Bass shakers, Buttkickers, Tactile Transducers
… now you can feel the shake!
Tactile Sound in Home Theater

A few bass shakers or buttkickers can help transform your home theater experience from ordinary to more than great!

Home theater is all about being immersed into the movie action. A proper setting of the movie image and sound is essential for an enjoyable home theater experience. 

Add the accurate sensation of tactile sound using a few bass shakers or any other appropriate tactile transducer, and your home entertainment will take a totally new dimension! 

Tactile sound makes for a more complete experience when watching a movie. You get easier immersed into every movie action by combining the sense of touch with your sight and hearing. It lets you feel the jolt as the Titanic hits the iceberg, or the ground shaking as the creatures in Jurassic Park walk by.

Perceiving Sound Energy

Airborne vibration is not the only way sound reaches our ears. Sound energy is also perceived through various pathways within our body:

• Muscle and deep tissue

• Sense of touch (skin sensation)

• Bone conduction - in particular the skull.

All these fall within the category of 'Tactile Sound'. Expressed differently, tactile sound is 'felt sound'. It is the low frequency feeling one gets when a large magnitude event takes place nearby. Most humans can feel sounds in the range 10Hz to 800Hz. 

Tactile Transducers in Home Entertainment

A trend that is catching up with home theater enthusiasts is the mounting of tactile sound transducers under home theater seats and couches. This is typical with low power transducers such as the range of Aura Bass Shakers. 

Some theater seats come also in a tactile-ready version; this means that they come pre-equipped with the necessary bass shaker hardware - just connect to your tactile amplifier and it's all done!

It is also possible to mount tactile transducers on wooden floor support structures such as home theater risers or floorboards. The Aura bass shakers mentioned earlier on are not really suitable for this purpose. More powerful transducers (e.g. the Buttkicker 2 or the Clark Synthesis tactile transducer) are required to move these heavier structures. 

Tactile Transducers Basics 

The majority of tactile transducers are simple low frequency electromechanical devices. Particularly, this is the case with Aura bass shakers in view of their extremely limited frequency response. 

Tactile transducers are designed to attach directly to large surfaces such as home theater seats, couches, and flooring. 

Once activated, these will drive the supporting surface structure into vibrations over the tactile range. The surface now acts as the diaphragm, somewhat similar to the cone in an ordinary speaker.

Some tactile transducers will even cover the lower end of the audio spectrum. For example, Buttkickers have an effective operating frequency range of up to 200Hz. On the other hand, Clark Synthesis transducers can reach 2000Hz in the tactile range even though the human tactile response falls off at around 800Hz. 

Tactile transducers help the viewer feel rather than hear the low-end frequencies found in movies and music. They are calibrated specifically to produce an accurate tactile sense, otherwise missing from music and movie sound tracks.

When attached to a resonant surface, they will effectively increase the portion of tactile sound as 'felt' by the viewer in comparison to that produced by sub woofers and ordinary speakers. Consequently, the viewer will be able to feel the natural percussive impact of sounds when watching a movie or listening to music.

Unlike a sub woofer and normal speakers, tactile transducers do not make the room overly load. The greater perceived loudness of a tactile sound transducer equipped system allows listening at lower sound volumes. 

This does not mean that tactile transducers are there to replace sub woofers and speakers. This is not the case; rather their presence should be to complement the sub woofer and speakers performance. 

The optimum sound level for a sub-woofer is when you can just feel rather than hear the bass. Through the use of tactile transducers, this is even easier to achieve while maintaining the sub woofer sound at a more natural level. In a similar manner, the best setting for the tactile transducer is when you can just feel the seat shaking. Do not overdo it. The illusion that the percussive impact of sound is a natural extension of the movie soundtrack should remain.

In addition, use of specially designed rubber mounts on home theater seats and flooring equipped with tactile transducers, will help keep effects and vibration isolated from other things in the room. In other words, in a proper installation, low frequency vibrations will not be carried throughout the entire house. 

Installation of Tactile Transducers

The key to a successful installation of bass shakers and tactile transducers on home theater seats, is to ensure that they are secure enough to shake the entire seat sub-frame. Choose a location that is easily accessible. The selected supporting member should be such as to conduct the low frequency vibrations from one piece of the seat sub-frame to another. A flat cross-member connecting the main frame structure is ideal for this purpose. 

Kinetic Isolators: Seats or supporting structures equipped with tactile transducers should be isolated from the rest of the room through the use of kinetic control isolators. These are specially designed rubber mounts designed to isolate the vibrating structure from its surroundings.

This is essential for a full low frequency response of your home theater seats.  Most seats and couches will not provide adequate low frequency response when resting against an unmoving floor surface.  The solution is to use of some kind of a suitable rubber cushion to serve as a kinetic isolator between your home theater seats and a fixed floor. 

Similarly, kinetic isolators are also required if the transducers are mounted on a floating floor structure. Ensure to mount enough isolators to take the full load. In other words, ensure that the aggregated load bearing capacity of the rubber isolators, is sufficient to take the full load of your home theater seats, people, and platform/riser if any.

Mounting orientation: Transducers should be mounted in the vertical orientation over a horizontal supporting structure.  Mounting the tactile transducer otherwise will lead to distortion and increased wear on the transducer moving parts.

Wiring & Audio Connections: Our recommendation is to drive these transducers using a dedicated amplifier. Some home theater receivers incorporate a tactile output; if available, use this signal to drive your tactile amplifier.

Most manufacturers instructions suggest to run your tactile transducers off your main left and right preamp outputs via a dedicated amplifier. This is not always practical as most receivers have only a fixed level line-output. In addition, the extended frequency response of some transducers may lead to vibrations not normally felt in real life - especially when listening to music. 

The best approach is to drive your tactile amplifier using the low frequency end (SUB-WOOFER/LFE) signal. This would give a far better response to the special sound effects and other low frequency signals normally associated with film soundtracks.

Which tactile transducer - Aura Bass Shakers, Buttkickers, or Clark Synthesis tactile transducers?

Major tactile transducer manufacturers include:

• Aura Systems Inc. with their bass shakers range of products

• Guitammer Company Inc., manufactures of the Buttkicker devices

• Clark Synthesis.

Aura Bass shakers:  These are in reality simple low power bass shakers with a limited frequency response of 20Hz to 80Hz. They do not have the finesse in their response found on Buttkickers or Clark Synthesis transducers. For best performance, these devices should be driven via the SUB/LFE (subwoofer or Low frequency effects) output. 

Power rating is 25W for the standard shaker, 50W for the Pro version. Depending on your application, you may have to use a number of bass shakers (in view of their low power rating), to achieve the desired result.

Though the Aura bass shakers do not have the power of the Buttkicker or Clark Synthesis Transducers, yet they can produce several times the sensory bass effect of a sub woofer at a reasonable cost.

Buttkickers: If you want something that can kick you hard during action movies, then the Buttkicker is a good choice. These devices respond with great fidelity to the low frequency content (5Hz to 200Hz) in a movie soundtrack. 

Buttkickers are high power devices - rated at 1500W max. They require a minimum of 400W driving amplifier - 1000W is even better. This explains the impressive shaking force produced by this device once in action.

Clark Synthesis Tactile Transducers: Clark Synthesis is our preferred solution. Buttkickers and the Aura bass shakers are more suited for watching movies and are best switched off when listening to music. On the other hand, the Cark Synthesis tactile transducer is more of a capable all-rounder.

In comparison to the Buttkicker, the Clark Synthesis tactile transducer is rated only at 200W RMS. Surprisingly enough, the Clark Synthesis still has enough capacity to deliver a good kick during action movies. Further more, its response characteristic makes it suitable for music listening as well.

Most bass shakers are designed to cover part of the low frequency tactile range only. In contrast, the Clark's tactile transducers can produce vibrations over the full range of tactile and audible frequencies (5Hz to 20KHz). In addition, these can also handle inaudible frequencies up to 200Khz. 

For this reason, its applications go well beyond home entertainment. These include military applications in simulators and submarines. Other applications include swimming pool installations for synchronized-swimming team training, and also applications in active noise cancellation systems.

Additional Information links:

Access the respective manufacturer sites for additional information on available products:

• Aura Systems Inc.

• Guitammer Company Inc.

• Clark Synthesis

 

An interesting transducer directory site is also available here:

• Transducer Resources with lots of information about various types of transducers.
  http://www.transducerdirectory.info