We took up the cause of dynamic home movie theater with enormous efficiency far over 90 dBS when we introduced the matching center to the Audible 17 and 34. If you want to reach a high level with fewer watts, you'll have to forego the bass depth. So our loud home theater was not complete with the fifth element because today the moving pictures depend on low-frequency effects which do not want to rank behing the satellite power. Another subwoofer had to be added which would shake the foundation. No problem. A few days ago, we received a quite grown-up increment in the AXP family, which was immediately introduced in the magazine. We selected the AXP 12 as the suitable candidate for completing the theater.
As is general practice for us, we input the parameters in LspCAD which calculated an ideal volume of 77 liters with a 145 cm² reflex opening with 161 mm channel depth for the AXP 12. But we are never really satisfied with what a simulation suggests. Therefore we enlarged the box by 12 liters and agreed on a seemingly insignificant deeper 2 Hz. The new WAM 150 is the reason for this measure which we got accidentally at the same time as the new chassis and wanted to immediately find the first, meaningful use for it. It has a slight bass boost at 35 Hz that we considered in the housing calculation.
Well then, doesn't the capacity decrease if the sound pressure of the chassis is electrically raised down below? That's right, of course, but through the larger housing, we automatically won 3 dBs more level and could now turn down the volume control with deeper separation with more deep bass as compensation. This all does not look really dramatic on the simulation charts, but with such a high efficiency loudspeaker, everything works that adds something below more or less free of charge.
It was thus clear how the housing for the Audible Sub 12 had to look. The chassis diameter of exactly 33 cm predetermined the front width with 40 outside centimeters. With a height of 65 cm, the tweeter was at ear height, also with the Audible 17 placed on it or an upright standing center. Now 89,000 divided by 36.2 and 61.2 (interior dimension at 19 mm MDF) and another couple of cms for the reflex channel yields 44 cm of interior depth. A couple of boards for reinforcement were still lying around in the basement. The CNC milling machine took care of the front and rear wall. A drawing was generated for do-it-yourselfers in Sketchup.
So that there are no questions on the construction, we documented it with photos.
...and then it happened. The bracing board under the cover protruded far into the module cutout and had to be replaced by a smaller one. Luckily the joint glue could still be forcibly separated after ten minutes without causing major damage.
After the polishing, it was on to the installation of the components.
We need to say one or two words about the WAM 150. We’ll make it easy for ourselves and copy here what can also be found on our Intertechnik Shop webpage:
|Output power 4 ohms||150|
|Low pass range||40Hz|
|High pass range||200Hz|
|Power supply (switchable)||110/230|
|Peaking power ||Ja|
The Audible Sub 12 was now ready for use and we could take a couple of measurements for the report. First we recorded what comes out of the cube with 2.83 V input without activation which is placed one meter high on the test site. How the module acts in the LFE mode can also be seen.
The positive effect of the boost at 35 Hz is shown clearly on the bass response. But we come now to the point where real counseling is needed. We measured different crossover frequencies and at the same time, took photos of the controller on the front. This makes it clear what happens in which position. The measured input voltage was 1.414 volts; the volume control was just between nine and ten.
For better comparison, we again copied the measurement curves into two pictures. On the one hand, we summarized the meaningful separations below 100 Hz; on the other hand, we could also imagine a similarly structured Duetta, semi-active three-way speaker for which the separations for the relief of the mid-woofers can be much higher. Thus two subwoofers are probably easier to sell to interior decorators because it saves the stands for the satellites.
Especially in the higher crossover frequencies, a few people may miss the deep bass in the diagrams. It should be said that a subwoofer in the living space is rarely installed at a meter of height. It is known that the correct floor position provides for a couple of dB more in the lower range. For illustration purposes, we recorded both reliably similar settings at the beginning and at the end of the rotary regulator at 40 and 200 Hz for this set up variant and placed it over the measurement curve.
We hope you can forgive us for not actually watching a movie with all the necessary effects after completing the very audible Audible movie theater. We understand however nevertheless that you can have a lot of fun with it. With the Audible Sub 12, that is certainly guaranteed and we thus closed the last link in the volume chain. Now we are looking forward to the next construction suggestions which we can implement with the magnificent AXP chassis. In future there will certainly be some smaller living room dividers, for those their mistresses can warm up with. The eight and ten-inch are still waiting for their application. And we have already gauged the first model of the five-inch and found it to be good.
|Drivers||Gradient AXP 12||Wood list in 19 mm MDF:|
|Sales||Intertechnik, Kerpen||650 x 400 (2x) front/ back wall|
|Construction||650 x 440 (2x) sides|
|Function principle||Bass reflex||100 x 440 (2x) reinforcement boards|
|Nominal impedance||8 ohms||89 x 440 (2x) reinforcement above|
|Damping/insulation||6 bags Sonofil|| 20 x 440 (1x) reinforcements for lid
|Aktiv Subwoofer Modul||Wyntek WAM 150||362 x 440 (2x) lid/ buttom|
|362 x 130 (1x) reflexboard
|100 x 130 (1x) reinforcement reflex board|