Sound through speaker and headphones at the same time

[Fred]

At work I have an HP DC7600 which is exactly one year old and it comes with an onboard speaker. I use this computer for CBT (computer based training) and I can hear the lessons through the mono speaker from inside the case and it's not real loud, but loud enough in a quiet room. The problem I have is when other people in he same small room use nearby comuters for their CBT and everybody can hear everybody else's audio from different lessons. Makes it a bit hard to concentrate. So off to the store we went and got a bunch of USB and regular headphones so that we could do CBT without bothering the neighbors. But when we plug in the headphone what happens is both the internal speaker emits sound as well as the headphones. I would have thought that the internal speaker would know that we plugged a headphone in and would automatically shut off. Is this commonplace or is there something I can configure to get the internal speaker to shut down when I plug a headphone in?

 

[kimsland]

Normally pushing the headphones all the way into the headphone jack will stop any other speaker from emitting sound

I suspect your new Headphones are USB

got a bunch of USB and regular headphones

Do both the regular and USB Headphones do the same thing?

If so, go to Control Panel-->Sounds...-->Audio tab
And confirm your default audio playback, and tick only use preferred devices

You may also have a Sound/Audio start menu (program) group
Just search the list
There can be adjustments made in this too (just to be confusing!)