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Pictures from the Loudspeakerbuilding community to this speaker kit
Corresponding articles from our community
Berlin school project
To create happy ears, eyes and faces, all you need is wood, a little know-how and some friendly support from Intertechnik. What the above equation is trying to represent, with just a few pictures and the charmingly beautiful results, is the process that eight craft, music and technology-loving students at the Beethoven Oberschule in Berlin-Lankwitz enthusiastically completed over the course of the last semester.
After a friend told me about the possibility of building your own loudspeakers, I put together a Quickly 18 assembly kit for myself. Then it occurred to me that we could bring “box construction” to our school as a group project. The positive response surprised me; after a short demonstration during recess to pitch my idea, we collected two full pages of contact information from interested students. The first eight took part in the project, and in this report they talk about what they experienced and learned during the construction phase and while listening to the boxes at home.
L. Mühlfeld, Berlin August 2012
Juan, 10th grade Model: Quickly 18
Dear box donors,
I am very honored that you gave us these boxes almost for free!
When the project was first introduced, I decided right away that I wanted to be involved. That’s partly because I’m a huge music fan, and partly because it would help me meet a lot of new students I hadn’t known before. I also got to know a different side of the teacher who organized the project. It wasn’t like just being in class.
Besides, building the boxes was really, really, really fun! We met in a classroom (almost) every Friday after school. We listened to music, talked to each other and of course we had a great time!
When we needed help, our teacher helped us out or we looked at the instructions, of which we had plenty. The other thing I really liked was that not only was it fun, but I also learned something about working with electronics, which I hadn’t really ever done before.
Just a couple of comments about the excellent sound of the boxes: when I was done with them, naturally I was dying to find out how the sound was. After just a quick demonstration, I was incredibly excited! Right from the start I had been looking forward to making my own boxes, but this project exceeded my expectations. To be honest, I hadn’t expected that the sound would be soooooo phenomenal!
Finally, I’d like to say a few words in conclusion. The box-building project is highly recommended as a project – above all, it was a wonderful experience. I would definitely repeat the project if it’s offered again. As I said already, dear readers: I highly recommend it!
Yours truly, your box-building team member Juan
Timo, 10th grade Model: AX-6 Hr
Dear INTERTECHNIK team!
Heavy loads you helped me carry
For smaller things you heard my call
I just want to quickly thank you
For all those things both large and small
Thank you very much for very generously donating the speaker boxes. We had a really great time gluing, soldering, painting, sawing and sanding them.
The new white boxes are a super addition to my room, and they contrast brilliantly with the red wall. The sound is phenomenal. If you close your eyes while you’re listening to music, it feels like you’re at an amazing live performance.
Thank you very much,
Niklas, 11th grade Model: Quickly 18
I walked into the room and there were big cardboard boxes everywhere. The others were there already, so I was too late to help them carry things. After I noticed how everyone was hanging around the boxes, it was obvious: here they were. The assembly kits were here!
Now it was time to start unpacking and sorting everything. It turned out to be a smart idea to make an overview plan with little sketches of the various parts and the associated numbers. Also very helpful for future professional builders.
Then we got started right away. Since I hadn’t bought my boards yet, I started with the technology. It was really amazing to see the individual parts of a speaker, and especially to put them together myself by hand when normally they just come ready-made off the assembly line. I printed out the circuit plan and got to work with the soldering iron. It worked great, you just have to avoid breathing in the soldering smoke or you’ll get dizzy. My strategy with the electronics was to glue everything to the provided circuit board and then solder the ends of the respective parts together. That worked really well, too, because the ends always had a little bit of extra wire that you could also cut off if there was too much.
When I did finally buy my boards, I decided to finish the wiring first anyway. The second circuit came much easier with practice. What’s really fun is doing a project with recognizable results – the box, the sound. It was still going to take a while, though, since now I had to get started on the cabinets and they each needed a week to dry. That meant a little bit of rough hand-crafting, too. Sanding and cutting them to size temporarily covered one corner of our workshop in sawdust. In general, it was a really great atmosphere – our teacher played his finished speakers for us, so we could hear how our final results would sound.
Once the cabinet was finished, I painted my boxes classic white. At first I thought it would make a good foundation, but then I realized they actually look really nice like that, so I left them white. Totally sophisticated! After collecting a permanent souvenir of the project in the painting process – a paint spot on my sweater – I took them back upstairs and started installing the electronics. I was starting to feel some time pressure because I had decided to give the boxes to my father for his birthday and it was only two weeks away. So I had to take full advantage of the two remaining weekly sessions.
The speakers were wired, the electronics were screwed in, and the first box was more or less finished. Then Mr. Mühlfeld came up with the idea of trying it out right away. We connected it directly to his professional party stereo system and listened excitedly. It worked! The music was totally clear and crisp, like from a commercial box. Then we connected Mr. Mühlfeld’s box again. With the immediate comparison, we did notice that my speaker sounded a little duller than his. We thought about it for a while until my teacher said, “Well, you have the insulation in there… hmm…” No, that’s exactly what I had forgotten. Dammit! So I unscrewed the loudspeakers, put the insulation in and reattached everything. And voila – once it was connected, the sound was crystal clear! It was amazing. I could hardly believe I had built the box myself. Everything – the electronics, the cabinet, the paint. It’s a great feeling to have built such a familiar, often-seen electronic object myself. And now I know what the thing looks like on the inside. I even finished the two speakers in time for my father’s birthday.They still smelled like paint, and the boxes worked. My father was really happy, and at first he couldn’t believe I had built them myself. Even today, whenever he listens to music on his stereo through the homemade boxes, he always says, “Thanks Niklas, what a great present!” It was really a great project and a lot of fun. I also want to thank our teacher again, who made it all possible because of his ambition. Thank you! It’s super fun, and the final results are fantastic. Doing it yourself is really worthwhile!
Vanessa, 12th grade Model: Quickly 28
“We’re leaving together, but still it’s farewell.” Those were the first lyrics I heard from my new boxes at school, preceded by the spectacular intro to “The Final Countdown.” Naturally at the corresponding volume, since we wanted to appropriately celebrate the two months of work I had put into them.
But it’s definitely worth it. After all the wood-cutting, sanding, gluing, drilling holes, sanding again, six (!) coats of paint, soldering, laying cables and screwing things together, I am extremely pleased with the results. Now I have two “Quickly 28” boxes standing in my room. They not only look good, they also provide outstanding sound, considering I had really awful speakers before. What I especially noticed in addition to the great bass was that you can still hear a lot of detail even at low volume; they don’t get swallowed up. Besides, you always feel proud about having built your own acoustic equipment – how many people can say they did that?
In that sense, there’s also a connection with the Europe lyrics, even if it is quite melancholy: I’m taking off with my finished speakers, and saying goodbye to the time I spent creating them.
Julius, 10th grade Model: First Time 12
I chose the “First Time 12” for our school project. I looked at the description ahead of time and thought about it for a while. What I expected: a detailed sound!
It was fun building this box, since it turned out to be a little more complex than I thought, and during the assembly phase I got more and more excited about the results. Some of the manual labor was really hard work. The final results completely confirmed my expectations. Extremely clean high notes and a strong, hard bass. The mid-range speaker combines these two “tonal worlds.” Of course I tinkered with the sound a little and set the equalizer up accordingly… but the sound was very impressive. I also thought the construction was very elegant, especially because of the slightly hidden woofer.
Akira, 9th grade Model: Quickly AX-5
Music is something wonderful. Everyone listens to it, everyone loves it, and if someone doesn’t listen to music, he’s probably deaf or doesn’t know about it yet. But out of all the places you can listen to music, my favorite spot is inside my own four walls. For the last few years, I had a couple of speakers and a small bass box in my room, worth about $60. The sound was correspondingly basic.
But then a young, dedicated teacher at my school had the idea to help a few selected students build their own boxes, and I was totally excited! I chose the Quickly AX-5 speakers because they were not only relatively large, but their angled fronts also gave them an unconventional shape.
Building the boxes was pretty interesting, and it was obvious that everyone had fun doing it (and of course we had music going in the background the whole time). By helping each other out, we all finished our boxes in “just” half a year (well, we only had one day a week to work on them, after all).
My friend connected his amplifier to the boxes, excited to hear how they would sound. I picked out one of my favorite tracks on my iPod (Marsimoto – Eine kleine Bühne), and we were both speechless:
The bass, with its perfect rhythm, made everything in my room vibrate. The high notes – especially Marsimoto’s high-pitched voice – reached deep into my soul and switched off everything else around me.
Mr. Westendorf, 1.grade Model: Quickly 18
As I write down my impressions here, I am enjoying the beautiful, full sound of the boxes that I built for myself after all (Quickly 18).
I wasn’t actually planning to build any for myself, although I needed some – I had moved, and it was a good opportunity to swap out the old dogs attached to my stereo system – but naturally I was planning to buy some in a hi-fi shop somewhere. It didn’t occur to me at first to build my own, but I decided to do it when my colleague Lennart happened to mention the project. He was planning to build some speakers with his students to teach them the basics of electronics and acoustics. So I joined the group, even though I’m notoriously short on time and I had no idea how I would fit an extra hour of speaker-crafting into my week. But now the boxes are finished, and I’m very happy with the way they sound and look – they’re exactly the kind of thing I wanted to buy for myself.
Building the boxes took a fairly long time, since the box assembly group could only meet one afternoon a week – Fridays after 8th period – and I couldn’t make many of the dates. But if you add up the actual project time, it was surprisingly very fast.
What I really enjoyed was the wide range of handicraft activities – gluing, sanding, soldering, puttying, screwing, painting, etc. – and working as a group. The atmosphere was relaxed, we had good music (and the finished boxes were tested right away), the assembly was uncomplicated, and you could exchange tips and see how others did things. Overall, it was a good experience, with very pleasing tonal and visual results.
Thank you from Mr. Westendorf
Naturally, we all want to thank Intertechnik, the assembly-kit specialists who made our box-building project possible through their generous donation. We all had a great time exploring the insides of a loudspeaker and understanding the technology behind it. There’s nothing mysterious about building your own boxes if you use the many well-documented suggestions on this page – we recommend it to everyone who hasn’t dared to try it yet.
The box-builders at Beethoven-Schule Berlin-Lankwitz
9.2 ways with Davids FT12
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. ;-))))))
The FT 12 by Thomas
It’s been more than 20 years since I built myself a pair of Alto pedestal boxes. And it was just over two years ago that I sold them. I’ve been getting by with a couple of unremarkable Control Ones ever since. Until last spring – while the weather was still cold and dark here – when a good friend brought over an issue of a do-it-yourself magazine. We listened to all kinds of CDs on my freshly restored Harman Kardon, and philosophized about the loudspeakers described in the magazine. There it was again, that feeling that I wanted to build something of my own, to really enjoy music again and even lose track of time so often. Like many of you, I came across this magazine online too, during a specific search, and got hooked.
I decided on the FT6, which I thought was very interesting because of its band-pass filter and compact structure. One Sunday, I sent off an email asking about the FT6. The response came right away: we don’t make the FT6 anymore. But the FT12 is basically its successor. I went back to the magazine and looked up the FT12. Yes, the blue cube looks very compact.And a 3-way band-pass filter? That sounded interesting, not to mention highly promising. Once I had discovered Christian’s ingenious version of the FT12, my mind was made up, and I ordered the assembly kit the same day. The package was delivered just as promptly, by the next Tuesday.
I myself am not quite that fast. Another two weeks went by before I finalized my assembly plan. I was imagining a cabinet that was just as compact as the original box, combined with the wonderful curve of Christian’s FT12. I live in a small half-timbered house with 5-foot-9-inch ceilings in the living room – which has trained me to adopt a humble kind of posture – and with a pitched roof in my “music chamber.” So a pedestal box is out of the question. I sketched some designs on paper and tried to determine the volume of the three chambers. Since integral calculus seemed too complex for finding the parabolic and elliptical areas, an estimate would have to do.
But how was I going to manage the curved side walls? Constructing the sides with six or seven layers of bent plywood was too complicated for me. And the method of forming them with vertically glued wood strips, the way Christian did with his FT12 and Matthias did with the beautiful Duetta Standtop, still didn’t give me the right thrill. Once again, a succinct email helped me out of the fix. The tip was to look for slotted MDF, which is also sold under the name of Topan. To my surprise, our village cabinetmaker had several boards of it in stock.
I took the plans for the baffle board and the three horizontal boards to my woodworking neighbor. He also got the #16 MDF for me, for the assembly. Meanwhile, I had the cabinetmaker cut the slotted MDF to order and glue on some macassar veneer. That saved me the trouble of adding the veneer later once the cabinet was built. The expert waved away my concern that bending the veneered MDF would cause the macassar layer to crack. And he turned out to be right.
The skeleton emerges
The preferred substance for gluing is joint glue. The trimmed boards were easy to fit together, in just two steps. First, I connected the baffle board and rear wall to the lower frame and the lid of the box. Then the two separators were attached inside with glue. By then it felt like I had sweated out more liquid than was in the crate of mineral water weighing it down. The volume separator for the bass and tweeter/mid-range speaker, consisting of a horizontal and a vertical board, did not want to stay in position and kept sliding around. I was finally able to use a clamp to convince the boards to stay in place. The finished skeleton gives you a good idea of what the FT12 will look like.
Sanding, part one
Since I had glued the baffle board and rear wall to the horizontal boards, I needed to sand off the projecting edges on the sides and adjust them to the radii of the sides. It was a welcome excuse to buy myself a belt sander. Equipped with #80 grit, the tool smoothed out the edges in no time, making our terrace look like it had been in a sandstorm. Good thing it was supposed to rain the next day. The transitions with the radii needed more fine motor skills to get them sanded halfway decently. What I found incredibly helpful was lowering my visual standards for the final product, since the three horizontal boards and their radii are not perfectly aligned.
Attaching the first curved layer
I spent a long time pondering the best way to glue the sides onto the skeleton. I researched it online and read other building reports. There is the method with the opposing frames, which Frank perfected with his Minetta. That sounded ingenious. Other people use clamps, wood slats and ratcheting tension belts to hold them in place, but my options were fairly limited, so I had to improvise. I hoped that the jigsaw would magically create something like a frame, with an even radius, from a 40-mm-thick board. But none of them were the same size and the radii didn’t match the actual curves on the box, even though I was working with a drawing template. How was the pressure supposed to be distributed evenly throughout the curved surface? The tension belt method didn’t seem safe to me. The images of the cracked MDF from Frank’s building report had been burned into my brain. But it was the only option I had. I discussed the possibilities with a friend, who told me to attach the first layer of flexible MDF with screws as well as glue. That sounded doable. I fixed the MDF boards in place and drilled another 20 holes with the same core diameter as the 3.5 x 25 Spax, then countersank the holes. But what was that? The MDF was splitting along the lower frame! I was reassured by another email: simply glue the crack together with joint glue (hmm… maybe that’s where the name comes from). I glued on the first layer of flexible MDF with the smooth side facing inward. I applied the glue to the skeleton, placed the board on it and attached it with the screws, starting from the center. The glue that was squeezed out on either sides told me whether or not the pieces were attached evenly.
Up to that point everything had worked well, and I was fairly optimistic. Meanwhile, I had glued the crossovers together, wired them, and anchored them into the cabinet with hot glue. Here, too, I had some help from afar, with a glance at some pictures of my crossovers. I had a healthy respect for gluing on the veneered sides, since I couldn’t attach those with screws. In order to force the veneered flexible MDF to fit the radius, I had to press it on. I did some “dry runs” with tension belts, clamps and a couple of boards, and I made some markings on the edge of the lid and the tops of the side pieces that would need to align in order to make the overhang about the same in the front and the back.
I squeezed joint glue across the surface of the ribbed sides of the first box, and spread it out evenly with a piece of cardboard. Then I leaned the two veneered side pieces against the standing cabinet – veneer facing outward, everybody. :) I quickly tightened the four tension belts with wood caps so that the MDF would lie tightly and evenly along the curve, always making sure the markings at the top weren’t misaligned. The MDF didn’t fit exactly at every spot, but I consoled myself that the joint glue would fill in the small gaps and hold it in place.
After 18 hours, I finally dared to open the package. When I rapped my knuckles on it, it sounded the same all over – a good sign. I did the same with the second box, and then it was back to sanding.
Sanding, part two
Now the front and back overhangs on the side pieces had to be evened out. Once again I went for the belt sander. It was Sunday, and I had the place to myself. To keep from bothering the neighbors, I set up a sanding corner in our 200-year-old vaulted cellar where I could make as much noise as I wanted. It took me five hours to get both of the cabinets sanded smoothly, using #240 sandpaper.
I covered the veneered surfaces with paper. Then I puttied over a few of the more obvious defects. Since I didn’t have much experience with puttying, though, the results were mediocre. The sharp edges of the MDF kept showing through as I sanded. I set up a temporary painting corner in the attic. First I followed the cabinetmaker’s advice and gently sprayed the cabinet with paint, closing the pores in the MDF and creating a foundation layer for the filler. This was followed by three cans of spray filler, which I distributed among the two boxes in several steps. The uninsulated attic was so hot that the spray filler particles dried before they even got to the surface of the MDF – at least, that’s how I explained the numerous “blemishes” to myself. But the blemishes had to go. I took care of them with an orbital sander and #240 grit. Now the recognizable shape of the loudspeaker had a good surface feel, too. The projecting edges and a few other small irregularities were still visible, but that was fine. I wanted to be listening to music by the end of the weekend, so I decided against buying another can of Premium White at Toom. One can would have to do it, and I put it mostly on the baffle board and the lid. I was less careful with the rear wall, for practical reasons.
Sanding, part three
Now it was time to go back to sanding. I only treated a few areas of the painted surfaces with #1500 wet abrasive paper, since this time my focus was on the veneered sides. As soon as the paper was removed, the contrast between the white paint and the dark wood showed up very nicely. I used #240 and #400 sandpaper, mostly by hand. Then I oiled the veneer with linseed oil, which I thought looked pretty good. All that was left was the sound equipment.
Crap, I had cut the provided wires a little too short. Maybe I should have positioned the crossover lower down. For the mid-range speaker, it took a delicate touch to solder the wires onto the solder tabs. A third hand would have been helpful, but in the end it worked out fine. After the chassis, I installed the simple pole-piece clamps, which had been a splurge. I like them better than the black plastic containers. I quickly tapped in the bass reflex tube – oops, I broke it off. The hole diameter was a little too small. Now what??? I remembered the pragmatic approach often mentioned here in the past, and reached for my hot glue gun. It solved the problem by bonding the tube to the baffle board.
In the mind’s ear
A moment of uncertainty. The loudspeakers were connected to the amplifier, CDs at the ready. Would everything work on them? What about Katie Melua? Later! First, Eddie Vedder’s Ukulele Songs. And they sounded great! Vedder has a beautifully deep, gruff voice, and there was plenty of volume. Then came the others. From Dire Straits, Sade, Pink Floyd, Marla Glenn and Supermax (“World of today,” 1977), to Stevie Ray Vaughan, Björk and Mando Diao, all the way through to Sven Väth’s techno classic “The harlequin – the robot and the ballet-dancer,” I listened to all of my CDs. It was a pure joy !!!!!
Thank you for your advice, tips and endless phone calls. Thanks also to those of you in the community, for your creative building reports and the many helpful hints I found in them. I just have one problem now: I could become a multiple offender. It was really fun building the boxes. After all, the little guy wasn’t called the “FirstTime” for nothing, right?
First Time 12 by Nils
My First Time 12
I ran across the First Time 6 in a forum, but there was one problem. I ordered the assembly kit from an online supplier, and despite the guaranteed availability, it never arrived. I only found out by email after I had finished the cabinets for the FT 6, with just the cutouts left to go, that the components for the FT 6 weren’t available after all. So I started to pelt the developers with questions about whether there were any other chassis elements I could use. And of course, the answer was “no.” The Lautsprecherbau.de team told me they were about to introduce the First Time 12 online on Wednesday evening, but buying it without reading any reviews was out of the question for me.
A demo listening session? No problem! I called my buddy Stefan, and we were standing in the listening studio even before the report was published. My first reaction, instead of reeling at all of the great loudspeakers, was reeling because I had to use the bathroom. But that was nothing that couldn’t be solved. Then I started to get a dry mouth because my jaw was constantly dropping. Listening to live pieces, guitar solos and drum riffs, Stefan and I were simply amazed. It was incredible that that sound was coming from those two boxes – we just stared at each other. I asked about the price and whether all the parts were in stock, and this time the answer was “yes.” Quick as a flash, the money and the assembly kit changed hands. And I was happy.
The next day I bought the wood. Since I liked the look of the other box in beechwood veneer so much, that’s what I decided to use. Unfortunately, the hardware-store employee was a little careless, so I had to make more than one trip. On the other hand, the cashier only scanned half of the boards, so I saved 30 euros on my wood. Sometimes you just get lucky.
The actual assembly was pretty easy. I had a little bit of trouble assembling the first crossover, but once it was finished and I looked at the circuit diagram again, it made sense. The second one was no trouble at all. In some ways I’m sorry that the project is already finished, except for a couple of minor details on the surface. It was a lot of fun.
What else can I say? I still sit there with my mouth open when I listen to music, except that now I’m at home instead of in the listening studio. I still don’t know how to describe the sound – or did I just do that? The boxes “chime”! They have highs, a mid-range and a bass! And what a bass! My buddy Stefan said that anything bigger than the FT 12 would be a waste of space. And I have to agree.
I put in Metallica’s S&M DVD and listened to the whole concert. Whether it’s drums, guitar, bass or string instruments in an orchestra, you can hear everything you want to hear. Even some things you don’t want to hear. I turned off a Falco record (Wiener Blut) because the disk had clearly suffered over the years. The FT 12s don’t make any exceptions – they transmit scratching and squeaking too, so you know right away what the record looks like without actually seeing it. What impresses me the most every day, though, is that I built 40-cm-tall speakers that have a truly rich bass. Where I used to play CDs and records in the background, now I really listen. You automatically sit down and listen to the music. What used to be just pleasant background noise is now a real pleasure.
So go to the studio, listen to these things and buy them! I didn’t regret it, and now I’m actually glad that the FT 6 wasn’t available.
PS: Leave yourself plenty of time – when you go into the studio for a consultation with Udo, you fall into a time warp. You go in, listen to 1 or 8 songs, enjoy a little chitchat, and the next thing you know three hours have vanished into the ether.
Christian’s FT 12
The FT12 came as if called, although I myself almost missed its call. I prefer small, narrow boxes that exceed your expectations. If they’re free-standing boxes, all the better. That was the first problem. I had enjoyed my Needles for two years, both tonally and visually, and I had so much fun building them that I wanted some reinforcements. My goal was to build a box in the same style as the Needle, but with a deeper bass range. Anything in the 30-centimeter range in terms of width and depth was out of the question for me. During my search, I eventually had the idea of turning the FT12 into a free-standing box. Why not? I also wanted an oval body with a perfectly integrated bass. The building challenge was an additional incentive.
I started by drawing the basic form on my computer as a template; I printed it out and glued it to the MDF with a thin layer of wood glue (incidentally, expired credit cards make the perfect palette knives). I used a jigsaw to make a rough pre-cut, and a belt sander mounted at a 90° angle for the detail work. A circular saw cut 1.5-cm MDF slats, and I glued them on one at a time with wood glue.
I decided my first prototype was too clunky for our living room. Compared to the Needle, it was just too wide. To get a couple more centimeters out of it, I had the idea of installing the bass at an angle. At the same time, an angle of more than 30° wouldn’t have made sense either, since the magnet would have stuck out. I think it bought me about 3-4 cm of “overall width savings.” That should be workable without any loss in sound – plus, as I said, the building challenge...
So one more time from the top, and this time I was convinced by the visual results of the prototype. Installing the bass at an angle takes a little patience. The support element also needs to be sanded. Still, despite my clever approach, the two boxes only vaguely approximated the reality. But it’s not easy with rounded sides and angles. In the building process, in addition to wood glue, I relied on a glue that works with wood and also fills in joints. PU foam was out of the question for me because of the hazardous substances, but assembly adhesive is just as good. I also needed to limit the volume for the high and middle range – fortunately without any angles here.
I attached all the boards with plenty of wood glue and moved them into position.Once the glue was dry and the boards were bonded, I filled all of the joints and holes with assembly glue. It’s nice that you can work a little sloppily when you have the right glue to fill in the gaps. Gluing on the slats and filling in all the gaps with assembly glue meant that the whole box was pretty solid, despite the thin MDF. Then I installed the bass, which involved a lot of dexterity, and screwed it in. I gave the interior of the band-pass cabinet a cross brace to reinforce it. To adjust the volume, I simply measured out some sand and poured it into the box. It’s an idea that works well with small free-standing boxes, and it’s easier than estimating the square centimeters on graphing paper. Especially when there’s an angle involved, the sand method is my first choice.
The crossover network was a bit sportier here than in the Needle, but doable. It’s really fun to operate the chassis elements outside the cabinets at first, switching back and forth and then gradually blending them in to hear the differences. Finally, I sanded and painted them several times. Next time, though, I would glue flexible plywood to the sides. I had a hard time taming the 3-mm MDF to fit the small radius. Still, I’m very happy with the results, and the boxes look awesome!
The FT12 now does what the Needle couldn’t. I have a nice bass and a warm tone. Still, the FT12 and the Needle play so differently that I can’t call one of them better or worse. I think the Needle’s sound is cleaner, but it’s not as comprehensive as the FT12. Maybe the two need each other?! Paul Simon sounds great on the Needles. The new Milow album, on the other hand, seems like it was made for the FT12.
First Time 12
Once upon a time ... That’s the start of a sentence we always liked to hear as children, since it was associated with the joyful anticipation of a (grand)mother’s sweet fairytale. Only much later did we realize that it also meant a departure, and that things were no longer the way we remembered them. We had to use those words often for more than a year whenever people asked us about the FirstTime 6, and our listeners were not always pleased. Again and again, they asked about a follow-up assembly kit, but unfortunately the W 148-4 doesn’t play well with band-passes, so it wouldn’t work as the interior driver. We also couldn’t come up with any usable results from simulations with the other cost-effective #15s in our product range. So we stuck our heads in the sand for a while and didn’t have any plans to redesign the box, until Gradient finally finished developing the W 176-4 and it fell into our hands. Despite the larger diameter, it didn’t take up any extra space, and it solved the problem that had so far successfully prevented us from making a follow-up box. Since there were also new playfellows in the mid-range and tweeter area, it would have been unfair just to attach an MK 3 to the FT 6 title – all of those changes deserved a new name: the FirstTime 12.
Once we had decided which bass would be housed in the future box, the only other issue was finding the right companions for it. Our experience with the FT 6 taught us that using components from the same family was the best approach. First its tweeters fell victim to the end of production, then the bass and mid-range speaker disappeared into the nirvana. That’s why we stayed with the Gradient Select series, which made choosing the tweeter very easy. Sesame Street’s Count von Count, whom people Udo’s age will remember well from their childhoods, would have responded to the command “Count the tweeters!” with a resounding “One! In any case, the GDT 104 N is still unrivaled. It’s already doing a good job in many assembly kits, so we used it. There was more to consider with the mid-range speaker, since both the W 148 and the W 115 were available, both of them in either four or eight ohms. The larger mid-range speaker has already been used in the FT 10, where it gives a bravura performance. Both versions do require a larger cabinet, though, in order to reach the 100 to 150 Hz needed for the band-pass connection without any exaggerations. That conflicts with the clear goal of seeing only tiny speakers while being completely blown away by their bass presentation. So we just had to choose between the two W 115s. The four-ohm version provides 3 dB more sound pressure at the same amplifier setting, but it does create a critical impedance dip under 3 ohms in the transition area to the band-pass, due to the considerable hot flashes often produced by do-it-yourselfers’ multiple amplifiers. So that took care of that part of the chassis selection; then we moved on to drawing the cabinet. The measurement data for the chassis in question can be found here, along with the downloadable zip files: (Quickly 18 update), (FT 11) and (Chassis test)
For the band-pass, LspCAD calculated 7 liters of enclosed volume and 5 liters of reflex volume, including the entire length of an HP 50 BR. With an additional 2.5 liters for the W 115-8, we had all the dimensions we needed so that SketchUp could turn them into a square box, nested inside one another. The goal was to move the internal boards around until they weren’t in each others’ way or in the way of the chassis. That was easy once I showed the mid-range speaker to its place in front of the closed band-pass chamber and stuck the reflex chamber under it. There was also plenty of room for the forward-facing reflex tube. Before the assembly, I sawed a hole in the middle board for the interior driver. In order to avoid installing the bass while we were still gluing the boards, we also put together a frame that could be screwed onto the floor board later. That gave us access to the belly of the box without damaging its stability. We didn’t take any pictures of these simple steps or the gluing, but the assembly plan should be enough to help you build the planking. The whole structure can be seen three-dimensionally in SketchUp, and turned in every direction. Any missing dimensions can also be measured easily in this free program.
The assembly plan file is provided in zip format.
The MDF was quickly shaped into the new form; once the joint glue was dry, we sanded it and made the cutouts. We used the shadow-gap router to trace all of the cut edges, which gives the box a slimmer figure. In order to hide the color of the MDF somewhat, we painted the boxes with a blue stain. There are a few pictures of this, with explanatory texts.
Once the paint was dry, we packed two whole bags of Sonofil into the box, installed the chassis elements that were connected to the outside world by wires, and were then able to start building the crossover. The first idea behind the band-pass principle involved using the mechanical filter that is represented by every type of cabinet. The enclosed part limits too-deep frequencies to 12 dB/octave, and the reflex chamber does the same for the top range. According to this nice theory, the reflex tube then only transmits a narrow frequency band that can get by without an electrical filter. Unfortunately, things look different in practice, because of course the bass speaker also blares mid-range notes into the box And that’s exactly how it sounds when it has to make do without any other components. Using a core coil and an electrolytic capacitor, we roughly weakened the mid-range enough that it was more than 20 dB below the useful level.
The closed chamber behind the W 115-8 also acts as a mechanical 12-dB high-pass filter, which protects the mid-range speaker from large lifts at low frequencies. It is supported by a large electrolytic capacitor that creates an additional 6 dB of edge steepness. In order to make sure the W 115 doesn’t interfere with the tweeter’s work, I limited its audible activity in the upperrange using an upstream coil and a parallel capacitor.The GDT 104 N was also able to manage with a network of a capacitor and coil, as well as a potentiometer to adjust the volume.
Overall, the individual branches add up perfectly if the bass is welded onto its partners out of phase.
Since there are always questions about installing the components, we have provided photographic documentation.
Now all that’s missing are the measurement diagrams:
|Frequency response and phase||Impedance||Frequency response under 0/ 30/ 60°|
|Distortion for 90 dB||Step response||Waterfall|
Of course, things got exciting when the FT 12s were finally set up in the listening room, where they had to prove themselves with an AVR. We would have preferred to listen through an old stereo amplifier, which is more likely to be the sound source, but due to a lack of assets that wasn’t possible. Unfortunately, the range of CDs that the FT 12 will be asked to play is probably also fairly small in most cases. So we started by throwing Katie Melua into the machine, and she responded with pleasure. Her soft but well emphasized voice proved it, with good spatial resolution and without any of the sharpness that much more expensive calottes would have given us. Still, there was no shortage of detail – they just weren’t crammed inappropriately into the foreground. The bass goes lower than in the FT 6, which makes a subwoofer unnecessary for music even in my 42 m² of space. Its clear notes are located behind the singer, next to the short, dry beats of the drums – right where it belongs. Now, playing mellow cuddle music is not really a challenge for any halfway decent speaker; heavy rock music is more of a challenge, like the Rammstein that came crashing around my ears next. That needed to be a little louder without making my ears hurt, everything coming out a little more spectacularly. No problem for the FT 12, but a bit harder for the AVR, whose alleged 7 x 160 watts are missing the zero, realistically speaking. Peter Fox, on my Bravo Hits CD, required fewer simultaneous loud and soft notes. There were also plenty of stomping low notes to support the Pussycat Dolls, who followed on the heels of the bard. Even Madcon had no reason to complain that their bass, recorded slightly too loud, was hidden in the background. In order to avoid filling this report with almost-forgotten artist names, we put on something more contemporary at the end of our listening session, switching over to the built-in tuner to hear the latest news. In a clear voice, the announcer crisply told us what was going on in the world. We’ll save ourselves the trouble of explaining the contents this time – much of it was harder to understand than the announcer himself.
Short postscript: A user from a forum has just left the listening studio, the FT 12 assembly kits in his trunk. It was great to see his incredulous face when Yello’s “Baby” hit his ears. Naturally we asked if he would write up a sound description for us, but he was simply speechless. He looked like he had found himself in a fairytale.
|Chassis:||Gradient W 176-4||wood list in 16 mm MDF|
|Gradient W 115-8||per box:|
|Gradient GDT 104 N|
|39,0 x 32,0 (2x) Sides|
|Sales:||Intertechnik, Kerpen||39,0 x 18,0 (2x) Front/ back wall|
|Construction:||Udo Wohlgemuth||28,8 x 18,0 (4x) lid/ floor/ division board|
|23,2 x 18,0 (1x) mid range -clip board|
|Nominal impedance:||4 ohm||Milling depth:|
|Damping/insulation:||2 bags Sonofil||W115-4: 4 mm|
|Terminal:||T105MS/AU||GDT 104N: 3 mm|
|HP 50 BR unshortend|
Approx. cost per box:
|96,00 EUR/USD||Wood cutting: 12 EUR/USD|