Is it safe to connect two subwoofers in one receiver's subwoofer output?

[edong]

Using a cheap Y-splitter, I already tried it and I like what I heard contrary to what others say that the setup 'might' cancel out each other's bass. I just want to confirm with anyone who has done this already that I will not damage my receiver. Both are active subwoofers (10-inch).

Harman Kardon CP15 HTIB with 100-watt subwoofer. Receiver is 40-watt x 6 channels
Additional subwoofer is 100-watt Velodyne VX-10

[Constant Gardener]

If they are active subwoofers, presumably they have built-in amplifiers and will not overload your receiver. There are two ways to connect them: in-phase and out-of-phase. Get it wrong, and it will sound weird, but it won't hurt anything.

If you're ever playing with multiple unpowered subwoofers, connect them in series. Many receivers have problems with the low-impedance load presented by paralleled speakers.

[johns0]

Check to see if one of the subwoofers have a reverse phase switch in case they are not in phase with each other,you will lose a lot of bass if they run out of phase.

[edong]

Thanks, guys.

The Velodyne has a phase switch and I played with it pressing the button up and down(0-180). I could not tell the difference. The Harman Kardon sub is in the corner behind the TV while the Velodyne is about 5 feet away in the middle of the wall. I believe I can get a more decent bass if the sound is confined in the family room only. But it's adjacent to the kitchen and living room and there are no dividers.

Anyway, I have my eyes set on a Polk Audio 12" 300-watt sub that sells for $179 at Amazon. Then I might upgrade the receiver, too.