Emerald Physics CS2 Loudspeakers

Emerald Physics CS2 Loudspeakers

October 7, in Hi-Fi Systems Reviews


  • Type: 2 way active design. Dipole below 1kHz, Monopole above 1kHz
  • Impedence: minimum 4 Ohms, Maximum 9 Ohms Woofer Drivers: 4 Ohms composite nominal Tweeter Diver: 8 Ohms nominal
  • Driver compliment: Mid-Tweeter (1) 1inch compression driver, (1) 12inch acoustic wave guide
  • Mid-Woofer Drivers: (2) 15 inch pulp fiber cones
  • Sensitivity: 100db 2.83v @ 1M @ 1kHz
  • Crossover: DSP based, active network at 1kHz, Linkwitz-Riley 48db/octave symmetrical
  • Amp Configuration: Bi-Amp (not included)
  • Signal Processing: Outboard 4 channel DSP configuration, factory setting installed
  • Frequency Response: 20-20kHz -3db down points with dsp correction
  • Finish: Body-Black cloth, optional cloth available. Base-Silver or black painted aluminum billet
  • Dimentions: 48in (1220mm) H x 18.5in (470mm) W x 2.5in (64mm) Baffle depth x 6in (152mm) overall depth
  • Weight: 62 pounds each, Shipping weight: 80 pounds each

When I started two and a half years ago I made my wife a promise, no large speakers in the house. Until May of this year I had kept my word. Then, one day I got an email from Walter Liederman of Underwood HiFi. The main part of the message was simple, “call me”. If you’ve never spoken with Walter, be prepared, he can go 45 minutes without repeating himself and give quite an education in the process. “Mark, I’ve got a set of speakers that you MUST hear……”. Then began my schooling into what Walter believes is a paradigm shift in speaker quality.

Now, you may say why is Walter spending so much time working with the publisher of an e-zine dedicated to the average audio fanatic instead of those blessed with a large chunk of disposable income.

“Look at it this way, the Emerald Physics CS2 speakers allows for those with a total budget of $7000, to experience $25,000 plus sound”

claimed Walter. The key he exclaimed was the pairing of a dipole design with a programmed Behringer DCX2496 digital crossover “within .5db from 100-20,00hz”. Now having previously published two very positive reviews of the Behringer (stock and modified), I was very intrigued. However, I knew that speakers of this magnitude need some serious amplification, especially since they required biamping, and that meant extra $$$. This is where Walter jumped in with another shift, instead of using standard amps, save money and go with a four channel, class D ICE amp. Now this was getting interesting as class D’s have made great strides in the past few years. At the end of the hour plus conversation (I spoke for maybe 90 seconds), I had agreed to take on the CS2’s for a review. After doing the laundry I was able to smooze the wife into accepting the invasion of these black monoliths (also available in beige, blue, and red).

Emerald Physics CS2 review

The Design

The creator of the Emerald Physics is Clayton Shaw. Clayton has been playing around with speaker design since the late 1970’s. For those of you with encyclopedia knowledge of speakers since that time you might connect the name to Evett and Shaw. The point is, Clayton is no newbie and has been fascinated with out-of-the-box solutions to speaker limitations for quite some time. The Emerald Physic CS2 is his end result of thirty years of audio pursuit.

The best way to describe the CS2 is to think of a giant version of a Pepperidge Farm Milano Cookie wrapped in black spandex with the ends squared off. The fabric covers the open baffle design including two-fifteen inch woofers. Uncovered is a twelve-inch circular wave guide. A one-inch compression driver screws into place (shipped in a protective box). Two pairs of high-quality 5-way binding posts sit just above the base. The heavy metal base is attached via four bolts. In a nice touch the label for each speaker is on the base, making for easy viewing, if necessity arises. (Control the directivity of the driver)

Emerald Physics CS2 Loudspeakers red

One of the first surprises is that Clayton doesn’t use fancy, esoteric drivers with obscure minerals or NASA designed materials. Instead, the 15 inch drivers are standard professional PA woofers. This keeps the cost way down, not to mention the ability to handle high power and volume without issues. To be honest, this approach is quite refreshing in this day and age of extreme materials and scientific labels. Four quality spikes are provided for use once you have determined your final location. As with all my previous experience, the spikes will improve the resolution of the Emerald Physics.

Speaking of the Behringer DCX2496, this digital box is the soul of the Emerald Physics CS2, as it is the crossover for the speakers. This digital controller may put some audiophiles off who adamantly defend the purity of analogue signals. However, for the majority of audio fanatics based upon forum discussions, it is a non-issue. In fact, Walter makes a strong case for the benefits of digital crossovers by pointing out that the CS2’s achieve a mind-boggling +/-0.5db from 100-20Khz. Remember, when it comes to 99% of speakers the standard is +/-3db.

A second factor that makes the DCX2496 so compelling is that it allows for the usage of more modestly priced pieces of gear. The sonics are adjusted to provide the optimum output to the drivers. The Adcom GFP 555 preamp used in this review is a fine budget performer, but it does have its limitations. The DCX2496 takes the 555 to the next level.

The sonic equalization programmed into the DCX2496 in conjunction with the open baffle design allows it to avoid the problem that traditional box speakers create with sound reflecting off of side walls. As Walter enthusiastically puts it, “It takes the problems of typical rooms out of play”. The DCX comes preprogrammed with distance from the back wall being the selection choices starting at 3 feet in one foot increments. I played around between the distances of three and four feet. In my room with the toe-in I found the best results at 39inches from the speaker’s inside edge to the back wall and set the crossover at —-feet. I highly recommend using a measuring tape for confirming distance.

For those of you who are a bit trepid about working with a digital processor, no need to panic. Clayton does a fine job explaining how to setup the DCX2496 in a clear and complete manual. Even though Walter tells every buyer to feel free to call him during the setup, it only took a couple of minutes following the manual for me to have the CS2’s ready for music.

In order to make the Emerald Physic CS2 run, one MUST bi-amp. Now before you give up on the thought of owning the CS2’s keep in mind that Walter thought up a reasonable solution to this potential deal-breaker. Using a combination of his relationship with Rick Cullen of Wyred4Sound and Internet-direct sales leverage, the buyer can get hooked up starting for just $2500 for a model with 250wpc for the bass channels, and 125wpc going to the upper frequencies. For a full review of the Wyred4Sound MC4 4 channel amplifier see Issue 33. Most important, the amp can be configured in a variety of power setups.

If you plan on using existing amps, be warned, in order to get a quality performance, the amps should be gainmatched. Otherwise, it will cause some tonal balance issues you’ll be in for a very frustrating and disappointing listening experience. Those who can not gain match their amplifiers can go into the DCX2496 and adjust the gains. Secondly, due to the very linear nature of the CS2’s, tube amplifiers are not recommended. For those that must have “tube” sound, I suggest a tube preamp, or in my case a tube cd player to get the glowing glass sonics.

The Sound of CS2

Normally, I allow review speakers to break in for at least 100 hours before I do any sort of serious listening. But from the instant the first disc started playing I couldn’t help but to pay attention. The CS2’s create a presentation that is eerily familiar to The Carver Amazings in that the starting point of the sound comes from such a wide space. It brought a whole new definition and reference to the phrase,”wall of sound”. That doesn’t mean that the CS2’s don’t benefit from break in, they absolutely due. Walter went so far as to inform me that I shouldn’t be surprised to experience improvement even at 400 hours, especially the lower registers. During the first days the bass frequencies were tighter and thinner than I expected for 15 inch drivers. But several days in a row of playing Morph The Cat by Donald Fagan flexed the massive cones leading to a more powerful bass presentation.

Morph The Cat cover

During the initial 100 hours I played around with the wall distance, as well as the toe-in. I settled on 39 inches from the back wall, and an axis that had the speakers crossing just inches in front of my face. After switching back and forth I settled on the 3 foot preset in the DCX2496, Sitting in the sweet spot can be a stunning experience depending upon the recording material. The entire score of Dances With Wolves was as wide open as the Dakota prairie where the movie was filmed. From my understanding, the recording was produced with the vast open spaces in mind, which led to the cd being criticized in some circles as lacking three-dimensionality. Listening on many monitors could only confirm this to many listeners. The French horns alone sounded like they cascaded over the grassy hills. I now understand why Clayton is working on a center channel; certain films would be absolutely spine chilling to hear with a CS2 home theater setup.

Over my three months of review time, I listened to quite a bit of classical and symphony pieces, it’s fair to say that the CS2’s love reproducing the vast and complex harmonies, tone and depth/width that an orchestra provides in person.

Spyro Gyra cover

I thoroughly enjoy the modern jazz from groups such as Spyro Gyra. The song “Telluride” from the Freetime cd is a great piece to test speaker’s capability to reproduce a clean electric guitar, xylophone solo, solid bass, and a clear saxophone in a single song. The guitar notes in the intro are so pure I caught myself leaning in and to the left just to locate the specific spot where the instrument was placed. I’ve mentioned in previous reviews my belief about the xylophone being one of my test instruments. The solo in “Telluride” which sounds understated with most speakers has never sounded so forward. The bass is full and forward yet tight, something that I appreciate as a despiser the rumbling thump thump that ruins so much music today. The note is felt, and just as importantly you know what without question its frequency. No muddying of the sound across 20 Hz of frequency.
That detail is something that is eye-opening to a monitor fanatic like me.

On one particularly hot summer morning I was looking for some piano music to play. In an attempt to cool down I chose December by George Winston. I know Christmas in July, but hey I wanted to cool off, and psychology is a powerful tool. The nuances and more importantly, the tone of the lower frequencies were absolutely right on target. Usually bass frequencies are somewhat forgotten in solo piano work. The Emerald Physic CS2’s reproduce the bottom end without any compromise, and with a natural decay. The upper frequencies on such songs as “Carol of the Bells” rang with an expansive clarity equal to my favorite tweeter, the Vifa Ring-Radiator. Otherwise, the compression driver presents a far different sonic signature. The clarity is a bit disarming at times. I attribute that to the +/-0.5db measurement, which is a tighter tolerance than even the Wilson Watt Puppies. Such low distortion forces reviews such as me to pause, think and replay multiple times the same song to accurately determine whether the sonics are true to the original or false.

Rock and roll fanatics will need to audition the CS2’s carefully. Not because they struggle to articulate the music; but instead, because they reveal significant flaws that seem to be a part of the current recording process. Overly dynamically compressed recordings are reproduced so honestly that I found myself leaving the room, it was that uncomfortable. After discovering this flaw, I decided to play a couple of tracks burned at 192mp3 quality. The result: a nightmare listening experience that is how true the CS2’s are to the source material.

But on quality recordings such as The Lonesome Jubilee by John Mellencamp, the results are outrageous. The special presence and depth is soul grabbing. “Cherry Bomb” with its toe-tapping accordion intro and blue grass violin hopping in and out between lyrics was sheer nirvana. The CS2’s made the entire recording a “sit down and awe” experience. There is something about a fine rock and roll recording that can energize a person for a day, and, when it’s presented on terrific gear all the better. It’s a great way to spend a part of a day.

The Lonesome Jubilee cover

What about vocals? Never in my home have I had an easier time hearing artist’s voices from other rooms. The CS2’s are so very distinct and detailed, even when off angle. Some artist were absolutely stunning, the best example was Ricky Lee Jones from The Magazine. As Affordable$$Audio senior writer John Hoffman pointed out last month, her voice is so very difficult to reproduce with clarity. Well, the CS2’s were more than up for the challenge. This disc quickly became my favorite with these speakers. Every vocal nuance is allowed to come thru in a quality I’ve never before experienced. So profound was the presentation of The Magazine that I delayed packing up the CS2’s on consecutive nights just to get one last experience with Ricky’s vocals.

Finally, near the end of my review time I decided to put the CS2’s to the difficult room test. After cleaning out the garage one day, I bear-hugged the speakers out to the garage, followed by Wyred amp, Adcom GFP 555 preamp, Jolida cdp and speaker wire. With the concrete floor, steel garage doors and flat drywall the space is a sonic disaster zone. To my amazement the CS2’s do just what Clayton intended and Walter promoted. The speakers do indeed make a very difficult sound reproducing room sound very good. No, it’s not a replacement for my living room, but much better than I thought possible.


No speaker or piece of equipment is perfect, they all have some imperfection, however, the Emerald Physics CS2 does a terrific job of making the critical listener forget about detecting such limitations. But these are my few observations:

The CS2’s need space; a standard size spare bedroom just won’t do them justice IMHO. In spite of the abilities of the DCX2496 to take the room “out of play”, they flat out prefer playing in space. But if a small room is all you have available, the CS2’s won’t disappoint, though an interior decorator may tell you to go with a lighter-colored cloth wrap.

They also benefited from the sonic attributes that my Jolida tube CDP has over two solid state models. The warmth of the tubes mellowed bright recordings such as Donald Fagan’s Kamikirand.The compression driver/tweeter sounded edgy when I used both solid state units, but the Jolida rounded off the treble edges just enough and added in a hint of warmth. This is in keeping with Walter’s statements during conversations that a tube cdp or, even better a tube preamp will really make the CS2’s appeal to those who desire a romantic hint to their system.

Bad recordings will make one run to change material. The Emerald Physics CS2’s are similar to the Thiel’s in that they are true to the recording. They hide nothing, clean up nothing; what ended up on the master tapes is exactly what the listener will hear. This is especially true in the upper registers, where a poorly recorded flute can be a noisy mess. For example, I did detect a hint of harshness in the ringing tone at about 1:50 into the George Winston song “Night, Part 1: Snow”. In all fairness, since I was unable to confirm whether this was a limitation in the compression driver or a result of the amplifier, as I had no other bi-amping capability during this review, I’ll let owners in the forums take that task on.

Final Thoughts about Emerald Physics CS2

Not long ago I was having a conversation with a friend and as we chatted about life and such, thoughts turned to real estate and the type of dream house we’d each want. As he talked about his wish for a large, vaulted television/music room in a log cabin home my thoughts quickly turned to the speaker I’d most want in that space. After three months with the CS2, I knew that they would be my first choice without question. With their ability to create the highly desired “wall of sound”, and the capability of taking difficult sound spaces out of play (large window-filled walls, etc.) at a price that belies their sonic capabilities it was an easy choice.

The Emerald Physics CS2 may just be the next game changer in the digital music wave. Clayton Shaw by dedicating the crossover to the digital realm has shown a path for taking speaker measurements down to +/-0.5db without fancy or exotic materials. The question becomes: Will others in the industry take a chance on digitalized crossovers? My prediction is that this will be much like the music server category whereby the industry will cautiously watch as a few non-conformists take on Clayton’s vision. In the meantime, Emerald Physics will continue to use its pioneering spirit to benefit customers one at a time thru the single distributorship of Walter Liederman at Underwood HiFi. Someday, down the road digital crossovers may just be the norm, and Clayton Shaw revered for blazing the path.

Review Equipment

  • Adcom GFP-555 preamplifier
  • Wyred4Sound MC4 amplifier (125 x 2 wpc, 250 x 2 wpc) Modified Jolida JD100 cdp
  • Onix CD-88 cdp
  • AudioArt cabling
  • PSAudio Quintet surge suppressor

from affordableaudio, By Mark Marcantonio

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