How to Connect Two or More Subwoofers in a Home Theater Setup

Getting more bass when you need it

Subwoofers provide that knock-your-socks-off low-frequency impact that any solid home theater system needs. They deliver the high-energy boom of explosions in sci-fi and action movies, and the oomph of bass and kick drums in music.

In surround sound, the subwoofer is assigned to its own channel. It is where the ".1" in "Dolby 5.1" or "7.1" comes from. It is also referred to as the LFE (Low-Frequency Effects) channel.

Just because you have a subwoofer in a home theater setup, doesn't mean you're getting the bass impact you need or want. If you have a room that is large, has acoustical problems, or is irregularly shaped, you may need more than one subwoofer.

Before adding a second subwoofer, perform some basic room placement and bass management setting tasks to see if you are getting the best performance out the subwoofer you already have.

Hooking up More Than One Subwoofer

If you find that you need an additional subwoofer, it may be worth investing in one of the same brand and model. This enables the same low-frequency reproduction profile for your room.

With some added attention, however, you can combine different size subwoofers, such as a larger 12-inch sub with a smaller 10 or 8-inch sub, or subwoofers of different brands and models. Be aware of any differences in power output, size, and frequency range.

Before you buy a secondary subwoofer, make sure it has the connections needed to fit within the three possible setup options listed below.

The Two Subwoofer Solution

Here are the three ways to add two subwoofers in a home theater system:

  • If you have a home theater receiver that only has one subwoofer preamp output (sometimes labeled Pre-Out, Sub Out, LFE, or Subwoofer Out), use an RCA Y-Adapter to send two parallel low-frequency audio signals to two separate subwoofers.
RCA Audio Connection Y-Adapter w/Sub Pre Out
  • If your home theater receiver has two subwoofer outputs, connect one of the outputs to one subwoofer and the second one to the other subwoofer.
Onkyo TX-NR787 Home Theater Receiver – Subwoofer Preamp Outputs
Onkyo
  • If one of your subwoofers has both an RCA Line-in and Line out connection option, you can connect your home theater receiver's subwoofer pre-out to your subwoofer's line in, and then connect the subwoofer's line out to the line-in of a second subwoofer.
Subwoofer with Input and Output Connections

Connecting Three or Four Subwoofers

If you are planning to use three or four subwoofers, the best option is to make sure all the subwoofers have either RCA or LFE line out connections and daisy chain them together using a series of subwoofer cables.

If that is not possible, you may need a home theater receiver that has two subwoofer preamp outputs that you will have to split so that you can feed up to four subwoofers. As you can imagine, that means a lot of cables.

The Wireless Subwoofer Option

One additional subwoofer connection trick is to go wireless. Sunfire, MartinLogan, and a few other manufacturers make wireless subwoofer adapters that are able to transmit subwoofer audio signals to two or four wireless compatible subwoofers, respectively. In this case, stick with Sunfire or MartinLogan subs if possible, but the systems can adapt any subwoofer with RCA line inputs into a wireless sub.

When considering wireless subwoofer kit options other than Sunfire and Velodyne, check the manufacturer's specifications or user guide to make sure the wireless transmitter will work with more than one compatible wireless subwoofer or wireless receiver connected to a wired subwoofer.

Sunfire SDS-WITX and WIRX Wireless Subwoofer Kits
Sunfire

The Bottom Line

Regardless of how many subwoofers you use, you need to find the best spot in the room for each device. This will require a lot listening and moving around, along with precise setting adjustments to get the best result for your listening environment.

The considerations and options discussed above are designed to be used with standard powered subwoofers. If you are using passive subwoofers, you will need an additional separate external amplifier(s) to power each passive subwoofer.

Buying multiple subs and setting them up to get the best result can be an expensive and time-consuming project. If you don't think you are up to the task of doing this yourself, consult a home theater expert to come out and evaluate your room and current setup to see if you really need multiple subs to get the best bass performance.