How do I add a compact subwoofer to my audio system?

In order to reproduce low bass notes, subwoofer enclosures (the box) are often three cubic feet or more in size. By compact we mean an enclosure size of one cubic foot or smaller.

We know of two ways to do this: MaxxBass® and the Dual voice coil (DualVC) system designed by Dan Ferguson.
(MaxxBass is registered trademark of Waves, Ltd.)


MaxxBass® is a psychoacoustical method of producing sub bass. That is, the low notes you hear don't exist except in your perception so a small 'speaker can be used. This may seem like "magic" but it has been known about for hundreds of years. Waves, Ltd. has patented a method to make it happen and supplies a small part that can be built into audio systems. You can find more information on the Waves web site at

We have a MaxxBass® system, our model 907. Please click here to take a look. I also wrote an article on MaxxBass® that was published in the November 2004 issue of AudioXpress Magazine. You can download a copy of that article (as an Adobe pdf file) by clicking here.

Currently, the model 907 is just the MaxxBass® processor and you will also need a one-channel (mono) power amplifier and a loudspeaker. We developed our model 9071 'speaker just for MaxxBass®. Shown below, it measures just 12 inches high, 8.5 inches wide and 9.25 inches deep which is just a litle over one-half cubic foot (0.55 cubic foot to be exact). For the current price, please see our price list.

Dual Voice Coil System

Daniel L. Ferguson wrote an article: "12 inch Dual Voice Coil Subwoofer System" that was published in the September 2004 issue of AudioXpress Magazine. This is one of the most innovative designs that I've seen during my career in audio electronics. I immediately built one for evaluation. It performed excellently so I built another enclosure for an 8 inch dual voice coil 'speaker that measures 12 by 12 by 12 inches for a size of one cubic foot. It too performed excellently. This enclosure is shown below.

The 8 inch 'speaker in its one cubic foot box will reproduce bass notes down to 30 Hz. If you are interested in the technical details, you can download a copy of my extensive notes and measurements on this system at

We are currently working on building a easily-useable, home version of this system, our model 912. It will include the processor and a power amplifier in a single box and the 8 inch 'speaker shown above. All you will need to do is to connect it to your audio system as shown in the diagram below. Position the 'speaker box between your stereo speakers, more-or-less in the center (it's not that critical) and about the same distance from your listening position as your stereo speakers.

When the model 912 is available, we will announce it in our "What's New" page. However, you can come and listen now -- just phone or email for an appointment.

Connect the components as shown in the diagram using stereo RCA cables to interconnect the preamplifier outputs to the model 912 stereo inputs using cables that are not overly long. That is, its neater to use a 3 foot cable when a 3 foot cable is long enough. (Red connectors are for the "right" channel and black or white connectors are for the "left" side.) You will notice there are two cables to be connected to each of the preamplifier stereo outputs. How do you do this? Probably the easiest way is to use a pair of "yadapter cables" as shown in the photo below. These have a male RCA connector on one end that plugs into the preamp out connector. Each of the two short cables has a female RCA connector that connects to your normal RCA interconnecting cable. Most audio equipment shops should stock these but if you have trouble finding them, they are readily (and inexpensively) available from as catalog number 240-127 or 181-692.

Then connect the power amplifier output connector to the sub bass speaker using a speaker cable. I agree with others in the industry who believe speaker cables should be at least eight feet long for best sound quality. Technically, this does not make good sense but I agree that it sounds better.

TDL® Technology, Inc.

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