Open Baffle Subwoofer built by Javad Shadzi - (just sharing here)
Some quotes from Javad on these.
Some quotes from Javad on these.
Unrestrained Mystery OB Subwoofer Finale
I designed and built an open baffle speaker system last year called the Unrestrained Mystery, you can read about it here: https://m.facebook.com/groups/DIYLoudspeakerProjecPad/permalink/1400546016967898/
In a small room they have great bass down to 40hz, in a bigger more open room they need some help below about 50-60hz so I decided to design a dual 15” open baffle H-Frame subwoofer using a pair of the newish SB Audience open baffle 15” drivers, the Bianco-15OB350.
This is an easy subwoofer to build with good in room response down to 20hz and below, this wont knock paintings off your walls but for any music they will play full spectrum bass to a solid 110dB 1-meter and sound great with movies too. A pair of these would add 6dB and be a very nice setup.
The dimensions of the H-frame are 36” tall internally, 16” deep and 18” wide internally. I used 1.5” thick material so outside dims are 37.5” tall not including the feet, and 19.5” wide. A top cap simply needs to cover the top and will be determined by your final material dimensions.
I am running the pair of woofers stereo off an Adcom GFA-555 with a MiniDSP 4x2 HD before that and the amp for the UM towers.
This is a very easy build, it could be done with 3/4” plywood easily but I’d recommend doubling you the baffle at least. I made this from 1.5” birch counter top material from Home Depot and it’s held together with pocket screws so it’s easy to disassemble if I want to move it.
I only used one EQ filter at 30hz, these don’t have a ton of excursion so you can’t get carried away with EQ, and 24db/octave crossover at 80hz which hands off to the towers also crossed at 80hz.
OB bass doesn’t interact or pressurize the room like a boxed speaker does, they are generally more forgiving of room modes, these sound great in room and really disappear, I’d like to add a second, that would be perfect for movies.
in general I really like the sound of open baffle bass, it actually doesn’t sound any different, it’s just not very efficient, but what bass frequencies are produced sound clean and uncolored.
As you can see the response of this subwoofer goes well below 20hz and it can produce 110db of bass at 1 meter and loud sounding bass in room. Two 15” ported subwoofers would use a lot less power to get there and get even louder, at least 6db.
Does 20hz OB subs sounds substantially different from boxed subs? not substantially, this subwoofer sounds clean and accurate, just like any properly designed subwoofer should. OB bass is also more immune to room modes so the bass sounds more even anywhere in the room.
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