Recommendations for a new subwoofer?

Hi OP

l would stick with Rel as you are there already to go with the dialling in with your pre use qualifications. No need for apps, just a good pair of ears.

Go for a T7i or T9i second hand. Both have 10” drivers, the higher the number the greater the amplifier power. No point in paying for a new X model in those sizes, there was no discernible difference to my ears. You may find a stereo pair would fit in your budget if used ones are abundant. They both have high level Speakon and low level RCA inputs. Rel developed this first and l advise you do not accept other brands that do not offer this. High level for Stereo and low level for those extra channels for home theatre…..it’s a no brainier with total flexibility. Rel may only go down to 30 Hz but l never found this a problem, my neighbours yes. Also don’t go for extra large drivers as your bass can end up boomy and bloomy. Smaller drivers are quicker and slicker.

l use two Rel T9i subs and as a guide, l bought second hand for £650 and £550 (roughly $1500) in the UK. One would be enough but two for me are best as you don’t have to drive a single sub so hard. Less chance of a bake off frying incident. You will take a risk of course with no warranty, but the choice is yours.

Modes, Nodes and Anti-nodes (sounds like something out of Star Trek)

A well known fact…… A stereo pair of subs actively reduce extreme room modes (and within my own experiences).  The sound waves emanate from different areas and bass dispersion is more uniform. Of course there are people with multiple subs, and stacked subs which are an altogether different room experiment.

Subs should be seen and not heard.

In other words……

1.  You can see the sub or subs (unless hidden behind furniture or out of sight)

2.  From the sub or subs, no attention sound wise should be apparent. (No sound appears to emanate from them)

If your sub-bass does not integrate and appear to be coming from your speakers and spatially within the musical performance then:-

       A. Your sub or subs are rubbish.

                               OR

       B. You have not set up correctly.

Subs should not attract musical attention to themselves. They should be fundamentally “seen, but NOT heard”

Magic happens if subs can become invisible as well. That for me truly demonstrates everything’s optimal and set up correctly.

Footnote

Just to avoid any confusion, Myself and the OP are talking about high level SpeakOn (Nuetrik) speaker level line inputs.

Nuetrik connectors are regarded by professionals as the recording industries highest standard, for their robust construction and connective integrity.

Speaker level inputs, not outputs. Oops

I think we all got that as a typo. 
Your observational reference about the general absence of line inputs…..

It constantly amazes me that hi level inputs are not offered as an industry standard on all decently priced (up market) subs. Why cut corners?  Maybe a deliberate marketing ploy by those manufacturers for a more customer perceived competitive retail price point versus the ones that do offer line inputs.  Hmmm

Well done Rel for taking the guess work out of it and offering line inputs AS STANDARD.

@mcraghead Go ahead and get that Rel T9x

At last the side of reason……

But others will say, joining the side of reason….. is not always a good reason.

@m-db 

Great advice there and overall analysis and choices to consider.

Rel recommend the bass crawl you describe. It is in their set up manual. They even suggest an actual CD track (from James Horners “Sneakers” Soundtrack) for a constant repetitive bass drum strike lasting several minutes, to find the best location.

Quite by chance l had it…….. l collect film soundtracks... Simples!

I started with a Rel Quake 20 years ago….added a second. Graduated to a T7 after one Quake failed after 15 years. So impressed with the T7 l bought a T9i. I have now sold on the T7 and bought a second T9i and now run a stereo pair.

l would have no problems recommending this company to friends or family. Rel only make subs…. It’s what they do.