speakers/headphones

[Bruce Dawson]

TARogue wrote:
> For some reason, when I plug in my headphones on my laptop (Thinkpad R61 
> series) the speakers continue working. So the sound is coming through 
> the headphones and the speakers.
>
> This only started happenning after I trued using a USB headset. Before I 
> ever plugged that in, I didn't have this issue. When i had headphones 
> plugged in, the external speakers were mute.
>
>   
The USB part was critical - thanks for mentioning it.

There's a little mechanical contact in most earphone plugs that opens
(or closes) when the male jack is inserted. This contact is used to turn
off the speakers. (And makes that scratching noise when one slowly plays
with the jack.)

Some more modern systems detect a change in impedance when one inserts a
head set and then turns off the speaker circuit. This of course requires
a driver for the various devices/circuits.

You probably have the former (mechanical contact) since the sound driver
isn't attenuating the speakers when you use the headphone.
> Any ideas?
>   

You should have two audio "devices" running in the system - one for the
USB channel and one for the "hardwired" channel. Try turning one off.
The program you use to do this depends on a lot of things, and can even
be distribution dependent. Need more info.
> Thanks
>   Tom
>
>