|
You are reading the older HTML site
Positive Feedback
ISSUE
24
Audio Nirvana Super 8 Minimonitors; 4 CDs from Telarc; 2 CDs from Chesky; with some views on
deHavilland amps and Ecosse cables
A Little History In the ancient (Pleistocene Era) annals of audio, the speaker world was not divided into three parts (like all Gaulle). The world was not yet made up of woofers, tweeters, and midrange drivers. Mostly there were a bunch of what are now called "high-efficiency full-range-drivers." The Western Electric and RCA 15" drivers, for two, were loud enough for most purposes, but they couldn't reproduce the entire audio frequency range, lacking deep bass and high highs. During the monophonic era, soon enough, the loudspeaker manufacturers found they could get a full range system to work well if they used specialized drivers, and we were offered many three- way systems marketed by firms such as Altec-Lansing, Electro-Voice, Klipsch, James B. Lansing, and University. Such systems were often large as a refrigerator and frequently demanded a whole corner of a room. They used drivers found at football stadia, on board ships, and in gymnasia that variously honked like a geese, rang like anvils, rumbled like large trucks, and sizzled like bacon in the pan. As the giant dinosaurs were trapped in tar pits, giant loudspeakers similarly went on the decline as newer, smaller speakers employing newly developed "acoustic suspension" woofers appeared, with fabric dome midranges and tweeters much flatter in response curves than their compression horn predecessors. They seemed a natural match for the new, higher-powered, transistorized amplifiers. At the dawn of the stereo era, the true music lover or audiophile willingly made space for two such speakers, requiring only a fraction of the space of one corner horn. Such pairings of acoustic suspension speakers (AR, KLH) with early transistorized amps (Marantz, McIntosh) could soon be found on the bookshelves in many living rooms, providing decent stereo sound while commanding much less space. With flatter and broader-frequency-bandwidth loudspeakers audiophiles could reproduce from the deepest regions of organs to the highest regions of glockenspiels. Along with that improvement came a new awareness (largely due to the arrival of the alternative audio press) of other sound system qualities, like spatiality and sound staging, harmonics and timbre. Single Point Source The family of full range speakers that did a great job as a single point source of monophonically recorded music became important, again. These loudspeakers, such as Tannoy and Lowther manufactured, did an admirable job in those regards. They were free of multiple drivers and crossover networks. This design is some sixty years old now, first arriving in the 1930s, when the most powerful amplifiers might have been able to produce ten clean watts. Their virtues are that in addition to being efficient (96-102dB/1 watt depending on the model), they don't require any crossover with all their phase and gain problems tagging along. In addition they offer a very stable sound stage, very realistic musical projection, lots of dynamic range, and they can be run on high quality but low power amplifiers such as single-ended triode amps with their euphonic super-tubey quality (warm in the cellos, sweet in the violins) that is all the rage nowadays. David Dicks's operation distributes to dealers and sells retail to the public Lowther, Fostex, and P-Audio loudspeakers, as well as Audio Nirvana. See www.commonsenseaudio.com for more information on the single-point-source products he handles. Dicks, an older dude and a good guy, has been involved with these drivers for decades, experimenting with various drivers in various enclosures, at various room positions, with various cables. Through the years, there is little he hasn't seen, thought about, or tinkered with in his specialized realm. The Audio Nirvana Super 8 is a modern driver in this full-range/single-point-source family of designs, built off-shore to his specifications. It is much less expensive than the Lowther with many of the same pluses. Dicks says compared to similar Lowthers, the Audio Nirvana Super 8 has "85% of the performance for 7% of the cost at $148/pair," for the raw drivers. Then there is the somewhat "warmer" Audio Nirvana 8 that has no phase plug at $118/pair. It is, possibly, one of the true bargains in the field. Woofer Section Design
The Audio Nirvana Super 8" is a paper cone driver that is heavily influenced by successful designs that have come before, and it has incorporated some of the subtle improvements (the shape of the whizzer cone, for one) that some others have come to use. There are also design elements where it has forged out on its own so as not to be a slavish imitator of the original designs. One example of that is, it has a pleated cone surround (rather than an open cell foam surround) that has been found for decades in Pro drivers used in P.A. and high-gain Rock systems. In this case, the Super 8 doesn't require an expensive, labor-intensive, rear-loaded, exponential plywood horn to be effective. With its considerable magnet, and its treated-fabric pleated-surround, its paper cone makes plenty of bass that rolls off gradually down into the 50Hz region (he claims useful bass down to 37Hz), which makes it a pretty good candidate for the bass reflex enclosure that David Dicks has designed for it, his variation on the ported box. Whizzer Cone So what we have in his Audio Nirvana, Super 8, Minimonitor is a highly efficient (98dB/watt in this enclosure, he claims), full range, eight inch paper driver, with a whizzer cone set in a dual- concentric mode on the same voice coil, with a metal phase plug in the center. Actually, what is called a phase plug is a mechanical device that manages to align most of the high frequency waves so as to correct for arrival time anomalies produced by the whizzer cone. The phase plug really doesn't effect phase so much as eliminate time smearing. To correct for out-of-phase a mechanical device would have to find the outer cone going in and out in reverse (or nearly) of the whizzer cone. That can't actually be the case as both cones are affixed to the same voice coil, the difference in their mass and diameter making a mechanical crossover. But a center plug can correct for treble frequencies coming in part directly from the whizzer cone's front, mixing with back waves that then reflect off the larger cone behind it. Lots of manufacturers use phase-plugs, even on less complex (no whizzer cone) models, to adjust the arrival times of frequencies generated by the inner and outer regions of a driver. See the Parts Express website www.parts-express.com, or Madisound's www.madisound.com. Phase Plug No one has yet come up with a quick, two syllable phrase for anti-time-smearing-plug, so it is known in the trade as a phase plug. (Perhaps "nose cone" would suit the purpose better.) In this case it is lathe-turned from a solid ingot of aluminum (to avoid the ringing that comes from hollow plugs), that is copper-plated for performance and cosmetic purposes (Aluminum, un-plated, gives off a moldy-looking white powder oxide that looks crummy and can find its way into the voice coil gap.). This plated and lacquered nose-cone is bolted and glued to the center of the speaker's chassis. Theoretically, the plug deflects the high frequencies from the frontal waves of the whizzer cone so they take a path less like a flashlight beam, and in so doing arrive at the listener at about the same time as the back waves of the whizzer cone reflecting off the larger cone. I'm not up on the math of exactly how this works, but if having a wide and deep sound stage is any measure of the success of this speaker's ability to eliminate time-smearing, then I'd say it is a pretty successful design in that regard. Interconnects and Speaker Cables This speaker is more sensitive than most to cable selection. At first I thought I'd set the speaker up with some of my inexpensive interconnects and speaker cables to make a complete low-budget system. I had a home-brew set of interconnects I'd made of teflon-insulated, silver-plated copper, multi strand, co-axial cables I made up with WBT type RCA jacks. They cost me a fraction ($25) of what I'd have had to pay for factory made. I used them with an FM tuner that had lost its crispness. I also had a pair of speaker cables I'd made from Home Depot, orange and black, outdoor AC extension cords that were a favorite of the DIY crowd a few years back. I paid about $15 for the pair, and all I had to do was to snip the AC plugs off and they were ready to use. The HD 15 cables (for Home Depot, not High Definition) delivered a pretty high percentage of quality sound I'd gotten used to with brand name cables, and they were pretty neutral, I'd thought.
Through my "Son" the bass got surprisingly robust, as David Dicks said it would, but the trebles were still too shrill, the violins too "wiry." I swapped out my Home Depot speaker cables (which work fine with other speakers needing some sparkle), and I put in a pair of Goertz, copper-ribbon, "MI 2 Veracity"speaker cables made by Alpha-Core, the least expensive but truly high grade cables I know of. That really did it. Finally I'd found the combination that worked excellently with the speakers, (which cost more than my lo-budge cables, but less than the fancy schmecker stuff I have around the old surfer shack), and I was confident the speakers sounded as good as they could. I believe the reviewer has a responsibility to the readers and the gear to get everything sounding its best before it is evaluated. It is time consuming, but only fair. How'd they sound?
They sounded surprisingly good. They are very
clean, and have this quality of seeming to place you in the room with the
musicians that is sometimes uncanny. On records I know and like, say, Marta
These Audio Nirvana Super 8s (through my "Son") seems to capture the nuances of such music with startling immediacy, with a correctness of detail that is much like the Lowther's presentation of the same recordings I hear at my pal Alan Shapiro's through his PM5a's and Nelson Pass's First-Watt F-1 amplifier (designed by Pass especially for the Lowthers). That is not to say this speaker is the equal of the Lowther, nor this 30 year old amp the equal of the Lowther-dedicated Pass amp, but they do get close. The quality of the sound is similar, and maybe David Dicks' quantitative estimate of 85% is not too far off. They are in the same ballpark, which is in itself a helluva compliment. On Mahler's Songs of a Wayfarer; Philharmonia Orchestra, Ben Zander, cond, (Telarc 2SACD 60628); the orchestral sound is drop dead gorgeous, tenor Christopher Maltman's voice is likewise (no excessive chest tones or metallic head tones), and the recording engineering makes everything sound as if in a very large venue (lots of width, depth, and spread between instruments) in my smallish and acoustically challenged room. Each of the individual instruments has correct pitch and (from what I can judge) spot-on timbre. Again, there is a lot of dynamic range with no strain, from the percussive wallop of the tympani to the delicacy of the flute, playing on a bed of strings and harp, accompanying the voice of the tenor. In the finale of Mahler's Symphony #1 (same CD), the loud music is densely orchestrated, and the Audio Nirvana Super 8 Minimonitors just sail along without congestion or any other sign of distress while resolving nearly everything I can hear on my big rig. Don't forget they are only rated at 30 W. Of course they will sound strained if you over-drive them. That said, this speaker is a terrific performer, particularly in a relatively small room where you won't want to crank it up. Listening at a slightly lower level just places me a few rows further back than usual. If it looks like I'm plugging Telarc recordings, I must confess I am. In early 2005 Telarc won an award from Gramophone Magazine as "Label of the Year" for 2004, which I interpret to mean in recognition for overall excellence in recording engineering, the talent of their performers, and the selection of the programs they coax out of this combination. I'd say the Chesky label is not far behind, if not as prolific, as some of their recent releases are equally good.
So, David Dicks's Audio Nirvana, Super 8 speakers, in his Minimonitor enclosures pass the tests of making enough bass to be used without a separate sub-woofer (except if you insist on the bottom octave or so), they are somewhat bright but not too much, they produce great detail at high or low volumes, they reproduce ambiance very well from a small group (Marta Gomez) to a large Orchestra (The Philharmonia), accurately serving groups from jazz trio (Hiromi and Pacquito D'Rivera) to an a capella choir (Ladysmith Black Mambazo). A few caveats: if you don't have a big budget, you can find less expensive cabinets around in pawn shops, though the cabinet Dicks has chosen is quite good (attractive, relatively resonance free, tuned for this driver). If you can't stand to listen without the organ pedal tones, you can buy or build a self-powered sub-woofer. You might have to spend a little more than usual on cables to bring the trebles into line. Finally, when stressed to their power-handling limits, these speakers will exhibit strain in the form of audible clipping in the middle of the soprano range. This list should not deter you if you want a good stereo pair of speakers to run on a moderately powered amp, or a good set of five speakers to use in a home theater system. As with anything else, the speakers present choices because they are designed around trade-offs. I find these speakers' trade-offs very acceptable. So acceptable, that I recommend them highly, if used as specified. Don't forget, a 98dB sensitive loudspeaker will achieve a LOUD 110dB with only 16-watts (at 8 ohms). Most of the time these speakers will be coasting. Dudes!! Just when I thought I was finished with my commentary on these speakers, a pallet of new gear arrived at my little beach shack, including a single ended triode (SET) driven amplifier, the deHavilland IOS 845, 25w/ch stereo model. This amplifier was sent to audition a pair of recently developed Alerion model Lowther speakers that haven't arrived yet. My specially designed two story fork-lift enabled me to get the heavy mother up to my lab window. From there it wasn't too much of a job for my audiophile buddy Alan Shapiro to help me set it up. Tubes warmed up and biased in less than a half-hour, and the amp began making glorious sound, except I kept hearing a small burr on some recordings of sopranos. We then swapped out a pair of Twisted Pairs (using Ohno Constant Casting copper, I think) speaker cables that had sounded pretty good with jazz, and installed a pair of Ecosse Monocrystal Copper, SMS 2.4 speaker cables, the metallic burr went away. In addition, the bass got a tad rounder and fuller, and cymbals got a bit softer and less tizzy. Together the deHavilland amp and the Ecosse speaker cables brought the Audio Nirvana Super 8 Minimonitors to a level of performance where slightly annoying anomalies became inaudible, proving the speakers could deliver quite pure sound if teamed with superior gear. Even if at their power-handling limit they did complain noticeably, they did such a good job with lesser demands I'd have to say they were outstanding. Of course pairs of these speakers retail for $655 in their David Dicks enclosures, and they sound their best with about $8K of support gear, but that is my philosophy in testing gear. The critic must get the gear to sound its best before making a judgment. I'd go on to say that if you are a guy living on a student budget, you could get very happy with these speakers and some rebuilt "Golden Oldie" tube gear. You have to know which is a golden oldie and which is just an oldie. Then you'd have to take it upon yourself to bring such gear up to modern standards by swapping out old resistors and capacitors for new, a time consuming job, but well worth the time and effort considering what you wind up with. You might find some cabinets in a pawnshop that are about 1.5 cubic feet of interior dimension. If you are handy with tools you could cut a new baffle and glue and screw it on top of the old speaker cut out. With such speakers and cabinets, an old Fisher or H.H. Scott tubed stereo receiver to rebuild, an inexpensive walk-around CD player, and some cheap original Monster Cables you could develop some great sound for cheap. Until the time when you have such a complete system, you could use a Boom Box as the head unit, disconnect the boomer's speakers, connect up the Audio Nirvanas to the low watt amplifier, and you'd have at least passable sound you can live with. Of course try to get a Boom Box with some Watts. Do you find this kind of project intriguing? My Man! Just grab your Zappy Mama and Merengue around the room to your computer and off to www.commonsenseaudio.com to order a pair. Or telephone my man David in St. Louis at 314-579-0088. By the time you see this in print, he will have likely just returned from an adventure, sailing around the Tierra del Fuego. When you do speak with him, be sure to tell ‘em Maxie Waxie sent you. Ciao Bambini!! Max Dudious
|
With the Audio Nirvana Super 8 Minimonitors,
this combination sounded too bright and overly detailed, probably from a
rising high-end they generated in combination with my cables. First, I
replaced my homebrew interconnects with a pair of 18" Straight Wire
interconnects sold by HeadRoom. (
Gomez's Cantos De Agua Dulce (Chesky JD 281), there is something very
realistic about the percussive instruments, drums, wood block, drumsticks,
hand clapping that I hear on few speakers. Then, a few ticks later, there
is a hear-through-the-veils moment, a segue to a very delicate guitar
accompanying Gomez's haunting voice. To me it feels as if I am in the
studio, or listening to the master-tapes of dreams, her dreams, and it has a
captivating effect. 
For example, Chesky's recording of The Jazz
Chamber Trio, Paquito D'Rivera cond. (JD 283), was Grammy nominated for
"Best Classical/Jazz Crossover Album." It is a kind of jazz that has been
as influenced equally as much by European chamber music as it has by jazz.
The first tune played by this piano-cello-saxophone trio on the album is
entitled "Preludio et Merengue," while the fourth is "Night in Tunisia,"an
hômage to Dizzy Gillespie. The recording was done in an intimate
room and brings to mind the much reported "Barrueciads," musical evenings at
the home of guitarist Manuel Barrueca and Asgerdur Sigurdardottir, where
friends and colleagues often gather and play for each other until late into
the night. This album took Pacquito D'Rivera about three December days and
nights in 2004 to complete and the sound is so good, the performances so
relaxed, it is a pleasure to listen to. A pleasure. The sound carries the
desired audio halo of jazz played small. It is a good test of ambiance,
placement, and timbre of instruments. Dig it.
Recently Telarc issued a new Hiromi album
entitled Spiral (Telarc SACD-63631), which is pretty damn groovy and
which is jazz thought large. The sound they get out of a piano-bass-drums
trio is very lifelike, and BIG. (She calls it a three piece orchestra.) Hiromi's musical sensibilities seem to make her a direct descendant of Chick
Corea's, which ain't bad. Through the Super 8 Minimonitors the reproduction
of the sound is very natural: that is to say, the piano sounds neither too
metallic, nor too pearly (like a forte-piano). The drum kit sounds about
how they sound to me live when I go to Baltimore's An die Musik to
hear quality jazz. And the bass has that ratio of attack, sustain, decay
that my ear tells me is right-on for an acoustic bass, tho some cuts have an
equally convincing electric bass. Occasionally Hiromi's voice pops out of
the mix and that really adds to the in-the-room illusion. These bargain
speakers really do capture it all, from Hiromi's tickling the ivories to her
pounding her piano into submission. What makes this a great test album is
to see if your system can recreate a club-like listening experience in your
listening room. In my er, ahem, "lab" the Audio Nirvana Super 8s do just
fine.
Another Telarc issue is the latest
Ladysmith Black Mombazo album, Long Walk to Freedom, on Telarc's
"Heads Up" label, (HUSA-9109). It was twenty years ago today, Joseph
Shabalala taught the band to play, on the Paul Simon album,
Graceland. Since then, they
offered many albums on a few different labels. Now with Heads Up they sound
as good as ever, singing by themselves, and with the addition of a handful
of guest artists such as; Zap Mama, Melissa Etheridge, Joe McBride, Sarah
McLachlan, Natalie Merchant, Taj Mahal, Emmylou Harris and an equally long
list of other performers unknown to me. What makes this album a great test
is to see if the listener can isolate one or another voice (there are only
eight members of Ladysmith), and follow it through a given song. It is a
good test to see if the pair of Super 8 Minimonitors are closely matched in
frequency response. And the review pair I've got are just fine. The
soloists stay to the center front, and the ensemble is farther back and
spread across left-to-right. To my tired old ears these speakers keep every
voice separate, no mean feat. The test here is to see if this system can
recreate the illusion of eight or so singers in a moderately sized room
(studio or small church), and they do this admirably.