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October 2003
Enjoy the Music.com Review Magazine
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Lucidity With GR Research's New Diluceo Loudspeakers
Review by A. Colin Flood
Click here to e-mail reviewer


GR Research Diluceo Loudspeakers   First impressions of GR Research's black n' tan Lucidity Series Diluceo were good. The GR Diluceo are high-sensitivity, two-way, three driver tight D’Appolito configuration. The bass reflex cabinet with ribbon tweeters is assembled in attractive blonde wood and quite impressively built for only $1,679 a pair. Writing about their looks, features and specifications was easy – the hard part was to come later.

Diluceo is a Latin word meaning to be light enough to distinguish objects apart; hence, to be clear, evident (rare). It is pronounced like "dill" (like dill pickle), "Lou" (like the name) and "Ceo" (like the name Leo but with an Italian "C"). Roll them off your tongue together like a Soprano character ordering pasta, "dill-Leo-Ceo." Makes you want to put your fingertips together and shake your fist in the air, like an Italian does, for emphasis. Dill-Leo-Ceo!.

The Lucidity Series line is joint effort, with Creative Sound Solutions, located in Abbotsford, BC Canada. This line is by Danny Ritchie; offered by CSS, in Canada, and through GR Research here in the United States. Since 1995, Danny Ritchie is the man behind GR Research driving this business "by the passion and desire for realistic music reproduction." Danny Richie says "t was once a hobby, then a part time business, now it is a full time occupation."

My review models arrived tightly dressed for the  Arctic , with two layers of Styrofoam and cardboard boxes. When I finally slid them out of their winter clothes, I saw a creamy light Maple veneer, oil rubbed, with a satin clear coat. The cabinets are tall and narrow, with 0.75-inch rounded corners, making them appear thinner than they are. The "Golden" depth-to-width ratio minimizes standing wave problems and the small front surface area minimizes unwanted reflections. Three black drivers crowd together in the middle of the box like interlocking Olympic rings. So while unpacking the GR Diluceo was not as simple as I would like, remember, I have to keep the boxes in good shape to return them, this was not the hard part.

Construction material of the GR Diluceo is MDF with the front baffle 1.25 inches and the rest of the enclosure 1-inch thick. Two internal 0.75-inch MDF braces run through the box. Internal dampening material is Blackhole 5 padding. Dual ports or vents on the rear nail the particular tuning required for the two mid-range woofers. GR is trying new 2-inch flared ports from Precision Sound Products in this model. The edges are seamlessly joined together. Drivers are snug; the tweeters are nicely routed into the front baffle. There are no covers. Overall appearance is excellent. The narrow boxes rap like solid wood. The solid box seems to impart little or no coloration to the mid-bass or mid-range. The over-all affect is one of elegance, like the buttery leather of a luxury sedan ride.


What A Team!

The dual 5.25-inch mid-range woofers, teamed with the mid-range ribbon tweeter are obviously the key ingredients. Danny has a distributor for Focal, Cabasse, PHL, etc. He has worked with most of the drivers considered best in the world. The dual mid-range woofers made by Eton , he says, "top my list." Voice coil on the dual mid-range woofers is 24mm. The cones are treated Hexacone, a Kevlar composite. Free air resonance (Fs) is approximately 50Hz. "They combine a stiff cone and really low distortion with the natural sound of the paper cone. It produces as good a mid-range as any driver I’ve worked with" says Danny. He had Eton build a custom Magnet version of this woofer.

The dual mid-range woofers handle their portion of the musical range with aplomb. There is little obvious boom or punch, yet they are not dull or weak sounding. Where something like the Axiom M80Tis – mentioned above – give so much bass, sound and treble for so little money; the GR Diluceo give a reference quality accuracy, evenness and tonal balance through-out most of the musical range. Horn instruments do not have that realistic blat or blare like my big ole horns. On jazz singer Cassan! dra Wilson's tribute album to Miles Davis, Traveling Miles (Blue Note 724385412325), the GR Diluceo showed less buzz. The mid-range is gentle, without being milquetoast passive. I found the GR Diluceo to be noticeably free of artifacts, without the blandness of mediocrity.

The mid-range tweeter is sweet, without sounding sharp. It is smooth, without sounding bland. It rings, but does NOT have as much sizzle as the dual tweeters of the Almost Excellent Axiom Audio Millennia M80Ti Line Driver Arrays. The GR Diluceo tweeter does have some of the crispness of electrostatic loudspeakers, but without the airy sound. It does not have the exuberant sparkle that plagues ribbon drivers. The driver combination provides a very natural presentation with a wide variety of music, with excellent balance, good soundstage, good imaging, long-term listenability and far above-average accuracy.

The crossover is asymmetrical at 2.5kHz, second order on the woofers and third order on the tweeters electrically. The impedance hits its low because of the minimum driver impedance. Despite crossing over right in the middle of the ear’s sensitive musical range, the seam is unnoticeable and does not adversely affect presentation. Every loudspeaker made should come with its own impedance and frequency response chart. The GR Diluceo do. Each assembled speaker is individually measured, tested and comes with its own response curve and impedance curve! Impedance is low at 4 ohms nominal and 3.8 ohms minimal.


The dual mid-range/woofers are 8-ohm drivers wired in parallel; thus the 4-ohm load. The load is high where the crossover components increase impedance. Danny says Diluceo's little brother, the Criterion, uses a series network, which keeps the impedance from rising. This low impedance can give flea-powered tube amplifiers, such as my Bottlehead 2A3 Paramours, a more difficult load than powerful solid-state amplifiers. Danny recommends only 8 to 100 watts for the amplifier. He says, "a 50-watt amp is plenty with these loudspeakers."

I felt my lowly yard-sale solid-state amplifier (see bio) did a much better job with the GR Diluceo than my delicious Paramours. The notes were quick, fully formed, snappy or strong. The solid-state amplifier was a better match for upper bass and lower mid-range. Horns recovered some of their blat. Cymbals rang again. Snare drums snapped. Pianos had better resound; the right hand keys, more sparkle. The GR Diluceo were also easily driven by 1970s vintage Nikko and harmon/kardon receivers, but the differences were not so dramatic. So matching the amplifier was not the hard part – that was still to come.

Danny says the best loudspeaker placement is determined by room response. "All rooms are different so please play with it until it works well in your room." The farther out into the room and away from boundaries, the deeper, wider, and more realistic the sound stage will be. Angle the creamy boxes almost straight to you to minimize sidewall reflections and maintain the smoothest response. This pair ended up closer by a foot (three feet in total) to the sidewalls than other loudspeaker models. Therefore, placing the GR Diluceo was not the hard part either.

GR Research's A/V series loudspeakers are their most popular: they offer the greatest bang for the buck. Eighty percent of GR customers buy in kit form. About half of them build their own enclosures. GR sells slightly more of the creamy Maple than other finishes. Danny says many have a custom finish. These models were broken in. Danny suggests a 50 to 100 hour break-in period. GR loudspeakers are ordered factory direct, fully assembled, or as kits. Purchasing the Diluceo's can be three different ways:

1. Driver Kits: For the tweaking audiophile with some wood working skills, seeking the greatest value and flexibility; this is the least expensive route. The simple crossovers can be purchased assembled, though it looks like any tweaking audiophile, who knows what end of the soldering iron to hold, should be able to master it. GR Research does assemble the crossover networks, if it is ordered that way ($60). The kit alone is only $995.

2. Kits With Assembled Enclosures: With only the drivers to pop in, only the drivers to pop in. as a kit with enclosures, the Diluceos are $1,445. Crossovers must be assembled as well, unless ordered that way.

3. Fully Assembled: GR Research does offer models fully assembled by themselves, for 'fraidy-cats like me, who want something plug n’ play and someone to blame if things go wrong. Fully assembled, this pair is $1,679 and with shipping weight at 55 lbs. each. There is nothing to upgrade on this model. It uses the best components available, Alpha Core foil inductors, Sonicaps and Mills resistors. Fully assembled units are dampened with Black Hole 5. Black Hole 5 is a complex multi-layered dampening material (1 3/8-inch overall thickness). Warranty for factory-assembled kits is 5 years. Deciding on which way to purchase the GR Diluceo wasn’t the hard part either: that part was decided for me.



The Diluceo frequency response is quite flat, smooth right down to about 55Hz, where it is down 3dB. Go to their frequency response as seen below.


This flat frequency response means no obvious anomalies, but is it also means no startling sonic effects either. Describing the “barely there” presence of the GR Diluceo in the music and movies they reproduced wasn’t easy. This was the hard part. Terms like neutral, even, balanced and smooth came to mind. However, little else suggested itself. So...

I dithered, I dathered, I procrastinated, and I delayed until I realized that the GR Diluceo suggest little of themselves. They add less coloration than the other speakers I have seriously auditioned for EnjoyTheMusic.com. Their sound is hard to describe because there was so little of it. Compared to some of my favorite loudspeakers - seriously auditioned, in my own home, with the same music and equipment, for EnjoyTheMusic.com - the mid-bass definition was excellent. The GR Diluceo do not growl as low as the leaning Newtronics Skate transmission lines. Diluceo's mid-bass is not overly quick or tangible, but it does make good percussive magic. They are not as punchy as B&W's yellow Kevlar cones, but still compellingly smooth, even and balanced. They are amongst the most levelheaded mid-bass to upper mid-range I have heard.

1. Compared to my memory of the bargain-basement Axiom Audio Millennia M3Ti, the GR Diluceo have smooth, elegant, flat sound with a clean and clear mid-range. They are more revealing of details without being overly lush. Unlike the charming M3Tis, they do not come across with a quick mid-bass and ringing treble. They do come across as accurate, transparent and uncolored.

2. Compared to the winner of my personal Wife Acceptance Factor (WAF) award, the pearlescent-blue Omega TS1s at half the price, the GR Diluceo loudspeakers also have a nice, even balance throughout the mid-range, but without the softness of paper cones. They exhibit a sharp, clear response over a larger range. Compared to the GR Diluceo, the easy-to-drive Omegas sound high, bright, little thin and a bit "boomy." The GR Diluceo provide a more accurate and balanced sound. If you like the clear openness of live music versus the close, warm feelings of the studio, you will prefer black n' tan Diluceo to soft sounding models like the Coincident Triumph Signatures. I think they make excellent monitors for studio work.

3. The black n' tan GR Diluceo have a few features in common with Vince Christian's Urbane E6c satellite system. Both are relatively expensive loudspeakers: at the top of the list for the models reviewed here and offered in retail salons. They both have only a mid-bass 55Hz bottom, so they need a powerful sub-woofer ($1,000+). Yet, neither feature is a great concern; not when compared to the joy the GR Diluceo bring. Although in a price range where many speakers are consciously competent, the GR Diluceo captures most of the musical range. They are one of the few loudspeakers I’ve seriously auditioned that are worth stretching the stereo budget. They deserve an investment in a really good sub, one powerful enough to match their dual mid-range woofers.

Even though the "Big White Boxes And Wide Black Horns Of Classic Audio Reproductions' Cinema Ensemble Loudspeakers," also with dual mid-range woofers, easily top my wish list for their super-efficient, wide, open, clear, punchy, joyous, exuberant and effortless "All That Jazz/Chicago" presentation, the GR Diluceo score near the top for their well-balanced presentation. I want these black n' tan boxes for a simple bedroom or office system, especially for any music mixing or CD ripping. Although there are many loudspeakers whose sound I like better – these are the ones that I would trust for sonic truth. I loved the dual mid-range woofers and mid-range ribbon tweeter combination.


Stand By Me

The GR Diluceo do require stands though, which adds another factor in the movie and music reproduction system equation. The proper stand, mounting and use of pads, or spikes, may make as much difference to the sound as different cables do. GR offers matching stands, with the center column covered from the same veneer sheet as the speaker cabinets. The stands have an MDF center column, radiused with 0.75-inch corners to give smoothly elegant appearance. The column is hollow, so it should be filled with sand, lead shot, or even kitty litter. For use on carpets, try spikes. For use on hard floors, try soft isolation points, like rubber tipped spikes or rubber pads.

GR is not open to walk-in retail traffic, but people come from all over the country for appointments. They are located near Wichita Falls, a 2 hour drive North West of Dallas, Texas. The next consumer electronics show where people can see GR loudspeakers is VSAC 2003 and Enjoy the Music.com™ will be there. Catch up with them if you can. Of the dozen or so loudspeakers seriously auditioned for Enjoy the Music.com, these GR Diluceo loudspeakers are very highly recommended for their overall accuracy and even tonal balance, and are well worth the long-term investment.




Sub-bass (10 Hz - 60 Hz)


Mid-bass (80 Hz - 200 Hz)


Midrange (200 Hz - 3,000 Hz)


High-frequencies (3,000 Hz on up)






Inner Resolution


Soundscape width front


Soundscape width rear


Soundscape depth behind loudspeakers


Soundscape extension into the room




Fit and Finish


Self Noise


Value for the Money


Editor's Note: heard these loudspeakers recently and increased the values above as i was mighty impressed with these units. They appear to be excellent value for the dollar :-)



Type: two-way, three driver bass reflex design

Tweeter: CSS ARG2 ribbon tweeter

Midrange/Woofer: A pair of Eton 5-880/25 HEX-b driver

Frequency Response: 50Hz to 20kHz

Sensitivity: 91dB/W/m

Dimensions: 17.875 x 8 x 12.375 (HxWxD in inches)

Finish: Various standard and premium finishes are available


Company Information

GR Research Inc.
910 N. Jackson
Iowa Park, Texas 76367

Voice: (940) 592-3400
E-mail: info@gr-research.com
Website: www.gr-research.com












































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