Wall 150 (Series: Wallstreet)
It has always been a particular goal for us to build boxes that the world actually needs. That’s why we are always listening to our customers – the great advantage when you also sell the products that you invent. Magazines that survive solely by selling ads do not need to worry about having active reader participation; for us, it is the only measure of our work. In the past, it has been responsible for several successful products that we did not come up with ourselves. As an example, let me just mention the “BlueNote,” which was born out of an idea from Ulf and Guido. The tradition lives on today in the “Wallstreet 1,” which would probably never have occurred to us if it hadn’t been suggested by several readers. After all, who voluntarily hangs their speaker boxes on the wall? Many people, apparently, who want to set up a home theater that won’t be in the way more than 20 hours a day. So with our in-house number 1, we are launching the “Wallstreet” series. An easier name to remember is the Wall 150.
A wall installation, despite providing a large baffle board, does not necessarily mean a lot of volume. Usually the box should not project too far from the wall, so you lose some depth. That’s not a huge tragedy, because in a home theater the essential powerful bass is not provided by the satellites, but by a matching subwoofer. That’s not the subject of our review today, but it is worth mentioning our bass boxes and the flat-profile Sub 275, designed to be installed close to the wall, which have no trouble at all – alone or as a set of four – in relaying even the most dramatic filmic depiction of the apocalypse.
So if the bass isn’t a requirement for the satellites, 60 to 80 Hz is plenty for the lower limit frequency. A #17 on the wall will fall flat, but the mini cubes that are so popular with the other half of TV viewers are no alternative either – their visual superiority unfortunately comes with a tonal disadvantage. A #15 is the best choice for a home theater; with its resonant frequency around 50 to 60 Hz and its space requirement of 6 to 12 liters, it fulfills all of the conditions for a successful compromise. Now, our diverse product range offers plenty of chassis elements in this size category, ranging from very affordable to world-class. It was no coincidence that we chose the Dayton RS150 S-8 for our application. It has a very refined appearance with a cast metal basket, blackened aluminum membrane, phase plug, rubber surround material and a thick, shielded magnet, and at under 50 euros it is at the lower end of its category in terms of price. Its measurement values did the rest of the work of convincing us.
The selection of tweeters was just as large – we wanted it to match the RS 150 S-8 in terms of tone as well as price. We had already found a chassis at Dayton, the RS 28 A-4, which also offered the allure of the new, but that was exactly what made us hesitant about it. When it came to the fine resolution of the 5-inch model, we were looking for the benefits offered by ferrofluid-free tweeters, which are more dynamic than their oil-soaked colleagues. SEAS offers almost perfect calottes, for which we bear at least some responsibility. After all, our NoFerro 900 was the first of its kind after the invention of the cooling liquid in the air shaft, which the Norwegians had manufactured for the do-it-yourself market. Its positive review in a hi-fi magazine ten years ago made it one of the most successful tweeters, and its popularity is still holding strong. There was no reason not to use it for our wall project, especially since it had already proven itself in the Elip series. At 24 euros, it is well within the price range. As a result, the chassis for the Wall 150 is less than 70 euros, which is very attractive given that every do-it-yourselfer will need 5 assembly kits.
The look of the little cabinet for the Wall 150 was almost predetermined; if you want to mount a volume of 10 liters to the wall in a reasonable way, you need to consider that early reflections will take place, which will combine with the direct sound in a way that the human ear cannot separate out. Therefore it is advisable to make the front as wide and tall as possible and to avoid making the box too deep. Ideally, you would even have a flush wall installation, but that is usually not possible. In order to meet the need for at least 80 Hz of bass depth, a reflex channel was needed; we put that along the bottom. We used SketchUp, the free 3-D CAD program from Google, to quickly draw a box with external dimensions of 36 (W) x 40 (H) x 13.8 (T) cm that could comfortably house our chassis. This is what the two-dimensional cross-sections looked like:
The three-dimensional assembly drawing, to be downloaded and colored in yourself, can be found here. Since we happened to have an extra roll of film for the digital camera lying around, we took a couple of shots of the assembly for clarity’s sake.
Cross over network
Unlike the normal procedure, we were unable to develop the crossovers for the free-standing box this time because in real life there is always a wall behind it. It was very helpful in this case that our standard wall in the measurement lab is permanently set up for the chassis tests. We attached the Wall 150 to it with a rubber band, and soon we were able to set up the crossover with the desired usage conditions. We let the bass cable peek out of the reflex channel, and we connected the tweeter with the pole terminals, which we screwed into the bottom. We placed the microphone at the height of the tweeter, which was positioned under the bass for the wall installation.
The bass amplitude went up and down a bit, most noticeably in the area where it was responsible for the humps at 700 and the dips at 350 and 1400 Hz. This is due to the installation site right in front of the wall. We are not too worried about the dips for now, because they will fill in by themselves as the angle increases, as shown by the last measurement (compared to Wall 150). So the first issue was the upper limit, which we trimmed neatly to size using a slightly weakened second-order filter made of a coil and capacitor plus resistor. For the peak at 700 Hz, we placed a suction circuit parallel to the bass, which flattened it out at the top. The tweeter was even easier to tame, using a voltage divider, a capacitor and a coil. We let the Seas NoFerro 900 pull upward a little bit right at the top, which allowed it to maintain almost its full volume at the 30° measurement up to 20 kHz. When the Wall 150s are hanging on the wall, the listener will hardly be on the same axis with all of the front boxes. The fact that our work was technically flawless can be seen from the overall curve, which is above the branches in the entire transition area.
In order to make the crossover assembly work even for DIY novices, we also took a few photos of that process and the installation.
Sound descriptions are a part of every box introduction, but they are by no means the speaker builder’s favorite task. For the first time, there was an unavoidable hindrance during a listening test in our facilities. No, it wasn’t our disinclination to be bored stiff by senseless, no-plot action scenes. The problem was the walls. Naturally our studio is surrounded by four of them, but none is empty enough to let us hang up boxes at ear height. In consideration of this circumstance, we had only put together two boxes rather than five; there also would have been little point in running them from our old Yamaha AVR, whose technology is about as far from today’s as the Wright Brothers were from the moon. So we set the boxes on a shelf; in the absence of a worse sound source, we simply connected them to our SAC pre-power combo and were just listening to the first notes of “EST live in Hamburg” when Markus walked in. He has given us official permission to use his initial reaction, “Whoahhh…” for our review. Without a subwoofer, the line was drawn at Dvorac’s 9th Symphony when the kettledrum started up, since naturally the kettle was missing. Well, okay, a Dayton SD 315 BP and a Dayton APA-150 were standing around with nothing to do, so we decided they could work a little bit too. They weren’t just here for their health, after all. Thus equipped, after a bit of a spectacle, we were able to hear the frozen hell on “Hotel California” after half a minute, in the form of the familiar dry, grainy bass drumbeats. We were also able to enjoy the acoustic guitars, which were no less clean and crisp.
We will leave further descriptions of the sound experience to the first people who build these wall-hangers themselves. We expect the reviews to start popping up fairly soon – because who better to judge the success of our work than someone who paid their hard-earned money for it? We are very optimistic that no one will report feeling tricked.
Wall 150 loudspeaker kit with Seas and Dayton
|Chassis||Dayton RS100 S-8||Wood list in 19 mm MDF:|
|Seas No Ferro 900||36,0 x 40,0 (2x) front/ back wall|
|10,0 x 40,0 (2x) sides|
|10,0 x 32,2 (1x) lid|
|Sales||Intertechnik, Kerpen||10,0 x 30,3 (1x) floor|
|Construction||Udo Wohlgemuth||10,0 x 18,0 (1x) reflexboard|
|Nominal impedance||8 Ohm||Milling depth:|
|Damping/ insulatiuon||1 bag Sonofil||
Woofer: 5 mm
|Terminal||K 42 AU|
|Approx. cost per box:|
|100 EURO/USD||Wood cutting: 10 EUR/USD|
Frequency response and phase
Distortion for 90 dB
Frequency response under 0/ 30/ 60°