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SVS PB12-Plus/2 Build Quality

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Figure 1

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Figure 2

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Figure 3

SVSound PB12-Plus/2 Hardware (Ducts not showing as they were not removable). Drivers feature aluminum cones, santoprene surrounds and strontium-ferrite magnets. Note port plugs perched in the back, right hand corner of the cabinet top. Beneath the drivers is the cabinet base plate.

Both Photos: System flipped upside down, drivers removed. Top photo: looking aft, towards power amp. Note internal cross bracing also serves to brace the internal duct work. Bottom photo: Looking forward, note port flaring, heavy gauge internal wiring and thickness of front panel & internal bracing.

Set-Up

Treat a thoroughbred right - whether it be, say, a race horse or a car (such as a Ferrari) and it will deliver like nothing else can. Don't, then you're denying yourself the exceptional performance that puts it in the thoroughbred rank to begin with. The same holds true for subs in the PB12-Plus/2 class. It is a thoroughbred and it is absolutely essential you take the time and make the effort to set this sub up properly.

A side note is in order here. With a system capable of dissipating into a listening space the kind of acoustic power the PB12-Plus/2 can do (with ease) you'll find that the architecture of your home will play a surprisingly substantial role in determining just what your listening experience will be. Here I'm not referring to the well known phenomena of room modes setting up within the space of your listening room - that's a given.

What I am referring to are resonances setting up in the floor the sub sits on or in other architectural features, such as a fireplace. In my case, the sub could excite floor resonances to the point that the floor would vibrate like a big, fat wooden drum head, making furniture weighing (in some case) several hundreds of pounds jiggle to an unsettling degree. At one point when I had the PB12-Plus/2 really opened up, it excited the naturally occurring resonances that set up in my fireplace chimney located at the south end of the listening room. Subs that don't crank that kind of acoustic output will not elicit those kind of responses, hence they won't require the degree of complexity in setup that creatures such as the PB12-Plus/2.

At any rate, with the system tuned to 20 Hz, the crossover and parametric EQ disabled, and phase at 0°, I moved the sub to the main listening position and began some preliminary setup tests. Using a looped, swept sine wave signal (300 Hz to 16 Hz) as a test signal, I walked the room to get an idea (acoustically speaking) what options were available regarding final placement.

In the end two candidates (one, about half-way back along the west wall of my listening room, the other about three-quarters back along the same wall next to a sofa) emerged as frontrunners: I settled for the latter, position that minimized the visual impact of the system. Once placed, I followed the set up procedure provided by the manual. After about two hours of careful listening - and judicious use of the phase, crossover and paraEQ features sported by the system - I arrived at a settings mix that sounded very well tempered. (See Figure 13 for a before/after PEQ).Over the following next few weeks I did a lot of recreational listening, occasionally tweaking a setting or two until I was satisfied I had the sub performing at its best. Then the critical listening begin. It should be mentioned in passing that all listening tests were done using the PB12-Plus/2 processors (crossover, PEQ, etc) were used. No other processing upstream of the sub was used.

Listening Tests

Music

clip_image008_002.gif I've always considered music & video soundtrack playback as two largely separate roles (though distinctions can blur, of course) that a subwoofer in the > 1$k price bracket should handle with equal success. For the first part of my critical listening tests - what I'll refer to as the "finesse" segment - I chose a number of tracks that would show how well (or not) the sub could perform by not calling attention to itself. Essentially I was looking for as seamless integration with the rest of the playback system as possible.

(Unless otherwise noted the music playback portion of the listening sessions were conducted with the system tuned to 20 Hz).

From the Crown SASS Microphone CD I selected a few tracks featuring plain, old piano. I was interested in getting a sense of how well matched, in terms of timbre, the SVS sounded vis a vis the rest of the system. Tonally speaking, I wanted every note to sound as if it were coming from the same piano, with no apparent telltale differences above and below the 80 Hz point.

At first, the piano sounded a little too warm in the 80 Hz region, though it wasn't bad for a start. Tweaking the crossover setting cured that problem: lowering the LP crossover point to around 60 Hz brought everything into proper perspective. The PB12-Plus/2 handled that easily enough, though I've seen other subs fall down in the face of this particular challenge.

clip_image010_000.gif Kim Mitchell's Aural Fixation CD provided a variety of tracks, such as World's Such a Wonder with lots of kick drum action . After passing the piano timber test, I wanted to know how the PB12-Plus/2 would behave when faced with a signal source, such as a kick drum, transient in nature and with a fundamental frequency within an octave's breadth of the resonant frequency of many subs. I like using Aural Fixation for testing purposes because the kick drum sounds like it was compressed and EQ'd as you'd find in a typical live music setting which is a sound I'm pretty familiar with.

Though there's no hard & fast rule where it comes to tuning kick drums, kick drum tracks can nevertheless be a useful testing tool because, as previously mentioned, they tend to be tuned to frequencies in the neighborhood of many a sub's resonance frequency. Subs designed and built on underdamped alignments (tweak out a few extra dB at system resonance, but at the expense of system response elsewhere) reveal themselves pretty quickly as such when faced with this type of test signal.

As mentioned previously, I had the sub tuned to 20 Hz, a choice providing for flattest passband response. So how did it sound? In a word 舑 great! The sub handled the tight kickdrum sound with ease, in a way reminiscent of some superbly engineered closed box systems I've heard elsewhere.

clip_image012_002.gif If you've experienced a choral or organ music concert in a large cathedral, you know a reverberant space that size has a unique, memorable acoustic character. One distinguishing... and surprising... aspect of recordings made in spaces such as this are the amounts of low frequency acoustic energy captured in those recordings, even when the material is choral. Surprisingly enough, recordings of this type can, on occasion, contain infrasonic information in the 8 Hz - 10 Hz range. As well, occasional excitement of room resonances that are at sub-harmonic frequencies to a particular note played or sung, all give evidence for the necessity of having a subwoofer in place to more faithfully reproduce the event and thus more fully present the illusion of moving the listener to the space. Poorly designed subs that exhibit high mechanical noise floors fare poorly where it comes to convincingly resolving such low level information. The Tallis Scholars 25th Anniversary Silver CD set was used to subjectively test how well the sub would handle subtleties of this nature. The PB12-Plus/2 didn't have any such noticeable difficulty in handling the LF portion of any tracks played from this particular CD set. As a matter of fact I found the sub did so well I ended up listening to both disks in the set; a rare treat with the PB12-Plus/2 adding an essential dimension to the listening experience.

 

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