About to purchase 4 srx 828sp..
Having recently heard proper cartiod setups, and my own experience playing with multiple QSC kw118s in cartiod, my question is.. will adding 2 srx 818s to the purchase order, and placing 1 818 behind 2 stacked 828s offer enough cancelation to achieve a good cartiod setup
In a directional sub setup ( cardioid or endfire) it is always BEST to use the same model sub (not just the same manufacturer) in order to get the most subtraction/cancellation at the rear and the most addition in front.
If you have the tools and the knowledge to be able get the same freq AND phase response (across the freq range), then you can use different model subs. Most people don't have that ability however.
You will get "some" cancellation, and it might be enough for your needs by using different model subs, but not the best overall performance
Also many people wrongly assume that a directional setup is always best I NEVER use it, unless the rear rejection is more important than the sound out front. And yes, there are times in which the rear rejection for people not at the event IS more important.
There are always compromises when doing directional setups, especially cardioid. The SPL out front will not be as loud as if you just used the same number of boxes and had them stacked or side by side. The punch/impact of a cardioid sub setup is less that all facing forward. The low freq extension is less with cardioid than all facing forward.
An endfire setup sounds better, but has less rejection over a narrower range.
So it depends on what is most important to you and a particular gig/setup.