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

Getting More Bass When You Need It

Subwoofers provide the knock-your-socks-off low-frequency effects impact in a home theater system for all those sci-fi and action movies, as well as the low frequencies from acoustic and electric bass, and even kettle drums, from those jazz, rock, and symphonic albums.

In surround sound, the subwoofer is assigned to its own dedicated channel (that is where the .1 comes from in 5.1, 7.1, etc...). 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.

SVS SV-4000 Dual Subwoofer Option
 

Hooking Up More Than One Subwoofer

After working with the subwoofer and room you have, if you find that you need, or want, more than one subwoofer, the main thing to consider is that it is best that all the subwoofers are the same brand and model. This enables the same low-frequency reproduction profile for your room.

However, with some added attention, 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. In these cases, in addition to the differing size of the subwoofers, as well as their frequency ranges, you have to be aware of any differences in power output.

Before you buy your subwoofers (or combine ones you may already have), make sure they provide the connections that fit within the three possible setup options 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), just use an RCA Y-Adapter and use it 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 another 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 line 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 more cables.

The Wireless Subwoofer Option

One additional subwoofer connection trick you can take advantage of (and isn't that expensive) is to go wireless.

Sunfire, MartinLogan, and other select 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

No matter if you use one or more subwoofers to get the best bass coverage for your room, regardless of the brand, model, size, and connection option(s), you need to find the best spot in the room for each one that provides the best performance for each one and all of them together. To accomplish this be prepared to do a lot listening and moving, along with making setting adjustments to get the best result for your room and listening preference.

The considerations and options discussed above are designed to be used with standard powered subwoofers, if you are using passive subwoofers, in addition to the 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 dealer/installer to come out an evaluate your room and current setup to see if you really need multiple subs to get the best bass performance.