36" THTLP driver options

[Arcane]

Hi everyone.

So I decided to pull the trigger and get started on a THTLP build for my living room / home theater project. Space is limited, so I have to be smart with my design and therefor I purchased the LP version. My goal is punchy, precise bass with as much LFE possible without running into group delay issues. I wanted to follow all the recommended steps to get maximum performance, however importing two Dayton Audio rss390hf-4 15" drivers to my home country of South Africa is incredibly expensive given import costs, duties, etc, so I'll have to choose from locally available drivers. We dont have anything like a Parts Express here, so the options are chinese made "professional" style drivers or car audio.

My design has incorporated two of the 36" versions. I'd prefer not to have them 36" wide, as that means the bottom of my tv would be at least that high off the ground. I'd prefer to get it lower. I know they should be corner loaded for best performance (and I possibly have a solution for that if I can go with a slightly narrower cabinet without losing performance) but I obviously want the most low end extension I can get without losing too much of the available space in my living room. The space in between the two horn openings in the attached image are about 500mm, which is less than the prescribed 2.8ft / 850mm as detailed in this post: viewtopic.php?t=398

When it comes to driver choice, there are many posts on this forum stating the following:
Preferred driver T/S specs are fs 17 to 30Hz, Qts 0.3 to 0.55, Vas 100 to 320L, xmax no less than 9mm.
Drivers with fs on the high end of the range work best in narrower cabs, those with low fs are better in wider cabs.
Output is determined by xmax, so the longer the better.

That 2nd line caught my attention... I cannot find a locally available driver with an FS as low as the Dayton's 19, and when it gets even close to that, the QTS (damping) is way too little. It goes far over the recommended maximum of 0.55

After much research, the locally available brand who's 15" driver specs most closely match the recommended t/s parameters is Kicker Audio. I've narrowed it down to 3 candidates in order of highest to lowest XMAX.

https://www.kicker.com/app/tsparam/50CVX152.html
50CVX152
FS 26
QTS 0.321
XMAX 20.65mm

https://www.kicker.com/app/tsparam/43CVR152.html
43CVR152
FS 26.35
QTS 0.388
XMAX 17mm

https://www.kicker.com/app/tsparam/44CWCS154.html
44CWCS154
FS 25.55
QTS 0.5305
XMAX 16.1mm

Now finally, to my questions. (I know right?! )

1: Which of the listed drivers best suit my requirements, given the FS on all of them is on the higher end of the scale
2: As the FS is high, what exactly does "work best in narrower cabs" mean, given that I dont want to sacrifice low end output?

[Bill Fitzmaurice]

The driver Fs does not need to be 19, it needs to be between 17 and 30. Lower Qts is better than higher. The cab width is explained in the plans. Placing subs below a TV is a very bad idea. The low frequency output will vibrate the TV, the shelves and everything on the shelves. You also don't want two subs on the same end of the room. Determine the best location for the first via the subwoofer crawl (google it) then with both subs operating do the crawl again with the second sub. There's no reason to build two 36" wide cabs, with a pair of them 20 to 24" wide would suffice. Two 36" wide cabs would be sufficient for a 50 seat theater. As for group delay, that's an audiophool myth. Below 80 Hz you can't hear it. Above 80 Hz if you did hear it the speaker would be so totally flawed that you wouldn't be able to listen to it. 'Punchy' and 'precise' bass are also euphemisms used by audiophools. They don't define anything where acoustical engineering is concerned. Ask any audiophool what the correct acoustical engineering terms are for what they're trying to describe and the only sound you'll hear is crickets. As for driver sourcing, others in your area might be able to help, but we don't know where that is. You should complete your profile.

[Arcane]

Thank you for the quick response, Bill. Great aftersales support! Well, I definitely dont want to be an "audiophool". I simply appreciate good sound. My current setup is an Anthem MRX 740 receiver in a 5.1 setup. M&K Sound LCR950 speakers all round and the subwoofer is a Bowers and Wilkins PV1D which I borrowed from a friend. My hope is to use this THTLP build in order to replace his subwoofer. It performs well, but it's output is not enough for what I'd like. The room is 14.5ft by 13.8ft with an 8.4ft high ceiling and and it opens into a large open plan area on one side. Integrating the subwoofer into the tv cabinet was my attempt at utilizing the space as efficiently as possible. I am familiar with the 'subwoofer crawl' process, but as you can see from this top down view, there really isn't any other place the sub can go other than my front wall, due to the size and layout of the couch. I suspect that it means I'd have to look at a single 15 or 12's?

[Bill Fitzmaurice]

Even a small TableTuba will crush that PV1D, any of the full size TableTubas even more so, while a THT is to the PV1D as an Abrams tank is to a Mini Cooper. For the smallest footprint place them upright. I only use one TableTuba 2x4 and it's plenty.