connecting 2 radios to one set of speakers

[abraxus]

What about an audio input source selector like this:

http://www.ebay.co.uk/itm/4-WAY-PHONO-RCA-STEREO-AUDIO-INPUT-SELECTOR-SWITCH-BOX-/201026176083

 

[William_H]

Back in my day as a radio installer in small aircraft it was normal to have a switch panel for selection speaker or headphone for a range of radios and receivers. In the speaker position radio outputs were paralleled happily. Now these radios were mostly the valve to transformer output style. I think even less concern with complimentry symetry output stages in transistors. However if you are concerned and want isolation you fit a resistor in each speaker output line (+ve or active) of about 5 ohms. So 4 resistors for OP.
This will isolate to some degree the outputs. While wasting a little of the output power. (usually very adequate) good luck olewill

 

[funk-an-bord.de]

You can not let work two motor engines on one single helix.
If you try to isolate with such a 5 Ohm resistor,
you will get a worse sound,
becouse the loudspeaker is a mecanical system with resonance characteristics.
These are damped by the low resistance of the output stage.
If you use a ohmic resistor of 5 ohms,
then the resonance is less damped
and you will have a sound with resonance characteristica.
I would stay with a loudspeaker for every radio.
Wilhelm

 

[PeterR]

The set up I'd like would be FM (eg R4)radio to the cockpit with an auto mute/changeover to VHF (eg Ch 16) on incoming msgs, (like a phone call incoming on a car radio)

N

I don't know how to do the auto mute bit but I connected one of the FM radio cockpit speakers to the external output of the VHF radio via a 2 pole 2 way changeover switch. It means I can either have stereo FM radio and no VHF in the cockpit or mono FM and VHF.