Bass shakers could very well be one of the best “bang for the buck” additions to any home theater. Yes, a 5.1 home theater audio system gives you the full range of aural dimension but adding these bass shakers, more formally called tactile transducers, can bring a new and exciting dimension of feeling to the sights and sounds of your home theater.

Not only will you see and hear action in whatever you are watching, but you will also feel it! Bass shakers allow you to experience every thump, thrust, and shake...the way bass sound was originally intended.

What Is a Bass Shaker?

As already mentioned, a bass shaker is a tactile transducer. Tactile refers to touch, and a transducer is simply a device that converts energy of one form (sound) into another (motion). So, a tactile transducer converts audio into something that you not only hear, but also feel.

In the case of a bass shaker, I’m talking about an electromechanical device that shakes (yes, it literally shakes). It’s similar to a loudspeaker woofer driver, but without the cone. The bass shaker is connected to an audio amplifier and mounted to a solid object such as your sofa, loveseat, wall, or even floor (see Figure 5-2). When the low-frequency signals from your home theater are fed to it, the vibration is transmitted to the object it’s mounted to, hence the tactile sensation.

Buying a Shaker

Several manufacturers make bass shakers. The following list details the most popular brands:

• Aura Systems (http://www.sensaphonics.com/aura.html)
• RBH Sound (http://www.rbhsound.com)
• Rolen Star (http://www.invisiblestereo.com)
• Buttkicker (http://www.thebuttkicker.com/)

The Auras are the least expensive (and a great value); the Buttkickers usually are rated as the best, but also are the most expensive.

Sample Installation: Aura Systems

The Aura Systems bass shakers look like Figure 5-3.

When you get your kit, you’ll have the parts shown in Figure 5-4.

Installation is pretty straightforward:

1. Turn your sofa or loveseat upside down. Carefully remove the fabric cover on the back or bottom. Find two places on the sofa frame that allow for some resonance and mounting of the shakers (D).

2. Mount the shakers (D) from the inside of the frame, as shown in Figure 5-5. Use the provided Phillips screws (H).

3. Attach the RCA cable lugs (C) to the shakers (D) and lead the other end of the cables out of the back of the couch before reclosing the cover fabric with new staples (see Figure 5-6).

4. Plug the RCA connector (C) into the OUT jack of the amplifier (A) and the transformer (B) connector into the POWER PACK jack of the amplifier (A), as shown in Figure 5-6.

5. Plug one end of the first 3.5mm mini cord (E) into the SOURCE jack of the amplifier (A) and the opposite end into the splitter jack (F), which you then must into the second amplifier (A). Attach the second mini cord (E) to the music source and to the splitter (F).

6. Plug the amplifier transformer (B) into the nearest AC power outlet.

7. Turn on the amplifier (A) by setting the VOLUME and FILTER levels to your desired intensity of bass vibrations. Level 5 is suggested. For bass only, set the filter level to 10. For optimum performance and volume, the green LED should light (signal input indicator), with occasional flashes of the red LED (clipping indicator).

Figure 5-7 shows a single-sofa installation.

Figure 5-8 shows how to set up an installation with a sofa and two loveseats; this is a bit more complicated, but really gives a nice group effect.

Filtering

Because most transducers cut off around 50 Hz, they can produce a buzzing effect at higher frequencies. This can be annoying: you’re watching The Lord of the Rings, and it sounds like there are flies behind your seat. There are a couple of ways to eliminate, or at least reduce, this buzz. The first is to source the signal for the shakers from a subwoofer output via the receiver’s tape or headphone output jack. Because you’re pulling from a sub signal, you’re not going to get any high frequencies. The drawback here is that many receivers won’t provide an output of this type; the only headphone out is the general output, which still transmits high frequencies along with the lows.

The other option is to make use of an inline low-pass filter, which blocks the higher frequencies. You can get a 50-Hz low-pass filter at Parts Express (http://www.partsexpress.com) (part #266-250) for about $25 or at Accessories4less (http://www.Accessories4less.com) for only $14.99. Both are great buys and are perfect for this purpose.