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I have been looking at the REL T/9x but the only go down to 27Hz at -3db. Should a sub not go down to 20Hz?
I live in Denmark so I have fewer options. I really like the swarm sub array but to costly to get it to Denmark.
I am looking for recommendations. It could be DIY or a specific sub.
I am open for suggestions"
Re: swarm sub array (or DBA), any sub brand and size in a quartet will do. Some may feel otherwise, but I would stick to 4 similar subs should you go this route. Moreover, from my POW: have them placed symmetrically, like 2 of them flanking the mains in their respective corner, and the other 2 placed symmetrically in the corners behind you. This way you can also maintain a left and right field and couple them in stereo if crossed above 60-70Hz (and should you decide to high-pass your mains). I know, to some there’s a rigid 80Hz barrier below which bass supposedly isn’t directional, but I disagree with such hard cut stances.
I would like to make a comparison with horns. Horns used from the upper bass/lower midrange on up can be small(er) or rather large covering more or less the same frequency span, the main difference being that the larger horn is able to maintain directivity control lower in frequency compared to the smaller ditto. This is vital for a number of reasons. Predominantly smaller horns are used in the domestic realm simply because smaller size equals better sales, and very generally speaking the smaller horn variant will sound as if focusing the energy of sound in a more concentrated fashion vs. a bigger horn covering the same frequency range. This concentrated characteristic of the smaller horn is not without merit and can have its own lively quality in a sense, but when you hear the bigger horn here (which is usually much bigger) there’s a more relaxed, room filling and physical presence or sphere of sound even. Which is to say: to my ears, all things being more or less equal, the bigger horn will sound less like a horn, or just less reproduced overall, and not unlike very large (and very dynamic) panel speakers.
Moving our attention to subwoofers there are things at play not wholly unlike above horn example; the bigger and more efficient the subs, the less they sound like subs. What does a ’sub’ even sound like, typically? Like something that would call attention to itself as a separate entity. For some reason I’ve never been able to integrate smaller cube-sized, lower efficiency subs in a satisfying manner with the mains: they always end up drawing some kind of attention to themselves, less pronounced though when set up as a DBA.
Using big, efficient subs on the other hand is generally a different matter. They’re not impervious to or unaffected by bad implementation, but properly set up they blend in and fill the room more effortlessly and smoothly while usually having less lag. Bass just happens in the listening space, not least via horn-loaded principles, and once you get used to that there’s really no turning back to them small cubes.
So, if you choose to go with the smaller cube-sized and less efficient sub solution I’d recommend you don’t skimp on driver size, and use at least two of them. Should you go with 4 subs for a DBA - indeed, in any case - set them up symmetrically. Consider high-passing the mains as well to relieve them of LF.
If you want to try out big, efficient subs, start out with a pair placed symmetrically to the mains. If you’re not afraid to venture into DIY consider the Cinema F20 front loaded horn sub by "lilmike" (Google them), or his slightly smaller PicoWrecker tapped horn. Both will reach down to honest ~20Hz, but be aware they’re not small (the F20 takes up 20 cubic feet per cab). Add a MiniDSP and a pro power amp, and you’re good to go.