The $30 bass shaker story

Or what I did during my summer holidays

By Max Christoffersen

April 2003

Over the past few years tactile transducers have become one of the most exciting, entertaining and talked about innovations in audio.

So what are they? In short, tactile transducers shake anything they are connected to. Some act just like a speaker cone, but instead of creating soundwaves, they generate 'bass waves' you feel when the transducer is attached to furniture or floor joists.

Bass sound is no longer something you just hear - it becomes something that touches you and involves you in the soundtrack.

They can add dramatic bass impact to explosions or car doors slamming or kick drums or bass playing. You really have to feel it to believe it!

Tactile sound is a very addictive (and guilty) pleasure! And it's fun. The early adopters of tactile sound were amusement theme parks and aircraft simulators. More recently home theatre enthusiasts have been using them to add the final tactile dimension to a soundtrack – for films and music you really feel!

But how to do get tactile sound at home cost effectively has been the question.

The DIY story below outlines how to get tactile sound into your home
for around $30.

Don't blame it on the sunshine

Blame it on the weather and a rainy day mid-summer with nothing to do. Except for those Aura bass shakers lying around the beach house somewhere gathering dust. Hmmm...

I had time to kill, a bit of wood and a couch begging to get rattled. So what’s a boy to do?

And that’s where it all started. Drill in hand, gleam in the eye, you know the rest.

Despite buying into the idea of tactile sound back in 1998, I’d just never got around to trying the Aura shakers out in a dedicated seat install. So here’s what I did.

What’s under the hood?

The Aura transducers can be purchased separately, in a cushion or backpack. You can use them as supplied, or remove them and screw them into a couch or chair sub-frame.

But before you do, you need to take a look at your couch. See if there is anywhere to mount a piece of wood from one wood joint to another. It may be a complete side-to-side piece stretching over two seats or maybe a half couch install (see photo below).

The key here is to find a location that is:
• low enough so you won’t find yourself sitting on the wood (once seated)
• secure enough to rattle the entire chair sub-frame
• accessible enough for you to screw the wood into the sub-frame
• hidden enough so no one can see the woodwork underneath
• far enough away from any foam or material (minimal fire hazard)
• ‘transmissive’ to connect vibrations from one piece of the sub-frame to another

Wood work and surgery

This is where it gets a bit fiddly. To make the most of your install you will need to get a good solid piece of wood or MDF and make a hole big enough to mount the transducer, allowing for the big lip of the Aura unit to fit into place on top.

Screw the unit firmly into the wood minus the rubber mounts. (Note: You will need to make a small notch to accommodate the speaker connection terminals. Also use some heat shrink on the terminals to make a tidy and safe lead connection).

In my own install, I used two shakers with each at the far end of the wood mounting board (see picture above) based on the theory that the transducer vibrations need to be close to the chair’s subframe for better tactile transmission!

The further they are located away from the chair’s subframe the less effect may be transmitted - distance equals tactile decay.

Add a wood brace (see triangle piece of wood bracing the platform to
the chair frame - picture below) as a way to stiffen the whole platform and ensure a secure mount to the chair or couch. Glue and screw these in and let them set overnight using epoxy, Aliphatic Resin or PVA.

Do a ‘test sit’ to make sure the board is not too high and you’re now sitting on it. Good in theory - bad in practice!

All done? Now you have a piece of pine or similar with a vibrating piece of metal attached to it. Great! Now what?

More wood work and surgery

The next part requires a little bit of planning. if you’re going to mount the wood across a section of your chair or couch, check where you can screw it in. Also check access and if there is anything touching your mount that you don’t want to vibrate (seat recliner mechanisms) - vibrations are good - rattles are not!

It must be a firm mount and glued and screwed for best effect. So check - is there room for a screwdriver and a drill to get in there? The fit must be snug, which may mean you have to use a bit of ‘forceful persuasion’ to get the board mounted exactly where you want. The more surfaces you can touch with the board the better.

Check how secure it is and if necessary, try a test piece of music just to ensure there are no stray rattles.

I used screws and glue in my own Aura install, but liquid nails is a good final touch, but only after you’ve checked everything is working as it should. Apply Liquid Nails liberally. Make sure it gets into all the nooks and crannies where the wood may not be flush. This will create a near seamless bond between shaker platform and couch ensuring good transmission of vibrations.

Remember – once it’s in, it’s in! (You may want to try placing your transducers screw side down, so you can remove them if necessary.)

While you’re probably keen to get going, let everything settle and dry before your first serious audition! The last thing you want to have to explain is the nice puddle of glue on the floor.

Secure the cables neatly to the couch so if you need to move it, the cables move right along with it.

Shaky town

Connect the amp/processor subwoofer-pre-out to the Aura amp. Solder an RCA plug to the transducer speaker lead and plug in the transducer and it’s set to go.

Put on a bass heavy scene or piece of music, and sit back and enjoy the sensation of low bass rattling you and your immediate environment and feel explosions or study bass lines or kick drums in detail! Most enthusiasts start with the effect (over) high and then lower the shaker level to blend in with a subwoofer.

The best effect is when you’re aware the seat is shaking, but the illusion is a part of the soundtrack’s normal bass extension.

Tactile sound is one of the great grin factors of home theatre and doing it yourself is that much more fun.

And if you’re keen, you could always try the bedroom... Maybe next summer!

Note: This install is based around the use of the Aura shakers on sale at the time of writing at Jaycar, but the same installation approach applies to The Buttkicker and Clark Synthesis tactile transducers and other similar transducer models. Some small modifications may be necessary to accommodate larger, more powerful units.

For your nearest Buttkicker dealer