OMA - MONARCH Speakers DIY

Hello dear friend this is my first post and Greetings from Sakartvelo i think you are doing great job helping each other also shearing helpful information so I also need your help.

I saw oswaldsmillaudio/monarch series speaker and i fall in love so i don`t have 300 000 $ but i must have this speakers at home.
i am good at woodworking and i can build exact same cabinet by myself with custom dimensions, but i could not decide what drivers to use in this build so please help. also my budget is pretty limited max 400$ per speaker (plus minus 50$) also room dimensions for this peace of art is 26 feet X 26 feet X 19 feet (ceiling high ) i know that for 400$ i cant do much to fill this room with crystal clear sound but this design need some good sound, ( also i thought to build World's Second Best Speakers! with pair of full rage tang band w8-1772 speakers and attach wings and design to his built cabinet ) but horn on OMA Monarch speakers should be 3 way horn driver sorry for my English
 
As far as I know, it's 'just' a pair of 15in woofers in a triangular shaped sealed or vented box with extended front wings to lower the step-loss frequency right down to the point where room gain / modes dominate, partnered with their own compression mid-tweet and horn. So basically -pick whatever quality 15in woofers you can afford that suit your preference for sealed or vented loading, pick whatever quality compression mid-horn you favour that can get down to at least 800Hz, and likewise the compression driver. Without knowing your budget it's hard to make any useful recommendations though.
 
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If you pick one of the "ready to print" horns that are presented as STL files in the https://www.diyaudio.com/community/threads/acoustic-horn-design-the-easy-way-ath4.338806/ thread, chances are that the results are even better than the original OMA horn.

Something like this: https://www.diyaudio.com/community/...he-easy-way-ath4.338806/page-394#post-6760060 might work.

st280e-4-png.976425

That's the 280E,

The 260 is the default example from that thread but loads the CD a bit less:
https://at-horns.eu/ST260.html

But it's a free tool and with a bit of elbow grease, with the new version you can even make a petal horn but with smooth directivity control as a plus.
Just use more petals to come close to the OMA design. Printable in pieces as many users have demonstrated.
 
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As far as I know, it's 'just' a pair of 15in woofers in a triangular shaped sealed or vented box with extended front wings to lower the step-loss frequency right down to the point where room gain / modes dominate, partnered with their own compression mid-tweet and horn. So basically -pick whatever quality 15in woofers you can afford that suit your preference for sealed or vented loading, pick whatever quality compression mid-horn you favour that can get down to at least 800Hz, and likewise the compression driver. Without knowing your budget it's hard to make any useful recommendations though.
can you recommend any 15 inch subwoofer ,compression mid-horn and compression driver in 400$ price range?> i haven`t heard any speaker from parts express ( i want full range frequency response ) thanks for reply
 
I want to know exact parts compatible with each other sub+mid+horn
Maybe consider finding the 1.5" throat horn with the shape you like then asked the manufacture if they have any plans to mate it to a 15 and CD or something a DIYer completed. Otherwise you'll have to design an original crossover which isn't so hard anymore with current low priced and freeware tools.
 
Hello Forum,
Just a quick update on my speaker build—I’ve finally started working on it and wanted to share my progress with you.

🔧 Driver Selection:
Woofer: Dayton Audio DC300-8 (12", 8Ω)
Midrange: Dayton Audio MB620-8 (6", 8Ω)
Tweeter: Eminence ASD1001B compression driver with B-52 PHRN-N01 waveguide (8Ω)

📏 Enclosure Details:
I designed the box using WinISD. Here are the specs:
External Dimensions: 89 cm (H) × 40 cm (W) × 40 cm (D)
Net Internal Volume: 92.45 L (3.26 cu. ft.)
Slot Port:
Height: 3 cm
Width: 36.5 cm
Depth: 34 cm
Port Area: 263 cm²
Tuning Frequency: ~30 Hz

🎛️ Crossover:
I’ve measured the drivers independently and calculated crossover schematic that I followed, but I'm unsure how accurate or well-matched it is.
crossover.jpg



also, this are the pics from my build:

IMG_8638.jpg
IMG_8641.jpg
IMG_8652.jpg


this is measurement using Denon AVR Measurement microphone ( i know it is not suitable but i have destroyed my dayton audio measurement microphone while testing so i had no choice)
this is REW data :
IMG_8689.jpg


i want to point out that my room is not near perfect it is 8 meters wide and 8 meters long with ceiling at 7 meters high so i get no Bass i was looking for i want bass down to 30 herz please help how to achieve it /. i have asked ChatGPT and it suggested to widen port to 6.5 cm to get this bass but i think my room is issue so i will bring speakers to different room and test after 1 week


If you have any feedback or suggestions on the crossover design or box tuning, I’d love to hear your thoughts!
 

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