Task Tags Audio

The purpose of this task is to demonstrate how to produce sounds in real-time using analog outputs as part of Kinarm Lab.

For an alternatively method that does NOT play sounds in real-time, but instead works through the Dexterit-E computer, please see the other sample task entitled Tone player – non real-time

This task produces sounds by sending a pre-defined waveform over one analog channel output. If that output is connected to a speaker, then the user will hear the sound.

In order to make sounds in real-time, the following are required:

• one or more analog outputs connected to the Robot computer (e.g. via a PCI card such as NI-6229 connected to a BNC-2090A panel)
  • You will need one analog channel for each independent speaker
• speakers with built-in amplifiers (e.g. headphones, or computer speakers)
• method to connect the analog output(s) to the speaker(s)
  • e.g. if connecting two channels of a BNC-2090A panel to speakers that have a single 3.5 mm stereo jack, the following would work:
    • 2 BNC to RCA/phono jacks – e.g. Newark (54M7978) or Digikey (367-1013-ND)
    • An adapter with 2 RCA/phone plugs to a single 3.5 mm stereo jack – e.g. from Radioshack or the Source
• vector containing the waveform(s) of the desired sound (e.g. download one from the internet, record one yourself, etc)
• MATLAB R2015a is recommended, but not necessary: because Task Programs are run at 4 kHz for R2015a and later, vs 2 kHz for R2013a and prior, using R2015a doubles the frequency range of sounds that are reproduceable

How to use this task:

1. process the desired sound using the attached processWaveformForKINARM.m
   • please read the comments in the code for how to do use this script
   • a sample waveform of a piano keyboard is included
2. connect your speaker(s) to the analog output(s) and turn the speakers on
   • the sample code in this example uses a single analog output (DAC0OUT) of a PCI-6229 card
   • Note: if you have a different analog output card, you will need to modify the task to use the Simulink block corresponding to your card
3. build the task and run it
   • during the build process, the sound waveform becomes embedded in the sample code. So if a different waveform is required, the Task Program will have to be re-built.

This task was built using R2015a SP1, and was compiled for Dexterit-E 3.6.2

We get many requests for how to play sound to a subject. There are lots of options for how to do this:

• Analog outputs to the NI cards
• Specialized sound cards that are xPC compatible
• Playing sounds from the GUI computer

The attached example is a very simple version of the final option: playing sounds from the GUI computer.

For an alternatively method that plays sounds in REAL-TIME though the Robot computer, please see the other sample task entitled Play sound file in real-time

You will need to have Java available in order to run this example. You can obtain the most recent Java from: http://www.java.com. This example requires a small program to run on the GUI computer. Once you unzip the example files you will need to:

1. Find the folder you have unzipped the files to using the Windows Explorer.
2. Hold shift and right click on the folder in Windows Explorer
3. Select “Open command window here”
4. At the command prompt type: java -jar toneplayer.jar
5. At this point you should see: “Ready to play tones…”.

When you run the task, if you have speakers plugged into the GUI computer and they are turned on then you will hear 3 tones played, one each trial. As the task runs it will create UDP packets that get passed to the Tone Player program. The Tone Player program interprets the packets and creates an appropriate tone. It must be noted that sound playback in this way is not real-time, but it will be close to real time.

I have provided the Java code that plays the tones, you are free to modify it to your needs. This code could be modified to play *.wav files or possibly even *.mp3. I have not done that. This is purely a proof of concept.

The task was built for Dexterit-E 3.5 and MATLAB 2013a.