VMPS RM 30 Ribbon Hybrid Loudspeaker

VMPS RM 30 Ribbon Hybrid Loudspeaker

There’s a New Sheriff in Town!

Frank Alles

 September 2004

Over the last several years, the VMPS RM 40 loudspeaker has been highly praised in the audio press by the likes of J. Peter Moncrieff of International Audio Review and Martin DeWulf of Bound for Sound. It is a VERY large and heavy system weighing in at no less than 240 pounds per speaker and is the predecessor of the RM 30. The RM 30 is rather nimble by comparison, weighing in at a scant 110 pounds and measuring 48”H x 20”D x 8”W. It is sort of a scaled down RM 40 with a different, more modern visage. With its narrow front baffle and side-firing 10-inch woofer it reminds me of an Audio Physic Virgo on steroids!

The RM 30 is an unusual 4-way system that uses VMPS’s best ribbon super-tweeter, three proprietary Neodymium planar-ribbon midrange drivers in a vertical line source, two 6.5” front-firing mid-woofers, one side-firing 10” woofer, and two down-firing 6” passive radiators. Whew!

Very importantly, the three Neodymium planar-ribbon midrange drivers, which are very linear and very natural sounding, handle the range between 200Hz and 10kHz (although there is some overlap from the two mid-woofers into the lower midrange). I believe this is the key to the superb octave-to-octave coherency this system demonstrates so well.

There are two micro-adjustable L-pads on the back panel that are used to set the midrange and super-tweeter levels and the bass can be fine tuned by removing very small pieces of Mortite damping compound from the passive radiators (more on that later).

The frequency response of the RM30 is rated at 32Hz to 35kHz -3dB, sensitivity is 89dB/1W/1m, and the impedance is 4Ohms (resistive above 200Hz). The price is $3500/pr for the base model. Available options include 6.5″ carbon-fiber mid-woofers at $380 per set of 4. The standard capacitors are a Solen/Axxon blend. Auricaps add $550/pr and premium quality TRT Dynamicaps add $1,200/pr. Heavy, brass bi-amp terminals are standard, as is Soundcoat (dampens cabinet resonance by 10dB broadband). I must say that while I like the heavy brass speaker terminals they are best suited to spade connectors. Brian Cheney of VMPS says that longer outer connector nuts can be ordered to better facilitate banana plugs. The Analysis Plus jumper straps supplied with my speakers function extremely well in terms of connection quality and they proved to be quite neutral sounding as well.

Standard finishes include light oak, dark oak, and piano black; optional cherry finish adds $400 per pair and rosewood or walnut is available for $800/pr.

For those into home theater, the RM 30 can also be ordered as either a vertical or horizontal center channel speaker at a cost of $1,600 per unit. The center-channel versions do not include the side-firing 10” Megawoofer.

My particular pair came in the light oak finish and has the Auricaps and the carbon fiber, mid-woofer upgrades. Price as delivered was $4,150/pr.

The light oak finish looks very deep and rich, possibly due to the protective clear coat that VMPS applies. The main cabinet could pass for furniture grade and is quite appealing to the eye. That said, the black-coated MDF used to construct the bass port and baseboard does not give one the impression of solidity and the finish is not as thick or durable as it ought to be. The quality of the base and port do not seem commensurate with the quality of the main cabinet, in my opinion (kind of like wearing Duck boots with a suit).

The bases are made to couple the speaker directly to the flooring and are not designed for use with spikes of any kind. In fact, the designer says that using spikes will likely degrade performance. On my carpeted floor, the speakers could be slid into position with a modicum of effort and were reasonably stable on my flooring. I could see where some might want to use a thin pad under the speakers if mounted on hard flooring. If one wishes to angle the speakers to alter the tweeter dispersion, a large tapered shim is recommended, although I don’t know where you’d get one of those. It might be easier to alter your seated position.

What I want to stress about the RM 30’s high frequency reproduction is that it’s the least colored, most detailed, and most natural high frequency reproduction I’ve yet encountered in ANY speaker.

Early Impressions 

The bass of the RM30 was very strong and punchy right out of the box; however, it rolled off just below 40Hz in my room after some initial positioning. I began with the side-firing woofers facing inward and later changed them to face outward, which I didn’t think made a huge difference. After a couple of weeks of positioning, playing the speakers, and removing a bit of Mortite from the front passive radiators (PRs) of each speaker, I did measure fairly flat response to 31.5Hz in my room. So the bass is quite robust and extends fairly deep. For my taste, I could take or leave a good subwoofer. Those that insist upon strong output in the bottom octave will require a good dedicated subwoofer system. The response does roll steeply after 31.5Hz and was down at least 10dB at 25Hz. I achieved these figures with the front plane of the speakers about 37 inches from the front wall.

At first, the quality of the bass was a little difficult to judge because I have a broad upper bass rise in my listening room between about 120Hz and 160Hz. This rendered certain recordings with chest-pounding oomph at the expense of obscuring some detail and it lent a certain unnatural heaviness to the fundamentals of some instruments. Cheney claims the RM 30 is flat through the upper bass and I tend to believe him because all the speakers I’ve tried in this listening room to date have exhibited the same upper bass bump. I measured the rise at about 5 or 6dB with a RadioShack meter, so It isn’t terrible, but it’s definitely noticeable. I also measured the rest of the audible spectrum at my listening position and it surprised me to find that the response only varied about 1.5dB from 200Hz–10kHz. That’s very linear response for a virtually untreated room!

Both of the PRs come with Mortite damping compound on them and the user is supposed to fine-tune the bass by removing very small amounts of the Mortite, via fingernail, from each passive radiator, one at a time. As you might guess, it’s a somewhat tedious and hit-or-miss process to get it right, and once the speaker bases are in place it is very difficult or impossible to reach the rear PRs to remove the Mortite. Luckily, I was able to achieve very good results by removing a small bit of material from only the front PRs of each speaker. Also, when I substituted a Rega Planet CD player for my CAL Icon II/Perpetual Tech 3A combo, the room-related bass hump tamed down a bit as the Planet seems to have less bass energy in the upper bass area.

The adjustable L-pads for midrange and treble are a definite plus when fine-tuning these speakers. It is noteworthy that you can tune each speaker individually to compensate for different room characteristics from one side to the other. In my case, the right wall is much closer to the speaker than the left wall, plus the left wall has an opening to a stairway and a hallway, so the reinforcement of reflections is quite different from one side to the other. Fortunately, with the larger VMPS speakers a little tweaking of the L-pads can even out the response to effectively preserve the speaker’s great imaging characteristics. The micro-adjustable pots are very sensitive, so only turn them small increments at a time.

In order to appreciate the full capabilities of the VMPS super-tweeter, one’s ears must be within a couple of inches of the vertical plane of the tweeter. The center of the tweeter is approximately 45 inches off the floor and my listening position had my ears at about 42 inches high, which seemed to work well about 10.5 feet from the front plane of the speakers. When positioned with radical toe-in (VMPS recommends angling the speakers to cross a couple of feet in front of the listening position) the sweet spot was at least a couple of feet wide and not nearly as confining as that of my previous speakers, the InnerSound Eros Mk-II. Two people could sit side-by-side and still enjoy a very good stereo image and frequency balance. This is about as good as it gets for most current high-end offerings. That said, I’d loose some high frequency extension and detail when I stood up unless I was more than 15 feet from the front plane of the speakers. Cheney claims a 30-degree vertical window for the super-tweeter, but in practice it seemed closer to ±15 degrees (maybe that’s how he meant it). Still it did not sound bad out of the sweet spot, just a little rolled off. My subsequent comments on high frequency performance correspond to a seated position with the ears slightly lower, but close to the tweeter axis.

I will tell you that the RM 30s are VERY sensitive to positioning issues, both in the bass and in the midrange/treble. Getting even response and imaging over the full audio spectrum will take some time and attention to detail. Small movements in adjusting the angle of the speakers can yield surprising results. I also found the RM 30s to be very sensitive to the other components and cables throughout the system. The results are extremely gratifying when you achieve a synergistic blend. My review pair started to sing with some very modestly priced gear once I hit that magic combination. These speakers are quite revealing, and you will hear the difference if you change even the slightest thing.

My feeling is that the RM 30s benefit from pairing with a solid-state amp of at least 100 watts per channel into 8-ohms. In my large room I used an amp rated at 150 Wpc into 8 ohms and felt it was ample for my volume requirements most of the time with most material. I specified a solid-state amp for bass-control concerns. I believe that very good results could also be achieved by bi-amping with a big solid-state amp on the bass and a fairly robust tube amp on the mid/treble, but I did not have a suitable tube amp on hand to test that theory. That said, I found the RM 30s to be very well balanced and there is no need to use tubes to tame the highs as there would be with some other designs.

Is it Live…Or is it VMPS?

As my subtitle implies, these are VERY competent speakers. There are many decent speakers on today’s market that seem to excel in a few performance parameters and then fall short in other areas. The RM 30 is unique in my experience because it excels in the majority of performance parameters and exhibits a paucity of weak points to taint the sonic landscape.

The RM 30 is capable of delivering lightening-quick transients, with incredible dynamic contrasts and purity of timbre, and then is able to stop on a dime. This rapidly became evident when playing “Stream” from Dave Matthews and Tim Reynolds: Live at Luther College [RCA 67755]. On this cut Tim Reynolds’ picking on the acoustic guitar gives new meaning to the phrase, “blinding speed,” and the RM 30 launched the deft notes into space just as blazingly quick as Reynolds had played them, replete with their original intonation and ferocity. And when he’d palm the strings to instantly stop the sound, the RM 30 went to dead silence in the same microsecond. The ebb and flow of this very spirited musical performance was reproduced with all the speed, nuance and purity of tone one could hope for – and then some!

A couple of other recordings with a unique assortment of high-frequency percussive instruments clued me in to just how “right” the RM 30 portrays the treble band. Listening to various cuts of spirited zydeco music from Queen Ida–Caught in the Act [GNP Crescendo GNPD 2181] and Vinx’s unique Afro-jazz from I Love My Job [PANGÆA X2-13152], the RM 30s gave holographic life to all manner of shakers, washboards, wood blocks, and cymbals. They provided a wealth of fine detail without sounding hard or unpleasant. I also tried the Manger test CD because the first track is a recording containing an amazing battery of what sound like large church bells gonging away in a church tower. The RM 30s reproduced the complex harmonics of the large bells where I could hear the initial strikes and then the various harmonics as the entire bodies of the bells began ringing, each in its own time, with its own tonal and decay characteristics. The bells were definitely in harmony with one another and there was a great deal of depth to the sound field. This was way cool!

What I want to stress about the RM 30’s high frequency reproduction is that it’s the least colored, most detailed, and most natural high frequency reproduction I’ve yet encountered in ANY speaker. I offer this with the caveat of its somewhat limited vertical dispersion, which I mentioned earlier.

To elaborate, the best electrostatic speakers I’ve heard, although detailed and non-fatiguing, have time-smear distortion in the highs. This is due to their use of comparatively large panels trying to simultaneously reproduce extremely short wavelengths across their entire width. Some designers partially circumvent this distortion by using specialized tweeter panels or curved diaphragms, but these measures do not entirely correct the time-smear and usually introduce other problems. As much as I liked my previous InnerSound Eros Mk-IIs, I believe the VMPS super-tweeter has much better focus (less time-smear) and a more natural sound. It preserves transients beautifully and it seems to provide more detail, speed, and extension than other ribbon designs I have tried. A possible exception is the ribbon driver in the Magnepan 3.6R, which has excellent extension, but does not sound as natural or precise to my ears.

On the other hand, when competing with dynamic dome-type tweeters, whether they’re soft-dome, metal, diamond, or ceramic, I have never failed to hear some sort of inherent coloration that keeps the treble from sounding completely transparent and natural. In fairness this is partially related to the types of crossovers used in these designs. I believe the VMPS tweeter has the added advantage of crossing over at the very high frequency of 10kHz; and the cross appears to be virtually seamless when you have the controls properly set. As much as I love my Audio Physic Virgo’s treble performance, it cannot quite match the overall transparency of the VMPS. It is not too far off the mark, but if you heard the two side by side you’d definitely appreciate the difference.

It’s been said many times that full, extended bass response is necessary to provide a proper foundation and add scope/dimension to the sonic illusion. I believe that’s true, but I also believe that exceptional high-frequency performance is an even more crucial element in the quest for the most natural and lifelike reproduction. Many of you remember back to the days of the first generation CD players and how terrible early CDs sounded on those long-obsolete machines. There was no ambience, no life, and worse yet, it was difficult to recognize many instruments because the overtone structure was so badly mutilated. Was that a trumpet or a trombone or a coronet? Who could tell? It was really that bad! Point being that the better the high frequency production, the more natural and authentic instruments are able to sound.

But great highs alone do not make a speaker sing, and I’m happy to report that the RM 30 has true state-of-the-art midrange performance to match its unmatched treble performance. You want great vocals? You got ‘em! You demand deft reproduction of acoustic guitar? It just doesn’t get any better! How about a perky polonaise on piano? Yeah, check that one off too! 

Today I broke out my classical and acoustic jazz recordings just to double-check the capabilities of the RM 30s before finalizing my conclusions. I put on George Gershwin’s Rhapsody in Blue from Dayful of Song. [Delos DE 3216] and let ‘er rip. Upon hearing the introduction I knew I was in for a special treat. I love this piece and when Litton’s piano came lilting in, I had to hold back tears just from hearing the sheer beauty of the magnificent instrument. Not only was the piano sweet and natural sounding; but the transient speed, pitch definition, and superior dynamic envelope left no room for illusion or doubt. This, folks, was real! From the same album, An American in Paris contains some bombastic bass drum blasts during the crescendos near the finale. I must admit they came across loud, weighty, and clear through the VMPS. There was no overhang, the drum just came out of nowhere, rocked the house, and vanished without fanfare.

But what really cinched it for me was listening to Branford Marsalis’s Trio Jeepy [Columbia CK 44199]. Playing “Housed from Edward,” Marsalis’ bass sax never had so much body and so much unstrained dynamic range. It was like he was standing there right in front of me (though actually he was to my left). And when Milton “The Judge” Hinton started plucking his bass and “Tain” took charge on the drums, well, it just doesn’t get any better or any more intimate. I was truly impressed by the tonality and detail that jammed forth in a froth from his tuneful drum kit. I totally enjoyed Tain’s drum solos. And Hinton’s runs on the big double bass were easy to follow and palpable.

As further proof of the RM 30’s superior reproduction, my teenage son Eric came downstairs (unsolicited) to sit beside me while listening to Trio Jeepy. I actually saw him lean into the music during a few passages to try and gulp just a little more of that great performance. And then, just when I though it couldn’t get any better, my wife made the scene and stopped to listen for a while. I don’t think I need to spell out what an amazing feat that was, as she too, fell under the music’s alluring spell!

Likewise, vocals were rendered with honesty and immediacy; and lyric comprehension is absolutely first rate. Whether it be Rebecca Pidgeon, Lyle Lovett, Johnny Cash or Norah Jones, the RM 30s were as convincing as Clint Eastwood playing Dirty Harry. Do you hear me? Well, do you, PUNK!

Finale, Finally!

Make no mistake. At its asking price, the VMPS RM 30 provides an overall level of performance that is all but unbeatable. VMPS’s Brian Cheney deserves high praise for his ability to design and market such a remarkable product for under $5,000 USD. I don’t believe it is likely to be embarrassed by any speaker at any price.

The RM 30 is a speaker that can match the dynamic capabilities of competent horns, the immediacy of electrostatics and planar-magnetics, and the fine detailing and imaging of the best dynamic designs. Although the 32Hz bass extension is adequate for my needs, bass aficionados will probably want to add a good dedicated subwoofer system. Being a moderately large floorstander, the RM 30 won’t fit into everyone’s plan for a killer system. Pity! Meanwhile, the rest of us can kick off our shoes, get cozy, and drench our souls with some great music.

VMPS Audio Products
3429 Morningside Dr.
El Sobrante, CA 94803
Phone: (510) 222-4276 
Fax: (510) 232-3837
Web: www.vmpsaudio.com
e-mail: vmpsaudio@aol.com

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