Originally Posted by andyadler
Sorny: Can you tell me more about how you use the MiniDSP in a multi-sub system?
You would use a single subwoofer/LFE output from your receiver as input 1 of the MiniDSP. Each subwoofer gets an output from the miniDSP. Using REW and a measurement mic (Umik-1 or the like), you take measurements for each sub. Using REW, you can see the individual response of the subwoofers, including phase (delay). Using REW, you then adjust the subs to get them all in phase by adding delay to individual subwoofers on the output of the minidsp. Once all 3 subs are in phase, you use the EQ tool in REW to generate EQ filters for the combined 3 sub response to get your desired response; be it flat, or a house curve (where bass level rises the lower in frequency you go to better approximate how our ears work).
That's a high-level overview of how it is done. There are numerous application notes on MiniDSP's website for how to integrate multiple subwoofers, as well as many youtube videos about how it is accomplished.
REW is free software, though donations are welcome. A miniDSP 2x4HD runs about $200, and a umik-1 from minidsp runs under $100. So, it is adding about $300 worth of hardware, and whatever you choose to donate for the software, but integrating multiple subs without it is like herding cats and you're still at the mercy of room modes.
I went from 2 subs to 3, and then from 3 to 4. Once I got past the couple hours of learning curve on REW and MiniDSP plugin software, it was a breeze to get my subs behaving the best they can.
I've attached a couple graphs, showing what can be done with a MiniDSP/Umik-1/REW and 4 subs... The end result has a significant house curve by design. I could just as easily have EQ'd it flat, but I like the boosted low end bass as it sounds subjectively better to my ears.
This is not something easily done without proper tools, that that's what MiniDSP, Umik-1, and REW allow. They give you the tools to make outstanding subwoofers perform to their best; and HSU subs are definitely outstanding subs capable of incredible output and fidelity when you undo the damage the room is causing.