Installing Headphone Jack?

[Biff Byford]

Today I wired a headphone jack into my cabinet and installed it on the back lip of the control panel. The requirements were:

1) I want to be able to shout "use the headphones!" at the kids and have them be able to accomplish this simply by plugging a pair of phones into a jack
    1a) Plugging the phones into the jack should disable the entire speaker system, including subwoofer
    1b) The act of plugging phones into the jack should fully route the signal to the phones -- no software switching should be necessary
2) I'd like the volume control I mounted on the back of the control panel to affect the headphone volume as well as the speaker volume
3) I'd like the volume to be relatively balanced between the headphones and the speakers, so that a volume setting of '5' results in a nice medium listening level, '10' is crisp and loud without blowing either set of speakers, and so on.

System specs:

* Sony Xplod speaker system, consisting of an amp/subwoofer and two satellite speakers
* The Sony Xplod volume pot is located in the center of the cord running from the PC to the amp/subwoofer. I have mounted this to the back lip of the control panel, right next to the headphone jack I installed
* Radio Shack 5-point, normally closed headphone jack
* Turtle Beach sound card, which seems to be designed to allow you to leave both speakers and headphones plugged in all the time and switch them with a software control -- there doesn't seem to be a way to plug a set of phones in and have it override the speaker output

I wired the phone jack in after the volume control and before the amp/subwoofer (see Diagram B, below), with so-so results. The problem is that the phones are receiving an unamplified signal, so it's awfully quiet. 0-7 on the volume pot are essentially silent, and 8-10 take it up to a medium volume. To raise the software volume control to the point where the signal is reasonably loud for gaming means that later, when you rip the phones out of the jack to use the speakers, the audio is EXTREMELY loud. I know the kids (and me for that matter) are not going to remember to turn the volume pot down halfway when unplugging the headphones.

I considered wiring the volume control after the amp/subwoofer but before the speakers (see Diagram C), which would seem to give better volume (because it's amplified), but it 1) risks blowing the headphones or hurting the listener -- I don't know if it's feeding the phones TOO MUCH volume, and 2) doesn't disable the subwoofer when you plug in the phones, meaning the cabinet continues to 'boom' when you're trying to be quiet.

Finally, I thought about extending the headphone jack from the sound card to the back of the control panel and just using that, but 1) the volume pot would have no effect on the headphone volume, meaning the kids would have to putz around with the software audio control; and 2) you'd have to use software switching to select 'headphone' or 'speakers'.

Is there a way to achieve the result I'm after in the requirements, above? Here's all the things I can think of:

* Discover some sort of nifty 7-point headphone jack, which works exactly like a 5-point jack, with the addition of a pass-through for the subwoofer signal, which simply gets broken when a pair of phones is inserted. This would let me put the phone jack after the amp/subwoofer. I don't know if anything like this exists?
* Wire in a small amplifier (maybe this? http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&product%5Fid=276-1731) so it affects only the headphone volume. Use this to balance the headphone volume with the speaker volume.
* Wire in some sort of volume pot or limiter into the signal headed to the speakers. Use this to balance the headphone volume with the speaker volume. My concern is that you're running the speaker audio through not one, but two volume pots -- worried it'll degrade the signal.

Can you guys offer any ideas to help me achieve what I'm after? Thanks ...