Eliminating Unpleasant Audio Sounds

Eliminating unpleasant audio sounds from Web Conference audio streams and recordings.

The Web Conferencing technology uses sound effects to notify participants when they can begin to talk, when they release the talk key, when someone enters the room and when someone leaves the room. These sound effects can become annoying. This is especially true with a large audience when you hear a chirping sound as each participant enters the room. An individual can disable these sounds on their computer but the sounds may continue and also be heard in web conference recordings.

In this article I will discuss the source of these and other audio sounds and show, using different scenarios, how they can be eliminated or reduced from the web conference audio stream and from recordings. I will begin with a brief and simple review on sound cards and then provide the scenarios with remedies. Since the emphasis is on simplicity some of this discussion may not be entirely accurate. A more complete and accurate description on sound card functions may be found at: Audio Codec '97

Basic Sound Card Overview:

There are many sources of audio signals on a personal computers. Some sounds are generated by programs, some by the operation system, some from the CD drive, some from MIDI devices, some from the microphone input jack, some from the line-in input jack and so on. Some of these sources are provided by the sound card such as the microphone and line-in and others from other devices on the computer. An output jack is provided on the sound card for a speakers or a headset. There are many different sound cards available with different configurations. Some are integrated onto the system board. The setup for sound cards varies by manufactures and even by different models from the same manufacturer. The sound card collects the signals from different audio sources, provides volume level controls for each of the sources and directs the output to the output jack on the sound card. Some of these controls are for the playback side of the sound card for those sources not originating from the sound card and others are for the recording side for those input sources offered by the sound card.

So far it is quite simple. If you want to listen to a CD, watch a flash movie, hear the system sounds and so on you would configure the sound cards settings, plug in a speaker and listen. Usually this is a plug-and-play activity. If you want to record your voice or stream your voice into a web conference you would plug in a microphone, start your recording software or the web conferencing software and start speaking.

But if what you need to include the audio from other sources such as a CD or an application with your recording or streamed into a web conference You will need to take these other audio signals and pipe them back to the recording side of the sound card. This is called mixing. Some sound cards provide this function and use terms like "Stereo Mix", "Mono Mix", "Wave-Out", "What-U-Hear" etc. If your sound card doesn't have this function you will have to invest in a software mixer if you want to mix audio signals. I am not going to cover software mixers in this article. They would achieve similar results with software rather than hardware but their operation should be similar.

Sound cards will generally have the following mixer function:

Mixer function not provided - a software mixer will be needed is mixing is required.
Mixer function is provided but only a single device may be selected for the recording devices. This means you may select the "Microphone" or "Line-In" or "Stereo Mix" but not "Microphone" and "Stereo Mix". If you select "Stereo Mix" the audio from the CD, applications, system and so on will be included in the audio output. If you need your microphone input you will need to select the "Microphone" in which case the other sounds would not be included in recordings or streaming audio.
Mixer function is available and multiple devices may be selected. This means you may select the Microphone and Stereo Mix. The audio from the microphone and other sources such as the CD, applications, system and so on will be included in recordings and web conference audio streams. The playback and recording volume controls may be used to adjust the levels for the individual audio sources plus specific devices may be muted.

Since mixing the audio devices will pipe all the sounds to sound card's output a general rule-of-thumb would be to have all conference participants ensure the mixer device is not selected if they plan to speak.

Some applications to may allow you to mute the sound effects generated by the application. For example you may disable the sound effect in the TC Web Conference room. This would mute all the sound effects generated by the web conference technology. This likely would not be practical for blind participants who need those sound effects, or at least some of them, when they use the technology. For example they would need the audio prompt advising them it is their turn to speak.

With this background will now look at some scenarios you could encounter when using the When Conferencing technology.

Scenarios:

Scenario 1:

The audio heard in the room was excellent but the recording included unpleasant chirping sounds throughout.
The chirping sounds would be the sound effects generated by the conference room technology, e.g. the Enter/Leave audio prompt, on the computer making the recording. There may also be other system generated sounds. These are included in the recording because the "Stereo Mixer" device was selection on the sound card of the recording computer.
To correct this problem unselect, or mute, the "Stereo Mixer" device on the recording computer.

Scenario 2:

A superimposed chirping sounds is heard on all computers throughout the meeting.
The chirping sounds would be the sound effects generated by the conference room technology, i.e. the Enter/Leave audio prompt, on the speaker's computer. There may also be other system generated sounds. There are heard because the "Stereo Mixer" device was selection on the sound card of the speaker's computer.
To correct this problem unselect, or mute, the "Stereo Mixer" device on the speaker's computer.

Scenario 3:

Occasional chirping sounds are heard on all computers though out the meeting.
The chirping sounds would be the sound effects generated by the conference room technology, e.g. the Enter/Leave audio prompt, on the computer of one or more of the participants when they are speaking. There may also be other system generated sounds origination from those participants. These sounds are heard because the "Stereo Mixer" device was selection on the sound card of the computer of the specific participant when they are speak.
To correct this problem unselect, or mute, the "Stereo Mixer" device for any participant who will be speaking. You may need to do some detective work to identify the specific participants. See rule-of-thumb discussion above for recommend settings!

Scenario 4:

The previous discussion resolves the chirping sound problem however, additional considerations are necessary if the room participants need to hear audio from other devices. An example of such a case would be the audible output from a screen reader when it is important for the audience the hear that information. This scenario is a extension to the solution offered for Scenario 2.

If the speaker doesn't have a sight disability that necessitates the use of a screen reader, select "Stereo Mixer" and disable all the conference room sound effects using "Disable All Sound Effects" in the Action menu. The conference room sound effects will be eliminated but the sounds from other devices would still be heard unless those sounds are muted or the components generation the sounds are terminated. If the sound card only permits selecting one sound recording device you will need to use the Control Panel or the "Microphone Settings" option in the File menu to select the microphone when you need to speak.

If the speaker is blind and uses a screen reader, some of the chirping sounds can eliminated by removing any of the four generated sounds; Talk Sound On, Talk Sound Off, participant entering the room and a participant leaving the room. This is accomplished using the "Configure Talk Sounds" option in the "Options" menu - in the "Configure Talk Sounds" dialog remove the parameters for the sounds not required and press "OK". At a minimum the "Talk Sound On" should remain so the user can hear the audio prompt indicating they have the microphone and can speak. Also select "Stereo Mixer" for the recording device on the sound card so the audio from the other sound sources are piped intot the sound card recording device. The conference room sounds still specified would continue and would be heard by all participants and be included in any recordings as would the sounds from other devices, unless those sounds are muted or the components generation the sounds are terminated. This approach will not eliminate all unnecessary sounds from recordings and streaming audio but it will suppress the most annoying, e.g. enter and leave prompt. If the sound card only permits selecting one sound recording device you will need to use the Control Panel or the "Microphone Settings" option in the File menu to select the microphone when you need to speak.