SB Acoustics 2-way as gift, bass alignment?

I am working on a gift for my father-in-law. looking for advice on bass alignment.

I have previously built the speakers you can see in this thread https://www.diyaudio.com/community/threads/3-way-w-sb-acoustics-ceramics-woofer-choice.348896/

My design is for an approximate 0.5 ft3 or 15 L box with a SB17 woofer and SB26 tweeter in a 6" elliptic waveguide.

Have the choice narrowed down between 2 passive radiators, or a 2" port.

1. Passive Radiator: SB15SFCR-00
https://www.madisoundspeakerstore.c...b-acoustics-sb15sfcr-00-5x8-passive-radiator/
Very similar to what I see used on commercial speakers with a 6" woofer. The F3 I am seeing is a bit higher than I would like, but my in-laws are by no means bass heads.
F3 51.1 Hz, F6 43.0 Hz, F10 37.2 Hz

2. Passive Radiator: SB20PFCR-00
https://www.madisoundspeakerstore.c...acoustics-sb20pfcr-00-passive-radiator-round/
With this I get a deeper extensions, but the moving mass is quite high. Having not worked with passive radiators before will this lead to "slow" response.
F3 46.9 Hz, F6 40.0 Hz, F10 35.1 Hz

3. Ported: 2" flared port
No surprises here, just an 8" or 20cm flared port.
F3 45.6 Hz, F6 38.9 Hz, F10 33.2 Hz

I have some desire to use a passive over a port as placement will not be ideal and it could be fun to do something different. Perhaps this is all moot if I decide to cross a sub at 80-120 Hz.

Details that will help guide advice. These will be placed on a large TV console. It is low and fairly deep, speakers would be about 12" from the back wall. Console is probably 96" wide. The room has a horrid echo, stone floors and ceiling height stone on the kitchen at the side. My in-laws live in Shanghai, so will be hand delivering the speakers my next visit. Will buy the electronics (integrated amp) when I am there. May also get a reasonable 12" powered sub as the room is quite large (estimate 18 ft by 40 ft).

Picture of design concept:

1716082867654.png
 
I use the SB17CRC-8 and a SB26STCN tweeter in a 7"x12"x9" bookshelf. 4th order filter on the woofer to really push those cone breakup resonances down, and a 3rd order with tweeter.

I am using a stuffed sealed box, using denim insulation.

Really good low end on this speaker in a sealed box. Meaningful 35Hz, not much audible below that tho. And quite tight sounding on drums and percussion.
 
Cooked up a crossover. Tried a few things with different cross frequencies, filter orders, and adding a notch. I think this simple filter will do what I need. Huge dip at 150 is the floor bounce. Directivity doesn't line up as well as with the smaller midrange and waveguide in my other build, but good enough at the 1.8kHz cross over.

Decided to go ported, the location does have some room to breath and it is just easier and cheaper at the end of the day.

Going to order parts and start the build soon. For the cost curious it will be about $500 in drivers and cross over parts, $200-250 to MJF/SLS nylon print the waveguide (may go for glass bead filled this time), have the $60 in MDF on hand, tools on hand (~$1k for table saw, router, etc.), veneer will borrow from my stash of raw wood Bolivian rosewood (would be $150 for a decent sheet).
1716561254709.png
 
I’m by no means an expert, but if I’m not mistaken you can often physically add mass to a passive radiator to lower its resonant frequency. If one PR has a slightly too high Fs and one has a slightly too low fs, adding a bit of mass to the high fs PR will give your desired frequency.