This article discusses a recording issue with Power Macintosh G3 Minitower and the Apple PlainTalk Microphone

The Power Macintosh G3 computers include a new sound architecture which is also included in Mac OS 8.1. With this new sound architecture, applications are now able to change which sound source to monitor. Apple provides a new SoundSource Control Strip which lets you select the sound source your computer will use. This is helpful if the application you are using does not provide a way to change the sound source from which you are trying to record. The benefits of this new sound architecture include:

• User interface changes to support monitor sources instead of input sources for the user to play back analog audio devices such as compact discs.
• The internal speaker and headphone port(s) act as a single output port once again. Thus, if a headphone is inserted, the internal speaker will always be inactive. This simplifies the user interface for output controls to a single set of controls, for example volume, mute, and so on.

If you are having difficulty recording audio from third-party applications on a Power Macintosh G3, check with the developer of the application for the latest Power Macintosh G3 or Mac OS 8.1 compatibility information. Apple Developers should refer to Tech Note 1121 for details about the new sound architecture.

The following article can help you find the Tech Note mentioned here:

Article 24493: " Apple Tech Notes: What They Are, Where To Find Them "