Tag Archives: Speech Compression

[Part 3] ALSA Speech Compression and FT-857D

This is an update of my previous post

As testing goes on, the .asoundrc file is getting more complexed in its setup. This is where we are up to now, we have 2 profiles going for ‘local’ and ‘DX’ and we select between the profiles by running in terminal


$ arecord -B 12000 -D local_eq_ -r 44100 -f S16_LE | aplay -B 12000 -D ladcomp


$ arecord -B 12000 -D dx_eq_ -r 44100 -f S16_LE | aplay -B 12000 -D ladcomp

And now for the dreaded .asoundrc file.
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[Part 2] ALSA Speech Compression and FT-857D

This is just an update from my older post. I have built an isolation box to use between the computer and the FT-857D which at the moment only consists of two 3K 1:1 audio transformers and 500K trimpot to not over load the radios audio input on the data port. I have still got to add the optocoupler into the box so can get the computer to control the PTT via the data port too.

At the moment there has been no noticeable different in the audio quality with the isolation transformers inline, and the compressed audio still sounds good :-)

ALSA Speech Compression and FT-857D

Well friend and I have been playing around with speech compression as the FT-857D on it own does not have the best DSP. As my friend is keeping a better log of it all and how to set up up on the Raspberry Pi head on over to VK2MEV’s site and check it out.

I have the speech compression running on my computer rather than the raspberry pi at the present moment for testing purposes, but will get around to setting it up on the raspberry pi at later date.

My setup consists of:
Creative Sound Blaster Play USB Dongle
Heil Pro Set Elite
Necessary cabling to connect between the data port on the FT-857D and the USB dongle and headset