Seems I was summoned here....
@
Roflmaot
A Coffee is good enough for me
Different ways to do this guys.
You can duplicate the HDMI or OPTICAL output to have one used for speaker audio and the other for tactile.
Various adapters can do this but it depends on the amplifier being used and its connections you are using what you may have to do. Get a good one as some may have lag/delay but I encountered this myself more so with HDMI. It so long ago that I was doing this I can't give you good recommendations for ones to buy.
THIS IS AN EXAMPLE but I can't confirm how well it works.
Going the Optical route and setting your console to output to BOTH HDMI & OPTICAL SPDIF output I believe is the best option. This way for the secondary Optical output for tactile you bypass complications like adapters having sync delay, or issues like 60Hz and 4K support to forward the HDMI signal to a display.
Remember you need a "sound adapter" not a USB based "soundcard"
Be sure to always pair 4ohm tactile with 4ohm compatible amplifiers.
Option 1 Digital:
Need a duplicator to create 2 sets of audio feeds from either HDMI or Optical outputs
One goes to TV the other into an AV Amplifier with tactile connected.
You can output either Stereo from console or Multichannel DD or DTS
With Digital Stereo use a ProLogic II based soundfield on AV Amplifier to generate multichannel from the stereo.
Or use A/B stereo switching if your amplifier supports two sets of stereo output.
With Multichannel DD or DTS then use auto detect on the AV Amplifier.
Take note that you may want to configure the AV Amplifier that it has NO LFE or SUB within your settings for speaker configuration. This will ensure all low bass goes to all channels.
If however you have a combination of typical/average tactile units but one larger or stronger unit like a BK Advance or you also want to incorporate a subwoofer to work with the tactile. Then you could configure the AV Amp to use the crossover feature set to around 40Hz. This will mean all bass frequencies from all channels below this (given value) will only go to the subwoofer .1 LFE output. This as many of you will be aware is usually not powered so needs its own amplification for a larger unit or subwoofer to be integrated.
Individual preference may be a factor also as some may find using Stereo only output from the console but having dual or often called A/B Stereo used on an amplifier (Front & Rear Stereo) can produce very good immersion too. You don't necessarily need 5.1 but it can bring unique sensation for rear and center channels with additional bass extension using the .1 output with larger/stronger shaker or subwoofer.
I found that having good audible bass working with the tacile gives a deeper/greater immersion in the way our bodys/brain combine each sensation.
Option 2 - Digital - Multichannel Analogue
To do this you need an adapter that converts the 5.1 DD or 7.1 DD into individual analouge outputs.
These often will have 3.5mm or RCA connections for all the channels. From here you can use multiple stereo amplifiers to amplify 2 channels at a time (eg Front Stereo = amp 1 / Rear Surround = amp 2 )
For a Multichannel all in one amplifier to be used it must have what is called "Multi Channel Inputs".
These are not common on todays models but can be found on mid - high range older models. I make example with models I have owned. The Sony 1200ES series or its larger brothers in the 2400ES or 5200ES. Amps like this once were quite high quality can be bought in abundance today for very little money. These from personal experience worked well for me and offer 4ohm switching within their setup menus. I still use my 10 year old Sony 5200 ES model which still works perfectly.
*Take Note Transducers like the ADX are much less demanding on an amplifier than shakers like a Buttkicker. Using multiple Buttkickers on an a single amp can be VERY demanding. Some amps could overheat with multiple units. So I recommend using models like the ADX / Aura Pro / Clark TST as these do not require pushing a large internal piston demanding a constant wattage to do so.
*NOTE you must ENSURE you buy a model that has 4ohm switching. Compatibility to operate 4ohm speaker load is needed for the vast majority of tactile devices. Do NOT run tactile with amps using 8ohm and even models available nowadays that support 6ohm may overheat and trigger their shutdown circuitry when powering multiple 4ohm tactile.
Very few current home cinema AV amplifiers from established brand names offer 4ohm support. Marantz and Denon however do have some models that do but will not likely have "Multichannel Inputs" and only use HDMI or Optical.
Multichannel Inputs
When using these you get direct amplification from the Dolby or DTS source.
You can not add bass/treble or alter with any EQ on the amp as these inputs bypass all that circuitry.
This also means you cannot apply different DSP sound fields but then you shouldn't really have to.
You can, however have control over the volume of each channel output and the master volume.
What I Did
I used Multichannel inputs but with an exception and for a reason.
Console Ouptut - Optical SPDIF Adapter - Multichannel Out -
Graphic Equaliser - AV Amp Multichannel Inputs - Speaker Out/Tactile
I had gathered 4x Behringer 31 Band Equaliser at the time to give me more control for the tactile PRIOR to the amplification stage. Using one Stereo EQ to control 2 channels at a time.
The best way to operate audio-tactile is with an equaliser
Models I used as these have excellent gain control to boost games with lower/stronger tactile sensations. They also have crossover control and 8 frequency sliders within the 100Hz range to give
more individual control of boosting or cutting specific frequencies.
Most EQ will only give you about 3 frequency sliders under 100Hz but that is just too limiting, more are needed if you want the best control. Having one with additional sliders/control also makes listening to music with tactile more enjoyable too as again you have much greater control of the source even into higher frequencies.
SEE THIS
I still have at least two of these available that I have not bothered to ebay yet but they deserve a good and loving home (lol). if anyone is interested within the UK in buying for a great price then, by all means please PM me. You won't get a better analog EQ for tactile control.
They are also compatible with Simvibe and look nuts too.
Different LED modes in operation
An alternative is going with multiple stereo amps and the inuke DSP1000 is the best bang for buck with built in EQ/Crossover and many other useful tools. Yet you need multiple amps of course to run 4-6 channels and these are quite loud. I have a thread appearing soon covering these models at RaceDepartment forums and how to do low noise fan/heatsink modification to them if desired.
Hope its some help....
I really appreciate the pointers, knowledge and advice. You even went as far to point me towards the correct hardware, down to specific models and such.. What kind of coffee do you like? 
