My earlier post (need help with a voltage-controlled-volume-control) went out of control with concern about my safety and ears - so maybe worth some clarification before someone sends me a hearing aid. The 5 watt stereo amplifier is driving 3 inch loudspeakers inside the helmet. Works and sounds fantastic but I would like to add an automatic volume control on the output of the iPod that would adjust the volume in relation to the wind noise. ie .. I can't eliminate the wind noise but I can adjust the volume of the music source (10-20 DB). I've read about voltage-controlled-resistors using FET's but I have no experience with this technology. Is it possible to build an attenuator with sufficient dynamic range and linearity using FET's? Any help is very much appreciated. Thanks again - sorry for the confusion I created on my first posting - Jack.
out-of-control volume control -
May 17, 2006
4 Replies
Fets are quite tricky to get good perfromance from in this application.
I already posted a link for resistive output optocouplers. These are very easy to use.
Graham
pay attention to riding the MC instead of listening to music...
isn't that the point of riding?
Mark
That's simple. Just line the helmet around the speakers with noise- cancelling foam, like on ear defenders and quality stereophones.
Good Luck! Rich
(I also agree that your attention should be on driving, not kicking back listening to tunes).
You might build something around the ssm2164. It's kind of pricey, especially considering the noisy environment you'll be listening in. You'll need some kind of op-amp after it to convert current to Voltage. Read the datasheet.
I still think you are going to go deaf. ;-)
--Mac
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