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Measuring Your Threshold of Sounds for Different Pitches
Posted: Fri Jan 17, 2014 9:21 pm
by ltdj4
Hi, I'm using 'Measuring Your Threshold of Sounds for Different Pitches' and I'm testing people from different age groups to compare the thresholds. I'm confused about what the graph in the Introduction means; what does it mean when the hertz are lower and the decibels are higher? Also, how am I going to compare the thresholds for the two different age groups (11-16 and 50-55) when there are 19 different frequencies? Is there some sort of range I can say that each age group can hear, and is it normal if the graph isn't a perfect curve? Thanks
Re: Measuring Your Threshold of Sounds for Different Pitches
Posted: Sun Jan 19, 2014 11:23 am
by deleted-71603
Hi. This is a very interesting project!
The graph in the introduction is supposed to illustrate that in order to hear each frequency at the same perceived volume, different frequencies will have to be adjusted at different levels in order for you to hear them. Think of a volume knob on the radio. If you want to hear frequencies 100 Hz and 1000 Hz at the same perceived volume (they sound the same volume to you), you will have to turn the volume knob up higher for the 100 Hz sound (because the graph shows a higher decibel on the graph) than you will for the 1000 Hz sound. So, according to the graph, starting at about 1000 Hz and going lower in frequency, the lower the frequency (the lower the Hz), the more you will have to turn the volume knob (the greater the dB) in order for you to hear the sound at the same perceived volume.
For your data, I assume you are taking multiple measures per subject and multiple subjects per age group. I would calculate the average count for each of your 19 frequencies. Then, calculate a dB reading for each frequency based on that average count. You will construct a graph much like the one in the introduction for your 19 frequencies for the age group. Repeat this process for the other age group. You can plot the graph for both age groups on the same plot and see if there are any differences. If the age groups were the same, the lines should be on top of each other (or very close to it).
According to the experiment page, not having a perfect graph is normal. Each person is different as to what they can hear. This can be for several reasons: genetics, hearing loss over time, etc.
I hope this helps. Be sure to write back if you have any more questions. Good luck!