The Seismic Sofa Project

I have been using tactile transducers for over 10 years.

My first installation was an array of 8 RBH FX-80's. (ultra high performance Aura units)
I used these for about a year and replaced the array with a pair of Clark Synthesis TST 329 Gold models and then stepped up to their TST 429 Platinums. I used these for about a year as well.
For a brief period I installed four Crowsen Tech TES-100's when they were released.

When I moved on to the ButtKicker I started out with a pair of original models. I drove each with a Carvin DCM-1000 stereo amplifier bridged mono. (1000 w @ 4 ohms) This was well before the release of the ButtKicker amplifier. Shortly after I purchased another pair of ButtKicker original models. The ButtKicker II/ButtKicker LFE model had not made it's debut yet.

I couldn't tolerate the fan noise of the Carvin professional amplifiers so I picked up a pair of also professional but convection cooled Crown K2 stereo amplifiers (800 W @ 4 ohms per ch) and have been using them to drive my BK's ever since.

At one point I have driven a single Buttkicker with a bridged K2 (2500 W bridge-mono @ 4 ohms)
They always stayed cool to the touch and never bottomed out. I have also used an Audio Control Phase Coupled Activator subharmonic synthesizer on their signal for a couple of years. This was before the release of movie material that contained more low frequency information in the sound track.

I started using the ButtKickers in conjunction with a pair of Velodyne HGS 18 subwoofers. I have also used them paired with duel 200 lb 18" Epik Conquest models.

Currently I am using them with duel Velodyne DD-18 series and duel HGS-18 subwoofers in my 13' 10" W x 21' 7" L x 8' 6" T (2537.84 cf) dedicated home theater room.

What ever subwoofers I use in my system I have never stopped using tactile transducers along with them. They add an extra dimension to the movie experience that subwoofers can never accomplish. I have tested the original Buttkicker with a 10 Hz sine wave and they produced it with authority. I did not have anything lower for testing. My favorite movie material test and demonstration is WOTW pod emerging from underneath the ground scene.

Even though I am using an Integra DHC-9.9 processor I still use my Parasound C2 processor in my system. I utilize it's programmable channels on the ButtKickers signal. I have them lowpassed at 20 Hz. I blend them with the subwoofers output. They hide in the system and extend the subsonics when necessary. If the tactile transducers are driven with to much output it is a distraction. After all it's not a carnival ride.

In my opinion high performance tactile transducers are an essential component of a home theaters sound.

I don't have experience with the ButtKicker LFE yet. I have had one for over six months and haven't hooked it up yet to test.
I have been told they are more efficient and just as powerful.

Specifications:

ButtKicker I
Size: 7.13" H x 7.5" W
Weight: 18 lbs

ButtKicker II LFE
Size: 5.375" H x 5.5" W
Weight: 11 lbs

John

My temporary uncovered platform





Comparison of ButtKicker I/ Buttkicker II LFE

I can't remember what I used to drive them. It was a few years ago. They would not be my choice for a HT application. They do not go low enough. I would recommend the ButtKicker over the Clark.

John

I do the exact same thing, except I'm rolling them off even lower. When I got a receiver with Audyssey, that freed up both channels of my BFD for tactile use. One channel is used for the Buttkickers on the floor joists, and the other for the Auras in my furniture. Since my floor acts like a giant infinite baffle sub, I filter it's output to almost nothing above 12hz to keep it from mucking up the sound from my sub (see this thread). The Auras are fine up into the 20s though, as they don't really produce anything audible. But the Auras require a completely different EQ curve... they have a huge peak @ 40hz, as opposed to 9hz for the Buttkickers.

What do you guys use as a low pass filter to keep anything above 20 hz from getting to the transducer. I was looking at FMOD's but the lowest low pass on I found was 50 hz.

By the way, is there anything special about using dedicated subwoofer amp?

I have an extra channel on one of the Audiosource Amp 300's that I am using to drive my system as well as an additional stereo amp that I could use to drive a transducer or two. If I were send a low pass signal to the amp, am I risking damage by driving tactile transducers? As long as I limit the load to the specifications of the amp will I be fine?

I use them. I ended up making my own. They are black rubber, and it hasn't rubbed off on the carpet (and my carpet is very light in color). If your transducers are buttkickers, they do make some kits where the buttkicker mounts to a plate, and you just set one of the feet of the sofa on the plate, while isolators get mounted to the remaining feet. I have some of these kits that came with some of the buttkickers I bought that I was going to put on ebay. If you're interested, let me know. But I can't vouch for them, as I've never tried them. I used Auras in my furniture, and mounted those inside the furniture.


I use my BFD. I agree, 50hz isn't low enough. The other problem with the FMODs is they need to be placed upstream of your amp. If you filter out content above 50hz, you run the risk of the power-on circuit of your amp only being triggered during bassy scenes, and missing part of the initial impulse due to the power on delay.


As long as you limit the load to the amp's specs, you should be ok. But if you're talking about buttkickers, they do need a lot of power.

Forgive my ignorance. What is a BFD?

An FMOD is a line level passive crossover.

http://www.parts-express.com/pe/show...number=266-250

And the BFD is the Behringer Feedback Destroyer 1124P. It's intended as a tool in commercial venues to reduce feedback in live performances, but it can also be used as an inexpensive parametric EQ. Many in these forums use them to EQ their sub.

Thanks. That is perfect and not that expensive.

Yes, a sub-harmonic synthesizer is certainly one way to get more infrasonic output. I haven't tried one, but I would expect the results to vary with the content, and also by personal taste. IDEALLY, movie sound mixers would include infrasonic content when things should shake, and for the most part, Iv'e found that to be true. The problem with a sub-harmonic synthesizer, IMO, is that it could be introducing shaking when things really shouldn't be shaking. It's essentially making up for the lack of infrasonic content. I would fear the result to be something like Batman Begins or Pulse... those are two movies that I personally have found that the shakers seem "gimmicky", because those movies have some very low frequency content at times when it just doesn't seem like things should be shaking. In Batman, there is a lot of very low frequency content when Scarecrow speaks. To me, I just don't think the earth should be shaking when someone talks.

But for the most part, I'd say most current movies, or at least most current "action" type movies, have good, relevant infrasonic content. For the most part, my room shakes when it seems like things should shake. I personally would rather restrict the tactile feedback to those moments when infrasonics are encoded in the soundtrack. In fact, I've gone to a lot of trouble to keep them from being activated by higher frequencies. But shakers seem to be subject to a lot of personal preference. Some people don't like them at all.

One point when doing this... if your feet are on the floor the effect isn't that great. Your body is shaking but the floor isn't. It works best with either reclining seats or with a small platform under the sofa to get the full shake effect.

Or just shake the entire floor.

I have dual Buttkickers mounted in my floor joists and it shakes the entire room. These came with the Mounting Accessory Kit. You can have both kits if you want to stop by and pick them up sometime.

Sorry, I only have experience with the Buttkickers and Auras. You may also want to check in the shaker sticky.

I tried all 3 (Clarks, Auraus, and Buttkickers) and I still have the Buttkickers. Just did a better job to me.

I think I am going to give the clark transducers a try. I don't know if my circuit would handle another 400 watts to power a buttkicker after the 1400 it is dealing with now.

I have a pair of Aura Bass Shakers under the seat of my couch and it does the job. Pair of shakers and 100 watt plate amp from Parts Express for around 170 is a nice way to feel the bass.

Bill

Just to get some opinions on what frequencies to send to the transducers.

I think I am going to go with Clark silver transducers, mainly based on value. They go lower than the Auras. I will be able to get by with my existing amplifiers and I just have to make a reclining loveseat shake.

My main goal is to get more realism and be able to turn the spl down a little. (This will make my wife happy)

My existing sub, a NHT 1259 in a DIY box goes down to about 25 hz.

The Clark transducer says that the tactile frequency range is 15-800 hz and the audible response does not start until 35 hz.

My best guess would be that low passing the signal to the clarks at 30 hz would work well. I would get the most out of them without worrying about them interfering with the sound from my subwoofer. However, it sounds like people low pass them even lower than that to avoid any potential noise. Has anyone had problems with hearing the clarks with frequencies as high as 30 hz.

I can't comment specifically on the Clarks, but as far as "hearing" them, a lot of that will depend on what you have them attached to. I am much less concerned about the Auras on my couch than I am the Buttkickers on my floor, because the floor behaves like a real speaker... the back wave is isolated (crawlspace). My floor is essentially an infinite baffle sub, while the couch is an open baffle sub. Having my couch vibrate at reasonably low frequencies doesn't produce much audible output. At such low frequencies, the wave is larger than the baffle, the back wave cancels the front wave (like a woofer operating without any enclosure). So if you're vibrating a free standing object in your listening space at 30hz, you probably won't get much audible output. But if it's the floor, you will.