Well, reading this post motivated me to register for the forums.  I've made my own "Bigger Betsy" baffles.  I bought a pair of Caintuck Betsys (with Lii Audio Fast-8 drivers) a few months ago and was instantly smitten with the sound.  Reading about the Decware Big Betsys on this site got me wondering what the Lii F15s would sound like.  So I built an upscaled Betsy baffle 30" high and 24" wide (my mathematically challenged calculation of a precise upscaling) from 3/4" birch plywood.  Worked pretty well but they could have been more rigid, so I'm just now finishing another pair of baffles with two sheets of 3/4" birch plywood glued together to make a 1 1/2" deep baffle.  Made them slightly smaller too, to better fit my small listening room (12' x 13').  They need a nother coat of finish but then they will be done.

I'll share photos when I've posted enough to earn attachment rights.

Ironically, I haven't heard the Betsy drivers.  My Betsys were shipped with the Lii Fast-8s because of an issue Randy had on his end.  I essentially got an upgrade from the Betsy drivers to the Fast 8 drivers.

So I can't compare the Fast 8s to the Betsy drivers. Actually, the only open baffle drivers I've ever heard are the Lii Fast 8 and the Lii F-15.  I'm a recent convert to open baffle speakers after building a Bottehead 300B Kaiju amp and needing SET-friendly speakers to go with them.  I had been Aerial speakers with a VTL amp, but the Aerials' low sensitivity wasn't going to work with a 300B amp, so I bought a pair of Betsys from Randy as a way to get my feet wet.

I was instantly smitten with the sound.  The Bottlehead amp sounds fine, but it's not a night-and-day difference from my push-pull VTL amp.  The Betsys, however, were a revelation after listening to conventional bass-reflex speakers for the last 25 years.  The immersiveness of the sound, the size of the soundstage: I found it intoxicating.

At Randy's suggestion, I bought an inexpensive subwoofer to fill in the Betsy's bottom octaves, but I still found the upper bass and lower midrange a little lean.  The Fast 8s sound terrific, and if I never listened to electronic music I could live with them happily, but they don't do, say, Radiohead as well as my Aerials do.

So after reading through the dozens of pages of Steve's "Big Betsy" thread on the Decware forums, I ordered a pair of the F-15s and decided to try my hand at building my own baffles--like Randy's, only scaled up somewhere between the originals and Steve's medium-sized Betsys.

Very good Larpy. I think you made the right decision. The fact that you won’t have to have supplemental bass is a money saver. I’ve yet to hear anyone say anything bad about the 15’s.

Now, get a Decware amp, and you will be set for a long time. Saying the ‘B’ word (Bottlehead) on this forum is not allowed🤓

Post pictures and give your impressions after you get things going!

As for the sound so far, in my experience, the F-15s need at least 50-75 hours of break-in before they sound the way they should. For the first 24 hours, I thought I'd made a big mistake: the F-15s sounded big but seriously muffled, and there was no soundstage.  The upper frequencies gradually filled in (though inconsistently).  I now have 100 hours or so, and they sound like I'd hoped:  like the Fast-8s but bigger, fuller.  They're not as detailed, but I'm hoping that will change with more break-in.

Even so, to get deep bass in my little room I'll probably still need a sub.  The F-15s are relatively linear down to 60 Hz, but they drop off quickly below that.  Maybe that will change with  more break-in, but I suspect it's the physics of my room and open baffle bass.

Hi Joey,

The amount of bass an open baffle will make is directly related to the surface area of the baffle.
The bigger baffles that Decware offers produce more bass than the smaller ones that I build.
Larpy is correct that the F-15 drivers drop off pretty quickly below 50 or 60 HZ ..... but the frequencies above that are very robust and there is the impression of deeper bass, especially in a larger baffle.

If you have a ZROCK and mount the F-15 drivers in a larger baffle, I am guessing that you will be happy with the results.

I use a small powered subwoofer in my listening room with the F-15 drivers in my smaller baffles. The results are very good in my opinion ..... probably because the subwoofer doesn't start contributing to the sound until around 60 HZ. The human ear is not as "picky" at that frequency as it is at 90 or 100 HZ .....

Happy listening,
Randy

I should add that the sound of these speakers is, after 120 hours or so of break-in, much like the Caintuck Betsys (with the Fast 8 drivers) only bigger, wider.  Significantly more bass and lower midrange.

I don't know if there's any advantage to the baffles I've built over the Lii 15 speaker Randy makes and sells.  I've not heard one.  But I enjoy the DIY aspect, and I was curious to see (hear) what difference a larger baffle would make.  Initially, I thought I'd contact Randy and ask him to make bigger Lii 15s, but I read elsewhere on this forum that he restricts his builds to the size that fit his shipping materials, so that option was out.