Audio Tuning

Starting with Version 1.9 of the mobile applications and Version 10 of the RedNode API – we are implementing both a graphical display of the Voice Over IP (VOIP) audio and some controls to adjust the audio levels. This is a work in progress, so expect changes as we get feedback from users.

Audio Analysis

For the Audio Analysis function to work you must have it enabled – at the bottom of the Node Detail screen tap “AllStar/Echolink setup”. On the setup screen in the “AllStar Server” section, make sure “Enable audio analysis” is turned on. If not, turn it on and tap the Save icon in the top right hand corner of the screen. Your ClearNode will recreate its configuration files from the templates and then reboot.

IMPORTANT: The audio analysis tool uses the AllStar audio archive functionality – if you are already using the audio archive, you should not enable this tool as it will conflict.

Once your ClearNode comes back on line go to the bottom of the Node Detail screen and tap “Adjust USB Audio Gain for VOIP”.

For each transmit and receive event (longer than 5 secs) the ClearNode will generate an audio WAV file and run it through an analysis tool called “SOX”, then delete it. The results are displayed as colored bar graphs as above.

The absolute numbers are not important – use this tool to compare your audio with the audio of others, so you can adjust your levels to be roughly comparable. I find that it works well to pay attention to the audio on your favorite Net – particularly the Net Control Operators, they tend to make some effort to ensure their FM deviation is within the proper limits. If your transmissions are making it into the red indication – you are probably over deviating and should adjust the level “To VOIP (rxmixerset)”, or back off your microphone or both.

Adjusting Audio Levels

To adjust the loudness of your voice transmissions into the AllStar and Echolink networks, adust the value “To VOIP (rxmixerset)”. Your goal is to get the various analysis values “into the green” somewhere around 50-60%.

Adjusting the “From VOIP (txmixaset)” is a little different. Changing this value adjusts the loudness of incoming voices from other users on the AllStar and Echolink networks. Note that this will NOT change the colored bar graph values – they will always reflect the loudness of the incoming signal – which is controlled by the remote user. This adjustment changes the local gain being applied to that incoming signal. Also note that “txmixaset” and “txmixbset” refer to the left and right channels of the stereo audio – generally “txmixbset” is not used, best to keep it at the same value as “txmixaset”.

In the top right hand corner of the screen are two action icons – Preview and Save. Preview will push your level changes into the live Asterisk server on your ClearNode so you can listen to the changes live. Save will permanently save the values in the configuration files and reboot the node. You must Save for any changes you make to be permanent.

Once you’ve adjusted, saved and confirmed that your audio is where you want it to be – it’s advisable to disable the Audio Analysis – it uses quite a bit of the CPU resources. Hop back into the AllStar/Echolink Setup screen turn off “Enable audio analysis”, tap the save icon and let your node reboot.

Typical Audio Levels

If your Hardware ID starts with “R21N” (i.e. you have the RedNode PCB version 2.1) – you should expect your “To VOIP (rximxerset)” to be right around 350. You may need to compensate up to +/- 70 for the different deviation characteristics of different HT radios – particularly if your ClearNode is struggling to recognize DTMF tones.