Audio Splitter : Radio and VHF ?

[eebygum]

Anybody know if there is such a thing as an audio splitter ?

When sailing I want to have an external speaker in the cockpit which is connected to the lineout of my mp3/external amplifier blasting away to my favourite songs ......but I know I should also maintain a listening watch on the VHF /forums/images/graemlins/crazy.gif

So is there some type of audo splitter which could take the lineout of the MP3 player and the VHF, but if the MP3 player is playing and there is then an output (however that is measured ?) on the VHF it would take precendence and cut in ?

Running out of gadgets for the boat so this one would be really useful /forums/images/graemlins/grin.gif

 

[steverow]

If you're talking about output level..ie speaker outputs..then apart from the standard switches and faders used on car radios etc then I dont think so.

If however you are talking about signal (line level) 220mV or greater, then a cheap small disco mixer would probably suffice.
Conect your mP3 to say channel 1, and connect your VHF radio to the mic in, and set the automatic ducking to on. When a signal is RX'd on the radio then it wil automatically drop the level of the MP3.

Long winded way of doing it but it's all I can think of at the'mo.

Steve.

 

[savageseadog]

I had thought of designing, building and selling an item to do just this many years ago. Didn't bother on the basis that everything that's needed that I've thought of has always seemed to be available already.

 

[markdj]

You will need a way of changing the speaker output of the VHF to line level and then have a seperate amplifier to drive your speakers. To do this you will require a DI box to connect to your speaker output and convert the level to mic level for input into the mixing desk. For the radio/cd you may need 2 DI boxes to convert both channels or some radios have a line out for connecting to an external amplifier. I wonder if there would be a way to make use of the "mobile phone" switching function of many car stereos. When something is received on the VHF that would be put via a relay to pulse the car stereo so that it goes to mobile phone mode ie. the volume goes way down. I'm not exactly sure what voltage level is required for the car stereo phone wire though. If you then had a separate speaker for the VHF then you wouldn't need a mixing desk.

 

[jubro]

The mute input on car radios (activated from a mobile phone) work by being connected to earth.

I think you could knock up a circuit that would throw a relay when the VHF had a signal, and therefore mute the radio. This could be done using the the speaker output, I think, though I haven't thought it through. You'd need to generate a DC current from the speaker output, enough to close the relay. The other way could be to tack into the LED that most VHFs have to indicate they're receiving.

It's all do-able, but you'd have to really want to.