Bluetooth Headset Support

[Jim Ancona]

I got a new set of Bluetooth earbuds and I would like to use them with SparkSDR. I have tested them in both Windows and Linus, but I'm unable to make them work with SparkSDR. I can get either audio output or input to work, but not both simultaneously. That is, if I select output to the earbuds and input from the laptop's built-in microphone, I get both input and output sound. But if I select the earbuds' microphone for input, I get sound from the microphone, but nothing in the earbuds. At that point, if I select the laptop's built-in speakers, sound comes back and the microphone works as well. The behavior is similar in both Windows and Linux.

I think this may be because Bluetooth microphone is only enabled in Handsfree profile, while the output device in the list is the earbuds using the higher quality A2DP profile.  

Is there anything I can do to get both to work at the same time? 

Thanks,

Jim

N1ADJ

[ahop...@googlemail.com]

Hi Jim,

what make/model of earbuds are they (just in case someone here has a set I can test)?  I use the portaudio library and that chooses which devices to list, I could try building using a new version or on linux you might be able to build the latest portaudio from source on the off chance something has been added/fixed.  

73 Alan M0NNB

[ahop...@googlemail.com]

Just keeping this in the group:-

From Jim

The earbuds I've been testing with are the Google Pixel Buds A-Series, but I can also reproduce it with another device I have here. So I think any Bluetooth headset or earbuds that supports making or receiving calls with your phone should work for testing. 

In order to use the mic, I think the device needs to switch to the Handsfree profile which only supports mono audio at 8 or 16 kHz. Does SparkSDR support output devices with those parameters? I never see it show up.

Jim

N1ADJ

Hi Jim,

I suspect you have identified the cause of the problem, I do filter out output devices that are mono.  It should not be hard to add support for mono output devices so I'll see what I can do.

73 Alan M0NNB

[Jim Ancona]

Following up, I was able to get this to work on Windows by using Virtual Audio Cable[1] to route output from SparkSDR to my earbuds. Evidently it presents a stereo device at the proper bitrate and then does the conversion to 16 kHz mono for the earbuds. It still would be nice to have SparkSDR support this natively and across platforms.

Jim

N1ADJ

1 - https://vb-audio.com/Cable/index.htm

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[ahop...@googlemail.com]

Hi Jim,

this is still on my list, I have now found something to test on.

73 Alan M0NNB

[ahop...@googlemail.com]

Hi Jim,

this https://www.sparksdr.com/download/SparkSDR.2.0.924.win64.zip should allow you to select the
mono headset audio device.

73 Alan M0NNB

[Jim Ancona]

Just gave it a quick try and that does the job--my Bluetooth earbuds now work for both receive and transmit audio. Thanks!

Jim

N1ADJ

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