ANY-maze Help > The ANY-maze reference > The Protocol page > The elements of a protocol > Inputs and outputs > Speakers > Setting up a speaker > Specifying what the speaker should play

Specifying what the speaker should play

In brief

Speakers can play white noise, tones (a sound at a fixed frequency), and most sound files. You can specify what the speaker should play by choosing an option from the drop-down list on the speaker's settings page.

Details

White noise

White noise is sound which contains random frequencies of equal power - a good example of something close to white noise is the sound a TV makes when it's not tuned to any station.

White noise is useful because it tends to mask other sounds, thus creating a more controlled environment. For example, if your lab has an air conditioning unit that switches on and off automatically, then it might be on (and making sound) during some of your tests and off during others - thus there would be an environmental difference between the tests. By playing white noise during your experiment, you could mask the sound made by the air conditioner so that the environment would be more closely equal in all the tests.

Tones

A tone in ANY-maze is a sound of a fixed frequency (the signal is simply a fixed frequency sine wave). The list of sounds that can be played by a speaker includes a number of 'standard' frequencies, ranging from 500Hz up to 4500Hz, which are useful for creating cues.

You can also create a tone at a precise frequency of your choosing, by selecting the option to Specify a tone... This will cause the Specify an audio tone window to open, where you can specify a tone, either as a certain frequency (in Hertz), or as a musical note.

Sound files

ANY-maze can play most sound files that can be played in Windows Media Player - this includes Wave (.wav) files, MP3 files and Windows media audio (.wma) files, although not MIDI files. Note that the .wma format supports digital rights management (DRM), and ANY-maze cannot play DRM protected files.

If you want to play a file that's currently on a CD, then you will need to 'rip' the CD first and then play the resulting sound file.

To play a sound file, you should choose the option in the sounds list to Browse for a sound file... - this will cause the Choose a sound file to play window to be displayed, where you can choose the file you want to play. Note that ANY-maze will usually convert the file you choose to a format it can play, and the converted file will be placed in the ANY-maze\Sounds folder. The list of sounds shown on the speaker's settings page automatically includes all the files in this folder, so having browsed to a file once, you will find it is automatically included in the sounds list thereafter.

Playing a random sound

You also have the option to play a random sound. If you select this option in the sounds list, the Play a random sound window will open. There you can either choose to play a sound file, chosen randomly from a selection you make, or to play a random tone, again chosen randomly from a series of tones you specify.

Sound quality

The quality of the speakers you use will also make a substantial difference to the perceived quality of the sound, particularly at lower frequencies. Most small, cheap speakers are unable to play sounds below about 300Hz, so trying to play a tone at 200Hz will create no audible output or, at best, a low volume vibration.

A note about MIDI files

As mentioned above, ANY-maze cannot play MIDI files, nor can it convert them to a format it can play. However, there are commercially available products that can convert MIDI files to wave (*.wav) files.

ANY-maze help topic T0205