I have a 1 year old child who is into everything. My wife can't seem to keep the baby away from stuff, so I have to keep things from him.
I have an Outlaw LFM-1 subwoofer, which has both a downfiring driver and ports, making it pretty child proof to begin with (no toy cars stuffed into ports, etc.). But like most subs, it has a removable power cord, just like we all have on our desktop computers. This type of power cord presents a potentially lethal hazard if he were ever to unplug the sub end of the cord and stick it into his mouth while the other end is still plugged in to the outlet.
So I poked around the web until I found a childproof solution, a power cord retainer clip. This is simply a bent-wire clip that attaches to the mounting screws of the power inlet and flips down to retain the power cord. THey are made by Qualtek, and I found them at mouser.com. Maybe you can find them locally, it cost me more in shipping than it did for the clip itself, but still only about $6 total, cheap for childproofing safety.
http://www.qualtekusa.com/catalog/na.../retainer.html
http://www.mouser.com/?Ne=3&handler=...er%7c%7cSField
To install the retainer clip you pull out the existing screws, and replace them with the retainer clip screws. Unfortunately, this means you may have to get to the back of the power panel, as the screws are often held in with nuts that are unsecured and will simply fall off when the screw is removed. So you will have to remove the amp from the sub, but removing the amp is very easy, just remove the screws and gently pry the amp away from the gasket. (at least that's the way it worked on my Outlaw LFM-1, your sub may differ). As with any audio gear, unplug the unit and don't touch any of the circuit boards, capacitors can sometimes retain a charge.
To make sure the child cannot simply flip up the retainer clip and remove the cord, use a plastic cable tie or a strong twist tie to secure the clip to the cord. I also added a large cable tie to the cord itself, which butts up against the inside of the clip and makes the connection very tight, but you can probably get away with just tying the clip to the cable.
Here is a photo of the clip installed. (and my serial number hidden from the Outlaw warranty police)

I have an Outlaw LFM-1 subwoofer, which has both a downfiring driver and ports, making it pretty child proof to begin with (no toy cars stuffed into ports, etc.). But like most subs, it has a removable power cord, just like we all have on our desktop computers. This type of power cord presents a potentially lethal hazard if he were ever to unplug the sub end of the cord and stick it into his mouth while the other end is still plugged in to the outlet.
So I poked around the web until I found a childproof solution, a power cord retainer clip. This is simply a bent-wire clip that attaches to the mounting screws of the power inlet and flips down to retain the power cord. THey are made by Qualtek, and I found them at mouser.com. Maybe you can find them locally, it cost me more in shipping than it did for the clip itself, but still only about $6 total, cheap for childproofing safety.
http://www.qualtekusa.com/catalog/na.../retainer.html
http://www.mouser.com/?Ne=3&handler=...er%7c%7cSField
To install the retainer clip you pull out the existing screws, and replace them with the retainer clip screws. Unfortunately, this means you may have to get to the back of the power panel, as the screws are often held in with nuts that are unsecured and will simply fall off when the screw is removed. So you will have to remove the amp from the sub, but removing the amp is very easy, just remove the screws and gently pry the amp away from the gasket. (at least that's the way it worked on my Outlaw LFM-1, your sub may differ). As with any audio gear, unplug the unit and don't touch any of the circuit boards, capacitors can sometimes retain a charge.
To make sure the child cannot simply flip up the retainer clip and remove the cord, use a plastic cable tie or a strong twist tie to secure the clip to the cord. I also added a large cable tie to the cord itself, which butts up against the inside of the clip and makes the connection very tight, but you can probably get away with just tying the clip to the cable.
Here is a photo of the clip installed. (and my serial number hidden from the Outlaw warranty police)

