Configure audio and dual reception

Radio Bench sends decoded receiver audio to the RX output device. The operating system controls the final device level.

Select an output

Open Settings > Audio. Under RECEIVE OUTPUT, select the Output device, then select Play tone to play a two-second 1 kHz tone.

If the tone does not play, see troubleshooting.

Set the listening level

Use the RX volume for the application level. Use the operating-system or device volume for the final acoustic level.

Start at a low level when you change an output device. Raise it after you confirm that audio reaches the correct device.

Configure transmit audio

Transmit operation uses the separate MICROPHONE and TRANSMIT OUTPUT cards in Settings > Audio. Select your microphone as the microphone input device and the radio audio interface as the transmit output device.

The TX test tone passes through output gain but bypasses speech processing. It checks output routing and level, not microphone processing or RF output. A radio using VOX can key when it receives the tone.

Audible distortion from the TX test can indicate excessive TX output gain. Reduce that gain before you transmit.

TX output and monitor levels are saved between sessions. The monitor starts disabled, so restoring its level does not enable listening. Returning from FSK also preserves the TX output level.

Microphone and device options

Keep microphone open controls when Radio Bench releases the microphone. Choose Auto, Keep open, or Release when idle.

Many Bluetooth headsets switch to a lower-quality listening profile while an application holds their microphone. Auto and Release when idle let the headset return to its high-quality profile between microphone uses.

Keep open holds the microphone between uses. Auto keeps it open only for an input that Radio Bench can identify as stable. Otherwise, it releases the microphone when idle.

Under DEVICES, refresh the device list after you connect an audio interface. On Linux, Show ALSA aliases also lists the low-level ALSA device names.

Use the Audio workspace

Open AUDIO to inspect received audio or transmitted speech. See Audio instruments and speech preview for the source selector, plots, and microphone preview task.

See transmit safely for the complete transmit setup.

Listen to the SDR and rig together

Dual reception combines SDR audio with a second receive path from your radio's USB sound device.

Hamlib carries control commands, not receive audio. Connect and select the radio USB audio input separately. Do not select that input as the TX microphone or open it in another application.

Start SDR reception in an analog mode, such as USB or AM.
Open Settings > Audio and find the RIG RECEIVER card.
Turn on Rig USB audio.
Select the radio under Input device. Until you select it, the card shows Select the radio's USB audio input to hear the rig. Radio Bench never uses the computer's default input for the rig.
Select Left / mono, Right, or Mix L + R under Input channel to match its audio channels.
Confirm that the status progresses from Priming to Active during RX playback.
Open RX AUDIO in the left control column.

Use the mute button before each level slider to listen to one receiver at a time. Adjust SDR level and Rig level until their levels are comfortable, then unmute both receivers.

If both receivers hear the same signal, adjust Alignment to reduce the echo. SDR + delays the SDR path. RIG + delays the rig path. This listening adjustment does not change either receiver's tuning.

Increase Separation to move the receivers toward opposite headphone channels. At zero they are centered. At full separation they occupy opposite ears. Select the swap button before the Separation slider to exchange sides.

The letter after SDR level and Rig level shows the side of each receiver. L is left, R is right, and C is centered.

The mute button before each level slider silences that receiver. Check both mute buttons if a receiver appears silent.

Recover a missing rig input

When rig audio is not playing, a line below Rig level in RX AUDIO gives the reason. Select the line to open Settings > Audio.

Waiting for active RX playback means the listening path has not started. Check that SDR reception is running in an analog mode.

No audio from the radio means the input is open but has been silent for a few seconds. Many radios keep their USB sound device powered by the computer when the radio is switched off. Switch the radio on and check that its USB audio output is enabled.

For an input error, close other applications using the device and check the cable and channel. Turn Rig USB audio off and on to retry.

Digital modes bypass dual-receiver mixing. Their audio and decoders use the SDR path. Your dual-RX settings remain stored for a return to analog listening.