Von Schweikert db100 loudspeaker

DB-100 HIGH EFFICIENCY SPEAKER
Designed Especially for Single Ended Triode Amplifiers

Single Ended Triode tube Amplifiers are becoming more popular as audiophiles recognize that high power ratings mean nothing if sound quality is sacrificed. The liquid sound and image float has endeared the SET sound to many listeners, including Albert Von Schweikert, who recognized the need for a speaker designed around the characteristics of these wonderful sounding amplifiers. Although characterized by very low power output, these amps can offer dramatic dynamic range and bass power if a correctly designed speaker is used. This means high efficiency combined with a very tight woofer system is necessary in order to hear the full capability of S.E.T. amplifiers. High impedance is also important, as is low levels of coloration and distortion, along with 3-D imaging characteristics. More importantly, high efficiency design also enables the magnification of low-level detail to the point of audibility, creating breath-taking vibrancy masked by low efficiency design.

LIMITATIONS OF THE S.E.T. AMPLIFIER/SPEAKER INTERFACE
Since Single Ended Triode amplifiers cannot drive conventional, low efficiency speaker systems, an appropriate design must have a very high level of sensitivity in order to allow realistic listening levels and exciting dynamic range. In addition, since the S.E.T. amplifier has less than ideal bass control over the woofers, a new type of engineering must be found to replace the common large paper woofer loaded into a boomy bass reflex cabinet. Horns are typically used for their high efficiency; however, boomy bass combined with coloration in the midrange eliminates almost every horn from the audiophile's wish list. The task at hand was to design a very high efficiency speaker system without resorting to horn loading in the crucial midrange or bass reflex loading in the bass range. In addition, the imaging of the system has to be as three dimensional as conventional audiophile speakers. For this reason, Von Schweikert Audio has spent several years researching the possibility of a 100dB speaker design for the audiophile with critical taste. Our former high efficiency speaker, the VR-6, had been named Product Of The Year by Audioland magazine in Hong Kong for its great sound and 96dB sensitivity. Although the VR-6 sold for $12,500, it was seen as a phenomenal bargain. The new DB-100 has many of the characteristics of the VR-6 in its sound quality but will retail for $9995/pr, clearly a bargain when considering the addition of the booster amplifiers and adjustable bass system.

WOOFER SYSTEM
Every audiophile likes bass response that is both deep and tight. In addition, most audiophiles have often wished to be able to adjust the bass levels to match their room, amplifier, and recording. To achieve these lofty goals, we have employed two 8.5" aluminum coned woofers with Low Distortion Motors in a large triple-chambered transmission line enclosure using a flared vent to tune the line to 20Hz. Since these powerful and accurate woofers have moderate efficiency, and since we desired to have tighter bass response than the S.E.T. amplifiers exhibit, we have engineered a Class A/AB High Current "power booster" to drive the woofer system. This booster/ amplifier has extremely tight control of the woofer system and can deliver very high volume levels at 20Hz with its 900-watt peak power capability (600 w.r.m.s). The amplifier has a volume level to allow adjustment of bass response in any listening situation, including the equalization of older records that have too little bass.

SOLID STATE BASS QUALITY VS. TUBE BASS RESPONSE
Since our goal was to faithfully reproduce the sound of the SET amplifier, including the romantic bass range, we engineered the DB-100's solid-state power booster/amplifier to mimic the sound quality of the SET, without adding distortion or otherwise modifying the sound. How was this accomplished? The input stage of this solid-state booster/amplifier has been designed to receive its signal from the output signal of the Single Ended Triode amplifier. The amplifier is completely faithful to the input signal, allowing the DB-100's bass response to take on the characteristics of the SET amplifier, including the tone, speed, and timbral qualities that SET's are sought for. If you have been yearning for extremely dramatic yet accurate bass, with extreme coherency into the midrange, you have found your speaker!

SPECIALIZED DRIVE UNITS

In order to increase the sensitivity of the drive units, it is necessary to lighten the cones and increase the flux density of the magnetic field driving the voice coil. Our midrange driver uses a 6" Aerogel composite cone resembling a lightweight ceramic material. Although extremely light and stiff, this cone does not ring or add coloration since the Aerogel cone is made from carbon fiber dust, Kevlar threads and cellulose acetate pulp. This proprietary cone has a very high Young's Modulus, or ratio of weight to stiffness. To boost the sensitivity, the small magnet was replaced by a 72oz monster, which drives the lightweight edge-wound aluminum voice coil. This is the clearest sounding cone we have ever tested and is far superior to any horn midrange in existence.

We have had Scanspeak/Vifa of Denmark fabricate a very high quality silk dome tweeter using horn loading to acoustically amplify the signal level. In this new tweeter design, the fabric dome is driven by a large ceramic magnet and linear motor system to attain high SPL levels at one watt. Unlike other horn tweeters, our design uses a 2" short horn without the typical throat constriction that adds coloration in conventional horn designs. The conical flare enables very wide dispersion combined with high clarity along with high dynamic range and low distortion. In addition, Ferrofluid magnetic oil has been used to both cool the voice coil and lower mechanical distortion caused by chattering of the voice coil in the metal top plate gap. To lower the resonance (a major source of coloration), we have designed a loading chamber behind the dome that is filled with an acoustic damping material. This technique enables very neutral sound quality not often associated with horn-loaded tweeters.

BYBEE QUANTUM PURIFIER
In addition, we have employed the Bybee Quantum Purifiers to eliminate high frequency distortion caused by RFI and other high frequency noise. These filters absorb distortion above the range of audibility to ensure very quiet operation of the horn tweeter in the critical range. Although this technique is controversial, the sonic effects are quite audible and dramatic. We believe the DB-100 to have the smoothest yet most detailed sound available, cost-no-object!

RECOMMENDED AMPLIFICATION
We have designed the DB-100 to operate with as little as 3 watts r.m.s and as high as 50 watts r.m.s. Although this speaker design can handle tremendous amounts of input power due to heavy duty construction of the drivers, crossover and cabinet quality, we have optimized its sound quality around the characteristics of SET amps with low power output. Push-pull tube amplifiers with low power can also mate well with the DB-100, as well as the new breed of extremely low-power silicon amps. We do not recommend high power solid-state amps with the DB-100, however.

ENGINEERING AND COSMETIC DESIGN OF TOWER
The dB-100 is a tall tower speaker using 2" thick MDF front baffle, with 1" MDF combined with 1" acoustic foam damping on all other walls. Extensive cross bracing is employed to eliminate the typical cabinet resonances found in bass reflex cabinets and horn speaker cabinets. In fact, the cabinets are so well damped that they weigh over 200lbs and have "zero" sonic signature! The tower is covered in black grill cloth with wood end caps available in dark red cherry, light natural cherry, or black ash. As an option, black Corian marble caps are offered at extra cost. The grill frame is removable to display the drivers.

The booster/amplifier is built into the rear of the tower, with one pair of Cardas top-of-the-line binding posts for connection to the amplifier. (Bi-wiring is neither possible nor recommended). There are also two controls, one for bass volume level and the other for Ambience Retrieval level (generated by the rear-firing dipolar ambience driver and circuit.

REAR FIRING AMBIENCE RETRIEVAL SYSTEM
Since recorded music is mainly a two-dimensional "construct" with depth encoding based on vectors, we have engineered a dipolar ambience retrieval system based on the typical recording microphone pickup pattern in reverse. A specialized circuit is used to "drive" a rear-firing tweeter to duplicate a dipolar dispersion pattern, enhancing depth perception and enabling a fuller, larger sound stage image. A potentiometer allows complete control over the depth enhancement, from 0 to 100% attenuation.

DB-100 SPECIFICATIONS:

System Type:	Three-way high-efficiency transmission line speaker using amplified subwoofer system, Ambience Retrieval system for concert hall depth replication, exotic cone technology for high definition clarity and transparency, and low distortion drive motors for smooth response. This system was specifically designed for Single Ended Tube amplifiers with power ratings of 3 watts or higher. The built-in solid-state woofer booster/amplifier allows the SET amplifier to drive the midrange and treble frequencies only, ensuring low amplifier distortion. Bybee Quantum Purifiers connected to the tweeters reduce distortion by eliminating high frequency noise from the signal path. The DB-100 has been designed to be the best speaker available for S.E.T. amps, cost-no-object!
Dimensions:	54" H x 12" W x 22" D.
Weight:	200lbs. raw, 215lbs in shipping carton.
Bass System:	2-8" cast frame aluminum-coned SuperDuty woofers with low distortion motors, long throw excursion, linear suspension, and high-temp voice coil (900 watt peak power capability). Triple chambered transmission-line bass loading with tuned port @ 20Hz and Dacron/acoustic foam damping for Q= 0.6. Design optimized for extremely fast transient response and very deep bass (16Hz @ -6dB).
Woofer Booster/Amplifier:	To drive the twin woofers, a specially designed Class A/AB high current solid-state amplifier with heavy- duty power supply is employed. Power rating is 600 watts r.m.s. with 900 watt peak. Automatic turn-on feature eliminates manual power on/off switching. Volume control enables woofer level to be adjusted for any level of bass desired. In addition, the bass level control enables any room placement without restriction due to boundary reinforcement.
*Midrange:*	6" cast-frame dynamic driver employing 72oz. magnet for high efficiency and high dynamic range. Lightweight Aerogel cone is a high-tech composite of carbon fiber powder, chopped Kevlar fibers, and cellulose acetate pulp binder. The Aerogel cone has a very high Young's Modulus (weight to stiffness ratio) ensuring very high signal accuracy and resulting transparency. Flat wire edge-wound voice coil allows far higher magnetic coupling than round wire, greatly increasing signal accuracy and dynamic range. Extremely flat frequency response ensures very high signal purity.
*Tweeter:*	1" silk dome tweeter hand made in Norway using horn loading to increase sensitivity, Ferrofluid liquid cooling in the voice coil gap and rear chamber for lowered resonance (650Hz).
*Ambience Retrieval System:*	Rear mounted 1" tweeter driven by special circuit design and Dimension control for effects level. Dipole operation results in correct front-to-back depth replication.
*Frequency Response:*	20Hz-20kHz, +/- 2dB.
*Impedance:*	8 ohms nominal, 10 ohms max.
*Sensitivity:*	100dB using one watt at one meter, in room
*Warranty:*	10 years Parts and Labor, excluding damage from abuse.
*Finishes:*	Standard finish is cloth wrap with light natural cherry, dark red cherry, or black ash end caps. As an option, black Corian marble caps are offered at extra cost.