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Design concept The BESL Series 5 bass module is a product we are especially pleased about. Consisting of the Peerless 10" XLS (Xtra Long Stroke) woofer and 12" passive radiator, this drone system shows lower distortion than sealed or vented systems. If the parameters are just right (as they are with the Peerless XLS drivers), no EQ is required from the partnering amplifier in order to achieve flat response. This subwoofer measures perfectly flat down to 18Hz F3 as shown by the SPL graph. The roll off is approximately that of a 6th order system in the subsonic band. You may notice an absence of vents in all BESL speakers. Vents have a few negative side effects, such as midrange sound leakage, self-resonance, nonlinear operation, no cone control below tuned frequency, etc. A drone on the other hand prevents all such problems. One lesser known fact is that it is a good idea to combine the woofer with a drone whose cone area is larger than the woofer's. This reduces the drone excursion in the subsonic band, and thus increases max SPL while reducing distortion. In a sense, the 10" woofer "migrates" to a 12" diaphragm at the lower frequencies. A 12" XLS woofer would still be limited by the 12" drone excursion, and yet require a larger cabinet. By positioning the radiators low in the cabinet, the floor bounce dip is eliminated from the middle/upper bass range. In spite of low pass filtering, all subwoofer drivers can show some harmonic distortion products. To this end, we located the woofer on the rear panel, pointing away from the listener. Look at how the dispersion graph shows a very circular pattern, but with the amplitude at higher frequencies increasing slightly in front of the woofer (in the 180-degree direction). Placing the stereo subwoofer/monitor speakers a little out ahead of the front wall baseboard provides quarter-space boundary reinforcement and increased amplifier headroom. When used in stereo pairs, max SPL increases by 6dB, distortion is lowered, and there is absolutely no localization of the subwoofers. Construction The 10" woofer just barely fits on the narrow rear panel of the S5-xls subwoofer cabinet, which tapers up to match the footprint of all BESL MTM monitors. This provides a pleasing narrow and stacking monitor/subwoofer cabinet set, with only the drone visible from one side. Most other subwoofers operate standalone, and exhibit the "washing machine" effect. In other words, without being held rigidly still, the sound output is slightly compressed, making the bass sound muddy or soft. By contrast the XLS performs best when located underneath the weight of a matching BESL monitor, and the bass sounds tighter, with more definition and punch. The cabinet is actually quite rigid, yet lightweight. Three "X-Y-Z" internal braces insure square assembly, while bracing the cabinet and clearing the drivers. Performance We have performed some very sophisticated measurements on the XLS woofer. Under free air conditions, it showed low distortion, met the advertised Xmax, and even exhibited composed performance to Xmax + 50%! Maximum half-space SPL is 102dB from 165 watts. We realize this figure is not as high as some competitor’s claims. Add about 5dB for baseboard loading (~107dB), or about 10dB (~112dB) for corner loading, and a few more dB still for the room gain effect. We are confident that you will be hard pressed to find true deep bass and high sound output from a package this compact. Furthermore, the power graph shows no compression up to the rated SPL limit. Finally, this subwoofer is even easy to drive. The impedance stays quite high all throughout the band of operation. Once again, it is a pleasant surprise that no pass band EQ is required for this particular alignment. Powering and filtering the XLS By comparison with the overall subwoofer design, the challenge then becomes one of finding appropriate power and low-pass filtering. Commensurate with the high-end pedigree of the System 5, outboard filtering via the DCX2496 DSP crossover and a high-current power amp of your own choosing are appropriate. This setup provides for high SPL, room EQ, electronic limiting, and fine control over crossover integration with the main speakers. A more financially prudent choice would be that among various plate amplifiers. This choice yields slightly more modest performance. We fully expect the Series 5 bass module to be a new benchmark against which we invite any other similar-sized subwoofers to be compared.
I only wish I could crank things up more often.
QuoteI only wish I could crank things up more often. Look like they can take it.... [/list:u]I'll watch for you review.Thanks.[/list:u]Chris[/list:u]
Very impressive jackman. Nice to see others using Speak-On connectors. I use these wherever I can. Think we can start talking cable companies to start using these!! Don't worry about the baby. I played my systems all the time when mine were little and it turned out that they became acustomed to it and never bothered them. Now they need their radios on when they go to bed. Start now before it's too late.
I don't know much about it either, but it's a common pro-audio connector - and it's GARGANTUAN!
I have to give props to Gilbert of Blue circle who started using powercon connectors in some of his wares. I really don't know why they aren't more readily adopted
Again, no worries about cords "falling out". I have always been anything but conventional.
I think the SP tech speakers use the speakon for byamping, so it might be hooked up a bit different then typical binding posts, best consult your manual or Bob. I just think I read that somewhere.
