How You Can Connect a Subwoofer to Your Stereo System

Does it take a genius?

Revel B110 back panel
Revel B110. Brent Butterworth

I was reminded just how complicated it can be to add a subwoofer to a stereo system. I heard the Revel Performa3 speaker system, and it included the B110 subwoofer -- one of the few subs I've seen that has an adjustable, built-in crossover to split out the low frequencies for the sub and filter the deep bass out of the main speakers.

Every A/V receiver on the market has a built-in subwoofer crossover, and most of them let you adjust the crossover point -- i.e., the frequency below which sound is sent to the subwoofer, and above which sound is sent to the main speakers. But I can think of only a couple of stereo receivers, integrated amps and preamps that have a built-in crossover.

Of course, almost every powered subwoofer has a built-in crossover, but most of them only filter the midrange and treble out of the subwoofer. A few filter the bass out of your main speakers, but usually at some fixed frequency.

So what's the problem? Well, the fixed crossover point is typically 80 Hz. That works great with larger main speakers, but it will send too much bass to small speakers, making them distort and possibly become damaged or wear out prematurely. If the crossover point is higher, say 120 Hz, that might save the small speakers but it might leave a "sonic hole" between the sub and the main speakers. Or it might make too much of the voices come out of the subwoofer, which will make everyone start to sound like Barry White.

Worse yet is if the subwoofer has no way to filter low frequencies out of the main speakers -- in which the main speakers will probably distort from too much low bass. Like the guys who crank up their car stereos way too loud.

Through a setup program you can run on a PC, the Revel B110's internal crossover can be set to whatever frequency you need. (You can see the B110's jack panel in the photo above.) The only downside is that you have to run a line-level connection from your preamp to the subwoofer and back to your amp. If you don't have a separate preamp and amp, you'll need a receiver or integrated amp with preamp out/power amp in jacks.

Another catch is the B110 is expensive.

Why, when the audio industry packs laundry lists of advanced digital features into inexpensive receivers like the Sony STR-DH830, can it not build a simple adjustable subwoofer crossover into a stereo preamp or integrated amp or affordable subwoofer? I still can't figure it out.

Are you using a subwoofer with your stereo system? If so, how'd you hook it up? Let us know in the Comments section below.