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Connecting a Motion Actuator to your System

by August 31, 2004



Q: I am using a Clark Tactile Transducer TST229 100 watts continuous and 350 peak @ 4 ohms. I am trying to feed it an LFE signal from my Integra DTR 7.1 that is split at the amp (One to the sub (Klipch 15") the other goes to the transducer via an Adcom 555 (600wats Bridged). I do not set the sub output on the Integra to more than +1 sometimes less depending on the type of music and or soundtrack I am listening to.

If I use a stereo output it works fine but as soon as I try a theater setting Dolby/DTS it keeps blowing the internal fuses in the Adcom.

The instructions from Clark say use the front speaker pre out but as the transducer is rather slow and the rest of my system is faster it distorts the sound or I get an echo but no blown fuses.

I spoke to Adcom and Clark both said there should not be a problem using the LFE out to the transducer. Any ideas?


Audioholics: Using the LFE out from the Pre Amp or Receiver is the preferred way of connecting any motion actuator.

Here is the correct way to set up an actuator for Home Theater Applications assuming you have the Actuator bolted to a chair:

  • Split the signal at the LFE output of your Pre/Pro or receiver with a "Y" connector one to the subwoofer one to the amp that drives the actuator
  • Turn the gain control or volume knob on the subwoofer's amp to zero Turn on internal test tone of receiver or Pre/Pro or use external test tones like Avia or Video Essentials and adjust volume to + 75dB level matching all speakers
  • Sit in chair and adjust subwoofer level output on the receiver or Pre/Pro until you start to feel motion (a mellow vibration is all you want you don't want hard pounding or shaking) Actuators are meant to add a subtle effect to the system not be the star of the show
  • Once you get the desired level for the actuator, move on to the subwoofer with the test tone still playing though the LFE channel and the system's volume set to +75db. Adjust the volume knob on the back of the subwoofer until your meter reads +75-+80 dB

Your system is now calibrated correctly with the motion actuator installed. Keep in mind you don't want any frequencies above 80Hz sent to the Actuator.

The problem with the Amp shutting down can be caused by Input overload at the Amplifier, Impedance too low at the speaker terminals at the amp, faulty wiring, or a short to ground.

Check the wiring carefully make sure it is in-phase and there are no strands on the speaker wire that go to the actuator sticking out touching each other or touching any ground.

The Impedance of the actuator may be too low for the Adcom when running in Bridge mode the adcom minimum Impedance should be about 6-8 ohms when running in bridge mono. I don't know why Adcom would tell you that running a 4 Ohm load in bridge mono is ok. Try running the actuator off the left or right channel with the Adcom in stereo mode. The actuator does not need that much power when calibrated correctly.

Enjoy the movies!


About the author:

RLA Home Theater and Hi-Fi began as a hobby and has expanded into a business. Ray took his love of music and movies and turned it into his personal business to bring movie theater sound and quality into the homes of his customers. Ray brought great knowledge and expertise to us from a custom installer/integrator's perspective.

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