FI is built in america with tougher american wound coils. Massive is off the shelf china same stuff with american bass and soundqubed same build house and motor designs for the most part. Its solid but its nothing special, dime a dozen (decent dime a dozen) but mainly geared towards spl. I'd go with the BL or BTL over the sp4, I've never been impressed by any SP4 builds but i've had my organs rearranged with BTL neos. SP4s dont have any decent efficiency and need stupid power just to get as loud as other subs.
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FI is built in america with tougher american wound coils. Massive is off the shelf china same stuff with american bass and soundqubed same build house and motor designs for the most part. Its solid but its nothing special, dime a dozen (decent dime a dozen) but mainly geared towards spl. I'd go with the BL or BTL over the sp4, I've never been impressed by any SP4 builds but i've had my organs rearranged with BTL neos. SP4s dont have any decent efficiency and need stupid power just to get as loud as other subs.
id love to give them a try but can’t buy any right now from there website. Any other places that you could purchase new and be trustworthy?