Output sound through two devices

Recently I got a new pair of usb headphones thinking I would be able to use them like normal headphones i.e. the same sound through my speakers and the headphones. However, the headphones have their own device driver so its one or the other. Does anyone kno of a way to use them simultaneously?

I've tried searching for a virtual sound card that would allow it but havent been able to find one. I tried using VAC but couldnt figure out how to make it output to two devices, so it seemed like it was for something else.

I tried audio repeater but the sound on the USB headphones was very low, hidden by hiss.

Virtual Audio Cable?

Check that your input device in Audio Repeater is "Virtual Cable 1" and that the output is the device you wish to have the sound sent. I was able to use "Virtual Cable 1" as the input for both my USB headset and my sound card without problem. I had the same hiss until I realize I had the wrong input device. I had to open an instance of Audio Repeater for each sound device. Also remember to set your programs to output to "Virtual Cable 1".

thanks ive tried it again and it works perfectly, initially was trying to just use audiorepeater to pass the primary to the USB headphones but this caused a lot of hiss but with VAC it sounds great.. now once i figure out a way to automate the whole process ill be happy