Very Solid Sub in macassar ebony

The VSS (Very Solid Sub) is slightly smaller than the Larger Sub but very stout and heavy, 5 cm (2") thick baffles, and built-in 1000W amp with electronic crossover and single-band parametric EQ which allows the user to notch out the floor-to-ceiling room mode (71Hz with an 8ft ceiling). Our new 38 cm (15") active driver is low mass and high acceleration, with a huge motor and very heavy, Dynamat damped stamped basket. Cone is a vitrified paper/Kevlar laminate. There is also a 38 cm mass-loaded passive radior in slot loading.

The VSS is zero dB down at 20Hz and will reproduce subsonics (-10dB/14Hz nearfield). Weight is 72 kg (160 lbs), of which 10 kg (22 lbs) is the driver. Dimensions are 76 W x 58 H x 46 D cm (30”W x 23”H x 18”D). The VSS is $1650 per each.

New Larger Subwoofer

New Larger Subwoofer w/Megawoofers

The New Larger Subwoofer, in its restyled round-corner lowboy cabinet, is the lowbass section of our renowned Super Tower IIa/R tower (active 30 and 38 cm polycone woofers (12" and 15"), slot-loaded 38cm passive (15")) in an 226 l, 63 kg (138 lbs) light or dark oak veneered enclosure made from 25 mm (1") thick MDF. It is designed for the audiophile desiring the ultimate in separate lowbass modules without the expense involved purchasing the best competitive units of other manufacture. Distortion (0.5% / 1W), bandwidth (-3 dB at 17 Hz), sensitivity (92 dB/1W), and maximum undistorted output levels (115 dB/1m plus at 20 Hz) are unsurpassed and not even approached by all but one or two very costly competitors. Press comment on the lowbass performance of the STIIa/R include: "World Class" (High Fidelity Ap 85); "Awesome...left bruises on my abdomen" (Hifi News & Record Review, England, Ap 85); "Excellent dynamic response and overall accuracy...superb power handling capabilities...has an ability to show that bass can provide the listener with important sound-stage information" (Audio, Aug 85). 

A single New Larger Subwoofer may be used with a stereo pair of satellites by driving each active woofer separately through two speaker level Passive Crossovers, which install inside its cabinet. 

None of the VMPS Subwoofers are powered (i.e. have built-in amplifiers) for a number of reasons. Installing an amplifier inside a woofer enclosure, the common practice with "powered" subwoofers, invariably leads to amplifier failure due to vibration literally shaking the circuitry to death within a relatively short period. Examine the warranties on powered woofers and discover that many expire within six months of purchase, or warrant amplifier components for a year or less. Worse, the quality of such built-in amplifiers, particularly the dreadful Class B and Class D designs now popular, is poor; often the entire amplifier component is purchased offshore from a vendor for around $60.00. When a built-in crossover is provided, it too is generally of minimal design and execution, with the cheapest parts and wiring. Such built-in amps are often far from linear, cannot pass even a good sine wave at any frequency, and are burdened with contouring (bass boost of various sorts), infrasonic filters which ring and color the entire woofer output, limiters to prevent the user from playing the sub louder than about 100dB SPL at 1m, and other exigencies which severely limit dynamic range, output levels, and distortion. VMPS Subwoofers require no equalization or filters, since all extend response well into the first octave at very low THD and high output levels. Any main system amplifier of good quality and 20W rms per channel or more may be used, and the Subwoofers will uncomplainingly accept prodigious amounts of power. 

Press coverage on the VMPS Original Subwoofer includes a full review in Stereophile magazine VIII/4 August 85. They comment: "The VMPS bass character is clean, quite tight, and thunderous, qualities that improved the (main speaker's) sense of dynamic bloom...its flexibility is such that it should partner well with a wide variety of speaker systems...it is a whale of a good buy and highly recommended". J. Peter Moncrieff, wiring in IAR Hotline 31 about the Widerange Ribbon speaker system which employs two Original Subwoofers for bass below 60Hz, comments: "A VMPS demonstration of the famous Dafos drum whack left no doubt as to the most powerful, well controlled deep bass we'd ever heard (sharing top honors with multiple Entec subwoofers.)" 

NASA's Langley Research Center has purchased two Larger VMPS Subwoofers as a source of 118+ dB, 20 Hz tone bursts. The Larger Subwoofer was the only commercially available system capable of so doing.

Audioreview
Audio Asylum

New Original Subwoofer / 215 Subwoofer

New Original Subwoofer / 215 Subwoofer (two models - same appearance)

A good subwoofer can greatly enhance the performance of virtually any music system: first by extending frequency response into the first octave (16 Hz - 32 Hz); second by generating much less harmonic distortion in the subbass and bass regions (200 Hz and below) than is typical of most fullrange speakers, which often produce tens of percent THD in that range; and third by reducing intermodulation and doppler distortion in the main speakers by relegating long wavelength fundamentals to a separate driver which is well suited to reproducing this most difficult area of the musical spectrum. The woofer fulfilling these functions should be reasonably compact, efficient enough and of low mass and inertia to match all main systems, and not prohibitively expensive. In all these areas the VMPS Subwoofers excel. 

There can be no clean first octave response from any speaker having a pronounced system resonance in the audible range, and the VMPS Subwoofers, like their full-range multiway siblings, are free of such anomalies throughout their operating region. This is achieved by means of a push-pull arrangement of active drivers and passive radiators. The mass- loaded passive, pushed by the low-resonant active woofer, provides most of the first musical octave thanks to its high compliance and a resonance frequency below the audio range (8 to 12 Hz). Another benefit of this arrangement is high efficiency, since front and back waves are utilized to produce sound, so typical subwoofer sensitivity reaches 89 to 92dB for one Watt input. Last but hardly least, the active/passive setup lowers bass cutoff to into the teens and early twenties, particularly when the optional high power, 80oz. stacked magnet woven carbon fiber Megawoofer is installed. VMPS Subwoofers are avoiding high moving mass (up to several pounds) of many competitors and thus offer flat frequency response to 300hz and higher. Electrostatic and other dipole radiators can therefore be crossed over in the more advantageous 175 Hz to 250 Hz range to minimize frequency response errors caused by the dipole effect (which in many planar systems starts as high as 700 Hz). VMPS Subwoofers reach undistorted output levels (for 5% THD) of 112 dB to 115 dB/1m and higher at frequencies much lower than other designs. Because of very low moving mass both of the active and the passive speakers, VMPS subwoofers are extremely quick and responsive, fast enough not to lag behind even the lowest-mass electrostatic or ribbon transducers now available.

Dedicated Subwoofer

Dedicated Subwoofer

It is easy to add a Subwoofer to an existing system. Our Passive Crossover (sold as option and built in subwoofers enclosure) allows single amp or biamp operation of woofers and main speakers, providing a fixed 90Hz rolloff of bass frequencies at 6 dB/octave and a variable roll-in of the main speakers at 12 dB/oct. while maintaining correct phase. This quasi second order design features high quality passive parts (large gauge solid iron inductors, bypassed nonpolar capacitors); a level control for the main speakers matches levels to the woofer. The Passive Crossover has three configurations: mono lowpass only, where the woofer is rolled off and the main speakers work fullrange (recommended with speakers having good, if limited bass or if the user does not want to route the main speaker signal through passive filter parts); mono low and high pass, which provides rolloff of a single woofer and roll-in of one main speaker; and stereo low and high pass (two full Passive Crossovers required), where both channels are fed to the Dual Voicecoil version of the active woofer driver and are then routed to the main speakers which receive no bass signal. Audiophiles able to biamp can use the passive crossover in the mono lowpass mode, and run the main speakers full range through a second power amplifier with a level control, or an integrated amp. Of course, the Subwoofers can also be operated via an external electronic crossover, in which case we recommend crossover frequencies between 60Hz and 200Hz at either 6dB/oct or 24 dB/oct. If you want to biamp but lack the extra channels, VMPS also sells two powerful, high quality Subwoofer Amplifiers well suited to the task. 

The question arises in many installations as to whether one or two Subwoofers should be employed, given the nondirectional nature of bass frequencies. Some also have suggested that woofer placement is relatively unimportant, for the same reason. Stereo imaging and dynamic range are much improved, however, by the addition of a second Subwoofer. Where possible woofer placement should be in close proximity and in the same plane as the main speakers. Directional information from the Subwoofers is available at midbass and high frequencies, due to the gentle crossover slopes we recommend and incorporate into our Passive Crossover. Also, a second Subwoofer generates twice the air displacement of a single system, a critical factor in properly reproducing high levels of very low frequency information. 

Users desiring a "faster" or warmer sound from the Subwoofer can adjust system Q through adding or subtracting mass from the bottom firing passive radiator. This feature allows the woofer to be tuned to a variety of electronics and listening environments, as well as compensate for listener preferences or changing program material. Subjective speed is improved by use of the woven carbon fiber Megawoofer, the cone of which is 40% lighter and stiffer than the polypropylene material of standard drivers. Owners of Quad or Soundlab electrostats can employ any of our Subwoofers for these systems, with which they are fully compatible.

The success of the Original VMPS Subwoofer, first introduced in 1983 and since internationally acclaimed for its high performance and low cost, prompted the release of two additional models, the Smaller Subwoofer (now Dedicated Subwoofer), and New Larger Subwoofer, designed for systems with particular demands for size and bass output levels. 

Dedicated VMPS Subwoofer features woven carbon fiber 30 cm (12") Megawoofer, working in tandem with a 30 cm (12") mass-loaded and slot-loaded passive radiator in a compact box the size of many bookshelf speakers. The 70 l system achieves a low cutoff frequency of 24 Hz / -3dB, with total harmonic distortion not exceeding 5% (1W drive) at any frequency down to cutoff. Horizontal or vertical mounting is permitted: standing vertically, the 66 cm high unit makes an ideal stand for any number of satellite and bookshelf speakers. High sensitivity (90dB/1W/1m) and high undistorted output (112 dB / 1 m SPL for 5% THD) allow the system to be adapted to virtually any main speakers including electrostats and ribbons.

 
Passive Crossover (internal) 
Type: quasi-second order, 90Hz lowpass fixed, highpass variable mono crossover (one required per channel, non-summing), speaker level 
Controls: main speaker level 
Insertion loss: approximately 1.5 dB 
Components: large gauge solid iron inductor, nonpolar electrolytic capacitors with polypropylene bypass, 12 gauge Monster Cable internal wiring 
Mounting: mounts inside woofer cabinets