Automatic Volume Control for all cars

I have searched for this but can’t find anything.

Can somebody please tell me how to make an Automatic Volume Control so that as the noise level in the car increases, the volume will increase too.

I would like to make something with an adjustment knob that goes in between head unit and the amps. I would install a mic in an appropriate place and adjust the sensitivity of it to give the Volume Control a base line. Then as the interior noise of the car goes up, the volume input of the amp is increased.

Thanks

The approach I would take would be to build a circuit to monitor the mic (if you have your heart sat on using a mic, I personally would base it off of the vehicle speed sensor).  Then, you would have to access the volume up and volume down functions of the radio in question.  You may be able to do this by soldering some wires on the main circuit board of the radio, although it would be very hard to find where to solder (especially if a detachible face is installed).  You other option would be to hack up an old remote control and use it to send IR commands to your radio to raise volume.

I wouldn't go with a mic as it would be hard to set it correctly, especially if you really feel liking cranking the radio one day (the mic would pic up the loud music and try to turn your radio up louder, causing a higher noise floor, resulting in a louder radio and so on).  By using the speed sensor you can adjust volume based on vehicle speed, which would provide a more predictable result.

I'm with kevin. Pull the speed.

With a mic your going to need some sort of hysteresis circuit to keep the volume from adjusting with the frequency of the noise or every time you hit a bump. Plus you will need to filter out the sound from the stereo

Check the Texas Instruments web site for AGC circuits. Might be something there. Or, if you have experience with micros, pull speed from the OBD port and adjust a digital pot accordingly.

Thanks.

I was going to put the mic behind the radio under the dash/center console because then it would not pick up the radio emissions as much. The general rumbling of the car would be there though and it would increase as speed etc increased.

I'll have to see if i can get to the tach or speedo to take a reading off those.

It's certainly going to be more involved that I first thought. but I hate having to constantly adjust the volume on this car. It's a sports car and makes slightly more noise than the average sedan.

Thanks for all your input. I will keep looking at his.

Turn it up loud all the time.  No need for adjustments when you've got it pegged already!

But really, I'd hate to see your experimental work end up frustrating you in the long run.  Spend some time in the car mentioned above and find out how annoying it can be.  My take is this:  adjustments are already "automatic" because we have the inate ability to compensate.  When the noise threshold gets louder, we automatically compensate for that noise.  When we watch TV lying down on our side, we compensate for the different viewing angle...and we would be annoyed if the TV tilted when we tilted our head.  Same thing with our hearing.

With either type of electronic compensation, there will be drawbacks because of the battle with your own compensatory tendencies.  When you shift through the gears from 0 to cruising speed, the noise threshold will increase, fall, increase, fall through the gearing and the subsequent higher/lower RPMs.  With mic sensoring, the music will increase and fall through these gear changes.  Speed sensoring would at least increase slightly during the gearing and be at max loud primarily to combat road/wind noise, but that has been proven to be annoying in the Bose systems that use it.  In any case, write up something in the end if you've gone ahead and built it and lived with it for awhile.  I would be interested to find out what you think.

Yes, you all have valid points and I’ve done some thinking about it.

If I had a steering volume up and down on the steering wheel it would have to be the easier way and I probably would never posed this question.

The car is a 1991 Honda (Acura) NSX, no volume controls on the steering wheel. The car is somewhat noisy, it’s not modified and quite civilised but its noise level changes dramatically.

1+2=10

So when I’m listening to the radio at a light, for example, then accelerate off, I need to constantly adjust the volume on the radio which is not easily accessible, it is low down on the dashboard.

Most owners of these cars don’t complain about this problem because they have the car as a Garage Queen, they only drive it occasionally.

But for me it’s my daily driver.

I thought of installing a couple of speakers on either side of the head rest, then the relative difference  in sound volume would be less (I can imagine) because they are closer to my ears than the door speakers way far away low down in the far corners of the doors.

Then I thought of the Automatic Volume Control. Then fitting steering wheel volume controls.

There are cruise control buttons on the steering wheel; I almost never use the cruise control.

Or actually install two micro buttons on the steering wheel. But might look ugly. Have any of you seen nice aftermarket steering volume buttons?

Small flat pressure buttons would be better, I could place them discreetly in one of the openings in the steering wheel.

That coupled with the speakers closer to my ears might be the way.