[solved] sampler issues (loudness, clicks)

blueb

Hi,

I have created some complex tones for my experiments in Matlab and I have normalized the intensity levels in Cubase SX3 using an external dB meter. All 44.1kHz/16bit mono wav files seem to be normalized when I play them in any player (e.g. winamp) but I noticed that when they are played in OpenSesame (during the experiment) there are differences in amplitude levels!

Also, during the experiment the stimuli don't always sound right, there are glitches during their playback, which don't exist when played in other players.

Thanks in advance, I would appreciate any help

sebastiaan

Hi,

All 44.1kHz/16bit mono wav files seem to be normalized when I play them in any player (e.g. winamp) but I noticed that when they are played in OpenSesame (during the experiment) there are differences in amplitude levels!

OpenSesame doesn't do anything fancy with the sound, so that would be odd. Are you sure that these amplitude differences are real, and not due to stuttering or incorrect pitch?

OpenSesame doesn't compensate for the sampling rate, so you'll have to make sure that the sampling frequency (under Back-end settings) matches your that of samples. Otherwise the samples will sound sped up (this happened for you probably) or slowed down.

See also

• http://osdoc.cogsci.nl/usage/sound/

Also, during the experiment the stimuli don't always sound right, there are glitches during their playback, which don't exist when played in other players.

That does indeed happen when the sound buffer size is too low. You can change this in the Back-end settings, which you can find under a button in the General tab. For example, setting the sound-buffer size to 1024 should make the stuttering disappear.

Cheers,
Sebastiaan

blueb

thank you very much for your response, problem solved @};-