David’s FT12 9.2 home theater
After I started a do-it-yourself project to optimize the bass range in my home theater, I ran across LoudSpeakerBuilding.com. So I quickly finished the two subs, and then it really started. I spent hours reading almost every DIY article, imagining in my head what you could do in a normal household with a jigsaw, a planer, a router and an orbital sander, and how I would be spending my time in the future (as if I had nothing else to do…).
Well, after a few Heco, Bose and finally Jamo loudspeakers, I read the article about the FT 12 and thought, “that’s the one for me!” For a home theater, and at least 7.2! Since I like to have everything at a single stroke and I love symmetry, I now had to build at least seven loudspeakers that would meet my visual needs and would also pass muster with the inspection bureau (my wife). I was very happy with my Jamo D570, but there was something missing. The form and design were great, but there was some trouble with the bass foundation, and all I had behind me were shelf loudspeakers. Well, fine then. The “FT12 masterpiece” with the little bass fireballs would need to show the Jamos what they could do!
I ran to the hardware store and bought the materials for the standard cabinet; I cut, glued, sanded, routed and primed them, and installed the hardware for the first sound check!
After the first sound check, or to be exact, 3 seconds after I had heard the loudspeakers, my decision was made – sell the Jamos and then make a lot of work for myself. The little FT12s are just amazing!!!! Now it was crunch time. I wanted the design to be similar to the Jamos because I liked their round shape, so I had to pull out my calculator, pencils, book of formulas and lots of spare time to make sure the required volume would work!
After hours of pondering and calculating back and forth, I ended up with the basic concept that I had already had in mind for a long time. So it was time to buy more materials and to explain to my regular lumber dealer that he needed to cut 180 sticks of 19-mm MDF for me, measuring 21 mm wide and 400 mm long. The large number was because I needed to build 6 FT12s for a 7.2 home theater, and flexible MDF was too expensive at that scale. I took some of the materials home with me right away, and the rest came later, bit by bit…
Then it was time to design the front. The first problem! With the stereo loudspeakers in the front, I wanted them to be as “clean” as possible so I wouldn’t have to stare into the bass reflex tube in the front. So I simply moved it to the back. There was no noticeable difference in terms of the sound. Second problem: the difference in size between the mid-range speaker and the tweeter doesn’t work AT ALL! So I made what might be the world’s first tweeter modification. After a lot of back and forth measurements, I had my mod in my head and down on paper. Time to implement it: I unscrewed the front panel of the tweeter and made it smaller. I sawed off the outer ring, which is only there to hold it on. The inner ring holds the magnet, and right in between them, the front is cut out just to the necessary size. Next step, grind down the edges and make it look neat!
Cutting out the front panels:
There is a gap of about 3 mm between the magnet and the baffle that you can use to keep the magnet and the baffle separate, and if you screw it in, it is more than enough to keep the tweeter stable.
Then it was time for the rest. I sawed, sanded and glued the boards for the cabinet, glued the sticks to the sides, planed them, sanded again, spackled, sanded again, and voila! The cabinet was done. Sounds easy and fast, but it wasn’t.
Anyway, now the front speakers were “done.” I changed the rear speakers a little bit because I thought they were too close to the wall behind me, if I wanted to put the subwoofer tube in the back. So now it is in the front, and the base turned out a little differently, too.
I covered all of the loudspeakers with white faux leather.
My idea for the lid and base plate was a custom-cut marble slab, but the volume and thickness made it a little beyond my budget. So wood had to do the trick again. I cut the MDF boards to size and rounded off the edges with the router. The effect is more than just visual because the paint is very rough – it made a nice rough texture that feels and looks great!
Now I needed to do the FrontHigh loudspeakers – the whole thing had evolved into a 9.2 system! After building 7 loudspeakers, though, that was easy. You just take the top part of the FT12 and build a simple, elegant cabinet.
The Center is also an FT12 (top part) with a few modifications.
On all of the loudspeakers, I put a couple of extra holes in the mid-range speakers (thank you for being so generous with the screws) to make them a little more unique – and they look better, too! For comparison, here is the original building suggestion.
And now for the final results: if anyone thinks it looks cold, don’t worry – I have a heater and a stove in case of emergency, so 28 degrees C is no problem.
One final comment:
I want to thank everyone for their support with the occasional problem, and for creating the loudspeaker-building page. Without it, this kind of project would be impossible. The sound is just amazing! And the little loudspeaker sounds so big that more than once I’ve had to prove the subwoofers were turned off during a listening test!!!
And my wife is excited about them, too. ;-))))))