Audio stimulation🔗
2 separate audio stimulation systems are available. Each system has a different frequency and latency response.
Both audio stimulation systems are connected to a USB audio interface Crimson 3 from SPL.
Select Natus TIP-300 or SoundPixx🔗
The button Speakers: A to B selects the system in use. If the button is OFF, the
speakers A corresponding to the Natus TIP-300 system
is selected. If the button is ON, the speakers B corresponding to the
SoundPixx system is selected.
Tip
If the SoundPixx is in-use, don’t forget to turn on the SoundPixx controller.
Microphone inputs 1/2🔗
The 2 microphone inputs 1 and 2 must be used without 48V phantom power and without
high-pass filter. The microphone 2 is connected to the black microphone used to speak to
the participant through the in-ear headphones. To enable the black microphone, both the
Inputs: 1|2 and Inputs: Mono button must be enabled.
Tip
The black microphone has a low volume. Don’t forget to turn the knob of input 2 to
a high value. However, don’t set it to max as it would leave a background noise. The
LEDs SIG of the microphone input 2 should remain off while the black microphone
is not in use.
Audio sources🔗
Auditory stimulation can come from 2 sources: the Chronos if E-Prime is used or
directly the computer sound (DAW). Only one of the 2 sources should be active at a time.
To use the sound from the Chronos, the button Sources: RCA must be enabled. To
use the sound from the computer, the button DAW: 1|2 must be enabled.
Note
On Windows, the computer sends sound to a single channel, DAW: 1|2. However on
Linux, it sends sound to both channels, DAW: 1|2 and DAW: 3|4, thus enabling
both yields a higher volume.
Monitoring feedback🔗
2 Bose speakers are used to monitor the sound played through the audio stimulation
system. The Bose speakers are connected on Phones 1 and volume is adjusted both with
a knob on the speakers and with the knob Phones 1 on the Crimson 3.
Main volume🔗
The main volume knob affects the volume from all sources. The volume should be gradually increased from a low value up-to the desired value to prevent loud sound from deafening participants.