Von Schweikert VR-33

TECHNOLOGY SUMMARY

There are several ways to create a decent sounding speaker. There are only a very small number of designs, however, that can offer the audiophile a complete package, where every performance aspect is balanced. The goal of the VR-33 was to offer an unprecedented level of realism not available in any other speaker system at anywhere near the $15,000 price range!

All audiophiles have seen small and large 2, 3 and 4-way speaker cabinets, all the way up to very tall line source designs using a large number of woofers and tweeters. All of these designs sound quite different, so how is the average audiophile supposed to choose between the hundreds of designs on the market? I propose that there is an optimum method to balance the sound, quality, and price; this paper seeks to explain my methodology.

While it is true that many different types of designs can sound quite good, it is also true that many of these designs trade off one aspect of the sound, in order to optimize some other aspect of the performance. That is the “art” of speaker design, most boutique speaker companies are run by fellows with strong biases – you can call this the “art” of speaker design (as long as we’re not talking about science). However, many audiophiles are not looking for “art” or “designer sound” but instead, are looking for a natural, realistic sound field in their home.

As a scientist, I decided to optimize every aspect of the VR-33 speaker system, so that it will more closely mimic the sound on the actual recording – without adding or removing anything from the signal. After reading my “design target” you will understand why the VR-33 sounds “live.” My goal includes the following important aspects, many of which cannot be found together in any other single speaker design:

1. The speaker must pass a signal without alteration of the signal – nothing removed, nothing added. No colorations of any type can be tolerated.
2. The speaker must have the same bandwidth (bass-to-treble range), low distortion, and dispersion pattern contained on the original recording. Note that I place a large emphasis on “dispersion” since that is one aspect that is neglected in other speaker designs.
3. The speaker design should have extremely fast transient response, clarity, and dynamic range, so that every listening session will become an amazing experience.
4. The speaker system must work with all types of stereo equipment, in any type of room.
5. The speaker should be massively built, to last a life-time, and should be the pride and joy of its owner, in both looks and performance potential. It should sound exciting!

HISTORICAL PRECEDENT

As a lab project in 1976 while I was a student at California Institute of Technology, I designed a “theoretically perfect” system called the Vortex Screen. It was a version of the Quad electrostatic in sound and cosmetic appearance, but used dynamic cone drivers for projection.

In July of 1989, Robert Harley, now Editor of The Absolute Sound, was the Technical Editor of Stereophile magazine, and his review of the Vortex Screen was a rave, generating sales over 500 pairs based on his statement that the Vortex Screen was a type of Holy Grail, based on outstanding performance combined with a very low retail price. We moth balled the Vortex design in later years, getting into expensive wood and painted cabinets with artistic pretentions and high prices. Due to today’s economy, we have decided to upgrade the Vortex design to the standards of a $15,000 pair of speakers with 21st century engineering and parts quality.

SPECIALIZED DRIVER ARRAY

In 1984, I was commissioned to build a “super speaker” by a client with $100,000 to spend. I spent four years testing different types of drivers, number of drivers, and baffle alignment to mimic the sound of a live performance. That speaker system, the VR-10, won “Best Sound Of The Show” at the 1994 Stereophile Show, awarded by Guy Lemcoe. That design led to the present VR-11SE model, sold since 2005 and shown on our current website. This type of design is called a Concentric Array, where the tweeter is placed in between a pair of bass-midrange speakers. This Concentric Array generates a point source sound field, with extreme focus and extremely wide dispersion. Many very expensive speakers on the market use this type of driver array, up to the $150,000 speaker system seen on the cover of Stereophile a few months ago. The clever aspect of this array is that the tweeter appears sonically to be mounted in the center of the midrange array, creating a highly focused and extremely accurate sound field image recreation.

I decided to use the Concentric Array technology to update the 2010 Vortex VR-33.

CABINET DESIGN

The most popular form of cabinet design uses 25mm MDF impregnated with a hard resin, and most other speaker companies building speakers at $50,000 and below use this material. However, we have shaped the cabinet to look like a wedge, with very thick shelf braces every 6” in order to make the cabinet extremely solid and non resonant. This cabinet weights 103 lbs! The trapezoidal shape is no accident, either, as it can be braced with the angled panels at a 300% higher Q than a plain, square cabinet. Later in this Paper, you will find that the dispersion pattern is also controlled by the angled sides, one of the most important and critical aspects that set the VR-33 apart from the competition. If you try the old “knuckle rap” test on the cabinet, you will bruise your knuckles and then believe we have used solid aluminum to fabricate the cabinet!

EUROPEAN DRIVERS

If you examine the photos included in this paper, you may recognize the same drivers as used by speaker systems costing up to $150,000/pr. This is not a coincidence, since we feel that using the most expensive and accurate drivers is an important requirement, even in a modestly priced speaker system. After all, wouldn’t you want to spend your money on great drivers instead of a nice finish, especially when the drivers are the most important part of the sound?

10” (250mm) Woofer – At the rear of the VR-33, you can see our custom-designed Tymphani woofer, with emphasis on extremely fast transient response to match the same transient response as the front-firing main array twin 6” bass-mids. With a crossover point of 80Hz, the rear-firing subwoofer can not be heard as a separate woofer, it is 100% integrated into the front wave. By using the wall as a reflector, we obtain the advantage of boosting efficiency, with the added benefit of being able to fine tune the bass by moving the speaker from 3” from the back wall, up to 20” from the rear wall. The woofer is enclosed in a Triple-Chambered Transmission line hybrid, using three damped chambers with a bass reflex port firing at the rear wall. We believe you will find that the woofer of the VR-33 is the quickest, cleanest woofer you have heard!

6” BASS-MID DRIVERS ON FRONT BAFFLE

After testing more than 30 brands and types of new midranges, we have chosen to use a Danish-Design unit, with similar sound and specifications as used in speakers up to $150,000/pr. Although this is a different model, made exclusively to blend with the other VR-33 drivers, it has the same quality and sound clarity as any midrange you have heard. Not even a ribbon or electrostatic driver will outperform our new bass-mid drivers! The specifications of the drivers are impressive- several patents are used, including the Low Distortion Motor, with copper clad pole piece, specially shaped top plate, triple wound voice coil, and elevated spider design to eliminate compression and wind distortion behind the cone. This is a revolutionary midrange! Two units are used, for power handling down to 80Hz, high dynamic range, loud volume levels, and the ability to mount the tweeter in between, creating a virtual point source. The Concentric Array, as noted above, results in the finest stereo image focus available, at any price.

1” SCAN-DESIGN SILK DOME TWEETER

Although we are justifiably proud of our woofer and mids, the tweeter is the most important driver in any speaker, since most dome drivers have high distortion and coloration. Most owners of planar speakers were driven to planars by the inherent distortion in dome tweeters that they could not tolerate. After trying diamond, titanium, ceramic, aluminum, and plastic film tweeters, we chose the plain-Jane silk dome tweeter for its natural and relaxed sound. However, our chosen tweeter has no audible distortion and will play very loud without break up. It also has extremely wide dispersion due to the dual ring design of the diaphragm, and has very high excursion potential. The rear of the dome has a large chamber behind it, to absorb the rear waves that normally cause the harshness and distortion inherent in less expensive tweeters. If you seek the sweetness of a real violin, combined with the shimmer and “air” of a cymbal, you have found your perfect tweeter. Please compare our treble quality to any speaker on the market.

CROSSOVER DESIGN AND PARTS

Although most of our speaker designs have utilized Acoustic Fourth Order circuits we call a Global Axis Integration Network, this is not a perfect design for a Concentric Array driver alignment for electro-mechanical reasons. We have reverted back to our original Vortex First Order design, with the circuit optimized for the drivers used and the wide dispersion sound we engineered into the VR-33. Since the First Order circuit uses less parts, we were able to afford the finest sounding parts available, like Mundorf and Clarity capacitors, Mundorf metal film resistors, American-made inductor coils that handle 1,000-watts before saturation distortion, and Analysis Plus internal speaker cable with 14 gage construction. Binding posts are WBT-styled Five Way units that will accept any type of connector, including bare wire. One pair is provided, since we don’t feel the VR-33 should be bi-wired due to the extra expense. The crossover board is built by hand, using point-to-point wiring, since circuit boards use thin traces that can’t handle high current without compressing the signal.

DIVER CONFIGURATION

The front baffle of the VR-33 is 8” wide, housing two 6” bass-mid drivers and a 1” Dual Ring tweeter, which is centered between the two bass- mids. The tweeter is located 37” from the bottom, directly at ear level.

Note that the driver layout is the famous Concentric Array, also known as the “D’Appolito M-T-M.” Centered between the two famous-maker 6” bass-mids is the 1” Dual ring tweeter. The front baffle is covered by a 12mm felt blanket, designed to absorb reflections from the baffle surrounding the tweeter. This enables the M-T-M array to behave as a point source, producing the finest three-dimensional image focus and depth available, cost-no-object. The VR-33 was designed to be listened to from off axis, not on axis, so you don’t have to aim them at you for best sound. Dispersion approaches 180-degrees in the horizontal plane, so you’ll hear a wide-open sound field from anywhere in the room, it’s amazing.

The 16” wide rear cabinet baffle is where the 10” woofer and bass reflex port are located. The VR-33 bass is tuned using a Triple Chamber Transmission line system. The vent can be damped with Dacron to “tune” the bass response to fit any sound room environment.

The 10” Tymphany subwoofer faces the rear wall, enabling the room to help “boost” the bass power. The crossover point to the front 6” bass mids is at 80Hz, so you can not hear that the woofer is mounted on the rear. Wave lengths at 80Hz wrap around the cabinet, making the bass appear to come from the 6” bass-mids on the front.

This design is unique and ensures extreme coherency between the deep bass, midbass, and midrange frequencies – a very desirable aspect. The front driver array sounds similar to a “one way” speaker system, while the 10” subwoofer augments the bass “invisibly” below 80Hz to provide incredible bass punch and “slam.”

The sonic realism of this design has to be heard to be believed!

ROOM PLACEMENT CONSIDERATIONS

Since most audiophiles do not have a dedicated listening room, it is impractical for customers to buy a speaker that must be placed several feet into the room. Most rooms are getting smaller, not larger, so we decided to design a speaker that can be placed several inches from the wall. In fact, the VR-33 uses the wall to develop its full sonic potential in the sound stage width, height, and depth, as well as generate the deepest bass power. The boundary design reproduces a “wall of sound,” as trite as that may seem. Keep reading to see how we accomplished this….

DEPTH RESPONSE

Many audiophiles mistakenly believe that “depth” of the sound field is generated by placing the speakers far away from the walls. This is not entirely true. Depth in the recording is captured by the recording engineer, using far-field mic placement at “live” concert recordings and artificial reverb in studio recordings. Your loudspeakers cannot “create” depth that is not on the recording! However, in order to preserve the recorded depth, the speakers must be specially designed to operate properly in the anticipated room environment. The VR-33’s sound field has been called “as wide and deep as the Grand Canyon” by one of our customers who replaced his aging Wilson Watt-Puppy speakers with this new design. The depth was achieved by designing the response of the speaker to work with the rear wall as a boundary, instead of designing the speaker to operate in an anechoic environment, i.e., far from the walls. The driver placement, crossover design, and trapezoidal baffle shape all contribute to the effectiveness of this design, which has three patents pending. More on this, below.

TRAPEZOIDAL SHAPE = CONTROLLED DIRECTIVITY

As the sound waves from the VR-33’s front drivers are directed side-ways by the slanted side walls, the initial wave launch does not initially reflect off the rear wall, it reflects off the angled sides. This provides what is known as “controlled directivity” and enables the size of the sound stage to be dictated by the size of the wall behind the speakers.

Since the frequency response of the speaker system must factor the boundary gain from the rear wall, the necessary response tailoring is accomplished in the crossover design, which “shapes” the response into the desired psycho-acoustic sound target. Our design actually enhances depth perception and a 3-D sound stage image, while also generating an enormous sound stage that has to be heard to be believed! In the past, only large line source speakers were able to create a huge sound stage, but the Vortex VR-33 has now changed the game.

REAR-FIRING SUBWOOFER

Since most narrow profile speakers using a pair of 5” or 6” woofers do not have enough of the bass “slam” desired by most audiophiles, we have elected to use a very powerful high-speed 10” subwoofer, firing against the rear wall for bass boost. Our Tymphany 10” subwoofer has a free air resonance of 25Hz, which is boosted by 3dB when loaded by the rear wall. By simply moving the speaker a few inches from the rear wall, the bass power and “weight” can be fine-tuned to the room or listening tastes. Since the entire rear wall acts as a “reflector,” the bass power of the Vortex VR-33 is simply amazing and can rival the “punch” of the finest subwoofers!

PSYCHO-ACOUSTICS OF CROSSOVER POINTS

Our sonic target was a speaker system with a very wide bandwidth of 25Hz to 30,000Hz, with sonically “invisible” crossover points. Since the front-firing 6” bass-mids have a response from 46Hz to 12,000Hz (which is almost the entire audible range!) we have elected to use cross points above and below the audible range. The subwoofer goes up only to 80Hz, where the 6” bass-mids start to drop in bass power. At the top end, we harmonically blend the Dual Ring 1” fabric tweeter at 6kHz, well outside the ear’s most sensitive hearing range. The effect of these cross points is a sonically invisible driver blend, with coherence and speed that only $15,000 + speakers can achieve! In fact, a famous electrostatic speaker was used for “coherence benchmarking.” During our beta-testing of the VR-33, no audiophile was able to guess what type of drivers, sizes, or crossover points they were hearing – in fact, most thought it was an expensive system priced at $15,000 to $50,000 based on the superior sound quality alone.

WHO IS THIS SPEAKER DESIGNED FOR?

If you have a decent 35- watt to 500-watt amplifier and an average room, and especially if you’re on a budget but would love to own a $15,000 speaker system, the VR-33 is the best speaker you can buy for the price! Every dollar of your hard-earned money was used on an extremely heavy-duty cabinet, high quality drivers, and the best crossover design in the world. If you truly want to experience your music but don’t have $15,000 to spend, you have found your perfect speaker system! No cheap, off-shore parts here, only American Hi-end Audiophile quality, built by hand in California by one of the most famous companies in the high end audio speaker business.

Available fabric grill cover is Tuxedo Black, with walnut veneer or Steinway Hi-gloss Piano black resin bottom and top caps available at the same price. Also available are Cherrywood caps.

VR-33 SPECIFICATIONS

Frequency Response: 25Hz to 30,000Hz, +/- 3dB.

Sensitivity: 90dB @ one watt/one meter when mounted close to wall.

Impedance: 8 ohms nominal, with a minimum of 5 ohms @ 25Hz.

Size: 50” tall x 8” wide (front) x 16” wide (rear) x 12” deep. Crate dimensions are 52” x 20” x 16”

Weight: 103 lbs per side, raw, 140 lbs in crate (each). Shipping weight is 280 lbs./pr

Subwoofer: Peerless-designed Tymphany 10” with Low Distortion Motor, laminated composite cone, elevated spider, long throw design, and copper clad pole piece. This is a “high speed” driver, with optimized transient response.

Midrange: Two Danish-Design 6” treated paper cast-frame bass-mids with Low Distortion Motors, elevated spiders, copper clad pole pieces, and composite laminated cones using cellulose acetate pulp, plastic resin, and carbon impregnation to eliminate standing waves on the cone surface.

Tweeter: 1” treated fabric dome, Dual Ring design with rear chamber for low resonance and powerful response down to the midrange band, Low Distortion Motor, and specialized voice coil/top plate design for long throw, high power use. Very high detail with smooth, natural sound.

Crossover: First order circuit using “audiophile-grade” parts, with cross points set at 80Hz and 6kHz. The minimalist design results in amazing clarity and transparency, with the flattest impedance curve we have ever seen (making it easy to drive).

Woofer Alignment: Quasi-transmission line design using three chambers, each tuned to a different resonant frequency to extend the bandwidth and reduce “one note bass” typical of ported boxes. Woofer “fires” at rear wall to boost the bass at 20Hz by 3dB, and can be “tuned” by user.

Power Rating: 35 watts minimum, up to 500 watts on peak music.

Warranty: Five years parts and labor (excluding abuse), non transferable.