The Betsy Baffle Project


Well-Known Member
Oct 11, 2010
My recent DIY subwoofer project has gotten me all fired up and itching for another DIY project, and in my pursuit, I stumbled upon the Open Baffle Subwoofer built by Javad Shadzi. This was my introduction to OB, and although I have seen them in the wild, I did not give them much thought. I was instantly enamoured with the beauty and the simplicity of the OB design and delved into a marathon session of mugging up on open baffle fundamentals and design which lasted several days and was devoid of sleep. Office calls and solid food were promptly ignored during this period, because, priorities!

My interest in OB automatically made me reach out to @yogibear. While he was kind enough to hold my hand and recommend a combination, I was already scouring the net at full speed, and I came across glow-in-the-dark-audio's Kevin Davis’ build of the Lii Audio F-15; while I was fully fixated on this build amidst the glowing review, he mentioned that he came across the F-15 from all the noise on the Decware Forum. Enter the Decware Forum thread on Steve Deckert's Big Betsy Project!

After thoroughly reading all 32 pages of the thread, I knew that this project was for me, and I was going to build the Big Betsy Baffle with the F-15. I have always been a minimalist, and the idea of a full-range driver in an OB was enough to convince me on multitude levels.
1) It would be a simple build
2) Crossover-less
3) Reasonably priced and gorgeous-looking driver.
4) Tried and Proven design

I have taken the first step towards this project by ordering the Lii Audio F-15. They also have a new 15" full ranger called the Fast-15 with an improved magnet, which promises even better extension on both ends. I avoided this as I have not seen any reviews of it in direct comparison with the F-15.

I will be using this thread to document the project in its entirety. It might be convenient or useful for someone in a similar boat.
I have chosen to go with the Decware ZF15L size baffle for this project, and have taken ample notes from the forum.
For the keen, It's fascinating to read about Steve Deckert's journey on his evolution in thought and design process for the ideal baffle size and how materials play a role in the resonance of the baffle. It's also heartening to see his style of engagement and encouragement for his fellow members in the forum.

Here are a few pictures of the Big Besty Baffles, (the baffles were originally inspired by Randall Rash's barrel-shaped baffles of Caintuck Audio)

Randy's Version of the baffle with the F-15
Size: 22.5" tall x 17.75" wide at the centre. The top and bottom width is 11"


The Big Betsy Baffle by Steve Deckert of Decware Audio - They come in two sizes.

ZF15M (Medium Size)
Size: 36" high


Size Comparison
The smallest is Caintuck Audio, and the medium and large are from Decware, all with F-15. The one in the forefront is with a 10" Lii Audio driver.


The largest baffle from Decware along with the smallest from Caintcuk Audio (with a smaller driver, not the F-15, but the baffle size is the same)

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Add a side baffle on one side along the side wall, concealed behind the front baffle. Depth of side baffle could be dictated by simulating on Basta. It’s important to acoustically off centre the driver.
I'll do a test baffle beforehand once i receive the drivers.
With Samir (@yogibear ) guiding I am in the process of building one for Lii Audio F6. I simulated the response on Basta and as Samir commented above offsetting the driver rather than centered as in the Betsy models in those pics affect the FR and in a good way.

The response of Lii F6 on various heights from floor (H) and offsets (from left edge of baffle) below. You can clearly see the dip in the FR when driver is centered. See the legends for the numbers. The last two number indicate the baffle size (w x h)

To keep the Betsy shape for aesthetics Samir has suggested a good idea.

Lii Audio F6 on 800 x 800 OB various H and Offset (1).jpg

Driver centered on 800 x 800 baffle.jpg
I received several PMs asking about the shipping and customs process for my order of the F-15. Here's the update,

I purchased the driver on the 11th on the Lii Audio website, and as instructed shot them an email on the shipping charges. When they returned to me with a quote of $182 from FedEx, I requested that they check with EMS. And here's the latest.

Screenshot 2022-10-13 at 20.12.07.png

Screenshot 2022-10-13 at 20.12.36.png
I recently needed some stuff shipped from Australia to Mumbai. 2 cartons with a total weight of 20 kgs. The supplier has a business account with DHL and DHL quoted US$170 (~₹14000).
When I asked DHL India for their retail rates they quoted ~₹47000. The differential of shipping prices between companies having business accounts and having no accounts with these shipping companies is huge!!!

This is mostly irrelevant to this topic but it may help someone, somewhere, somehow.
I received several PMs asking about the shipping and customs process for my order of the F-15. Here's the update,

I purchased the driver on the 11th on the Lii Audio website, and as instructed shot them an email on the shipping charges. When they returned to me with a quote of $182 from FedEx, I requested that they check with EMS. And here's the latest.

View attachment 72584

View attachment 72585
I checked with Lyric Audio in Spain for F12 who are agents for Lii Song. Their shipping to UAE was Euro 95 around INR7000. Lii china did not respond to my email.
I had to shoo away mice to pull this ply out of storage. I have made a test baffle in medium size, measuring 35.5" tall and 29" wide.


Here's how the driver measures at MLP with 1/6 smoothening. The reading in RED is with EQ.

You got lucky with customs? Good luck building lovely open baffles
I have been told that Fedex and DHL are accurate with the customs duty, taxes etc nowadays and their clearing services are by and large efficient. The customs product master list is also growing by the day with appropriate duty structures. I think when our folks here try and fool around with bill values, its then when issues crop up mostly…….
FR in RED as measured by Steve Deckert for the Decware ZF15L.
The HF extension measures better here, questions, questions!

RED is the ZF15L and the GREEN is the ZC10.png
Initial Impressions!

I had initially envisioned building the biggest baffle in the Betsy range. I built a test baffle in a medium size and quickly realised that if these aren't entitled to replace my main speakers, then I have a storage problem at hand! and settled for the Caintuck Audio's baffle size just to be safe.

I resisted a thorough finishing job on the baffles as I wanted to ensure it was worth the effort and plugged them in first. I have never heard an open baffle before. From my extensive reading, I was primed for all of its attributes.

I Pulled them as far as my cables would let me, that's 54" away from the front wall, set them 4' apart, warmed up a SET (Single-ended Triode), and pressed play for Woong San to do her thing via WiiM Mini, and a miniDSP Flex hanging around in the chain. First impressions? Flabbergasted!

I had read about the OB's attributes on imaging, but this was absurd. I was hearing the speakers independently with zero centre image. Added to this, the left speaker was louder. It would be as simple as turning the gain control on the amp to remedy it. But what about the speakers refusing to come together as a pair? I moved around the speakers until it sounded "acceptable", including toeing in just one speaker. I had already a long day and wasn't keen on tweaking anything further, but just Itching for a nice listening session. I checked to see if @ssf was thirsty for music. He raised his hand and announced that his throat had dried up. I had just the remedy for this symptom.

As is @ssf s practise with any new equipment, he walked around the OBs with his hands locked behind, inspecting every aspect, announced that the F-15 has a sizeable magnet, and enquired about the newly acquired toaster with tubes. After quickly sorting out the concoction to remedy our dry throats, we settled down and pressed play.

The sound was nothing like I had heard before. It sounded OPEN", as if music let loose, uncontained, unleashed, as if it had no source or direction, it was room-filling like the entire room was the source for the sound! Also interesting to note was that the sound of the voices remained consistent no matter which part of the house I was in, superb off-axis response! Also interesting to note with regard to the measurement of this driver posted earlier is that there was enough sparkle at the top. It was not detailed, but pleasant.

There was no razor-sharp imaging that I was used to from the box speakers, but the soundstage was huge! The image floated 2 feet above the baffles and was revolving within the room, the experience was surreal! @ssf was turning his neck rearwards at times to check on a feeble note that swished past his ears. The image kept jumping between the speakers with no consistency, but immensely enjoyable nonetheless, as the tone of the human voice was nothing like we had heard before. It was palpable, pleasant, and soothing! It was a huge win for the OB project, and we spent the evening rotating different speakers and amps for flavour.

This morning as the sacred spirits departed, it dawned on me that I should check the miniDSP settings and BAM! I found the felon.
In my attempt to test the sample baffle that I had fashioned earlier, I had set a time delay on one channel to augment with the subwoofer. The image is now balanced and centred, and the nerves are calmed! The scale of presentation remains, but no more of that Auro-3d effect!

This is a fantastic driver for anyone considering an OB. A word of caution, I have not tried any other wideband driver to compare. But from a tonality and presentation point of view, this is a no-brainer. I suspect this driver will only improve as slogged. Immensely happy with this, and now I can go ahead and finish the baffle with a nice texture finish!

6AS7G Parallel Single-Ended Pure Class A, No NFB Tube Amplifier


Sabaj A30a


Betsy Baffles!



An evening toiled with the Quad S2, Sonus Faber Lumina 1, Sonus Faber Venere 2.5, and the Besty Baffles.

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A big thank you to @aeroash for inviting me over. It was a wonderful experience with quite a few first time listens. Vocals and instruments sounded wonderful on the open baffles. The Sabaj was impressive too. After listening to the Quads on the tubes, am seriously thinking of getting one for myself.
A beautiful, well-constructed speaker with class-leading soundstage, imaging and bass that is fast, deep, and precise.