Product Review

Clark Synthesis Platinum TST429 Tactile Transducer (Floor-Shaker)

November, 2003

John E. Johnson, Jr.



● Tactile Frequency Range: 5 Hz  - 800 Hz
● Power Handling: 135 Watts Continuous, 400 Watts Peak
● Magnet: 20 Oz 42 MGO Neodymium
● Force: 932 lb-ft Peak
● Impedance: 4 Ohms
● Size: 8" Diameter x 2.25" Thick
● Weight: 6 Pounds
● MSRP: $349.99 USA

Clark Synthesis


We at Secrets have always enjoyed the wide array of components that make home theater so much fun. This includes shakers such as the Clark Synthesis Tactile Transducer, with its Tactile Sound.

Recently, Clark Synthesis reduced their prices by almost half. That is a very significant thing for consumers in this tight economy. So, I decided to review their top of the line transducer, the Platinum TST429.

The Design

Some people think the Clark units are similar to a speaker cone, but just attached to the floor or chair. That is not the case. It is a diaphragm that sits inside an oval enclosure, along with the magnet. In the case of the 429, the magnet is huge - 20 Oz -  and is of the very powerful material, neodymium.

In fact, it is so powerful, I had to degauss my computer monitor after mistakenly setting the 429 a couple of feet away on my desk while I was writing this review.

The underside of the 429 has a large bolt for attaching it to whatever structure you want to shake. The parts for attaching it are supplied with the unit, but it can also be purchased without the mounting hardware.

It is only 8" in diameter and a little more than 2" thick. This means it will fit just about anywhere you need it to go. And, as you will see below, I ended up putting it in a very unusual place to give me the most efficient shaking.

In Use

The 429, like their other models, is designed to be attached to the underside of chairs, couches, or a platform sitting on the floor.

I experimented with several configurations. I have a LazyBoy recliner which has tight spaces underneath due to the recliner mechanism. So, I constructed a bracket on which I mounted the Clark unit (photo shown below). I then attached a set of speaker binding posts to the short cable that is on the Clark, and attached speaker cable from the power amplifier to the binding posts. This way, I could disconnect the unit when I was not using it.

For these tests, I did not have the chair on the platform that I normally use with my existing ButtKicker, as vibrations from one unit would cause sympathetic vibrations in the other, and would thus invalidate any comparisons between these two products.

I utilized several power amplifiers, including a Cinepro 3k6 SE Gold, rated at 700 watts into 4 Ohms on each of six channels. (I only used one channel for the test.) The 429 is rated at 135 watts continuous, but I wanted to make sure that any anomalies were not due to the amplifier.

The bracket worked OK, serving as a lever for the 429 to rock the chair, which then pushed the front of the chair up, or when moving in the other direction, lifted the rear of the chair. However, it transferred too much of the power to the floor. If I mounted it directly to the chair or couch, it would still deliver too much (for me) energy to the solid structure that I was sitting on, and not enough to my body.

So, I tried putting it under the seat cushion, tucking it down the slot immediately behind the rear end of the cushion. This way, most of the energy went to me instead of the chair, and this gave me the best sensory experience. It also reduced the amount of amplifier power that was required to drive it. You just want to make sure you don't pinch the cable where it enters the unit, so tuck it carefully.

I tested the frequency range down to 15 Hz, with sine waves, and was surprised to find that even at full power, it did not make any noise at the lowest frequencies, indicating to me that it was essentially free of harmonic distortion. When I input a low frequency sine wave at more than 200 watts or so, the unit shut down for a couple of moments, even though it did not feel warm to the touch. In fact, it never got warm at all. I was a little disappointed at that, since I have some arthritis in my hip and would have liked to have something warm to sit on (:->)

Using the under-the-cushion method, I played all my favorite tests scenes from action movies I've collected over the years, including Schwarzenegger, Stallone, and Harrison Ford. Turns out the heat wasn't necessary, as my tail got a full massage with the 429 underneath.

Even Cookie liked it! This also gives you a size perspective on the TST429.

I could hear upper frequencies, such as music and voices, although I didn't really feel them. It produced an interesting effect. Perhaps more subconscious than conscious at those frequencies. If you use a subwoofer output jack and bass management, you can set the Clark to only receive low frequencies, just like your subwoofer. One neat thing is that you can use the 429 late at night tucked under your seat cushion, instead of a subwoofer, and get the full effect of low frequencies. It would also work great in an apartment, where the neighbors don't particularly like to have their walls serving as a sounding board to your low frequencies when you watch movies. Lastly, if you watch movies with your spouse on the couch, and she does not like tactile sensations from movies, if you put it under your seat cushion, you will pretty much get the brunt of the force, while the other end of the couch will not vibrate as much.

Any amplifier rated at least 200 watts into 4 Ohms should work, but if you like to have material lower than 20 Hz going to this 4 Ohm load, you should probably have a bit more power as reserve, say 250 to 300 watts rated into 4 Ohms. The recently reviewed Audio Source 250 watt (into 4 Ohms) Amp 5.3 monoblock is an example. Don't use an old mass market receiver, as they tend not to do very well at 4 Ohms and high power.


At $350, and because it can be placed in a different location than other shakers, the Clark Synthesis Platinum TST429 is a very useful product. Maybe not for Jane Austen movies, but certainly for action films. Its shape lets me put it in my chair only when I want to use it, instead of having to permanently mount it somewhere.


- John E. Johnson, Jr. -

Copyright 2003 Secrets of Home Theater & High Fidelity

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