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Reviewer: Srajan Ebaen
Financial Interests: click here
Source: 2TB iMac 27" quad-core with 16GB of RAM (AIFF) running OSX 10.8.2 and PureMusic 1.94g in hybrid memory play with pre-allocated RAM, Audirvana 1.4 in direct/integer mode, Metrum Hex, SOtM dX-USB HD with Super-clock upgrade & mBPS-d2s, AURALiC Vega [on loan]
Preamplifier: Nagra Jazz, Bent Audio Tap-X, Esoteric C-03, TruLife Audio Athena
Power amplifier: FirstWatt S1 monos, SIT2; ModWright KWA100 SE, Bakoon AMP-11R, Clones 25i [on loan]
Loudspeakers: soundkaos Wave 40 [on review], Aries Cerat Stentor [on review], Sonus faber Venere 3.0 [on review], Aries Cerat Gladius, AudioSolutions 200
Cables: Complete Zu Event loom, KingRex uArt split USB cable with Bakoon BPS-02 uninterruptible battery supply
Powerline conditioning: GigaWatt PF-2 on amps, GigaWatt PC3 SE Evo on front-end components
Equipment rack: Artesania Esoteric double-wide three tier with optional glass shelf, Rajasthani hardwood rack for amps
Sundry accessories: Extensive use of Acoustic System Resonators, noise filters and phase inverters
Room size: 5m x 11.5m W x D, 2.6m ceiling with exposed wooden cross beams every 60cm, plaster over brick walls, suspended wood floor with Tatami-type throw rugs. The listening space opens into the second storey via a staircase and the kitchen/dining room are behind the main listening chair. The latter is thus positioned in the middle of this open floor plan without the usual nearby back wall.
Review Component Retail: $5.000

This is a companion review to my prior Druid V report which introduced the Submission subwoofer. At 130cm tall and 32cm square, this tower of power would only visually disappear "as a corner plant stand with Rapunzel-type leaf cover" I said there. But like with muscle cars at the drag strip, there's no substitute for cubic inches when it comes to clean effortless coverage of infrasonics.

The Submission enclosure is a repurposed Definition IV with the same massive billet aluminium plinth for the downfiring Eminence LAB12. The innards were optimized for sub-only use. The UcD 400-based amp with linear power supply sealed in its own 6.3mm alu enclosure is pure Def 4 spec. So are the five main controls for volume, low-pass, boost gain, boost fix and phase.


The speaker level inputs with shared ground—those can't be used with a bridged main amp!—and stereo/mono line-level/sub inputs are obviously new. For the full skinny and more and larger photos of the electronics, reference the final two pages of the Druid review. What interests us today is how this hulking subwoofer plays with speakers other than Zu. The control settings below are how the company recommends one start with their own floorstanders.


soundkaos Wave 40: This superb Swiss 8" widebander with auxiliary Raal ribbon in a true instrument-style tonewood enclosure is specified to about 55Hz. In-room response of my 5.5 x 12m space confirmed this. Here I achieved a perfectly seamless blend with the attenuator at 3 and the low-pass at 40Hz. 4th-order low-pass filters aren't brick walls. They don't pass full sound at one cycle and completely lock the door on the next. It's expected that the final filter setting should come in somewhat below the main speaker's F3 if one doesn't mean to add fat.

Corners are often recommended for subwoofer placement because the confluence of three 'infinite' surfaces—two walls + floor—creates maximum boundary gain. I view it as the perfect recipe also for creating resonant high-pressure zones, mud, associated HF damping and directional reveal. The Submission is a true subwoofer. Its built-in headroom requires no boundary lift. I thus had far superior results placing it slightly off-center in the middle of the front wall. (Dead center would have obscured a painting, farther out into the room would have looked bad. Some concessions are required when a listening room doubles as living space. Minor asymmetry relative to the overall room geometry is often beneficial in and of itself.)


In some quarters subwoofers have gotten a bum rep. Chasing the perfect 80Hz hand-over where any 24dB/octave filter remains audible to 200Hz is arguably something of a fool's errand. Applying augmentation an octave lower is a different matter. This obviously requires main speakers other than typical micro or mini monitors. Anything good to about 50Hz will do. The vital power zone of the upper bass is handled in true stereo and directionally perfectly aligned with the higher registers. Now the subwoofer more or less concerns itself with just the first octave. Purists might argue that combining an electrically filtered sub with any main speaker whose mid/woofer or woofer rolls off merely acoustically will never add up perfectly. Possibly not. I'd argue though that the real question must be whether gains in overall performance outweigh possible deviations from perfection (which in an untreated un-eq'd room isn't achievable in the first place).

I'd also argue that getting 20-cycle bass from passive speakers is far more problematic on any number of counts. Segregating an infrasonic generator into its own box removes internal pressures and enclosure resonances from the main speaker. It affords discrete placement to minimize room mode activation. Without the sub's separate bass attenuator, full-range passive speakers often victimize their owners with no facility to turn down/off the boom. Subtracting from the main amp the considerable electromotive forces a big woofer kicks back isn't a bad idea either. Creating true 20Hz output from passive speakers requires that they be large and nearly inevitably also expensive. Finally if you play at low levels, bass intelligibility nearly always takes a hit. With a Submission-level sub simply compensate by slightly upping its relative output for such whisper sessions. It works a treat.

If you're still out in the cold wondering why one would even want 20Hz bass—surely that's fit only for the boom-truck brigade—the answer is simple. It's not about any rave, disco or reggae excess. It's about scale, soundstaging, ease, color saturation and rhythmic grip when kick/bass drums and related beat makers add weight, kick and pitch intelligibility. It might have been British REL subwoofer firm who first did girl+guitar type dealer demos with and without subwoofer. This demonstrated how recording-venue cues are seemingly associated with very long wavelengths at very low amplitude even on material that's apparently devoid of any real bass. That effect is very real. It's the first thing Martin Gateley, designer of the Wave 40, said when we added the Submission. More scale. Aside from the primitive obvious of more extended bass, the far more impressive transformation related to space and size. Everything instantly grew bigger and deeper. Save for hearing synthesized infrasonic chicanery on ambient and electronic albums which regular speakers can't reproduce fully, the primary benefit of building out the lowest octave thus isn't about more bass per se. It's what mostly instinctual (rather than directly audible) bass adds to dimensionality and participatory involvement.