Click here to purchase the entire book in PDF format. Common pitfalls Estimate the amount of time required to do the test wisely. Listening tests take much longer than one would expect in order to do them properly and get reliable results. This doesn't just mean the amount of time that the subject is sitting there answering questions. It also means the amount of experimental design time, the stimulus preparation time, scheduling subjects, the actual running of the test time (remember to not tire your subjects... no more than 20 or 30 minutes per sitting, and no more than 1 or 2 tests per day), clean up and analysis time... Whatever you think it will take, double or triple that amount to get a better idea of how much time you'll need. Run a pilot experiment! Nothing will give you better experience than running your listening test with 2 or 3 people in advance. Pretend it's the real thing - analyze the data and everything... You'll probably find out that you made a mistake in your experimental design or your setup and you would have wasted 30 people's time (and lost them, because after the ruined test, they're trained and you have to find more people...). Pilot experiments are also good for finding out a rough idea of ranges to be testing. For example, if you're doing a JND experiment on loudness, you can use your pilot experiment to get an idea that the numbers are going to be around 0.5 dB or so, so you won't need to start with a difference of 20 dB... your pilot experiment will tell you that everyone can hear that, so you don't need to include it in your test. Test what you think you're testing! Equalize everything that you can that isn't under test. For example, if you're testing spaciousness of two stereo widening algorithms, make sure that the stimuli are the same loudness. This isn't as easy as it sounds... do it right, don't just set the levels on your mixer to the same value. You have to ensure that the two stimuli have the same perceptual loudness (discussed in Section ).