Small footprint subwoofer

Thanks for the recommendations. The KEF is nice but it is out of my range. 

@soix The SVS SB-1000pro was a consideration a while back but still think would be too big for my room especially going two subs. I get the performance aspect of it but I really don't need anything lower 30hz since this is just a 2 ch music only system.

@jastralfu  True but my situation and room size, I dont need overwhelming bass. I do however have a room node at around 60hz but that can be fix with by integrating the sub with the proper settings on the sub and placement.  Even at that, the xo point would be lower then the node.

@big_greg I have the STF-2 currently and their about the internal volume as the SB-1000pro with the exception that the STF-2 is rectangle and a little taller. The SVS might be an option but it is a 12" but that is ok...I guess.

@ soix  I am not saying there is no instruments lower then 30z. There is but very limited and the experience is more of a feel then hearing it. 88 keys piano range can go 27.5hz and pipe organ can go as low as 16hz. A bass guitar has or a double bass has the lowest range at 35hz. For the kind of music I listen to my not required to go that low.

Thanks for the response. The room null I am have right now is above the xo point anywhere around 90 to 120hz. Most likely is due the position of the speakers and the in room response. The node is at around 60hz so I have corrected most of the issue with a inline 12db/slope 70hz crossover for the speakers and the sub setting at around 50hz. Theoretically this would be a 6 db less at the xo point. On the contrary, the null that I have is probably more complex to fix. Honestly, this is a bad room dimension but it is the only room in the house I can relax.

As far as the position of the Hsu sub, yes it is in a near null position by not quite. That is why it is off centered to compensate the difference. I have the tools to do measurements so finding the best place for the sub is not a problem.

I decided to go with the REL R218. This came with the high level cable. I have the option to high level or line level signal. What would be better to use on? For the high level, I am using an Adcom GFA-5500.

m-db  If you are referring the subwoofer crawl, I could have done that which can be a way to find the node but I found a much easier time saving way to find room problem. I personally use Rational Acoustics DIv2 software for this. Is pretty much a complex measurement software I use for other purpose which I happen to have available. It is pricey but very valuable tool. Of course your ears is the main tool. 

Thanks for the responses. I have purchase the REL R218 and I am currently auditioning it. It might be too early to comment on its performance but so far I am really enjoying how it is sounding. The bass is extremely clean and articulate for it size. I was very easy to seamlessly integrate with my speakers. However, with the sub I notice a few flaws I am somewhat disappointed. First, the R218 has a class D amp rated or 250 watts where as the STF-2 is rated at 200 watts. As far as gain level, I had to max out the gain on the REL to get at least acceptable level and this was used for both low and high level(speakon high level cable). With the STF-2, all I have need to set just less then half ways. This might not be a fair comparison since one is a sealed and the other ported. Second issue is that the REL for me does not go as deep and as the Hsu does. Both subs integrate well in my system and perform well but I felt the REL lacking impact with certain music. It does however sound tight, natural and articulate and this is great but the Hsu does have better impact.

@m-db To answer your question, mostly yes. It was measured at the listening position mostly and other parts of the room. All measurements are done in real time and delayed to compensate latency.