JBL JRX118SP and Yamaha DSR118W Powered Subs

Tech Tip: Using a Powered Subwoofer to Augment Your Existing PA

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Expand the power of your current setup without breaking the bank

More and more people are recognizing the benefits of a powered subwoofer, and not just DJs or techno musicians who need to pound out an earth-shaking beat. A subwoofer handles low-end frequencies very well and can offload some of those responsibilities from your PA’s midrange-oriented cabinets. You can buy a three-speaker system that includes a subwoofer (or will accommodate one when the time comes to upgrade), but anyone can use a subwoofer in any system at any time. The trick is in the mixer and the output it has called an aux send or aux bus.

Using your mixer’s aux bus, you can selectively route low-end signals to a dedicated subwoofer, leaving your top boxes, or midrange cabinets, to handle everything else—guitars, vocals, keyboards, and the drum kit minus the kick. For bands that have been getting along with their current PA and are starting to play larger venues, or just realizing they need to kick up the output a notch, investing in a subwoofer will often supply the additional power you need at an economical price. And you don’t have to scrap your current system!

Take the sub way

Here are some of the advantages of bringing a subwoofer into your system:

  • Maximize your total power by directing midrange and treble frequencies to the top boxes and low end to the subwoofers. This means that your system will be louder at the same power output, or that your maximum output power will be the same as a larger system’s.
  • You can be your mid-range or full-range cabinets for best directionality. Because the output of subwoofers is non-directional; you can place them almost anywhere.
  • You can keep stage rumble out of open microphones. This is especially important in outdoor gigs with makeshift stages that often ring and rumble when people walk across them or when vehicles pass by in close proximity. For rumble reduction, you need a high-pass (low-cut) filter that can be found in most crossovers and if you do a lot of outdoor venues and festivals, they’re well worth the money. Even when you can’t always hear it, without a high-pass filter your midrange components are expending energy inefficiently in attempting to reproduce those low-frequency sounds.
  • The two different signal paths can be processed separately. You can obviously apply individual effects and EQ to each channel, but sometimes it’s helpful to process the entire bus, such as when using feedback eliminators, crossovers or delay compensation. In these cases, a separate subwoofer path allows you to modify just the mid/high signal, just the low-end signal, or both. Want more bass? Don’t EQ, just turn up the aux send control!

Adding an aux sub to your system is easy. First, decide on what instruments will go to the subwoofer. That’s usually the kick drum and bass (electric or acoustic), though you could additionally add a floor tom and split keyboard part.

Sub mixing

Once the mics and inputs are taken care of, you have to set up your mixer so that the drum is sent to the subwoofer. This is done using an aux send. The aux send volume control is on the channel strip. The output of the signal is usually a back-panel jack to the right side as you face the mixer. Run a cable of the appropriate length from the aux send output jack to the subwoofer’s input. If you have other instruments to be run through the sub, set the appropriate channel’s aux send level too. It will be grouped with the kick and output to the subwoofer as well. You can now think of the aux send control as a low-end EQ. Turning up the level increases bass response.


Deciding whether a dedicated sub will suit you is easy to test. Borrow a subwoofer and you should hear the results immediately. With your full range speaker cabinets freed up to handle treble, mid and the upper end of the bass range frequencies, the result will likely not be subtle!

Check out the huge range of powered subwoofers available at Musician’s Friend.

Not sure which subwoofer will integrate best with your live sound rig? Call a seasoned Musician’s Friend Gear Head at 877-880-5907 and we’ll help you hone in on what you need.

Just getting started with live sound? Shop smarter with our buying guide How to Choose the Right PA System.

Tags: PA Speakers Speakers PA Systems


# John 2015-07-07 18:56
On a gigrac 1000 where do I connect a sub woofer
# orlando velez 2015-05-25 15:36
saludos.tengo un subwoofer peavy pv 118d activo y una mezcladora behringer xenix x1222 usb.ademas 2 bocinas behringer activas de 1000 watts.donde debo conectar el sub en la mixer.favor explicarme ,porque me tienen confundido otras personas.inclus o me dicen qie conecte en el rca.

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