the box pro DSP 18 Sub

I replaced my old passive system with T-box Pro products. With this in mind, I bought 2 sets of 2xDSP18 sub + 2xDSP112 Top sets.
So, I currently have 4 X DSP18 sub boxes. Unfortunately, the built-in DSP is not necessarily in line with the capabilities of the box. Since the lower limit frequency is 30Hz, it starts to limit too early, very far from reaching full volume. This should be reported, because there is more in the box than that. I use it with a dbx PA2 system processor, here I set the lower limit frequency to 41 Hz, which makes it sound much, much louder and more powerful. (This frequency is perfect for me because we only use them for rock sound reinforcement) The workmanship is absolutely good for the price, a solid, well-built product. I had to make carts for it, because unfortunately wheels cannot be installed. The 4 boxes are enough (with an external system processor, properly measured and set up) to organize an outdoor event for about 300-350 people. (Anyone who says 2 boxes are enough for this is lying :-) ) I plan to buy at least 2 more in the future. Thank you Thomann