[Help Needed] Dual 12” to dual 15” subs [or dual 12” + dual 15”]... Worth it??? [config w/dims, equip, performance, prospects and data inside]

[enthusiast_newb]

I recently got upgrade-itis, and I’ve homed in on upgrading my subwoofers.
Couple constraints:
- I'm married to my BDI cabinet… my choice cannot be taller or deeper than my cabinet (21”(H)x22”(D), I think that would look silly, and piano gloss wont match.
- I’m biased toward sealed, and want to stick w/sealed [hope to benefit from room gain]

What I’m considering [based on dimensions, constraints, and performance data I have found]: Starke SW15 or Rythmik E15/E15HP.


The data I can find suggests the Starke has ~4-6db output over the Arendals, from 25hz-100hz [anechoically].
That said, the Starke seems to have more distortion below 25hz [at the price disparity, I suppose that’s to be expected, I’m prob running into distortion anyway].

Unfortunately, I can’t find meaningful data on the Rythmik E15’s, I’ve attempted to extrapolate from the data off the 12’s and 18’s, but I don’t want to make a decision off extrapolated data, when the price is 3x that of the Starke’s.

I’ve seen/ read several reviews, which speak highly of both SW15 and Rythmik [in general].
Starke SW15 is currently $1000 [for 2], and Rythmik E15 is $2800 [for 2].
I expect both will have marginally better CEA2010 performance, over my [very good] Arendal 1961 1s…

Given the floor plan, equipment, and basic [current] overall integrated frequency response, and scope… here is my question(s):
Dual 12”s vs Dual 15”s…
Q1] Can I really expect to improve[increase] my overall bass response at a level that’s clearly perceivable, w/either upgrade?
Q2] Anyone have success integrating 2 12”s w/ 2 15”s?
Q3] Is this all really worth it?
OR
Should I just forget about this, and enjoy my… really quite awesome, current system. Saving upgrades for when I have a dedicated space,
and have committed to shelling out money, without being SO concerned w/penny pinching.


If I do pick up a pair of either… I plan to attempt to optimize the system to enable use of all 4 – I have a few placement arrangements in mind, to test in order to keep the aesthetic nice, and benefit from 4 subs… we shall see how that goes [ARC + miniDSP].
If that goes real poorly, I’m ok with a straight swap for now… and I will look to sell the Arendals… IF I can truly expect a meaningful, perceivable performance improvement.




My Configuration [mixed use/ open floor plan]:

My Current Freq. Response [w/small house curve]:

Datas for subwoofers of interest [w/current subs as ref]:

 

[shadyJ]

The Rythmik sub is certain to have superior performance, as well as it should since it costs so much more. However, if your destination is going to be four subs, you will probably have all the headroom you will ever want, even with the SW15 subs. A quad 15" system of any of these subs will have extremely low distortion as well. It's hard to ignore the value proposition of the Starke subs here. However, their main advantage over the Arendal subs is in mid-bass, not so much deep bass. You might swing for a sub that has more headroom over the entire LFE bandwidth. The Rythmik subs probably do. Another sealed 15" sub to look at in this category is the Hsu Research ULS-15 mk2. It's more expensive than the Starke, but it's higher performing as well as better-made than the Starke, not that the Starke is bad. I would just trust the longevity and reliability of Hsu more.