Windows Audio Routing
How to get the audio from a radio (not a SDR) to a piece of recording or decoding software on the same PC?
The following technique does not work for everyone based on their specific hardware and software, but it does work for a large number of users.
Many times a suggestion to solve this issue is to get a program like VAC (Virtual Audio Cable) that is designed specifically to do this. VAC and similar programs often work quite well, but they are not the only game in town. Many times you can achieve the same results using only the software provided under Windows, and using the "default record source" that has been a part of Windows for a long time. Default record source just tells Windows what input to look at as its primary recorded sound input, and this is the sound path that can be sent to almost any software in the PC, not just recording software.
The following solutions are not going to work for everyone, but it does work on many PCs under XP, XP Pro, and Windows 7, depending on the specific hardware and device drivers involved. Some older sound cards do not support this operation, and some modern hardware does support the operation but the drivers are not configured for it, leaving the user potentially high and dry.
Specifics of nomenclature vary across recording / decoding software, but they often use terms like "default recording source" or "primary capture device" to select the same source configured here.
Each OS, service pack, and audio program, may look slightly different, but the general idea or meaning is often the same. Each OS will be addressed separately, starting with Windows XP and then Windows 7.
It is strongly recommended that before you start these adjustments you create a System Restore Point that you can revert to.
For audio routing using a Software Defined Radio (SDR) you will need to use a virtual audio device. These instructions won't work in this case. See the SSTV article for a list of software that can be used to perform audio routing. USB connections are not designed to handle audio connections.
Windows XP and XP Pro
Setting up for "Wave Out" or "Stereo Mix" as your default record source under Windows XP.
Generally XP is very easy to set up for Wave Out or Stereo Mix (there are other possible similar names used with some sound card drivers, "Wave" seems to be the very common) as your default record source.
On the Desktop locate the "Systray" in the lower right hand corner of the screen. Locate the Speaker icon in the Systray. The drivers for some sound cards change this and supply a different control panel, if that is the case you might have to modify what is described here a bit.
After right clicking on the speaker icon pull up the menu and left click on "Open Volume Control".
The "Volume Control Panel" should now be open. Under "Options" menu pull down to "Properties" and left click that.
You will now want to make sure you are setting the right sound card input, if you have more than one sound card. You will also want to select the "Recording" option, this will bring up the possible record source devices. And then you will want to check mark any sources you might want to use for recording. In the case of what we are trying to do here it might be "Stereo Mix" or "Wave Out". In the case in the pictures "Wave" is the right answer. After you have made your selections hit "OK".
You are now in the "Recording Control Panel". Put a check mark in the "Select" box for the source you want the audio to come from, and adjust the Mixer sliders as needed to control the recorded audio levels. Close the window and you should be good to go, assuming your Decode / Record software is set to take the Windows Default Recording source.
Setting up for "Wave Out" or "Stereo Mix" as your default record source under Windows 7 Ultimate.
Widows 7 is sometimes a bit more difficult to set up for the default record source. 7 has a tendency to hide features from the user, and this case is no exception. Specifically disabled or unused sources are sometimes not immediately seen in some control panels, and unless you know to go looking for them and turn them on you might not think their use is even an option.
It the lower right corner of the Desktop locate the Systray (note that I have my desktop set up to look like XP). In Systray right click on the Speaker icon.
Move the cursor up, hi-lite Record Devices, and left click on it.
The Sound Control Panel should open, with the Record tab selected. This will show you all the record sources that you could select. Windows 7 often hides unused sources by default, so you may not see many sources there at all, or they may all show up, depending on your settings. The below image shows nothing but a Microphone selectable, and was the original configuration for my laptop audio.
Obviously the Microphone as an audio source is great for things like Skype, but does not work too well if we are trying to get the audio from an SDR into recording or decoding software. Right click in the white area under the Microphone, were nothing else is seen. This should bring up a pop-up with two choices, "Show Disabled Devices" and "Show Disconnected Devices". Select both of these options.
If at this point Stereo Mix ( or something similarly worded to that ) is not a selectable option then you may have a problem. In the case of my laptop it was not a selectable option until after I went in and edited the driver a bit, a process that is a bit lengthy and I will not cover here. You may, or may not, be able to do something similar, depending on your hardware and drivers.
Select the "Stereo Mix" icon to hi-lite it and then press the "Set Default" button.
If you have been successful there should be a green bubble next to the Stereo Mix icon and there should be a check mark in the bubble. Hit the "OK" button and the control panel should close.
If all has gone well the Stereo Mix should be your default record source, and if your record / decode software is configured to take its audio from the Windows Default Record source you should be good to go.
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