[AudioI] People Digest, Vol 21, Issue 10

[Mike Maynard]

A bit more of a layout here using an outline


   -

   Inputs to Pi
   -

      Mic
      -

      Headset 1
      -

      Headset 2
      -

      Radio RX Audio
      -

   Outputs from Pi
   -

      Speaker
      -

         RX Audio from Radio only
         -

         GPIO Volume knob and mute
         -

      Headset 1
      -

         RX Audio from Radio, TX audio from Headset 2
         -

         GPIO Volume knob and mute for each stream
         -

      Headset 2
      -

         RX Audio from Radio, TX Audio from Headset 1
         -

         GPIO Volume knob and mute for each stream
         -

      Radio TX
      -

         Chosen by operators from Mic, Headset 1, Headset 2
         -

            Maybe GPIO Driven to choose?
            -

            Unmute chosen input, mute others?



Also did a visual layout to a point and it can be seen here -
https://www.dropbox.com/s/gpn3skosyu0looq/audio%20interface.jpg?dl=0

On Sat, Oct 30, 2021 at 6:57 PM Christopher Hunter via People <
people at lists.audioinjector.net> wrote:

> > Today's Topics:
> >
> >     1. Ham Radio Audio Mixer (Mike Maynard)
> >
> >
> >
> > Trying to build an audio mixer for a ham radio setup.
> >
> > My goal is as follows:
> >
> > I want to take audio from the radio, bring it into the pi, and send it to
> > various outputs (one for speaker, headset a, headset b....)
> >
> > Then, I want to take mic audio from the 'selected' device, back to the
> > radio.
> >
> > Furthermore, I want to take mic audio from headset a and headset b, and
> > pass them directly to each other (as an intercom) while they still hear
> the
> > radio audio.
> >
> > I am hoping to use the Octo for this.
> >
> > Would this be possible?   What might I need for software to do this?  Is
> it
> > possible there is a better solution?
> >
> > I assume I am going to need some sort of amplification for the
> > speakers/headphone outputs?
> >
> > Open to suggestions!
> >
> >
> > Mike
> > K2GC
> >
> Mike
>
> The Pi is superfluous - what you're trying to achieve could be done
> either with relays and a bit of CMOS logic, or CMOS switches (like the
> 4066) and a bit of CMOS logic.  You might need some op-amps to amplify
> some of the routings, and if you're using your microphone input for
> amateur radio, some bandwidth limiting (simple filtering) and some
> compression and limiting might be in order to maximise your "talk
> power".  If you need further advice, sketch what you're trying to
> achieve, and drop me a line with your sketch, and I'll give you some
> pointers.
>
> Regards
>
> Chris
>
>
> --
> People mailing list
> People at lists.audioinjector.net
> https://lists.audioinjector.net/mailman/listinfo/people
>
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