decided to help you out a little and just made the tables already. See below.
Table 1 should include a row for each of the 5 things of which you measured the “level” with a column for each of the two ways or distances you measured that thing.
Table 2 should include (1) a row for a short description or name of each thing you measured, (2) a column for the respective frequency of that thing and (3) a column for the wavelength of that frequency. For wavelength you can express this using either meters, cm, mm, etc (with the 343 m/sec reference for the speed of sound) or expressed in feet, inches, etc (using the correlated 1125 ft/sec reference for the speed of sound). Just be consistent. That is, if you choose the metric system, stick with that for all of them. That would be my recommendation. (4) Calculate and fill out the columns for period in seconds and milliseconds for each frequency. You may have to round a little but go out pretty far. So if the period of a sound, as an example, is 0.0003927729 seconds, then round to the 100,000th place (0.00039).