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Conditioning Signal Test Sequence

Introduction

This sequence demonstrates how to use the option for ignoring portions of a stimulus, first presented in SoundCheck 10.  Many modern audio devices have signal processing that makes testing with a simple sine sweep difficult.  Often, the device must first be conditioned with some other signal type to initialize a stable state for testing.  The combination of this conditioning signal and a test signal can be applied to a number of applications, including: telephony, hearing aids, and devices with noise cancellation.

This sequence utilizes a three part stimulus.  The first section is the conditioning signal, which for this example is comprised of two seconds of pink noise.  This line in the stimulus editor has been unchecked for the “Analyze” option, meaning an analysis step will simply ignore that portion of the recorded time waveform rather than analyze it.  The conditioning signal is followed by the test signal, which in this case is a stepped sine sweep.  This line has the “Analyze” option enabled.  Lastly there is another pink noise signal, 1 second this time, also set to be ignored by the analysis step. 

The end result is that the sine sweep is placed directly in the middle of a pink noise signal, but the analysis step (Heterodyne algorithm) will only analyze the sine sweep portion.

 

Final display for conditioning signal example sequence

The sequence setup has purposely been kept simple, to test a single loudspeaker.  The reason for this is that this methodology can be applied to any number of different applications, and by starting with a simple base, it is easier to adapt for the user’s specific requirements.

 

Required Equipment

Hardware

• No specific requirements

Software

• SoundCheck 10.0 or later
• Stimulus Editor Listen p/n 2017
• Stepped Sine Stimulus Listen p/n 2018

 

System diagram

 

Hardware Setup & Calibration

1. Instructions for a loudspeaker test setup.  

   1. Calibrate the amplifier as instructed in the SoundCheck manual.
   2. Calibrate the reference microphone as instructed in the SoundCheck manual.
   3. Connect the channel 1 (or Left) output of your soundcard to the input of the amplifier.
   4. Connect the output of the amplifier to your loudspeaker. 
   5. Position your reference microphone at the desired test distance from the loudspeaker, and connect it to the microphone power supply.
   6. Connect the output of the mic supply to the channel 1 (or Left) input of your soundcard.

   You are ready to start the sequence.

Further sequence development

Ways in which you could modify or further develop the sequence include:

• The conditioning signal could be set to artificial speech or even real speech to stabilize a device with a vocoder.
• The calibration and setup of the sequence can be altered for any number of applications including telephony, headsets, and hearing aids.

Download Sequence Documentation (PDF)

Download Sequence (Zip file)

To run the sequence in SoundCheck, please save the zip file to your hard drive, then follow the instructions in "Sequence Editor: Exporting/Importing a Sequence' section of the manual. Download Manual.