WiNRADiO G303i/G305i receivers (internal PCI card models) require a full duplex sound card, which means that the card must be able to simultaneously process signals in two directions (i.e. record and playback) at the same time. The vast majority of modern Sound Blaster compatible cards are indeed like that. However, some older cards may not be full duplex.

WiNRADiO G303e/G305e (external models) are more forgiving and do not require full duplex sound cards because they have their own analog-to-digital converter (ADC) to digitize the intermediate frequency signal coming from the receiver; they only rely on the sound card for playback of the digitized signal after it is processed by the receiver software.

For the internal models, the Recording section of a sound card is used to input and digitize the IF (Intermediate Frequency) signal arriving from the receiver (only the Right channel is used, of the Left and Right stereo channels). The Playback section is then used to output the demodulated audio signal to the speaker(s). It is only with the internal models where there is a need to independently control both sound card sections. The Recording section volume needs to be adjusted to provide the correct IF signal level for the demodulation process; the Playback section control is needed to be able to control the speaker volume.

For external G303e/G305e models, if connected via USB, the Recording section is not used at all and the control is greyed out in the receiver's demodulator Setup. (The Recording section is only enabled if the receiver is used with the WR-G3E-SIO Serial Interface Option.)

For WiNRADiO G313/G315 models, the input is digitized by the receiver's own ADC, and the sound card is needed only for the output, to drive the speaker(s). In fact, for the internal models (G313i/G315i), the sound card is not required at all, as a speaker can be connected directly to the audio socket on the receiver card.

Typically, you would access the sound card Playback volume control panel by clicking a speaker icon in the Windows task bar. From this panel, you can get to the Recording control panel by selecting Options | Properties | Recording in the top bar menu.

However, the speaker icon may be missing. An alternative way of accessing the Recording/Playback controls is via the Windows Control Panel. Here you can also enable/disable the speaker icon.

The table below shows how to enable/disable the speaker icon, and how to get to the recording/playback controls from within the Windows control panel. The methods vary depending on the version of Windows you are using: