Tactile Transducers

Discussion in 'Archived Threads 2001-2004' started by Mike_Ped, Sep 6, 2001.

  1. Mike_Ped

    Mike_Ped Second Unit

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    Does anyone have a site they know of that outlines the construction of these bad boys? If so, please send a link on down my way. Thanks!
    Mike
     
  2. Jason Pannell

    Jason Pannell Auditioning

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  3. Bill Catherall

    Bill Catherall Screenwriter

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    A couple things I would do differently from the directions on that site are:
    1. Don't cut the entire cone off. Just remove enough from the basket so you can secure your steel strap. This will help keep the voice coil in alignment when you go to attach the steel strap to the dust cap. Once the TT is fully assembled you can cut away the remaining cone.
    2. I used a bolt as the core of the connection between the strap and the dust cap. I wouldn't use just epoxy. You may end up cracking the epoxy if it is extremely brittle. The bolt core will keep it from cracking.
    3. I found the cheapest source of weight was lead buck shot. I went to a gun supply store and they referred me to someone that sold 20 lb. bags dirt cheap (I think it was like $7).
    4. I used 3 lbs. of lead in a sock and taped it up in a tube shape with duct tape. Then I used cable ties to attach it to the strap.
    5. I used titanium epoxy with a dry time of 30 minutes. It slowed me down, but gave me plenty of time to work with it. It is filled with titanium flakes to give it extra strength. I found it at Home Depot.
    Tactile transducers are a very fun project. I wouldn't spend too much money on the woofers though. I got some really cheap 10" car woofers that Fry's had on sale ($10 each) and they work great. You just need something that's going to move the weight.
    I'm powering two TTs (hooked up to my couch) with an old stereo receiver. The subwoofer pre-amp output of the 5.1 receiver is split to the stereo pre-amp inputs of the stereo receiver. When I adjust the volume to my 5.1 receiver it also adjusts the volume of the stereo receiver. I also hooked up some speaker posts to my couch so I can easily disconnect it from the receiver without having wires to bundle up with it.
    People are just blown away with my couch when I give them a demo. It adds a whole new dimension to the home theater.
    ------------------
    Bill [​IMG]
    [​IMG]
     
  4. Mike_Ped

    Mike_Ped Second Unit

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    Thanks a lot! I got old Pioneer car speakers that I'm going to try this on...hope it works!
     
  5. Jason Pannell

    Jason Pannell Auditioning

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    Bill, when you say that you used a bolt as a connection between the dust cap and the strap, how exactly did you do this. Did you run a bolt from the middle of the strap to just above the dust cap and then epoxy this together?
    Thanks,
    Jason Pannell
     
  6. Bill Catherall

    Bill Catherall Screenwriter

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    Jason,
    The instructions on the link above tell you to drip epoxy through the hole in the strap to "build up" a connection to the strap. Basically, you're making an epoxy stalactite. Any surface cracks will propogate right through the epoxy and could cause a major fracture. I would put a bolt through the hole first, then cake the epoxy on around the bolt. This would give it a metal center.
    In my TTs I had about 2 inches of clearance between the strap and the dust cap. After stiffening the dust cap with about 7 layers of epoxy I also epoxied (sp?) on 4 washers being careful not to get epoxy into the holes. Then when I attached the strap I filled the washers full of epoxy and stuck the bolt down through the hole in the strap into the washers. Then I caked the epoxy all over the washers and bolt. I also built up layers of epoxy over the bolt and strap to solidify that connection. So the only thing holding the strap to the dust cap is still epoxy, but the epoxy is built up around solid steel. Any cracks in the epoxy will have a pretty hard time propagating through the steel bolt and washers.
    ------------------
    Bill [​IMG]
    [​IMG]
     
  7. Bill Catherall

    Bill Catherall Screenwriter

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    I'll come up with a webpage with some good pictures or drawings one of these days. This question seems to come up a lot, but I haven't had the time to build any more of these recently. If I find a really good (read cheap) deal on some 10" woofers one of these days I'll build another and take some detailed pictures.
    But for now here are some very crude drawings. These are sort of cut-aways, so keep that in mind. Also, as I stated before, I recommend only cutting away enough of the cone from the basket to be able to attach the strap. Leave the cone intact to the dust cap for now. It will help to maintain good alignment. You can completely cut it away as the very last step. (These illustrations DO NOT show the cone.)
    We start by layering epoxy all over the dust cap. Don't get any epoxy on the cone because you won't be able to cut it way. (The epoxy is shown in red.)
    [​IMG]
    Once you've got several layers on (many thin layers is stronger than a few thick layers) and the dust cap feels really stiff then you can attach the strap. Use lockwashers to keep the bolts from vibrating loose. You'll need to drill holes through the strap and basket to get it attached with the bolts. Also, do your best to center the strap to the dust cap.
    [​IMG]
    The next step for me was attaching washers to the dust cap with epoxy. Get them centered and don't get epoxy in the holes.
    [​IMG]
    Now you attach the bolt to the washers with epoxy. Stick the bolt through the hole in the strap (you did remember to center the hole in the strap over the dust cap didn't you?). You can put a nut on the other side of the strap if you want to. I did that but didn't illustrate it here.
    [​IMG]
    Build up epoxy around the washers, bolt, and strap. This cut-away doesn't show it, but the bolt and washers should be completely buried in the epoxy.
    [​IMG]
    You can completely cut away the cone at this time if you wish. Be careful not to cut the wires leading into the dust cap. I attached 3 lbs. of lead buck shot. The shot is in a sock and taped up in a tube shape with duct tape. I attached the weight to the strap with cable ties.
    [​IMG]
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    Bill [​IMG]
    [​IMG]
     
  8. Jason Pannell

    Jason Pannell Auditioning

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    Thank you Bill.
    I am planning on making a pair of these in the near future. I have another question for you however. In your diagram the weight is sitting above the edge of the basket, how did you mount this to a surface?
    Thanks,
    Jason Pannell
     
  9. Bill Catherall

    Bill Catherall Screenwriter

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    Jason, that requires some more crude illustrations. [​IMG]
    Here's a top view of the finished TT. When I made mine I made sure that there are 2 mounting holes available on each side of the basket.
    [​IMG]
    Then I used those mounting holes to attach the TT to some framing members in my couch. I added 2x4s to do this. Those 2x4s then attached to the couch structure. Make sure you have plenty of clearance for the weight to move. It doesn't require much, but you don't want anything to touch the weight and "muffle" the vibration you get out of these.
    [​IMG]
    If you have access to the floor joists you could attempt to attach the TT to these the same way. Just run 2x4s accross the joists and attach the TT to the 2x4s. You could also use these on a seating platform if you have one.
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    Bill [​IMG]
    [​IMG]
     
  10. rich r

    rich r Stunt Coordinator

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    I am intested in building a few of these TT's but what kind of power is needed to drive one of these babies??
    Would u need more or less power than a conventional woofer??
    And how much vibration can you get out of these things??
    thanks in Advance
     
  11. Bill Catherall

    Bill Catherall Screenwriter

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    quote: Would u need more or less power than a conventional woofer??[/quote]
    That's a difficult question to answer because it depends on the application. How much power does a conventional woofer need? I'm powering mine with 100 Watts @ 8 ohms each. That seems to be plenty of power for my needs. I really wouldn't recommend going lower than 100 Watts, but that really depends on how many TTs you plan on using and the quality of the amp. You want as much overhead power available as you can afford.
    quote: And how much vibration can you get out of these things??[/quote]
    Plenty, but it isn't like what you think. It's not going to make my couch walk across the room. It's also more like a rumble then a vibration. I didn't really know what to expect the first time I built mine. I just put them together to see what they could do and was very pleasantly surprised by their performance.
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    Bill [​IMG]
    [​IMG]
    [Edited last by Bill Catherall on September 07, 2001 at 12:38 PM]
     
  12. Mike_Ped

    Mike_Ped Second Unit

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    Awesome diagrams Bill, BIG help! muchas gracias!
     
  13. Bill Catherall

    Bill Catherall Screenwriter

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    Thanks Mike. By the way...one other experience of mine that contradicts the advice given in the link above. The "other guy" used rubber at the mounting points. He says without the rubber you will experience a rattle. I completely cut the rubber gasket off my woofers and mounted them directly steel to wood. I have no rattling. Personally I think putting rubber between the woofer and the wood would reduce the vibration and kill the effect, but I haven't actually tried it.
    The only rattling I do get is when the back of my couch is touching the wall. The clock and pictures on the wall rattle like crazy. So I just get up and pull the couch out a half inch and the rattling stops!
    If there's anybody that wants to build one of these but is a little gunshy then get in contact with me and we can work something out. Just click on the "Send Email" icon above. Maybe you can send me your woofers and about $15-$20/TT for materials and shipping and I'll make them, take pictures, and post better instructions on a website. I'll send them back to you and you can give me a review that I can post on the site as well. I'd build more but I have nowhere to use them right now and no money to buy woofers. I won't charge for labor, just materials and shipping.
    ------------------
    Bill [​IMG]
    [​IMG]
     
  14. Mac F

    Mac F Agent

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    Bill,
    I don't want to change the subject, but how did you post those diagrams in the earlier reply
     
  15. Bill Catherall

    Bill Catherall Screenwriter

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  16. Dennis Kindig

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    Good grief, guys!
    You must have nothing better to do! I purchased Aura Interactor vests on eBay for $5.50 each, stripped the transducers out of them, hooked the included amplifiers (with level and rolloff controls) to my subwoofer out, screwed the transducers to the couch and was done.
    Total cost for a U-shaped sofa unit using 6 transducers: less than $35.00.
    Dennis
     
  17. RickBlacker

    RickBlacker Stunt Coordinator

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    So, I am more interested in mounting these to floor joists, would these produce enough shake to feel it? Don't think my wife would like me putting transducers in our couch.

    What about using some 6X9 car stereo speakers. Would they produce enought vibration. Hmm, guess that also goes to ask, I have an old alpine car amp, is there anyway to power that from a 110 outlet and use it to power some these home made transducers?

     

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