The first thing you should do after buying a passive 12-inch subwoofer (or any other passive model) is how to power it since it just can’t function without an external power source. So, how to power a passive subwoofer? The solution is to connect it to an amplifying device. This can be an amplifier or a receiver. The easy-to-follow instructions for powering your inactive sub can be found below. However, don’t neglect to read the user manual that came with your sub before doing anything: its specifications should be compliant with those of the receiver or amp you want to connect it to. Otherwise, you risk blowing your amplifier/receiver.
How to power a passive sub via an amplifier
Step #1. Make sure that the amplifier has enough power to let your sub reproduce the low-frequency sound.
Step #2. You will need RCA cables. They should be color-coded to facilitate the connection process. So, see if you have any (they should come in a kit with your sub).
Step #3. Turn off the amp before making any connections.
Step #4. Locate the jacks on the amp labeled LFE or Subwoofer out. Connect the sub’s input jacks and one of these connectors using the RCA cables.
How to power a passive sub via a receiver
When connecting a passive subwoofer to a receiver, you have two different connectivity options: pre-out and speaker connectors. The former can be used if you already have connected your sub to an amplifier. This way, you can connect it just as you connect the powered subwoofer.
In the second case, you will have to treat your subwoofer like a set of speakers since you will be using speaker connectors. If your sub has a power cord, you can use an RCA subwoofer output on your receiver. Before that, you need to go to your receiver’s on-screen menu and make such changes:
- choose small front speakers
- switch subwoofer to “yes”
If the sub comes without a power cord, you can connect it to the front L/R speaker connectors on the receiver. In the receiver’s on-screen menu, make such changes:
- choose large front speakers
- switch subwoofer to “no”
If you are not going to connect your passive sub to an external amplifier, you should be ready that your receiver may not deliver enough power to let your sub reproduce the optimal sound.
So, how to power a passive subwoofer? Basically, you can either turn it into an active sub with the help of an amplifier or draw power to it using RCA subwoofer output or speaker connectors on your receiver. Of course, the first way is the best since it will allow you to use your passive sub just as you use an active one.