Test your Ears: User guide Hearing Threshold Test.
The control panel for the measurement of the hearing threshold.
You can adjust: The start and end frequencies, the number of frequencies to be used, the time the sound wil last, the pause time, the margin and which ear is to be tested.
The frequencies will be evenly distributed on a logarithmic scale. The margin sets the difference between the just noticeable and not noticeable sound levels to establish the hearing threshold. See the measuring procedure
The section "Current Testvalues" shows some values during the progress of the measurement.
In the section "Display" some properties for the graphical display can be set. A white background is often more suitable if you want to print the graph on paper. "Show Threshold" shows the standard human hearing threshold and "Show calibration" will display the calibration graph for the headphones. If you have only a single calibration value you will see a straight line.
The results can be stored on disk as a bitmap, a .BMP file of the graph, or as a comma separated text file which you e.g. can import in Excel. With the button "Select Directory" you can select the drive:\path, or make a new directory. (Carefully click on the name) . The filename is always the current date-time combination JJJJ-MM-DD-uu-mm-ss.txt or .bmp. Later on you can rename is as you like.
And here is the graphical result
The green line gives the lowest sound level I just could hear, the red line what I did not hear. I did this measurement in my far from silent study with a humming PC and sounds from outside. So this is not my hearing threshold, but what was above the noise in the room. And yes, above 12 kHz I'm rather deaf, but that belongs to my age of nearly 62. The blue line is the normal hearing threshold for young, healty ears in a completely silent room.
The measuring procedure
Here comes the box with the leds and buttons into play. (Why a separate box?)
It can be something like this.
Press the on-screen button "Start" in the window "Hearing Threshold". Then set yourself with this box in a very silent room.
While the middle led is on a tone is played. After that the left and right led indicate that you should press one of the buttons, the left button if you heared the tone, the right button if you did not hear it. After that the same tone is played again, but weaker if you heared it or stronger if you did not. If the difference becomes smaller than the "Margin" setting the same procedure is done with the next higher frequency. Finally, if all frequencies are done the middle led starts flashing, telling that the meaurement is done.
If you missed a tone or were in doubt because you made some noise you can press the middle button to play the same tone with the same volume again. Once pressed Yes or No there is no way back.
It is advised not to look at the computer screen while doing the test. It may mislead you.
Why a separate box?
The connection between the PC and the Attenuator Unit is by USB. The maximal length of a USB cable is 5 meter. Probably that is to short to sit in a silent place with the Attenuator unit, while the PC is somewhere else. With the separate box for only the buttons and the Led's you can use 10s of meters of cable. Also the cable to the headphones can be extended substantially.
If you use a Laptop which makes much less noise than the average PC, 5 meter may be sufficient. Then you can mount the leds and the buttons in the same box as the Attenuator Unit.