Test your Ears: User guide A-B-X test.
The A-B-X-test allows you to compare two sound files and to find out how well you are able to hear the differences between them.
The sound reproduction is not restricted to a headphones, for many tests also a (hifi) amplifier and loudspeakers can be used.
The buttons and fields:
With the buttons "Select file A or B" you can select which sound files you want to compare. The program solely supports the .WAV file format with most of the options of sample frequencies and sample sizes. If you want to use other sound file formats look here for a freeware conversion program which can convert between many sound file formats.
At the left you find the volume and balance controls for the files A and B. In all A-B-X-tests it is extremely important that the volumes of A and B are carefully adjusted the same. If your sound files do not have the same volume or balance you can correct that here.
There are also buttons to copy the settings from A to B or vice-versa, and there are buttons to center the balance setting.
On the bottom you see the well known buttons for play, pause and stop. These buttons do work, but you will not need them for normal testing. You can see which file is playing.
Very on the bottom there are two progress bars indicating in green how far the playing of that file has progressed.
In the field "sec" you can enter how long the playing of the sound fragments should last. Only if playing has finished you can enter your choice on the button-box. If you enter zero the file will play until the end or until you press a button on the button-box.
In the field "# tests" you can enter the number of tests you want to do. With zero the testing continues until you indicate that the test should be finished by pressing both left and right buttons on the button-box.
The checkbox "Continue" indicates that the sound files must be played from the beginning on or that they continue from where they were stopped. If checked also the file which does not play will continue on the position where the other one was stopped.
With the button "Start" you indicate that the test must begin. The button "Stop" is not really required, you can stop a test to from the button-box.
In the section "Score" you find the number of times the files A and B have played and the number you guessed right or wrong.
The field "Score" gives the amount of right-guesses in percent of the total number of tests. 100% means that you were always right, 50% means that a set of dice would have been as good, and 0% means that you were consequently wrong. Also very good!
The field "Reliability" indicates the chance that the result is not random. This number is calculated using the formula for the so called Gaussian or Normal Distribution
With the button "Reset" you can zero the scores. That will not happen automatically when you restart a test.
With the button "Save" you can save the score data. With "Select Directory" you choose where to store the data. The filename will be jjjj-mm-dd_hh-mm-ss.txt.
The meaning of the Leds and buttons on the button-box during the test
Keep in mind that after pressing "Start" there are 2 modes in which the test can be. At all times you can switch between these modes with the middle button.
In the AB mode you can consciously choose to hear file A or file B. This is indicated by the continuously lit middle led and the left or right led for A or B.
You chose with the left or the right button.
The "X" mode is where you must guess whether A or B plays. This is indicated by both the left and right leds being on. When the middle led flashes fast you may make your choice with the left or right button.
Middle Led:
- Constant on: You may chose to hear A or B with the left or right button. You can use this to adjust volume and/or balance correctly or to consciously listen to A or B. Left button is A, right button is B.
- Fast flashing: You are supposed to press the left or right button, depending on whether you think to hear A or B.
- Slow flashing: Test has finished.
- If one of these is lit it means that file A (left) or file B (right) is playing in the AB mode.
- If they are both lit file X (X=A or X=B) is playing. If the middle led flashes fast you may enter your choice for A or B by pressing the left or right button. Once pressed there is no way back. There is no "undo" button.
- The middle button allows you to switch between the "AB" reference mode and the "X" mode.
- If the middle Led is lit you can request to hear soundfile A (left) or B (right) as reference or to adjust sound level or balance.
- If the middle led flashes fast you can indicate whether you think to hear or have heared A(left) of B(right) .
- Simultaneously pressing the left and right button will end the test.