I got 4 Rockville W8K9D2 2000W 8” subs in a box, along with a 4000W Hifonics BG4000W amp on Facebook Marketplace.
Two of the subs are pretty much blown and have a noticeable rattle (they didn’t even work when I got them, the wiring was all wrong).
I’m thinking about getting 2 more subs of the same kind, and I’m curious if I can run them at 2 ohms. I’m still pretty new to this subwoofer stuff, and I’ve been researching but haven’t found a solid answer.
What I’ve gathered so far is that if I wire them in series-parallel, I’d get 1 ohm (2+2=4, then (4/2)/2=1). My amp can run 1 ohm, and that’s fine if needed, but I want to run 2 ohms at 2000W.
I know if I wire everything in series, it won’t be 2 ohms, and if I wire everything in parallel, it also won’t be 2 ohms.
Would I need to get two 4-ohm subs instead? Maybe I should wire it that way. I’m not sure. Any help would be appreciated, thanks!
That amp is not 4000W RMS. Forget about the Max or Peak ratings, they are just marketing fluff. It also asks for 2AWG wire, which is a red flag it can’t actually deliver 4000W.
Rockville and Hifonics aren’t great brands and love to inflate their “max” power numbers. Rockville does at least give an RMS rating of 500W for those subs, which is a more realistic number than the 2K they advertise. But they may also overstate the RMS rating, so even 500W might be optimistic. Still, four of them could handle 2KW if they’re up to it.
Hifonics doesn’t provide a reliable RMS rating. They also don’t include a fuse, which is a huge red flag. If the amp claims 1KW but has a 40A fuse, it can’t really do more than 500W before blowing. I saw a version sold with a 200A fuse, which would suggest 2.5KW at most, not the 4K they’re claiming.
If we assume their peak is double the RMS, you might be able to get 2KW from your amp at 1 ohm, which would mean 500W per sub—this would work well. But you won’t get 2 ohms with 4 of these subs. It’s either 1 or 4 ohms. If you had four 4-ohm versions, you could wire them to 2 ohms. This is why it’s important to plan your setup ahead of time to make sure everything matches correctly. Different subwoofer ohms give you the flexibility to match the load to your amp.