what´s the benefit of using two exciters in one single channel? Is there a way via Simhub of sending different signals to them?
This is a good question you ask...
Its not so much about having multiple exciters on a channel as I do not really recommend that.
What I coined as "Dual Role" is doing this but its really about
optimising performance for two different units and making better usage of low & mid-bass frequencies.
Channels:
A single output channel is just that, so all the effects placed on that channel would go to any duplicated versions of this channel or having multiple units working from that channel.
Lets say that we have a selection of 2-3 effects on a channel, normally all the generated frequencies from these effects go to transducers connected. So the effects during the output mixer/stage are combined into generated "audible sound" frequencies, they are not maintained or packaged as little individual effects to a unit to somehow output.
As the effects are now combined audio we can now control/direct it with crossover control.
This lets us have transducers/shakers perform optimally with frequencies that suit their specifications and abilities. So we can direct the "lowest bass" for example @ below 40Hz to operate only via a large BK unit and let the typical transducer or exciter operate as normal (decent activity from 30Hz upwards).
So by placing a large BK unit (larger the better) the more we can achieve from the low bass for optimal performance and then push this unit to only work with this range. While we then use the typical unit for the mid or higher (bass frequencies).
Doing this also reduces the workload on a single unit and additionally with two units being installed instead of one. While these are best kept close together, we create better dispersion potential of the effects.
It is more complicated, more costly but it can bring performance benefits.
Very few people have implemented "Dual Role", it is something my own build will do to extract as much performance as possible.