December 2001

World Premiere!
Relief from Horniness:
Albert Von Schweikert Gets Really Sensitive With The DB-100!
Review By Wayne Donnelly

  It's exciting to have first contribution to Enjoy the Music.com deal with what I believe is a truly significant loudspeaker. The word breakthrough is bandied about too casually in high-end audio marketing, but I'm tempted to use it here. It's more precise though to say that the Von Schweikert DB-100 loudspeaker uses a number of tried-and-true design techniques in an unusual and innovative way -- and in doing so establishes a new category of high-sensitivity speakers designed specifically for low-power Single-Ended Triode amplifiers. The combination of 100 dB/w/m sensitivity with fast, coherent, gut-wrenchingly deep and powerful bass is virtually a contradiction in terms in SET circles, but that is what we have here.

Although I've long been intrigued by the rich harmonics and musicality of the better SET amplifiers, I've never owned any of them. For me, the problem has been that just about the only speakers available that offered the kind of large-scale listening experience I like have been horn-loaded designs. Horns and I have never really clicked -- maybe my mom was frightened by Klipschorns when I was in the womb. I can appreciate their speed, detail and mid/treble dynamics, but to my ear those virtues have been offset by comparative deficiencies in midrange openness, seamless driver-to-driver coherence and the ability to scale realistically (e.g., the old giant solo violin).

One of my most serious reservations is the bass response of horn systems. The few that I have heard deliver real bass from a horn have been to my ear colored, and it doesn't help much that the extreme low frequencies from SETs are typically weak in relation to their lovely midrange. And it's difficult to successfully combine dynamic subwoofers with them; I typically find those hybrid combinations problematical in matching both timbre and them in timing. Now, many highly credentialed audiophiles love their horn systems -- including our esteemed Editor -- and I have no quarrel with them. Different strokes, etc. But my encounters with horns have at best led to respect, not romance -- a polite handshake rather than a passionate smooch. I haven't slammed the door -- I'm still willing to be convinced. But for now, back to the DB-100s.

What Hath Von Schweikert Wrought?
In explaining his design, Albert Von Schweikert points to the midrange driver, sourced from Audax, as the key component. It is designed for flat, extended frequency response and is 100 dB sensitive without horn loading. (For technical details on all drivers, see the Specifications at the end of this review.) In my three months with the DB-100s, I found this driver every bit as fast, dynamic and resolving as a horn, and superior in openness and tonal beauty.

The speaker is not entirely horn-free. Its two 1" soft-dome Vifa tweeters (front- and rear-firing) are horn-loaded, which accomplishes two goals. First, this implementation raises the tweeter's 93 dB sensitivity to the requisite 100 dB. In addition, the horn-loading locates the motor of the front tweeter the same distance from the baffle as the motor of the midrange driver. Von Schweikert uses this technique and the crossover design to achieve accurate time alignment without the sloped baffle typically employed for that purpose.

The rear-firing tweeter is adjustable by a rotary knob on the rear of the speaker. Dubbed the Spatial Dimension Control, this feature is designed to provide both ambience and timbral fill-in. Due to the peculiarities of my listening room (especially having no solid corners behind the speakers), it had relatively little effect, and I left the control turned all the way up most of the time. In a room with more conventional boundaries, a lower output might well be desirable. In any case, this control allows you to compensate for any overall brightness or dullness in your system's electronics.

There is also a secret ingredient in the sound of the speakers -- both front tweeter and midrange driver have Bybee Quantum Purifiers attached to the hot terminal. [In the spirit of ethical full disclosure, let me say now that Jack Bybee is a good friend of mine. I have put his remarkable little magic bullets into all of the electronics and loudspeakers in my systems, leading to remarkable gains in soundscaping & imaging, inner detail, dynamics and sheer beauty.] Albert Von Schweikert is one of a small group of adventurous manufacturers willing to admit that something "Not Invented Here" can materially improve the performance of their designs. Albert said to me, "I can't measure what they do, but they make a big difference, especially on the tweeter." Interested readers can check out at www.bybeetech.com.

Thunder And Lightning
The DB-100's bass system delivers a degree of low-frequency resolution and sheer slam that will seem revolutionary to SET owners. I've heard few stand-alone subwoofers that are as deep and quick. I discussed horn-loaded bass systems above. Both horn-loaded and conventional full-range high-sensitivity dynamic speaker systems exhibit deficiencies that inevitably derive from the poor damping performance of SETs and other low-powered tube amps. (I'm making the assumption that few listeners choose solid-state amplification for these kinds of speakers.) Woofers designed to be driven by small tube amps are typically fairly large in diameter and very low in mass (usually paper cones), reflecting the reality that SETs and low-power push-pull tube amps have high output impedances and very low damping factors. They can control only low-mass drivers in horn-loaded or some kind of bass-reflex vented cabinets, and the driver must be fairly large in order to move any air in the those environments. (Someone is probably going to write in indignantly about this amp or that speaker that contradicts my assertions. But I think that these observations are valid in most cases.)

 It is generally accepted that the transmission line (a ported labyrinth stuffed with damping material, into which the back wave of a driver is loaded) is one of the most effective designs for achieving very deep bass. A major trade-off is that transmission line designs are notably inefficient. Von Schweikert's solution is to incorporate an active transmission line subwoofer system in each DB-100 cabinet, powered by solid-state high-current 600-watt amplifiers. Each amplifier drives two 8" ScanSpeak woofers, providing bass extension well into the 20-Hz region. The elegance of the design lies in its functional simplicity. No external crossover or bi-wiring is necessary -- the solid-state amps in effect use the midrange/treble amplifier(s) as the input stage, and the output level of the bass is easily adjusted using a calibrated knob on the rear of the enclosure. This meant that when I was driving the DB-100s with, for example, the Wavac EC-300B SET amplifier, I had 10 wpc on top and 600 wpc below. Weird, no?

I suddenly have a vision of SET enthusiasts donning garlic necklaces and holding up crosses to ward off the solid-state Antichrist. Some of you won't believe this -- at least until you check it out for yourselves -- but the Von Schweikert scheme works beautifully. At different times during the review process I drove speakers with four different amplifiers: the WAVAC, a pair of Scott Frankland modified-beyond-recognition 300B monoblocks originally born as Golden Tubes, my 25 Wpc push-pull VTL Tiny Triodes, and Andy Bartha's ingenious little 50-watt solid-state monoblocks. Each of these had a distinctly individual sound signature, easily distinguishable not only in the midrange & treble, which were driven directly, but also quite distinctly in the bass. I've heard a number of speakers with active woofers and passive mid/tweeters -- Vandersteen V's (all dynamic drivers) and Martin-Logan electrostatics with dynamic woofers, for instance -- and none of them delivered as convincingly continuous and well integrated low-frequency output as the DB-100s.

Setup And Calibration
This design mandates a degree of size, primarily to accommodate the bass system. At 54" tall, they're definitely a presence in my not overly large listening room. My review pair -- the first production pair -- are cloth-wrapped; the nice brown cloth covers the woofers and the mounted-at-the-top midrange, leaving the tweeter horn and large flared transmission line port exposed. That look has now been revised: the cloth is now black, and wood end-caps are available in black ash and light or dark cherry. The cloth is cut out where the drivers are located, but otherwise covers all four sides. A removable cloth grille, when affixed, gives the impression of a completely cloth-wrapped structure. (I am told that a black lacquer cabinet option will be available at a $1000 premium.

Although speakers in my place load into a considerable volume of space, my primary listening area is nearfield. The centers of the front baffles are 8' apart, and I sit 9' from the plane of the speakers. In in this environment, I find the best soundscape and imaging with the DB-100s toed in sharply, the drivers pointing directly at my sweet spot. In this setup I am very happy with the spatial reproduction of music. Moving over to either side, however, means getting a left- or right-channel-dominated (im) balance. This narrow sweet spot is not unusual with high-quality speakers, and I don't really regard it as a defect -- just one of those trade-offs we make. And besides, most of my listening is solitary. I believe it is likely that the DB-100s would not exhibit as radical a narrow beaming effect in a larger room with, say, 15-20 feet separating speakers and listener.

Things sounded good from the start, although the top half of the speakers became noticeably smoother and more relaxed over the first month. The bass system required a bit more work. To begin with, I heard a ground hum after connecting the DB-100s. (Remember, they need to be plugged in to power the internal amplifiers.) Lifting the ground on the captive amplifier cords solved the problem. Rather than a drawn-out siege of adjusting the bass level by ear, I called upon a friend to bring his Real Time Analyzer, and we were done in minutes.

Still, all was not right. The bass was deep and powerful, but loose. Transient attacks were spectacular, but the woofers didn't settle quickly enough -- they sounded slow and poorly defined. I spoke to Albert, who sent me a box of Dacron to stuff into the transmission line port for more damping. The port is plenty big enough to insert my arm, and I embarked on a couple of hours of stuff/listen/stuff/listen, gradually tightening the bass output until it sounded as quick and precise as the rest of the system. Doing this didn't bother me -- this was after all the first pair, and they had originally been voiced in a much larger space. In subsequent conversations, Albert assured me that he has now adjusted the transmission line damping. In any case, adjusting bass with damping material and/or the level controls is easy, and gives the listener a chance to adjust the bass output to taste (or lack thereof). After I got the damping where I wanted it, a quick tune-up with my friend's RTA put the top-to-bottom balance exactly right.

I got very good results with a variety of electronics, but here I'll list the components that were in place for the majority of my time listening to the DB-100s: the transformer-coupled solid-state ($18,000!) Paravicini 312 preamp, Vendetta Research phono stage, WAVAC EC-300B SET stereo amplifier ($20,000), Basis 2800 vacuum turntable/Graham 2.2 arm/47 Labs-modified Myabi cartridge, Andy Bartha-modified Pioneer 434 DVD player (the mods make this little cheapie a killer CD player), Nordost Quattro-fil/SPM, Transparent Reference XL and Bybee custom wire.

Enjoyin' The Music
I could go on endlessly about the discoveries and new musical insights resulting from three months of listening to the DB-100s. But I'll boil it down to a few examples. The single-sided 45 RPM Classic Records reissue of the Reiner/Chicago Pines & Fountains of Rome was revelatory. In Pines, the interplay of woodwinds, the startling bite of the brass (especially Adolph Herseth, the greatest first trumpet I've ever heard, who just retired last season) had an immediacy beyond what I had previously experienced with these great records. The definition of the low strings in "Catacombs" gave me -- I know it's a critical cliche, but really -- goosebumps. The closing "Appian Way," one of the all-time great demo cuts, had almost overwhelming power -- and I've heard it probably a hundred times on all kinds of fine equipment.

Orchestral music on CD? For the past year I've kept returning to the Oue/Minnesota disc of Leonard Bernstein's music from Candide, etc. [Reference Recordings RR-87CD] -- one of the best digital recordings I know. In the Candide Overture, the extraordinary bass had more impact than ever, setting the double-glazed windows behind my listening seat to rattling (a first). The violins were not only gorgeously rich; I could hear individual players within the mass of the section.

Back to LP, with Patricia Barber's Nightclub [Premonition/Blue Note 90749]. I felt as if I could hear right down to the vocal cords; Barber's throaty voice suddenly had nuances that had escaped me in the 20 or 30 times I had played this record. The sonority of the piano was complete, from initial transient to decay, again to a deeper resolution.

Richard Thompson's Mock Tudor [Capitol CD, CDP 7243 4 98860 2 5] moves from sotto voce to loud, assertive singing, from delicate acoustic guitar to fiery rock 'n roll. This subtle artist creates complexly layered arrangements, which the DB-100s opened up with remarkable ease. The effortlessness of dynamics, the sheer speed of the speakers were dazzling on this rock masterpiece. I found, for instance, that I could easily follow Thompson's very complicated English-accented lyrics even in the most raucous songs. Damned impressive.

Thumbs Up? You Bet!
So, what we have here is a speaker that does -- well, just about everything a speaker is supposed to do, and extremely well. Tonality, detail, dynamics, extension, soundscaping, imaging. I would venture to say that no horn system I know, with or without subwoofers, can match the smoothness, coherence and dynamics of the DB-100. At $10,000 per pair, it's not just a value, but an outrageous value. The competition will come from speakers at double the price. My long-beloved Bybee-modified Eggleston Andras ($15,000 + mods) are simply not their equal. Anybody want a pair?

If the physical size and/or price tag still seems too big, take heart. By the January 2002 CES in Las Vegas, Von Schweikert will be offering the DB-99. This sibling is identical on top, uses a single transmission line-loaded 10" woofer powered by a 300-watt amplifier, is about a foot shorter, and will retail for $5,995. For anyone with a small to medium-size listening room, the DB-99 may well offer equal or even better performance than the DB-100. But whichever model interests you, this is a speaker design that demands to be heard. The SET world take note -- there's a new sheriff in town.

*NOTES:
1. It is quite likely that the soundscape ratings would change in a more conventional and larger listening room.
2. The Fit and finish rating could change, as I have not seen the new cloth wrap and grille. Construction quality is excellent.

 

Specifications
System Type: three-way high-efficiency transmission line speaker using amplified subwoofer system, Ambience Retrieval system and Bybee Quantum Purifiers; designed specifically for Single-ended Triode amplifiers.

Sensitivity: 100dB/W/m
Impedance: 8 Ohms nominal, 10 Ohms maximum
Frequency Response: 20Hz to 20 kHz (+/-2dB)

Bass System: Two 8" cast-frame aluminum-coned woofers with low distortion motor, long throw excursion, linear suspension, and high-temperature voice coil (900-watt peak power capability). Triple-chambered transmission line bass loading with tuned port @ 20 Hz and Dacron/acoustic foam damping for Q = 0.6. Design optimized for extremely fast transient response and very deep bass (16 Hz @ -6 dB).

Woofer Amplifier: Class A/AB high-current solid-state amplifier with heavy-duty power supply. Power rating is 600 watts r.m.s., 900 watts peak. Automatic turn-on feature eliminates manual power on/off switching. Woofer level control enables adjustments for bass output and room placement variations.

Midrange: 6" cast-frame dynamic driver employing 4 lb. 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 cone has a very high Young's Modulus (stiffness to weight) ratio, ensuring very high signal accuracy. Flat wire edge-wound voice coil allows for higher magnetic coupling than round wire, greatly increasing signal accuracy and dynamic range. Extremely flat frequency response. 

Tweeter: 1" soft dome tweeter hand-made in Norway, using horn loading to increase sensitivity. Ferrofluid liquid cooling in the voice coil gap; rear chamber for lower resonance (650 Hz).

Ambience Retrieval System: rear-mounted, horn-loaded 1" tweeter driven by special crossover design and Dimension control for effects level. Dipole operation results in correct front-to-back depth replication.

Dimensions: 54" x 12" x 22" (HxWxD)
Weight: 185 lbs. each
Warranty: Ten years parts and labor, excluding damage from abuse
Price: $9995 in cloth wrap finish.

Company Information
Von Schweikert Audio
21040-A Northgate Street
Riverside, CA 92507

Voice: (951) 682-0706
Website: www.VonSchweikert.com