A Tale of Two SVS Subwoofers

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    A Tale of Two SVS Subwoofers

    David Vaughn’s 2019 review of the SVS SB-3000 sealed subwoofer inspired me to request a pair of SB-3000s for a feature article on finding the best locations for dual subs. They were small and light enough to move easily around the room and the results were excellent.

    But because my listening space is open to much of house I had the urge to experiment with two larger, ported subs. The SB-3000’s big brother, the ported PB-3000, was an obvious candidate. SVS agreed to send me a pair. The SB-3000s were still on hand, so a comparison of the two was inevitable.

    Comparing two subs (or in this case, two pair of subs) is a tricky business. You have to ensure that they’re matched in level. If they offer adjustable on-board EQ, use it only to flatten the response above the lowest frequency that each sub, or pair of subs, can handle, and not attempt to extend their bottom-end limits. And last, determine room locations complementary to each pair of subs at a range of seating positions. The last of these conditions had already been determined in the above mentioned article, so I used those locations here for each pair of subs. But to keep the variables from growing unwieldy, I measured and listened only at the main listening seat.

    Both the SB-3000s and the PB-3000s have their own onboard DSP with a range of adjustments, including three bands of parametric EQ. You can adjust these controls by ear, but the result will be imprecise at best. I used the Parts Express Omnimic system to measure the responses at the primary listening seat. With each pair of subs I could tweak the controls while the Omnimic showed the results.

    I used the same locations for each pair of subwoofers. This meant repositioning the subs frequently. It took about 5 minutes to jockey them into and out of position, a time gap that made immediate A/B switching comparisons impossible. To compensate for this I used an identical and limited range of test materials on both pairs of subs. The sources were CD for music and Ultra HD Blu-ray for movies. I took extra care to make sure overall system levels (not just the subs’ levels) were the same for each selection.

    The rest of the test system included the Denon AVR-X6700H A/V receiver, Monitor Audio Silver 10 speakers at the front left and right, a Monitor Audio C350 center, and a pair of Revel Concerta S12s as surrounds (set to bipolar mode). The high- and low-pass crossover to the subs was at 80Hz. Each pair of subs were driven wirelessly in mono (i.e., not in a stereo pair configuration, the latter incompatible with positioning two subs to even out the bass response at different seating positions). The subs were driven from the Denon AVR using SVS’ SoundPath Wireless Audio Adapters.

    Apart from the PB-3000’s size and dual ports (which were left open for all of these tests) its features and amp power are identical to the SB-3000. The PB-3000s are priced at $1,400 each, finished in an ebony vinyl wood-grained veneer. The SB-3000 costs $1,000 in ebony vinyl but can also be had in gloss black for $1,100. The PB-3000 (21.9 x 18.3 x 26 inches, 82.2 lbs.) is also heavier than the more petite SB-3000 (15.6 x 15.2 x 17.8 inches, 54.5 lbs.). Both were made in China, as are most of today’s subwoofers.

    As I’ve often noted elsewhere, my room arrangement produces a significant peak between 100Hz and 200Hz with most speakers, including the Monitor Audios. This is above the subwoofer range, but if left untouched can skew one’s impressions of a subwoofer’s performance. I corrected this peak as much as possible by using the Denon AVR’s 125Hz and 250Hz graphic EQ controls (not parametric). Why not dial up the Denon’s Audyssey room EQ to further minimize the effects of the room? Because I wanted the subwoofers’ own EQ to be the only low-bass EQ used in the testing.

    SVS vs. SVS: Music
    For two channel music most of the source material came from a bass-mix CDR I assembled years ago from a range of sources. It includes challenges from organ to electronic bass, viciously struck Japanese Taiko drums to conventional bass and kick drums, and oddities as well. One of these is a deep, intermittent bass tone on a cut called “Bass Erotica.” Both the Taiko and deep bass drums were crisp and tight on the SB-3000s. A duet of string bass and harp was clean as well, with the string bass showing no signs of unevenness as bowed up and down the scale. They also handled electronic bass well, including challenging cuts from The Apocalypse Now Sessions.

    But the SB-3000s sometimes fell short in my very large room. The lowest frequencies on the aforementioned “Bass Erotica” weren’t there. The SB-3000s also struggled on a quiet but deep organ passage from Saint-Saens Organ Symphony with its iconic, 16Hz pipe, where it never provided the subtle but continuous sense of deep bass, more felt than heard, encircling the listener as it fills the room.

    The PB-3000 eliminated all of these concerns, as long as I didn’t overdo the playback level on the most difficult cuts. That 16Hz organ tone went as deep as the source called for, nor were the PB-3000s challenged by any of the other cuts. They were also every bit as tight as the SB-3000s where they needed to be. Both pairs of subs occasionally displayed a little bloat on some material, but this was rare and likely due to residual room modes — or were perhaps in the source itself.

    SVS vs. SVS: Movies
    On films there were fewer differences between the two pairs of subs. I’d used the SB-3000s for months prior to this evaluation, and was never disappointed by their performance on even the most challenging soundtracks. But comparisons are telling, and the PB-3000s offered a greater sense of ease in the deepest bass. Neither pair of subs overloaded on my A/V test material, but the PB-3000s had just enough more oomph (sorry for the technobabble) to pull ahead the win. There’s an impressive demo scene in chapter 10 of Godzilla: King of the Monsters (not to be confused with Godzilla 1954, Godzilla 1998, Godzilla 2000, Godzilla vs. Kong, Godzilla vs. Mechagodzilla, Godzilla vs. Goodzilla…), where one of the lead human characters (such as they are in this film) descends deep into the ocean to free Godzilla. There’s a huge explosion, followed shortly thereafter by deep, throbbing bass as Godzilla emerges from the sea. There’s little furious action in this sequence, but just enough to judge the bass and also isolate and evaluate more subtle details, including Bear McCreary’s score. Both pair of subs were effective here, but the PB-3000s were more effortlessly powerful and atmospheric.

    Conclusions and Measurements
    I certainly wouldn’t write off the SB-3000 (preferably a pair!) for use in an average-sized home theater space, perhaps up to or slightly more than 3000 cubic feet. But my room is at least three times that size, including not only the home theater area but also other adjacent environs it’s open to. That’s a challenge for any subwoofer, but at very loud (though not crushing) playback levels a pair of PB-3000s easily passed the big-room test. But even there, a pair of them, or even one, is unlikely to be physically inconspicuous. For a smaller room a pair of SB-3000s will be a solid and relatively nonintrusive option.

    The SVS PB-3000 (red) vs. the SVS SB-3000 (blue).

    I measured each pair of subs at the listening position, with the results shown in the figure above (1/12 octave smoothed). Your first reaction might be that the SB-3000 goes deeper, and at the 85dB level used to align both curves it does. But 85dB isn’t anything special from a sub. When I measured the subs’ compression at 20Hz (not shown), at the listening seat, the pair of SB-3000s started to compress at just above 90dB, while the PB-3000s were still chugging away at slightly above 105dB before compression began. (Compression limits how the output of a device responds to the input. With no compression an increase at the input will produce the same level increase at the output. Compression begins when the increase in level at the source results in a smaller (or no) change in the output level.)

    But the deeper response from the SB-3000s (with the level of both matched at 85dB) remains an oddity. My guess is that this is due to differences between ported and sealed cabinets, As the driver compresses the air in a sealed cabinet, that compressed air helps keep the driver from excessive excursions with high levels of deep bass. But a ported cabinet unloads the driver below its port tuning frequency, effectively making the driver work in open air. Sharply filtering the response below that frequency can help protect the driver from excessive excursions.

    Published at Tue, 04 May 2021 17:59:39 +0000

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