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diff --git a/posts/2021-02-23-flat5.md b/posts/2021-02-23-flat5.md new file mode 100644 index 0000000..22044e6 --- /dev/null +++ b/posts/2021-02-23-flat5.md @@ -0,0 +1,148 @@ +title: I built speaker cabinets +date: 2021-02-23 23:30 +tags: diy, audio +--- + +Yesterday I finished my build of the [Flat 5 speaker +cabinets](https://www.oaudio.de/en/loudspeaker-diy/breitbandlautsprecher/flat-5.html), +a transmission line speaker designed by Blue Planet Acoustic with a +single Tang Band W5-2106 broad-band driver. + +## The BPA package + +After I had ordered one Flat 5 kit from Blue Planet Acoustic I waited. +And waited. And waited. But nothing happened. Aside from the +initial order confirmation I had not received any other email. I +wrote them an email, to which I received no reply after several days. +Worried that my order was forgotten (and the advance payment lost) I +decided to call them. When I finally got through I was surprised to +be talking to a friendly person who informed me that my order was not +processed because I had only ordered *one* kit, but to build a set of +two speakers I would need *two* kits. + +Since the description on the order page isn't at all specific about +the contents of the package, I assumed that I would get two matching +drivers (approximately EUR 65 each), a bit of cheap damping material, +and simple speaker terminals. Turns out I was wrong and this variant +of the Flat 5 design comes with a filter circuit, which inflates costs +quite a bit due to the use of "audiophile" grade electric components. +In my opinion, "audiophile" is a meaningless attribute. I'm sure one +can get an accurate inductor, capacitor, and a low-noise power +resistor for less than what they charged me. + +I didn't want to cancel my order and the costs for an extra kit was +within my budget, so I decided to order a second one. I noted in my +second order that this is meant to be an amendment to my previous +order, and that I'd like them to drop the extra delivery fees. They +ignored my message and sent me the components. I paid delivery twice. +I probably won't be ordering from Blue Planet Acoustic again. + +The package came with the components and two A4 sheets of +"instructions". One sheet was the schematic of the filter circuit; +the other sheet was a front and side drawing of the speaker cabinets. +The drawing does not include any recommendations for placing the +filter components, nor does it suggest the order of assembly. + +## Cabinet assembly + +This was my very first build of a speaker cabinet. I wanted to reduce +the likelihood of failure due to my lack of experience, so I decided +to order pre-cut MDF boards from +[speakercase.de](https://speakercase.de). I don't own a router nor do +I have any power tools other than a powered drill and a jigsaw, so +cutting MDF boards and recessing the rim of the drivers would have +been very messy and very frustrating. + +When the MDF boards finally arrived after about three weeks (they are +made to order) I was pleasantly surprised to see how easy it was to +put them together with [Lamello wooden +biscuits](https://www.lamello.com/product/lamello-system-verbinder/original-holzlamelle/). +It looked all so very easy, so I didn't pay enough attention when +gluing things up, only to find out much later when attempting to put +on the front that the order of assembly matters a lot. There was no +way to put on the front *after* the transmission line barriers had +been glued to the back and the bottom and right side board had been +fixed. The presence of the barriers and the fact that the front and +back board both have matching dados to hold the barriers meant that +the front could only be lowered straight onto the barriers. So I had +to saw off the Lamellos that I had already glued into the side and +bottom boards... + +Another surprise was how very *tight* the fit of the internal barrier +boards and their slots in the front and back were. Even though I used +a precise square to make sure that the boards were glued perpendicular +to the back I still had to remove quite a bit of material to ensure a +flush fit of the front. The result is far from perfect, but I'm sure +that it won't be noticeable once I sand down the cabinets to apply a +black wax finish. + + + +It was especially annoying to me that the assembly order suggested in +the 2013/5 (August/September) issue of the *Klang & Ton* magazine does +not apply to a build with Lamellos. It's obvious in hindsight, but I +still feel like there must be a better way to put the MDF boards +together without leaving off four Lamellos for the front. + +## Wiring + +The kit from Blue Planet Acoustic included two sets of components for +an RCL filter to attenuate an annoying frequency bump in the response +of the broad-band driver. The inductor was surprisingly large and +heavy, so it took me a while to decide on a mounting place inside the +cabinet; I eventually decided to glue the three dead-bug-soldered +components to one of the transmission line barriers. + + + +The only difficulty was to solder the speaker wires to the banana +panel jackets, which are excellent heat sinks. It took a long time to +heat them up enough for an acceptable solder joint. + +## Do they sound good? + +Yes. + +I connected the two speaker cabinets to a Yamaha A-S701 amplifier, +though any decent amplifier would work just as well. Jazz recordings +such as the delightful *Mikarimba!* now have a surprising amount of +clarity; the bass is tight and clear, there is no "boom", brush +strokes evoke a visual response, cymbal strikes have crisp attack and +are never harsh; double bass has just the right amount of snarl and +body. Other jazz records, no matter the era, simply sound great +through these speakers. + +Chapman Stick recordings such as *Dream Recall* by Andy Salvanos sound +delicate and fresh. Listening to the influential *Friday Night in San +Francisco* is an experience from which I could only escape with +enormous effort. + +These speakers sound *great* at higher volumes. They don't sound +noisy. I don't have the urge to lower the volume and I have yet to +experience ear fatigue from listening to music with this setup. + +The first disappointment, however, came with the Dream Theater + Bruce +Dickinson cover of *Perfect Strangers*. It could be the fault of my +copy, but I had to turn it off just a minute into the song. The mix +just felt too compressed, but I also think that the upper mids of the +heavily distorted guitars and the compression in the higher +frequencies (especially on cymbal hits) just became much more +noticeable with these speakers. I didn't mind the problems of this +copy as much with my old Teufel soundbar (which was *okay* for the +most part, but made everything sound kinda washed out and blurry, +especially recordings of jazz ensembles). I'll try to get a better +copy and try again. + +Piano recordings (e.g. Chopin or Bach) sound good, but honestly I +never find them *truly* exciting. I can now hear the sound of the +pedals and keys bottoming out, which definitely adds to the +experience. I wouldn't say that it sounds as if a piano was right in +front of me, but perhaps this is because I don't really have memories +to compare with. + +## Conclusion + +Despite the initial disappointment in ordering parts, this was a lot +of fun. It didn't take me too long to put everything together, and +the result is a *vastly* improved aural experience for music that +benefits from finer resolution. I'm happy I built these speakers. diff --git a/static/css/screen.css b/static/css/screen.css index 7e663a3..6865fef 100644 --- a/static/css/screen.css +++ b/static/css/screen.css @@ -162,6 +162,7 @@ div#page { text-align: justify; max-width: 32rem; } div#page p img, div#page p video { + max-width: 100%; display: inline; float: right; margin-left: 0.8rem; diff --git a/static/images/posts/2021/flat5-almost-done.jpg b/static/images/posts/2021/flat5-almost-done.jpg Binary files differnew file mode 100644 index 0000000..4019160 --- /dev/null +++ b/static/images/posts/2021/flat5-almost-done.jpg diff --git a/static/images/posts/2021/flat5-wiring.jpg b/static/images/posts/2021/flat5-wiring.jpg Binary files differnew file mode 100644 index 0000000..9ee37d4 --- /dev/null +++ b/static/images/posts/2021/flat5-wiring.jpg |
