Hi all,
I completed my latest project, a high value inexpensive build based on the Dayton MX15-22 drivers that were on sale a while back for a pretty deep discount from PartsExpress. Pretty decent driver for the cost when on sale. These towers are 50 inches tall by 20 inches by 20 inches. The slot port is at the top and exits behind it with a 3" x 18.75" opening and a total length of 34.6 inches. I modeled them in larger cabinets in WinISD and then built a physical model with scrap to verify my calculations for my port and my final cabinets show the 20hz tuning pretty precisely so I'm happy with how it all worked out. The front is double baffled and I used 1.5x2.5 stud for bracing. Each driver is powered by a single Behringer NX3000 that I got on deep sale (50% off) in bridged mode and they're handled by a miniDSP 2x4 HD. The cabinets are made with 3/4th inch ply that already had Birch veneer on them that I found at Lowes for an ok price and I stained them with Early American minwax and sealed with a satin poly.
50" x 20" x 20" Cabinets
Bass Reflex, 20hz Port Tuning Frequency
Net Internal Volume 8.2 cubic feet
Dayton MX15-22 Drivers (wired in series; 4ohm)
Behringer NX3000 Amplifier (Bridged; each)
MiniDSP HD 2x4
Cabinet 1 DATS V3 Impedance Sweep to verify port tuning frequency:
Cabinet 2 DATS V3 Impedance Sweep to verify port tuning frequency:
Near field measurement of the driver and the port to show the relationship and also examine the port's output which has a nice gentle peak SPL output at the 19~20hz area.
Here's the two towers referenced at 95db individually and then with time/phase alignment in the miniDSP to get a summation result in in the dark blue line. The final net summation gain is about +5db from 17hz to about 60hz. No smoothing applied.
And finally, I use the summation results to then apply a heavy house curve EQ that has an overall 15db slope down to 19hz; again no smoothing applied. The room is 18 feet x 14 feet x 8 feet. Currently I have -6db in the miniDSP on the output as I have lots of headroom still from the summation gain and was peaking 115db while watching a few heavy scenes with my AVR at -12 and -10 to get an idea of things while auditioning and running REW RTA to see the peaks. So the amp limiter lights never blink and I'm comfortable with the 110db peaks. More than that and It starts to be too loud for comfort. At max output, everything rattles and shakes, and I'm not about that kind of noise. Overall they effortlessly do their job with lots of room to spare.
Very best,
I completed my latest project, a high value inexpensive build based on the Dayton MX15-22 drivers that were on sale a while back for a pretty deep discount from PartsExpress. Pretty decent driver for the cost when on sale. These towers are 50 inches tall by 20 inches by 20 inches. The slot port is at the top and exits behind it with a 3" x 18.75" opening and a total length of 34.6 inches. I modeled them in larger cabinets in WinISD and then built a physical model with scrap to verify my calculations for my port and my final cabinets show the 20hz tuning pretty precisely so I'm happy with how it all worked out. The front is double baffled and I used 1.5x2.5 stud for bracing. Each driver is powered by a single Behringer NX3000 that I got on deep sale (50% off) in bridged mode and they're handled by a miniDSP 2x4 HD. The cabinets are made with 3/4th inch ply that already had Birch veneer on them that I found at Lowes for an ok price and I stained them with Early American minwax and sealed with a satin poly.
50" x 20" x 20" Cabinets
Bass Reflex, 20hz Port Tuning Frequency
Net Internal Volume 8.2 cubic feet
Dayton MX15-22 Drivers (wired in series; 4ohm)
Behringer NX3000 Amplifier (Bridged; each)
MiniDSP HD 2x4
Cabinet 1 DATS V3 Impedance Sweep to verify port tuning frequency:
Cabinet 2 DATS V3 Impedance Sweep to verify port tuning frequency:
Near field measurement of the driver and the port to show the relationship and also examine the port's output which has a nice gentle peak SPL output at the 19~20hz area.
Here's the two towers referenced at 95db individually and then with time/phase alignment in the miniDSP to get a summation result in in the dark blue line. The final net summation gain is about +5db from 17hz to about 60hz. No smoothing applied.
And finally, I use the summation results to then apply a heavy house curve EQ that has an overall 15db slope down to 19hz; again no smoothing applied. The room is 18 feet x 14 feet x 8 feet. Currently I have -6db in the miniDSP on the output as I have lots of headroom still from the summation gain and was peaking 115db while watching a few heavy scenes with my AVR at -12 and -10 to get an idea of things while auditioning and running REW RTA to see the peaks. So the amp limiter lights never blink and I'm comfortable with the 110db peaks. More than that and It starts to be too loud for comfort. At max output, everything rattles and shakes, and I'm not about that kind of noise. Overall they effortlessly do their job with lots of room to spare.
Very best,
Last edited:
Haha, I had to. The humidity in Florida is unreal and it's been storming all November and quite a bit into December. So most of my building I have done inside on a tarp and used weights in the form of water jugs and lots of cheap clamps (Harbor Freight, $6~7 a piece). I did the staining outside in my shed to avoid the smell.
Each tower was under $600 USD (that's cabinet materials, it's own amplifier, wiring and terminals, driver, etc).
Looking back, I wish I would have thought about doing 48 inches x 21 inches x 21 inches instead, to save on extra cutting. Sigh, dunno why I was so hung up on 50" when 48" would have been so much simpler to cut.
Very best,
20 by 20 inch sides?
Perhaps I'm too Old School in my beliefs, but it seems to me that manufacturers have always held to a strict principle of not having two identical cabinet sides due to resonance/reflections that could result.
There was an article on this by a leading speaker maker in the past describing this issue.
Perhaps I'm too Old School in my beliefs, but it seems to me that manufacturers have always held to a strict principle of not having two identical cabinet sides due to resonance/reflections that could result.
There was an article on this by a leading speaker maker in the past describing this issue.
Yes, 20" x 20" give or take a few mm. Those resonances you speak of would manifest without bracing. But with bracing, they're not there in an appreciable way. 64% of the two walls are also part of a large long port. The front wall has two baffles and a cage bracing of studs. Each wall is stud braced every 8~10 inches on all 4 sides. The inside of the port is fully braced down the center. 8~10 inch total distance from one brace or corner joint to another in the entire cabinet.
Very best,
Youch, that looks heavy!
With the driver installed, I don't want to ever lift it, but will move it with a dolly/hand-truck. The cabinet itself without the driver, I can pick it up and carry it, but I won't want to do that in 20 more years.
Very best,
Thanks! They're fun so far.
What kind of build are you doing with them?
Looking back, with this project, I sort of wish I had made them 48" tall (to save a lot of time and material effort for cutting, mine are 50" tall and I'm a dummy for not shaving the height to save cutting time, I just got hung up on wanting taller cabinets and 2" just isn't much), and I think I should have gone up to 9~11 cubic feet instead and pushed down to about 17hz on the port. Then again, when I look at my RTA graphs, there's next to nothing below 20hz and I built these for movies. 99% of the movies and shows we watch, nothing below 30hz is really in the show/movie, some have it down to 20hz, but it's not often, just some major scenes. So when I think about going into infrasonic, I snap back to reality in that in my reality 99.999% of our content simply doesn't have anything below 20hz to even playback so building for it would basically be for the sake of measuring it and having graphs and that's about it.
We like to look at them though. Big tall wood cabinets. We like the break away from the utilitarian look of black coffins.
Very best,
Ive posted on avait forum and you replied.
It’s a table subwoofer. Going for dual opposed driver, ~2.5ft^3 sealed box. Illustrated with um15 in the screenshot, but cost of the um15 is a bit high for buying 2.
Yeah, totally understand this. As much as I like the look of big subwoofer box with black paint, I really like when people do something more “special” with their box.
Attachments
Looks great, I hadn't seen what you finally settled on building, looks like it will be nice!
Very best,