Buttkicker LFE Tactile Transducer - Shake your Seat With Silent Bass
This is a buttkicker unit
This article is about my experience with the Buttkicker range of tactile transducers, which are also known as bass shakers. They are devices that move your seat in time with the bass / LFE effects that come through your sound system allowing you to feel the bass as well as hear it!
I have two buttkickers fitted to my sofa in my home cinema, so thought I'd tell you what they are and show you how to fit them! I took some photos when I was installing mine, so I'll share them all with you so you can see what to do.
What's a tactile transducer?
A tactile transducer, also known as a bass shaker, is a device that works in conjunction with your subwoofer and the rest of your sound system. The way it works is that it vibrates the seating area in time with the bass that is going to the subwoofer channel of your home theater system. This means that the effect you get from the bass is increased, without needing to have the system up very loud.
The subwoofer channel that comes from your receiver is more accurately known as the LFE, or Low Frequency Effects channel. The sound that comes through the LFE channel is just the low bass frequencies, from 5-120hz. The bottom end of this range cannot be reproduced by the vast majority of sound systems apart from extremely expensive systems costing tens of thousands, but the buttkicker will happily reproduce the LFE signal all the way down so the effect you experience is far wider and more powerful, without being cut off because your system can't handle it.
Once you have fitted buttkickers, the effect is absolutely fantastic. It makes films far more immersive as when there is something with a big bass impact on screen, then you can feel it through the chair. They work best with earthquake effects in my opinion, but anything like a vehicle crash etc all feels great.
To set them up properly, you have them running with a subwoofer as a supplement. I have two large 18 inch subwoofers in my home cinema, but I still appreciate the effect from the buttkickers. To get the same sort of sofa shaking effect without the buttkickers, you have to have the volume up very loud, which is not always appropriate or comfortable.
As I said transducers reproduce the extremely low frequencies in the soundtrack. Most commercial subwoofers play from about 35hz upwards. If you have a high end commercial, or a DIY subwoofer, then you will get lower down in the frequency range (mine do), but even then you are not going to get all the way down to 5hz, so these allow you to not miss any of the soundtrack. There are times in films where the soundtrack is totally inaudible, due to not only your sound system not being able to play it, but the bass being so low it's below the human range of hearing. With these installed, you can still feel the bass even when you can't hear it. An example is the pod emergence scene in war of the worlds. If you have ever seen the film, you may remember the scene where the two policemen are arguing about what is going on down there and one of them says to the other 'I can feel it', referring to the ground moving. Without transducers, you have to take his word for it. With transducers, you can also feel it!
There are several different brands of transducer on the market, the buttkicker range are popular as they are the most powerful. I decided on the buttkicker LFE kit and bought another buttkicker unit to go with it. You can potentially run up to four buttkicker units from one amplifier. The LFE kit contains everything you need to get started and for most sofas would be enough, but I have a particularly heavy sofa, which is why I bought an extra buttkicker unit.
This is what you get in the Buttkicker LFE kit.
I have a very heavy handmade leather sofa, so I needed some real power to move it. At first I tried using one buttkicker on the supplied foot to try it. You bolt the buttkicker unit to the metal foot and this sits underneath one of the feet of your couch.
If installing outside the sofa, just sit the sofa feet on the Buttkicker unit like this
The problem with this approach is that the effect is good, but I felt like it could be better. There isn't much subtlety to the feeling. Subtle effects aren't really felt that well, but it can still rock the couch when there's a large effect. I decided to go for it properly and install inside the couch.
To install properly, first of all you have to get into the sofa. This is the view after upending mine and getting ready to cut. The flash on the camera shows up every mark on the fabric underneath, I guess it must have got dirty in the factory when they made it, as I'd never been under there before!
My sofa before opening it up!
After peeling back the fabric by undoing the staples, this was what faced me. As you can see there's a lot of wood and springs etc all really tightly packed in there. Some cheaper sofas have a large cavity inside, if so you have plenty of room. I'd recommend trying to fit a cross brace so you can get the buttkicker, or whatever transducer you're fitting as close to the middle of the couch as you can.
You can't work on something if you can't see what you're doing! I used an extra piece of timber here to make a cross brace before attaching the buttkickers.
After some fiddling I had managed to join both struts together with this extra piece. I wanted to try to really transfer the vibrations from the buttkicker units to as much of the sofa structure as possible. I put one on each of the struts that you can see.
This is what it looked like inside the sofa, once I'd drilled and bolted the buttkicker unit to the strut. I followed this with another one on the other side, then wired the speaker cable up to both.
This is the Buttkicker shaker unit bolted to the frame
You can just about see the buttkicker hidden in the bowels of the sofa!
After the sofa had been put back together this is how it looked. No one would ever know there were buttkickers inside. The effect is a million times better once you install inside the couch.
I used the free feet that came with the buttkicker LFE kit initially, but unfortunately my couch was too heavy and squashed them flat, so I had to upgrade to the larger feet. They're not cheap, but if the couch isn't able to move freely, the vibrating effect is greatly reduced, so they were essential.
Sofa back together again!
The front of the Buttkicker LFE kit amplifier
How to connect up your Buttkicker LFE kit
The way to connect them up is to use a Y splitter to split the signal from your AV receiver LFE/subwoofer channel output so it goes to your subwoofer and also to the buttkicker amplifier. You can then calibrate your subwoofer as normal with the buttkicker amplifier off, then once that's done, you calibrate the buttkicker by feel.
The buttkicker amplifier comes with a variable frequency cutoff. It can play from 5hz upwards. Although the LFE channel goes up to 120hz and it is a good idea to have the subwoofers play this whole frequency range, when you allow the buttkickers to play this much back, then it is too much in my opinion. After some messing around and trial and error, I finally settled on low frequency range cut off switched off, to allow it to go as low as possible and high frequency cut offset to 40hz. This means that only the lowest frequencies are transmitted to the seat.
You then need to adjust the gain, or as it is labelled on the amp, volume. The ideal setup is to have it integrate with your subwoofers seamlessly. Start with it low at about the 9 o clock position, then adjust up or down to suit. If the system is playing and you can't tell there are buttkickers, but the bass feels very powerful when seated, then you have got it right. It took me a while to get this level right, but you will get there in the end. There is a different amount of bass in different film soundtracks, what I did was select a few films that I knew were good for their bass, like War of the Worlds, Bolt and Ironman and then adjust it so the buttkicker is optimised for those.
Earthquakes then feel particularly good, but any heavy bass scene is improved. You have to careful though, during horror films, you can find the effect very scary! After I had installed them, I had a friend over. We were watching a film in which I knew there was a large explosion coming up. I hadn't mentioned the buttkickers at all. Anyway, at the point at which the explosion came, she almost leaped off the couch and as she jumped in the air she spilled her wine everywhere. Ok, it made a mess, but the added effect of the buttkicker, coupled with the subwoofers clearly had done the job!
Here's the kit if I've convinced you!
If you are unsure about buttkickers, or any other type of tactile transducer, all I can say is, you really needn't worry about whether they are any good or not. They're absolutely awesome and really add a huge amount more enjoyment to movies.
Some people think that tactile transducers are a gimmick and will just rattle the seat incessantly. Not so at all, if calibrated correctly, they simply add to the experience and can be every bit as subtle as your speakers.
The Buttkicker LFE kit, although not the cheapest of gadgets, is well worth looking at if you're into home theater. I wouldn't dream of getting rid of mine, no matter how large or how many subwoofers I had, as they add a great deal to the experience. If you haven't tried them, then do it!
I hope you enjoyed this article, if you have any comments then please leave them below.
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