koverhbarc wrote:I'd been wondering about doing this, but I don't want any possibility of ruining the board; I assume desoldering the buzzer is required first.
Since you've done it, does there need to be a DC path between + and -, or does there not? And I'm a bit surprised you can drive a 4 ohm speaker, I assumed it would be 600. I have many 8 ohm 'hobbyist' speakers, and one at least is quite loud enough - maybe too loud, since PC speaker games had no volume control ability nor does the speaker itself - although I suppose you could add one in the path if you're going to be changing it anyway!
Apparently it's not that difficult... Any crimped connector wires will do. First cut one side of the connectors off and use a wire clipper to expose the copper wires inside for soldering it to the + and - pads of the speaker, and place the connectors of the other side into a 4-pin header and connect it to the motherboard's SPEAKER pins just like the way you would with a buzzer (you can simply reuse the 4-pin header that comes with your buzzer for this, if you're already using an external buzzer that's plugged into the SPEAKER pins). On the other hand, if you have access to hot glues or insulation tapes it's better to put some on top of the soldered pads to avoid potential issues.
Also, no need to desolder the onboard buzzer anyway, as should the SPEAKER pins are connected to an external buzzer/speaker the on-board buzzer will be bypassed.
Besides, almost all motherboards can drive 4-ohm speakers from the SPEAKER pins as far as I can tell, just that the volume varies depending on many conditions, like power supply and the positioning of the speaker. Be noted that you'll often have to find a suitable place to support the speaker as they can be heavy and not suited to be placed too close to the motherboard. For that reason you may need to use relatively longer wires so you can have a good room for positioning it.