| Reference | Downloads | Github

Abstract method and entity

when the experiment is going to run, the below error is displayed:

Unfortunately we encountered the following error:

*** when setting the duration of the sound**
*** this method is abstract and should not be called.**

Try to run the experiment again. If the error persists, contact the experiment designer.

the duration (of entity) cannot be left empty since the project freezes on the first image/sound and does not continue.

Are you setting the sound in code or as a builder component? Please could you give your Python and JavaScript syntax or a screen shot of the component?

Best wishes,


Yes i am using builder. at the beginning of the experiment, there is an instruction routine with three components: an image, a sound and a key response to close the routine by pressing space.
Even deleting the key response and adding a duration to the sound/image component did nor solve the problem; namely, the same error was displayed (BTW i a using 2020.1.3 version of psychopy).
here is a screen from the first routine where i receive the error. the sound is played and the image is also displayed. but as soon as the space button is pressed to close the routine and start playing the trials (sounds), the error is displayed. here is a screen of the first routine:

What happens if you give the sound component a fixed duration but still ending the routine with the keyboard?

Thanks for your reply.
this time, i receive the same error code by clicking on OK button in the start screen (see below image please); i.e. where the participants are asked to insert their name _ before the image and sound of the instruction routine are being played.


I think you should leave the duration of the sound blank if it’s a wav file. In the python library cutting short a sound by using a duration value is supported but not yet in JavaScript I’m afraid.
The workaround for now is to leave the sound duratoin blank but then insert something to end the routine like a keyboard, mouse (important if supporting mobile devices), or simply a timed condition built into a Code Component

thanks a lot.
but, it seems that it does not accept any object that terminates the sound routine. i tried leaving the sound duration empty and terminating the routine by keyboard…still the same error occurs. so i wonder how the routines should be terminated???