Like the ads for the 1998 remake of Godzilla stated: “Size Does Matter.” We configured the SVS PB2-ISD to 2 different frequencies, and ran listening tests on each. For the first round we set the subsonic filter to “Bypass” and left only the one (top) port open. This configuration basically allows the subwoofer to achieve the lowest possible frequency response at the sacrifice of some SPLs at higher frequencies (see inset below.)

This graph is an anechoic chamber measurement of the PB2-Plus subwoofer – but is similar to the frequency response of the PB2-ISD and gives you an idea of how the subsonic filter and porting options affect frequency response.

It was during these listening tests that I was absolutely floored by the response and the felt realism of the subwoofer. Playing down to 15-16Hz is impressive, but playing that low at SPL levels that are actually audible (if you call it that) is something that needs to be experienced.

For the remainder of the listening sessions I altered the tuning of the SV subwoofer so that the subsonic filter was at 20Hz and 2 ports (the top two) were opened. There was a slight discernable drop in extension but a noticeable rise in SPL capability. We determined that this was probably the optimal setting for Reference System 3 (and probably for any medium-sized rooms that want to be able to play loud content without maxing out the driver and generating excess port noise.) Keep in mind that you will need to reset your reference levels with an SPL meter after altering the subsonic filter and port configuration. In this case, there was a 6dB gain in SPL simply from going from the 16Hz to the 20Hz tuning configuration.

All in all, the SVS sub picks up where the LFM-1 leaves off. Lower extension, even greater tactile energy transmission to the viewer, and the ability to quite possibly shake the foundation of a home, mark the characteristics of the PB2-ISD subwoofer. At equal SPL levels, the SVS subwoofer only slightly edges out the LFM-1 in terms of the above characteristics, however those gains are not as prominent in a medium sized room such as Reference System 3 . I did crank the SVS subwoofer to somewhat insane listening levels and have to admit – there is no substitute for the ability to play clean, hard and loud. Explosions took on a more realistic feel (and I mean feel) and the extra low frequency extension gave an ever so slight edge to many of the reference material scenes we listened to.

I would have to say that the SVS sub produces very theatrical sound. Indeed, it will provide more energy to the listening position than the local theaters - in this area at least. If you have a larger room, or need extreme SPL levels, this sub will perform.

Subjective Listening Tests – Music

FFH’s I Want to Be Like You CD has always been an album I go back to when I want to clearly monitor, not the low end extension of a sub, but the gentle sound of understated and sustained bass guitar. Calling up the title track and track 10 “Breathe In Me” we were able to hear that the SVS sub rendered flavor to these songs in a way that was natural and complete. The melodic bass lines in the latter track would sound just awful on lesser subs that tend to blare out monotonous thuds instead of expressive frequency-rich music from what is supposed to fill the lower spectrum of your home theater system. It seems that Godzilla does indeed have a soul – and that’s good to know.

For heart-pounding bass, we popped in a trusty copy of Seal’s 1991 album and cranked it up with the sub set to a tuning frequency of 20Hz (two ports open). At SPLs measuring over 98dB from the listening position (yes we could have gone louder, but adding more hot sauce to your wings has a point of diminishing returns too, no?) the SVS sub was kicking into high gear where it was made to run free, unencumbered by such things as volume constraints and compact enclosures. Track 3 at about 5:15 yields some incredibly deep bass (around 22Hz) that just about rattled the teeth out of my head as I sat listening to the PB2-ISD punch through it with ease. Many 8” and 10” subwoofers won’t even play these notes audibly unless the system is turned up very loud – usually resulting in low frequency distortion or clipping. SVS’ tectonic plate shifter didn’t even break a sweat.

Objective In-Room Measurements

We did some in-room measurements of the Outlaw Audio LFM-1 and the SVS PB2-ISD subwoofer using the Rives Audio Professional Test Kit and I think the results are surprising:

The above measurement is a low frequency sweep test using the Rives Audio Professional Test Kit. It was taken with the output of the sound card fed directly into each subwoofer and the microphone placed at the listening position. The units tracked fairly closely, with the LFM providing a bit more overall power around 50-60Hz and the SVS extending better down into the 20Hz region. Room modes aside, both subs provided excellent frequency response at 60Hz and below, which is where the system crossover point was set during most listening tests.

Conclusion – What Does It All Mean?

At the end of this review I had finished listening to two incredibly different and unique subs. The LFM-1 from Outlaw Audio is a stellar value performer – but it doesn’t stop there. It held its own against a much bigger, more expensive competitor under normal use loads. Producing an incredible (almost unbelievable) amount of tactile energy during home theater and music use, the LFM-1 had me constantly checking myself to see if I had mistakenly left the SVS subwoofer connected. That kind of frequency response and performance out of a package that is nearly 50% less in volume and about 40% lower in price is something to be acknowledged.

The SVS subwoofer is a bit of an enigma. Not because of anything bad, but because the unit sounds incredible but has none of the space-saving characteristics commonly found on other units. Is it the lack of self-imposed space constraints that makes the sub sound so good? Or is there something else at work? Its performance can be described as flat and yes, even musical. I couldn’t find a serious limitation or flaw, save overdriving the unit while tuned for 16Hz. The SVS has almost limitless power for most applications and doesn’t suffer from any of the typical constraints associated with making a subwoofer that fits through doors or doesn’t require a crane operator to get it into your house (OK, it’s not that big!) My overall impression of the PB2-ISD was that I wished it could pack this punch into a smaller package – but I still never wanted to let it leave my room – and that’s a pretty big compliment.

For those of you who still think “boom is boom. It doesn’t matter who makes it...” I offer these two subwoofers to you for trial. I think you’ll be pleasantly surprised.