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Discussion Starter · #1 ·
My friend and I have capable subwoofers and have all the SPL we need. I have an infinite baffle with eight Dayton IB 15in woofers, and he has dual Sound Splinter RL-p15's in huge ported boxes. However, we both want more infransonic effects in our home theater. His room transfers a tactile response MUCH more efficiently than mine does. My home theater room is in my living area, and with my house being an open floor plan and on a slab I literally have no tactile infrasonics from my system.


About a year ago I had a single Polk 10" powered sub with Aura bass shakers. They had a fun factor with them, but overall I felt their presentation felt like a gimmick. They were slow in responding to LFE, sloppy when they did, vibration decay was too long, and overall they felt like a buzzer and felt the same no matter what freqency they were responding to. Again, it was fun at first but in the end I concluded they didn't feel natural and I kept turning them down until eventually I just stopped using them.


However, the buttkickers or clarks respond down to 5hz and since they are a higher quality unit I'm curious about them. But I'm still extremely skeptical about them because of my first experience with transducers. So how do these units respond with infrasonics? More specifically, the 8hz Irene Scene from BlackHawk Down?
 

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FWIW, I think the problem you had with the Auras was due to their very severe peak in the mid/low 40s. They seem like a buzzer, because output in the 40hz range is just so much higher. I run my shaker signal through a bfd, and it took a HUGE cut around 45hz to mostly get rid of their output in that higher range. Don't remember exactly, but it was definitely in excess of a 20db cut. I've also found that the response changes depending on what you have them attached to. I have Auras on my sleeper/sofa, as well as a much smaller loveseat, and Buttkickers on my floor joists. The sofa and loveseat have slightly different peaks/valleys in their shaking response, since one has more mass than the other. And my floor (fortunately) doesn't really want to move much at higher frequencies. Once you attach them to something, the entire structure is going to have it's own resonance frequency. You can make them seem more natural by EQ'ing them such that the output increases as frequency decreases.
 

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Discussion Starter · #3 ·
The more I read in the archives, the more I'm learning that building a platform for my loveseat would have yielded a more natural feel with the shakers. But I never EQ'd the bass shakers since I was just begining to get involved with home theater. Looking at a response curve for the transducer is a great start, but is that the only visual tool someone can use to EQ them?


However, the question still remains... does infrasonics FEEL like infrasonics? In my friend's room, a 30Hz tactile effect feels much different than say a 10Hz effect. The vibrations are noticeably slower with infrasonics. I PM'd you this question, but does an infrasonic move your floor differently than a 30Hz effect would?
 

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Quote:
Originally Posted by FroDaddy /forum/post/0


Looking at a response curve for the transducer is a great start, but is that the only visual tool someone can use to EQ them?

I'm sure you could rig something up to measure vibrations, but really, I did all my EQ'ing by seat of pants, so to speak. May not be completely accurate, but it worked well. Just played test tones at different frequencies, and made notes of where it seemed like too much or too little. It took several rounds of fine tuning, but it wasn't too bad. It doesn't have to be perfect, but once you do some testing with test tones, you will see how uneven the response really is. Particularly with the Auras and their big peak in the 40s. And yes, different frequencies do feel very different. When done right, it just seems like your sub is more powerful, not like there's a separate effect going on.
 

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Discussion Starter · #6 ·

Quote:
Originally Posted by sjmarcy /forum/post/0


Did it, Buttkicker (originals) did great. Tons of strong way-below 20 Hz stuff, like just after 25 seconds into the chapter. If I crank it too much the BKs run out of travel, which is audible (necessary travel rises as the frequency drops). My floor lamps were moving around. If you play the scene on subsonic filtered subs only, you miss out.

Awesome! Thanks for doing this. I actually just have a clip of only the Irene scene, not the actual movie. So I'm guessing 25sec or so is when they fire up Irene and the soldiers are leaving the hangar? Was it more of a vibration or did it feel like someone was pushing on your seat back and forth?


I played it through my IB subwoofer and it will move the loveseat back and forth about a centimeter or so but if you don't know it's coming you can miss it. How many BK's do you have? I was thinking I woud purchase two of them for my loveseat and I thought I'd have enough headroom?
 

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I've been out most of the night, but I do have this movie, so I'll try it out tomorrow. But I will tell you quickly that I can't imagine you needing two buttkickers for one piece of furniture. I have two buttkickers attached to my floor, and unfortunately it's not that hard to reach the very audible ends of excursion during very intense use. But that's while trying to move the entire floor. A single buttkicker trying to shake just a loveseat should be able to shake your innards pretty well, with room to spare.
 

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Here is my experience. I've sold/installed Buttkickers, Clarks and Crowsons.


The Buttkicker LFE's do pretty well with Infrasonics and the Irene Scene is pretty convincing in my theater. The Clark Platinums are also insanely powerful...maybe a bit more potent per unit than the BK LFEs. The Crowsons are the fastest but they are a bit light on the really really deep stuff.

There is also a new shaker coming from Earthquake. Saw a posting and pic on it here from CES a few days back. Looks to be a larger version of the Buttkicker. Retail is higher but I'm quite interested to find out what the performance is in comparison.


Also, the way you mount the shakers (platform vs. seats with isolators) will have an effect on your infrasonic experiences. A platform with a large surface area will develop more flex and will seeming shake more on really deep stuff...at the expense of some speed at higher ranges. Using a BFD is a good idea but just be careful NOT to boost anything or you are likely to get some clanking and clacking going on...cuts only please!
 

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Whether you boost or cut shouldn't really be an issue, since you're likely going to adjust the overall gain regardless of your EQ settings. Besides, risk of overexcursion gets greater as the frequency gets lower, and boosting with a BFD gets more and more difficult the further below 20hz you get. I would boost more with my BFD if I could, just to help out the sensitivity of the auto-on circuit of the Buttkicker amp. The "no boost" guideline is really more aimed at people trying to alleviate room nulls with EQ.
 

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Discussion Starter · #10 ·
Well I think I've read almost every topic, post, and review on the 'net relating to the buttkicker LFE!! I found this piece of info relating to the Black Hawk Down realism quesitons I had... This is straight from Buttkicker's website:
Military

The Company is in contact with SAVIAC, the Shock and Vibration Information Analysis Center, in Arlington VA. SAVIAC is the Department of Defense's focal point for research and analysis in the field of shock and vibration technology. Specific areas covered by SAVIAC include rotating machinery, explosion effects, blast-induced shock, underwater explosion, ground shock, air blast, detonation physics, fragmentation, transportation and vehicular vibration, missile and torpedo vibration, biodynamics, earthquake technology, satellite or other space vehicle vibration and dynamics, ship dynamics and structure dynamics.


Military simulators are also an ideal application for ButtKicker technology. Recently, the ButtKicker has been installed in a CH46 Helicopter simulator. Other similar tests are being made throughout the country.

So aside from installing a Thigpen rotary subwoofer or replacing my 8 IB subs with soundsplinter rl-p15's + amps for more excursion, the buttkicker seems to be the solution for me right now.


Changing gears to installing a buttkicker, please chime in with suggestions on my ideas for install. I'm on a concrete slab covered in carpet so I'll build a platform for my loveseat. The platform will extend out far enough in the front and rear so that a BK can be installed in the rear middle and in the front will have enough room to rest your feet. It will be carpeted, trimmed, and elevated using isolators. It will be constructed to flex since I want to accentuate only really low stuff.


EDIT: I deleted out the last paragraph after I thought about a few things. I'm going to do this in a 3 stages:

- I'm going to do a temporary install first: build an unfinished platform, install the isolators, bolt the loveseat on, and bolt one BK on with temporary wires on top of the floor.

- I'll EQ / calibrate, then test for bottoming.

- I'll install a second BK to the platform, EQ / calibrate, then test for bottoming.

- The second phase will be an extended evaluation period with the setup that performs the best from first phase. This will determine if buttkickers are right for me, which was the original reason for this post.

- The third phase will either involve selling everything or finish the install.


Now all I need is some money
 

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"It will be constructed to flex since I want to accentuate only really low stuff."


The trouble with that is that the platform will flex differnt amounts at different locations.


The ideal to shoot for, and I believe BK says as much, is a platform very stiff so that it moves up and down on the isolators as a rigid body.


You might want to go with two, spaced at thirds of the longest dimension.
 

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Quote:
Originally Posted by FroDaddy /forum/post/0


... please chime in with suggestions on my ideas for install.

One thing I will throw in that I wish I had tried on my install (mine are attached directly to boards attached to my floor joists): I wish I had mounted the buttkickers with some small rubber washers, or some other form of slight isolation. I know it seems counterproductive, but the one thing that I don't like about Buttkickers is they are audible: the slugs on the inside move inside a cylinder, and you can actually hear a slight rubbing sound as it moves back and forth. It's not loud, and so far it's only been noticeable during testing with sine waves (real material typically has enough other sounds to mask it). But as it is, when mounted directly to the structure of my floor, those sounds seem to be transmitted very well, and even amplified by the large surface area of the floor. I would think some small rubber washers would help isolate the much higher rubbing frequencies from being transmitted to the floor (or platform in your case), while not absorbing TOO much of the larger amplitude low frequencies.


You could easily test this out yourself since you're still in the construction phase. Before mounting the shaker to anything connect one up to the amp, play low frequency sine waves, then while it's playing hold it down onto your platform and see if those rubbing sounds are amplified. Then repeat the test with some rubber washers sandwiched between the shaker and the platform. I'd be curious myself to see if they help... if so, I might make the trek back down to my crawlspace to re-mount them.
 

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I made my own tones, and burned them to a CD. If you like, you can download them here , they go down to 5hz, at 1/12th octave spacing. These are compressed as MP3s to make sharing over the web easier, but sine waves encode very efficiently, so the lossy nature of MP3 shouldn't be an issue. The files that have a single number are pure sine waves, while the ones that have two numbers separated by a "-" are warble tones ranging from the first and second number. Warbles have some advantages for overall FR testing, but you probably just want the sines for testing the BKs (and I don't think I did warbles down to single digits).
 
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