Overview

StimTracker Quad has a built-in voice key feature. It monitors the participant’s voice level continuously, and generates an event marker when the level rises above a threshold that you specify.

Any PC-compatible microphone can be plugged into the Mic jack in the back of StimTracker Quad. A headset is preferred because it maintains a constant distance between the microphone and the participant’s mouth.

Adjusting Thresholds

See Using the Front Panel for information on setting the threshold. 

Depending on the experiment, a participant’s response may be a single word or it can be a sentence that’s punctuated by pauses. You can use a filter so that StimTracker Quad does not send a new event marker after each pause. See using filters.

How Event Markers Are Delivered

The most common application is to use m-pod. m-pod takes the multiplexed signals that StimTracker generates and converts it into TTL output. By default, the output is “reflective”. This means that if the participant talks without a pause for, say, 500ms, the width of the TTL output pulse will also be 500ms. It is possible to change this behavior so that a shorter pulse is delivered on onset and another one is delivered on offset.

StimTracker can also deliver time-stamped event marker information via USB; this is turned off by default but you can easily enable it.

Event markers are also delivered via the “TTL Output” connector. Unlike with m-pod, output on this connector is always in “reflective” mode and cannot be changed.

Software Support

When StimTracker Quad detects the onset of voice, voice key information can be sent out simultaneously via:

• m-pod
• TTL signal via m-pod or via the “TTL Output” connector
• Time-stamped output via USB

By default, the output is enabled for the first two but not for USB. USB output is enabled automatically by SuperLab (version 6 or later) as needed. For other applications, you can enable it using Xidon.

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Last Revision: Apr 29, 2020