Even the small Needle, our small transmission line equipped with a full-range driver, is successful, even though the diaphragm area is actually too small for proper bass reproduction, even though the mid-high range excursion is much too high for clean reproduction, and even though the high-frequency range radiates much too bundled.
So where does the success come from? Quite simply: it also does a few things right. It is clearly fun to listen to. Even though it is clearly technically inferior to any two-way speaker. And if we derive a two-way concept from the Needle?
Voila: Here is the Family 11.
Thus, it should be possible to get a bit more clean level out of a floorstanding speaker with a minimal footprint. And at the same time improve the omnidirectional sound distribution. The Family 11 meets this challenge almost fearlessly - because: It is not much bigger.
As usual with the projects of the Family series, we have once again resorted to the Gradient Select series with its unique price-performance ratio. Thus, the tweeter was already determined, because there is only one in this series.
It was then combined with the W 115-4, which may celebrate its debut in this construction manual. The corresponding eight-ohm driver should clearly be the worse choice in a low efficiency transmission line, especially since the frequency response of both versions is almost identical - as are the other technical data.
After we have selected the drivers for the project, it goes to the calculation or design of the cabinet, we have specified a slim design. A TQWT (Tapered Quarter Wave Tube, i.e. a quarter-wavelength delay line loudspeaker) would have been possible, it would even have had a shape comparable to the Needle.
But we wanted to make the speaker even slimmer. Moreover, we had not yet analyzed the acoustic-chamber-reflex principle further, corresponding measurements were still pending. So we created a thin column with 96 x 10 x 10 cm internal dimensions, which according to LspCAD as a reflex box tuned to 67 Hz should take the following course in the half-space:
The measurements were made at our measuring site with a distance of the woofer to the floor of about 1.5 m.
The two measurements were made with different interiors: Once with half a mat of original Sonofil (blue trace), neatly folded into the box, and the other with three boards that left a passage of 80% of the membrane area open between the chambers (red trace). The differences do not look very dramatic at first glance, and yet the impedance measurement at the latest shows that the Acoustic-Chamber-Reflex cabinet results in a design that works similar to a transmission line. Further measurements indicated that the passband area as well as the size of the individual chambers do not have a decisive influence on the sound, but only serve for fine-tuning, as we are used to from the length of the reflex channel of a bass reflex speaker.
Since the computer simulation for the W 115-4 called for a chamber with 3 liters, we chose this size for the first chamber. We reduced the size of the other chambers a little. Incidentally, the separating boards to the other chambers serve to stiffen the housing.
Therefore, we only took a few photos of the quite simple case assembly.
After building the cabinet, we started to install the technology: insulation material, speaker chassis, bass reflex tube - wait a minute, there's something missing? Yes, that's right: The crossover had to be developed by us first, but if you use the finished construction plan, it's much easier and you can fall back on a ready-built crossover.
So during development we made sure that the cables to the drivers were accessible from the outside and started to dimension the crossover components. We took our cue from a previous project in which two W 115-8s were used, but in the end they also produced four ohms when connected in parallel. So we started the attempt to adapt only the voltage divider of the tweeter to the new situation - and listen, this kind of crossover development worked in this case - we liked the final result.
This almost inevitably led to another question: What is the interaction between the Family 11 and the Family Center in the home theater? With the same crossover design, this is obvious. A combination with the Family 12 also makes sense. Well, you can't use it for large home theaters in the basement, but in smaller rooms this combination is definitely an alternative. For larger rooms, the Family 14 and Family 18 are recommended.
We finally mounted the crossover with screws on the rear panel behind the tweeter and pulled the cable down through the maze to the connection terminal with a cord weighted down with a screw. Before the final assembly of the loudspeaker chassis, the damping material was placed appropriately and the bass reflex tube, shortened to 8.5 cm, was glued in place. Then the drivers could finally be soldered and mounted.
Then came the most exciting moment in loudspeaker (self-)construction: The move into the listening room with an explicit invitation to the sound test, because measuring instruments have microphones, but no ears. This time we used a veteran "Luxman L 215" stereo amplifier for the listening session, which did its job quite well compared to many a new home theater receiver.
Fittingly for the sound test, we had a customer visit, who was naturally eager to hear the newcomers when we let it be known that they had just moved from the test lab.
So we started the listening session with "Eleanor Rugby" by Musica Nuda on CD. The bowed bass provided a tremendous foundation, and the singer stood in the room with an incredible amount of air. However, this performance came into the listening room from a pair of Symphony 84s - we had to hook up the high-jack pair first. So we prepared ourselves for a terrible experience when reconnecting - usually much smaller and cheaper speakers are hardly bearable in direct comparison to larger ones. However, instead of disappointed cries of disgust, the Family 11 earned appreciative astonishment from the audience. The sound surprised even with complex recordings like "In the Hall of the Mountain King" from the Apocalyptica Celli with resolution and stage without drifting into an orgy of noise.
The comparatively added Needle didn't even do its job significantly worse, and yet the Family 11 are a completely different house number in terms of coarse and fine dynamics as well as the depth of the stage. The Needle is still among the best that can be teased out of a tiny full range driver, and yet a larger speaker naturally has the advantage. In addition, the listening area of the Needle was limited to the center of the sofa as a sweet spot, while the High Jack acoustically illuminates the entire sofa. Thus, with the Family 11, we virtually eliminated the Needle's design-related weak points, which we quite successfully did, as was later proven by further sound tests. No wonder, since the High Jack has significantly more diaphragm surface area than the Needle with the same cabinet width, and the additional tweeter provides better omnidirectional sound distribution as well as faster resolution.
Since the visitors actually wanted to hear larger boxes, we changed a little before we ultimately fell back on the Family 11, which immediately gave us an impulse purchase of the inexpensive kit. The simple housing without complicated angle cuts can be completely cut in the hardware store and can be built even by do-it-yourself beginners without any problems. Even in small rooms, it does not interfere with the furnishings thanks to possible installation close to the wall. Thus, the High Jack is virtually a "gateway drug" in the speaker DIY: You can already listen very, very good music with it.