This page explains how to present audio stimuli from an Audio CD to a test subject in the CMA 2 CSD Clinic Audiology Booths.


Sections of this Document


The audiometers in Booths B, E, F & G have external inputs which are fed from an Audiometer Aux Switcher which allow CD, iPod & PC external sources to be presented to the test subject.



Before Your Session

Power on the equipment in your booth. Instructions here. 

Select CD on the audiometer aux switcher. Note that the volume knob on this switcher has been disabled and does not affect output volume.

Volume knob disabled & does not affect volume.



Select External Input as your source on the audiometer.

~ Input Ext A corresponds with the Left output from the CD.

~ Input Ext B corresponds with the Right output from the CD.

Play the CD.

Calibrate the audiometer's external input trims using the test tone on the CD.

Test and confirm all transducers are working prior to your test subject's arrival. 

After Your Session

Eject & file your CD(s). 

Power off the equipment in your booth. Instructions here.


Troubleshooting CD Audio Stimuli Playback

No Sound from Audiometer CD player

Are you playing music from the correct CD player?

~ Some booths have 2 CD players in the rack. Ensure you are using the one labeled "Audiometer CD Player"


Is CD selected as the source on the correct switcher?

~ Some booths have 2 identical switchers in the rack (Audiometer Aux In & Mother's Distraction). Ensure the one labeled "Audiometer Aux In" has CD selected as the source.

~ Connect a pair of headphones to the Audiometer Aux In switcher. If you can hear the CD, the issue is downstream in the audiometer or transducers. If you cannot hear the CD, the issue is in the switcher or CD player.


Is the CD player time moving?

~ Ensure the CD player is turned on, has a CD loaded, and is playing. You should see the time indicator on the front of the CD player progressing.


Is the CD you're trying to play a burned CD-R?

~ Sometimes CD players have trouble with burned CDs. This could be due to the type of CD media or perhaps because the author failed to properly burn it for playback on an Audio CD player.

~ Ensure the CD was burned as an Redbook Audio CD (not MP3 CD, not data CD) using CD-R media (not CD-RW, DVD-R, not DVD+R, not BD-R, etc).

~ Ensure that when burned the disc was "closed" by the burning software. "Closing" the disc writes the table of contents to the disc and makes the disc readable by Audio CD players.

~ Try playing a commercially produced Audio CD instead and see if the behavior changes.


Are the transducers connected to correct jacks & working?

~ Test other transducers and/or replacement transducer.

Is there power to the Switcher?

~ The Audiometer Aux In switcher has a small blue LED to the right of the headphone volume knob. Ensure that this is lit indicating that the switcher has power.



reviewed 10/9/17 - Cox