SQ FROM WHERE THEY DID NOT EXPECT, PART TWO SWAT subwoofer speaker test of the second generation Master and Revolution series A little over a year ago, SWAT subwoofers from the initial Master and Revolution series visited the CARMUS laboratory, and then I was very surprised by their musicality. The article was called that - "SQ from where they did not expect." Now SWAT has released the second generation of these subs, and after studying them, I am pleased to state that the continuation turned out to be worthy, and in some moments even more interesting. In a word, SQ was not expected from where, part two. FIRST DESIGN STUDY This time I took the entire initial line of subs for testing - in the Master series these are 10- and 12-inch models, and in the Revolution series - 10-, 12- and 15-inch ones. It just so happened that I was a little aware of the preparation of these speakers for production, and therefore it was interesting to evaluate all the models in both series. From the front, all speakers look the same, all using the same type of polymer-coated pressed cellulose cones. Unlike the previous generation, the caps received embossed logos. The stitching and compound-filled seams on the back are the same as the previous generation. There was no need to change anything here. The top suspensions are narrow and high, so that the diffuser area is not affected. Mounting flanges are covered with rubber o-rings, and they are also with molded logos (the first generation used conventional universal o-rings). The main rigidity, as expected, is set by the lower suspensions, i.e. centering washers. There was no unification here - for each model, the washers were selected individually in order to eventually reach the specified parameters. By the way, these subwoofers were designed precisely from the parameters - they were initially clearly set by the terms of reference, and components were already selected for these requirements (in most cases, manufacturers do the opposite - they assemble subwoofers from existing components, and what parameters will turn out). The leads are made in the form of round braids and are sewn through the centering washers. Instead of the usual spring terminals - closed screw terminals. There is a little more fuss when connecting, but they provide more reliable contact (of course, if the installer does not have a pelvic-shoulder anomaly, well, you understand me). Baskets in both series are steel, stamped. Surprisingly, not sonorous at all, this is facilitated by a successful relief and rolling along the edges of the windows. Unlike the first generation, the magnets are covered with soft bright yellow casings. Another of the little things that noticeably changed the appearance of the speakers. The Master series uses 2" voice coils, so the dimensions of the magnet systems are moderate. In the Revolution series, the coils are already 2.5-inch, so the motors are larger. Plus, in this series, additional holes are made in the end plate for more efficient cooling. In a word, constructively, the speakers have become a little more interesting and have acquired some individual features. But the main thing is still their work, so I turn to measurements. PARAMETER MEASUREMENT In general, for 10- and 12-inch subs, the parameters turned out to be close to the application. Plus or minus a small spread, which does not fundamentally affect the calculation of acoustic design. In the 15-inch model, the hit is not so accurate, but in fact it turned out even better, this will become clear when calculating the case. Declared/actual parameters SWAT MAS-10 v.2: Fs (natural resonant frequency) - 33 Hz / 33 Hz Vas (equivalent volume) - 30 L / 28 L Qms (mechanical quality factor) - n. d. / 6.51 Qes (electric quality factor) - n. d. / 0.50 Qts (full quality factor) - 0.43 / 0.46 Mms (effective mass of the moving system) - n. d. / 142 g BL (electromechanical coupling factor) – n. d. / 13.8 T m Re (voice coil DC resistance) - n. / 3.3 ohm dBspl (reference sensitivity, 1m, 1W) - 85.5 dB / 84.8 dB Declared/actual parameters SWAT REV-10 v.2: Fs (natural resonant frequency) - 38 Hz / 35 Hz Vas (equivalent volume) - 18 L / 18 L Qms (mechanical quality factor) - n. d. / 7.48 Qes (electric quality factor) - n. d. / 0.53 Qts (full quality factor) - 0.50 / 0.49 Mms (effective mass of the moving system) - n. d. / 171 g BL (electromechanical coupling factor) – n. d. / 16.4 T m Re (voice coil DC resistance) - n. / 3.8 ohm dBspl (reference sensitivity, 1m, 1W) - 84.6 dB / 83.7 dB Declared/actual parameters SWAT MAS-12 v.2: Fs (natural resonant frequency) - 34 Hz / 30 Hz Vas (equivalent volume) - 52 L / 55 L Qms (mechanical quality factor) - n. d. / 7.56 Qes (electric quality factor) - n. d. / 0.54 Qts (full quality factor) - 0.54 / 0.50 Mms (effective mass of the moving system) - n. d. / 166 g BL (electromechanical coupling factor) – n. d. / 13.9 T m Re (voice coil DC resistance) - n. / 3.3 ohm dBspl (reference sensitivity, 1m, 1W) - 87.3 dB / 86.6 dB Declared/actual parameters SWAT REV-12 v.2: Fs (natural resonant frequency) - 35 Hz / 32 Hz Vas (equivalent volume) - 46 L / 43 L Qms (mechanical quality factor) - n. d. / 7.78 Qes (electric quality factor) - n. d. / 0.56 Qts (full quality factor) - 0.53 / 0.52 Mms (effective mass of the moving system) - n. d. / 190 g BL (electromechanical coupling factor) – n. d. / 16.2 T m Re (voice coil DC resistance) - n. / 3.8 ohm dBspl (reference sensitivity, 1m, 1W) - 87.3 dB / 86.2 dB Declared/actual parameters SWAT REV-15 v.2: Fs (natural resonant frequency) - 35 Hz / 34 Hz Vas (equivalent volume) - 118 l / 72 l Qms (mechanical quality factor) - n. d. / 7.98 Qes (electric quality factor) - n. d. / 0.73 Qts (full quality factor) - 0.59 / 0.66 Mms (effective mass of the moving system) - n. d. / 277 g BL (electromechanical coupling factor) – n. d. / 17.6 T m Re (voice coil DC resistance) - n. / 3.8 ohm dBspl (reference sensitivity, 1m, 1W) - 90.9 dB / 88.6 dB ACOUSTIC DESIGN CALCULATION The description provides not only a list of parameters, but also recommendations for packages. To check them, I took the parameters from the description (left graphs) and separately made my own calculations for the actual measured parameters (right graphs). For 10-inch models , very compact cases are obtained. Moreover, as in the first generation of the series, they are great for SQ-systems without regard to the low price and stereotypes about the brand image. In compact SLs, the very bass that is usually expected from this caliber is obtained - accurate, “fast”, dense. Great option for stealth. The bass-reflex design loses a little in bass accuracy, but noticeably wins in return. At the same time, large buildings are also not required - in fact, in 25 liters, both “tens” feel great. For 12-inch models , no questions arose according to the recommended sealed. You don't need less - the bass will noticeably lose accuracy and articulation, become more rigid, and even boominess may appear. More is also not needed, these subs are unlikely to dock with expensive powerful amplifiers, so the speakers need at least some kind of “air cushion” that keeps the cones from an uncontrolled increase in travel. But ported are offered unexpectedly compact for this caliber. Moreover, for MAS-12, the volume is even less than WL. I admit that this is just a typo, because the bass in such a case turns out to be quite hard, with a maximum output above 50 Hz. So I would increase the ported, especially for the model from the Master series. For the 15-inch model , the actual parameters are somewhat different from the declared ones, and therefore I calculated the cases without regard to the proposed options. The speaker turned out to be stiffer than declared (Qts is higher, Vas is smaller), although Fs remains the same, and in this situation it needs a smaller case without losing bass depth. Judging by the actual parameters, the REV-15 v.2 will play well in a medium-sized GC - in 60 liters the dynamics will be just right. The bass will turn out to be quite deep and at the same time even, without a clear emphasis on individual notes. Large calibers are chosen for the maximum depth of the bass, so it is logical to count the bass reflex for such an application. In 80 liters with a port on 35 Hz, a good option will be a good option for "blacks". True, with a universality of phase inverter clearance, it is more difficult for the phase inverter, so if not only "negros" are needed, then the option with sealed looks still preferable. HOW TO CHOOSE A CALIBER Subwoofers turned out - as in the textbook. If you need an accurate and “fast” bass, without much getting into the infrabass, but at the same time dense and “meaty”, we definitely choose the 10-inch model. In addition, this is a good option when there is little free space in the trunk. 12-inch speakers - station wagons. They can already play a little deeper and still without much loss of articulation. The bass, though not as accurate as that of the "tens", but for not too complex musical genres, the "dvenashka" will be even more preferable. 15-inch caliber - when you want, as they say, "deep and soft" bass. A closed box is a relatively versatile option, and in a bass-reflex case, you can build a sub with a higher return “for blacks”. HOW TO CHOOSE A SERIES Everything is easier here. If you don't have a very powerful amp, don't chase the older series. The initial Master series uses 2-inch voice coils, with these we managed to achieve a little more sensitivity even with more modest magnets. The price is lower, the return is higher, isn't it great? So if a pair of channels of a conventional amplifier that outputs 300-350 watts into 4 ohms in a bridged connection will work on a sub, then the Master series will be preferable. The Revolution series uses larger coils - 2.5 inches. This entailed the need to increase the magnets and, accordingly, affected the cost. But then you can use these subs with more powerful amplifiers. In addition, Revolutions have dual 2+2 ohm coils, so there is more freedom when building subwoofers on multiple speakers. SHORT It's great to see that SWAT is confidently shedding the stereotype of audio equipment for the most unassuming, in the last couple of years the brand has made a noticeable leap in engineering. For me personally, at one time the Master and Revolution subwoofers became a complete revelation, and their second generation definitely became more interesting. Subs have exactly the parameters that are needed in a particular application - for normal music systems without the removal of glasses and other self-destructive tendencies. For loud systems, SWAT has other series, but that, as one TV presenter says, is a completely different story. Technically literate designs Works well with moderate power amplifiers Speakers do not require huge cabinets (for their calibers) Have an increased return in ported
