Millisecond Forums

duration of sudio stimulus

https://forums.millisecond.com/Topic12881.aspx

By abhi - 4/2/2014

Hi

I am using some sound files as a stimulus .

I am using 'stimulustimes'  to present them followed by a visual stimulus of a word and subject has to respond to the visual stimulus.

Problem is that audio files are of different duration and sometimes word / visual stimulus appears before sound files has finished.

How to control it ? I cant use frames command also. How can I ensure that visual stimulus appears exactly  50 ms after the sound has finished.

Thanks



By abhi - 4/2/2014

Tobe more specific , following is script-

/ stimulustimes = [0=basicsound; 600=rectangle1,txluxury; 980=eraseshape,txluxury] 


Basic sound is a sound file and txluxury is a text stimulus at 600 ms

Problem is that basicsound has many sound files ranging from 200 to 900 ms . I want that once sound file is played completely only then after 50 ms txluxury is presented.

Thanks
By Dave - 4/2/2014

If your sounds vary in length, you need to play them in a separate <trial>.

<trial basicsoundtrial>
/ stimulustimes = [0=basicsound]
/ trialduration = 1
[...]
</trial>

<sound basicsound>
[...]
/ playthrough = true
</sound>

Then follow that trial up with the <trial> displaying the remaining stimuli.
By abhi - 4/3/2014

Thanks Dave,

Tried doing it this way but again stuck.

 Actually audio files are being used as prime. There are 20 files in total and just two target words. so total of 40 trials per block without repetition.

If I use audio files as separate trial and visual target as separate trial then I am not able to control the sequence of presentation. ( Its not random, no replace  and each audio file is not paired with both the words )

Am looking at counter option. But problem is presentation of audio stimulus again.

Hope you can help.

Thanks
By Dave - 4/3/2014

> If I use audio files as separate trial and visual target as separate trial then I am not able to control the sequence of presentation.

That is incorrect. You can control it in the exact same way as before, it really makes no difference. Cf. the "How to Present Stimulus Pairs" and the language reference for the /trials attribute topics in the documentation.
By abhi - 4/10/2014

Thanks Dave.

Could not do it but I did it the hard way.

Scripted large no of blocks and randomized them.

Worked fine and collected some data also