top of page

December 2018

​

  • Bass bin build in progress.

  • 4 x Fane Colussus Prime 15XS per box (sealed)

  • 24" x 36" x 48" (around 500 liters internal volume before bracing)

​

  • Once drivers, bracing and stuffing added, I expect Qtc to be around 0.5 or even a tad lower. I like the sound of oversized boxes (technically called under-damped)

​

  • ¾” regular construction grade plywood with double thickness front and rear baffles and double bottom as well.

 

  • Roxul SAFE’n’SOUND used internally

​

  • ¼” thick metal plate to finish top. (~60 pounds of extra weight)

unistrut speaker reinforcing

1st failure... (or learning what doesn't work)

​

Added 3 uni-struts in back, to reinforce the panel. Screwed them in and used PL adhesive. Barely doing anything as far as "knock test" goes.

​

You win some… you lose some. Lesson learned.

​

Added 1 more layer of ¾” plywood in back to reinforce it more and result are better. Paint is cheap. Will have to repaint the back again I guess.

quad 15inch bass bin

In testing...

​

Preliminary sound test were very promising.

~260 pounds each bass module :)

​

Measurements to be posted...

Capture.JPG

DATS test of 4 woofer boxes. (series parallel connection)

​

QES and QTS is higher than specifications due to internal passive resistors added in parallel to each 15XS voice coil (4 x 26 ohms)

​

No resonance seen on the impedance trace:)

​

Note that impedance doesn't go more than ~22 ohms VS 100 ohms for Fane graph specification.

​

This is due to my 26 Ohms resistor in parallel to every driver tweak.

August 2019

 

I realized I never published the result of the bass bin. My bad.

​

Of course, in a rental house with limited bass absorption and a severely vibrating wooden floor, doing measurements below 200 Hz proved very tricky. The kitchen pots and pans are dancing and 105 dB at 40 Hz excites huge room mode.

​

The graph clearly shows 40 Hz peak. However, it is the room. Perhaps one day I'll go measure them outside and get the true result.

​

Also, not having done a prototype prior to building those two fridge sized boxes, flaws were discovered and the enclosure could use a "MKII" upgrade.

I'm currently building a 3rd enclosure (for a center channel), and incorporating a few changes to see how much better (or worse) it’ll compare to the original MKI. Stay tuned.

​

Nevertheless, below are some measurements with the microphone 6" away from the enclosure center (in the middle of the box, not middle of one of the 4 speakers, as this is about the worse measurement position.)

​

Time domain measurement (step response) is a bit long to settle. This clearly shows the " air spring effect" of the big sealed enclosure. I may go Aperiodic loading in the future to improve that, it usually work great.

August 2019

​

Rarely is anything is ever perfect on the first try :)

Modification time...

​

My enclosure weakest spots is at the center, (see picture on left) where it vibrates the most and relies on triple internal bracing, reaching the rear wall to reinforce the front.

​

The knock test everywhere on the enclosure is solid but not in the yellow area. It could use some improvement.

​

I added a 32'' x 48'' sheet metal, 1/8" thick to the rear in an effort to solve the issue. ( single 4' x 8' sheet that I cut in 3 equal pieces).

 

Internal bracing connect the now much stiffer rear wall to the front baffle. What a difference that made, happy.

​

The 32" x 48" sheet weighs ~50 pounds each...

My cabinets will now exceed 300 pounds each!

​

I have three quad 15 inch bass bins, at 300 pounds each, my next move will be expensive...

20200531_154929.jpg

June 2020

​

​New center channel!

​

-Bass bin is exact same dimension and construction as my original stereo pair seen above but I've painted it black. (used leftover paint)

​

-Use same 1/4" thick metal plate mounted on top and metal plate on back for extra weight and incredible rigidity.

​

-Used 4x Celestion FTR15 4080F as they had a wicked sale on them when I was shopping.

​

-I did not finished the side perfectly smooth as my plan for the next audio room will hide the side anyway.

​

-not weighted it but should exceed 300 pounds as well. The FTR15 driver is a tad lighter than the Fane 15XS prime as it has less excursion capacity.

Yet, it is much more that what I require, as usual, I maintained a margin of safety.

​

------------

​

You can see on top a 350 Hz Tractrix horn and the Radian 950PB mounted on it.  Ready for the move in my new home.

​

​

I should test them and post result one day.

I'm yet to listen to the Tractrix and the center bass bin...

​

bottom of page