I am sure there is a simple way to do this but not for me. My electronics knowledge is minimal. I learned just enough to get my Airframe/Powerplant mechanic license. I Fly helicopters and when I do I am required to wear a flight helmet. I have turned the radio and the intercom volumes all the way down and yet it still is way too loud. I would like to build an adapter to mute the volume by 50 - 75%. I can then turn the volume up to a bearable level. My helmet has 2, 300 ohm speakers, L&R but not stereo. What do I need to do to accomplish this ? I can not modify my helmet so I need something I can plug into the headset jack and then plug my helmet into.
Any help would be greatly appreciated

 

Welcome to AAC!

You could insert a pot (variable resistor), connected like a rheostat, in-line with the speakers.

https://en.wikipedia.org/wiki/Rheostat

I'll attach a schematic later.

 

If the speakers are connected in parallel, you could do something like this:

Clockwise rotation increases volume.

You need to consider maximum power that can be delivered to the speakers. A pot connected as a rheostat could be burned out if you set the resistance too low. You could insert a resistor in series to limit the maximum dissipation in the pot.

300 ohms would let you reduce volume by 50%. I'd suggest that you select resistor values based on the lowest volume you can currently set.

 

So if I put a 300 ohm resistor in series with each speaker would that cut the volume by half ? Do I need a variable resistor or can I use a fixed resistor ?

 

So if I put a 300 ohm resistor in series with each speaker would that cut the volume by half ? Do I need a variable resistor or can I use a fixed resistor ?

Yes. If the speakers are connected in parallel, you'd only need one resistor connected before where the speakers are connected.

 

cool. Thanks I will give it a try