AV: SoundOut Volume Control Property in E-Prime, Actual Decibel Output, and MovieDisplay Volume Control Options [28039]

This article applies to:
E-Prime 3.0
E-Prime 2.0
E-Prime 1.x

Detail
Any sound output from E-Prime has its individual volume set to the maximum level by default. Editing the volume in E-Prime is ultimately reducing the volume level from the maximum level. The default value that a SoundOut object or SlideSoundOut sub-object is reduced from is 0. For any SoundOut objects or SlideSoundOut sub-objects, the option to specify volume is unselected. The image below shows the default Volume Control settings for a SoundOut object.

 
The decibel values that can be specified in the Volume Control options are specified in the entry field as numbers between -10000 and 0 with 0 being the maximum value (and default and loudest) and -10000 being the minimum (and quietest).

There are many factors that go into a finalized decibel output when running an experiment on a given physical setup. E-Prime alone cannot dictate any specific finalized decibel output, as is the case with any third-party Windows application. E-Prime does allow researchers to control the relative volume of sounds played within an experiment, keeping all other factors equal at runtime.

There are additional factors stemming directly from the integrated components of the machine that an experiment is run on such as the sound card, internal speakers, the operating system, any externally-connected audio output devices (such as headphones and external speakers), external audio interface devices, and intermediary amplifiers. Researchers hoping to achieve a uniform decibel output for a given sound played during an E-Prime experiment need to take into account not only the E-Prime Volume Control settings but also these machine-specific factors.

The value specified in the Volume Control settings field is in hundredths of decibels and has an allowable range of -10000 to 0. Keeping in mind that the human perception of loudness itself is not linear, the following are some examples of allowable Volume Control values along this logarithmic scale in comparison to the change in final decibel output:
 
-10000 = -100 dB
-1000 = -10 dB
-500 = -5 dB
-100 = -1 dB

To share a real-world example of a given setup, a researcher first measures a final, runtime decibel output of 90 dB. This is measured in a specific location within three-dimensional space on a given physical setup for a particular SoundOut object’s execution. The 90 dB reading acquired was achieved by leaving the Volume Control option to the default of unselected and the value set to 0, specifying full scale. If the researcher then to specifes a Volume Control value of -1000, the same SoundOut should then play at an 80 dB output at runtime when measured in this same location on this setup.
 
To confirm a finalized decibel level for actual intensity of a sound when played through E-Prime on a given setup, an external tool such as a Decibel/Sound Level meter, should be used to measure volume. Only by using the same audio files, E-Prime volume control settings, machine volume control settings, any intermediary device volume control-related settings and any external sound hardware, can the same volume be achieved at a given distance when collecting data across multiple setups. Additionally, differing acoustics between data collection environments and any potential outside noise interference should be taken into consideration when concerned with a uniformed sound level.
 
While MovieDisplay objects and sub-objects do not have the same Volume Control property in the GUI, the same range of decibel attenuation values can be specified through script. For example, an InLine object can be placed directly before a MovieDisplay object with script of this format:

'In this example, Sound is the name of the Sound Device in the Experiment Object

Sound.Volume = -1000

The image below further shows how to script this in an InLine window:

 
Since this script calls on the Sound device itself, this affects any other SoundOut object or sub-objects used in the experiment. To reduce the scope of this scripted Volume Control so that it only affects a single object's execution at  runtime, you may reset the Sound device to full scale by including an InLine immediately after the desired SoundOut/MovieDisplay object or sub-object (i.e., specifying a value of 0).

See Also:

E-STUDIO: Sound Devices [22725] 

E-STUDIO: SoundOut Object [22708]

E-STUDIO: SlideSoundOut Sub-object [23595]