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Audio Concepts Inc. Emerald LE

Bookshelf Speakers

[Italian version]

Product: Emerald LE Bookshelf Speakers
Manufacturer: Audio Concepts, Inc. - USA
Approx.cost: $ 749 USD
Reviewer: Scott Faller - TNT USA
Published: July, 2003

[Emerald Le's]
The Emerald LE's

Trivial Bits

Anybody that has been in the market for mini-monitors knows your choices are almost endless. I am utterly amazed at how many speaker manufacturers there are to choose from. It's almost mind-boggling when you start looking.

During my many searches for speakers to review, I kept running across Audio Concepts Inc. (ACI). This began to peak my interest. ACI is a nice sized speaker manufacturer that's received some nice press on his larger speakers but it seems nobody had done a formal review of the entry line of bookshelf speakers, the Emerald's.

As I read the web page for the Emeralds, it stated “The Emerald is the perfect speaker for high-end home theater”. Normally that statement would send my web browser pointing into a different direction but this time it didn't. In the same sentence it also stated that the Emeralds were “one of very few shielded speakers with the sound quality required by serious audiophiles”. Normally I don't give too much credence to manufacturers hype but since I've read really good things about the Emeralds big brothers, I decided to give Mike Dzurko a buzz and see if we couldn't schedule a review.

Not long after the phone call, I received a small heavy box that held the Emeralds. As you can see from the picture, the black and cherry combination makes for a very attractive pair of mini-monitors.

ACI offers a nice line of speakers that range from the reasonably affordable Emeralds (showcased here) to their high end Jaguar's at about $7000 a pair.

Manufacturers Published Data

Model Name

ACI Emerald LE


Bookshelf, 2 way, Bass Reflex

Driver Compliment

1" silk dome Tweeter, 5.25" Woofer (shielded)

Frequency Response

65 - 20kHz +/- 3 dB


88 dB in room

Nominal Impedance

8 ohms

Power Handling

30 - 150 watts, 200 if a sub and active XO are used


11 3/4" h x 8 1/8" w x 7 3/4" d


15 pounds each

Crossover Frequency

near 2.5k

Lets Listen for a While

The Emeralds behind the Korato/AKSA Combo
As usual, I listened to the Emerald's in two different speaker setups. First, I set these up to get the best bass reinforcement. I backed them into within inches of the wall. Much as expected, the rear port design, combined with the back wall interaction provided nice deep bass. Imaging and soundstage depth suffered a bit but could probably been cured with a bit of back wall treatments between the speakers, a heavy wool blanket or the like.

Second, I brought the speakers out away from the wall to get the best imaging. I love it when speakers (almost) disappear in my room. That's really tough to achieve in any room. When you actually have that happen, you immediately become an imaging junkie. It almost doesn't matter what that pair of speakers faults are, you gladly accept them because they "disappear". All that's left is music floating effortlessly in front of you. As always (or so it seems), when I brought the speakers away from the wall, the bass began to roll off. When this happens, you can add a sub to fill in the lowest octaves.

The Korato/AKSA made for a great listening combination, especially for Rock music. The Emeralds have a slightly "mid-hall" sound. They aren't too forward, not too relaxed, kind of ... well...."mid-hall". Speakers like this seem to do a great job on Rock especially when they are mated with a good sub, IMO. They tend to take a bit of that aggressive edge off of some music. The nice parts about the Emeralds, you still get ample detail to satisfy the audiophile needs amongst us all.

[Ooops....I'm in twubble....again]

Since the Emeralds liked to Rock, I spent loads of time rediscovering my Rock collection. I pulled out everything I had (or so it seemed) at one time or another, popped it on and just sat back and enjoyed the ride. One problem though, I kept getting in trouble with my wife. See the words Rock and Loud go hand in hand in my listening room. In turn, I kept getting reminded that there are other people in the house. Oh well........

As I sat down to finish up this review, I started reading the Owners Manual. Hmmm...... imagine that, reading the owners manual (OK girls, no cheap shots). As I read the paragraph labeled Positioning Your Emeralds the first sentence stated something like this, If your speakers will be positioned at or below seated ear level, the woofer should be at the top of the enclosure and vice-versa.

See..... this entire time, I've been listening to the speakers with the tweeter at the top. After reading that paragraph in the Manual, I decided to flip the speakers upside down and give them a listen.

After flipping the speakers upside down, the character of the Emeralds changed. See, I'm using the TNT Stubby's as stands. Top to bottom they measure 24" tall. That placed the woofer about 10-12" below my ear, now with the woofer on top, it sits about 2-3" below my ear. It's almost on axis.
Result...... more midrange detail.

OK, so how much are we talking about. Well, I'd give it a solid 6-7 on the old tweak-o-meter scale.
Well.......buggers. Now I've got to re-think how I'm going to write this review.

Slight pause while the reviewer listens feverishly to recover from being a moron.........

Well, after listening to loads of different music (this took several days actually), I think I've decided that I prefer the sound of the Emeralds installed with the woofer on the bottom rather than on the top. The woofer on the top brings the music just a bit too forward for my tastes. Reason, the woofer is almost on axis with my ears which brings the mid detail forward into the mix.
This is just my personal preference, YMMV.

OK, back to our regularly scheduled program.

The Emeralds Behind RAM 301
This combination worked like a charm. Here I found myself listening to a bit more Jazz, vocals and even some Classical rather than hard driving Rock. Nothing too noteworthy here. The Emeralds proved to be a fairly easy load to drive. Though Mike at ACI recommends a higher powered amplifier to drive these, I found them very enjoyable behind the RAM 301 for most music. I guess the reasoning is because of their low(ish) efficiency of 88dB. Though in today's terms, 88 dB isn't too bad regarding mini-monitors.

[The old HH Scott was just a bit thick in front of the Emeralds]

The Emeralds Behind the HH Scott 299
This combination wasn't the greatest in the world. Don't get me wrong, it sounded fine if I was playing "audiophile" music but when it came to average recordings, it was a little too thick. See, the old HH Scott has a bit of color to it. It tends to like exacting (or forward) speakers. Since the Emeralds are a bit mid hall sounding, the old HH Scott made them a bit too wooly and bloated. That's about as I expected it to be. Just one more item that lends itself to the "system matching" reality. Again, YMMV.

The Emeralds Behind the RAM 301's and Side by Side with the Dynaudio 42's
Here we have two completely different presentations. The Dyn's are more than a little revealing. They are definitely front row center speakers. On the other hand, the Emeralds tend to be a bit more relaxed. They aren't near as aggressive as the Dyn's.

Sidebar. Lets talk terminology for a minute, if you don't mind. The terms aggressive and relaxed are usually purely subjective terms. Each can have a negative connotation depending on your viewpoint. In my case comparing these two speakers, these two terms are dead neutral. They are neither positive nor negative. They just are. These terms I'm using are my way of trying to describe what a potential buyer might prefer in their sound. You either like an aggressive speaker (the front row center sound) or you prefer a slightly relaxed sound (the more mid-hall sound). All but too often, what is written gets misinterpreted. I just wanted to make it abundantly clear that my uses of the words relaxed and aggressive aren't in a negative light.

OK, back to Emerald's. One of the many recordings I used in the side by side was Pat Metheny's newest release One Quiet Night, this is a pure acoustic recording. It's Pat at his home in New York, his latest Manzer baritone guitar, a single mic and a recorder. Pat has used a low "Nashville Tuning" for this group of songs. If you are a PM fan, this one won't disappoint, it's simply lovely.

Anyway, the Dyn's put on a nice presentation. They are crisp with a decent soundstage. I'd say Pat's guitar is firmly placed 6-8 feet behind the speakers. The Dyn's did call a bit of attention to themselves on Pats fingerings when he slides up and down the frets. Other than that, they disappear in my room for the most part. The bass is generally deep, dynamic and relatively fast considering these are ported speakers.

Using the same piece of music, the Emeralds provided a very nice presentation. I found them very light and airy. They were less forward than the Dyn's (with the woofers down). The soundstage has opened up a fair amount and gotten significantly deeper. Pat and his guitar have taken about two or three steps back in the soundstage. Some of the crispness in the upper mid's and lower treble region of the Dyn's has been sent further back into the soundstage. Consequently, the ACI's give the illusion of making music with less effort. The music just seems to appear rather than being reproduced. I guess that's one of the reasons why I keep using the words relaxed and airy to describe these speakers.

Objective Stuff

Fit, Finish and Basic Design
The Emerald's are a basic two way bass reflex design. The port is on the back side of the speakers and itself is a bit unusual. Rather than being a traditional round/flared configuration, the port is rectangular with rounded corners.

The cabinet construction is nice and heavy. The black part that you see in the pics is HDF with a nice, heavy, semi-gloss finish. For aesthetics, Mike has routed two channels in the cabinet (racing stripes :-) I doubt they do anything for the sound but they look kinda cool. The speakers also have solid hardwood side cheeks. The demo pair I have are outfitted in Cherry. It's a finishing touch that sets these speakers off quite well.

The drivers Mike uses in this design are Vifa's. Loads of commercial speaker designers and the DIY crowd, use Vifa's on a regular basis, including myself. They always seem to be consistantly good performers at a reasonable price range.

To help cut down the baffle induced diffraction, Mike has installed a heavy felt ring around the tweeter. The ring is about 1 1/2" wide. No doubt, that helps cut down some of the splashyness in the highs.

When it comes to comparing the construction of the two, the Emeralds are heavier and subjectively sturdier (obviously I couldn't take the cabinets apart and inspect the bracing). IMO, The Dyn's are slightly more attractive because the veneer is on all sides of the speakers rather than just the side cheeks of the speakers. Ultimately, this will come down to your personal preference. Both speakers have their compromises. With the Dyn's you have slightly better looks but the Emeralds provide a slightly heavier build.

[The Emeralds were Very even handed]

Here we have a classic case of a fairly relaxed speaker. Not so bright or midrange forward that it runs you out of a room, yet more than enough detail to please most anybody. With the speakers positioned away from the back wall, the bass doesn't extend much into the final two octaves and starts to roll at about 70-80Hz (at least in my room). In turn, the bass dynamics appear to be a bit subdued. Take a look at what I just typed. I didn't say these speakers weren't dynamic. I said the dynamics seemed slightly subdued. Reason.... the slight roll off of the bass (mainly) and the shear nature of a relaxed speaker.

A great test for dynamics is EST's song The Return Of Mohammed on Somewhere Else Before. It's a simple yet very aggressive song. The trio of bass, piano and drums is very well recorded. The song starts out with the gentle taps on a ride cymbal and kick drum. Then reaching inside of the piano, Esbjorn joins in with the light plucking of the piano wires and follows with a light chording intro. Then Dan Berglund joins in with a simple seven chord statement on the double bass. It's a great intro that sets up the entire song.

The dynamics of the intro should be light yet firm. The cymbal taps should be clean and crisp. The kick drum should sound present but not overbearing. In turn, the double bass should be firm but not bloated. So, how does it sound on the Emeralds? Very good. The dynamics aren't such that they blow you away, but on the other hand they aren't so subdued that the music sounds lifeless.

If I had to narrow my description for the dynamics of the Emeralds to just a couple of words, I'd have to say Even Handed would be a good description.

Treble Extension
The treble extension is very good. Playing with my geek-o-meter (Sencore SP295c) in the upper ranges of sonics, the treble extension between the Dyn's and the Emeralds is about the same to well above 10k. At 16k and above, the Emeralds slightly better the Dyn's. This probably explains some of the airiness I mentioned earlier.

Treble Clarity
The Vifa soft dome tweeter Mike chose for this speaker is very nice sounding. It provides a clean presentation without having that sizzle that so many tweeters seem to exude. The overall treble region is fairly smooth.

On Marian McPartland's Live at Shanghai Jazz, the first track features Joe Morello (of the old Dave Brubeck Quartet) on the drums. Most of the song he lives on a large ride cymbal. As usual with the Vifa line of tweeters, the treble shines through with excellent detail. The treble is very accurate without the tweeters calling too much undue attention to themselves. I really feel that the felt ring surrounding the tweeter helps out quite a bit with the Emeralds treble clarity.

Doing a real time A/B of the two, the Emeralds are providing just a touch more definition. It's not much, but it is definitely there.

Midrange Clarity
The midrange on these speakers (with the woofers down) is slightly recessed. Recessed is just fine as long as it doesn't come with any changing of the tonal nature of the recorded instruments or worse yet, veil the sound. A piano still has to sound like a piano. It can't end up sounding like an electronic keyboard. When it comes to my using the word recessed, that does not mean that the midrange is veiled. I use the term to state that the midrange is sent further back into the soundstage, nothing more.

Here, Mike has done a good job. Proper crossover point, coupled with good driver selection, allows the mid's to come through without altering the original tone of an instrument. Any good speaker designer can tell you, that can be a feat all in, and of itself.

Both speakers do a decent job in the midrange. Each presents it slightly different. One is forward, the other further back. The nature of the Dyn's is slam and a front row presentation. In turn the midrange can appear slightly colored or warm. On the other hand, The Emeralds approach is to present a more relaxed sound. In turn the midrange is a tad leaner and maybe not colored enough. Basically, the advantage and resulting disadvantage of each speaker, cancels each other out resulting in my neutral rating.

Just A Little More Detail Please

OK, now for a little more on flipping the speakers upside down (woofers up) on the stands. Here, I played around quite a bit. I must have walked a mile back and forth between my listening seat and the speakers. I can almost see the wear marks in my rugs.

Although I said I liked the presentation better with the woofers down, there were some specific instances where I much preferred the woofers up. Mainly it was on quiet music like Jazz and Classical. It seemed to bring the performance a bit more forward. I definitely heard more detail from the recordings. On some recordings it helped quite bit, on others (like some rock) it actually hurt.

Again, this was just my personal preference. Obviously, your listening habits and preferences will probably differ from mine.

Bass Clarity
One of the best pieces I've found to test the accuracy and definition of acoustic bass, is Ray Browns Soular Energy. I'm lucky enough to have this both on CD and Vinyl (Pure Audiophile PA-003, look for the review soon). Stan Ricker's mastering of the vinyl version of this jazz classic is just short of phenomenal. More times than I can count, Ray goes into a mini-bass solo that gives you a really good sampling of how detailed and articulate a double bass is. In listening to Soular Energy, the Dyn's slam and immediacy can be very inviting. But when you've sat next to a double bass and heard what it actually sounds like, I'd have to say that the Emeralds get a little closer to reality.

In fact, just the other day I had my hands on a double bass. I was goofing around plucking and bowing. For those who have never heard one up close and acoustic (not amplified), a double bass is actually quite quiet, contrary to most recordings and (amplified) live venues. It's kind of interesting to hear a studio engineers (and producers) interpretation of this solitary instrument.

Bass Extension
Bass extension is fairly decent. Backed fairly close to the back wall the bass can reach about 50Hz or so in room. Since I prefer imaging to bass reinforcement, I choose to bring them away from the wall. In turn, the Emerald's begin to slightly roll off around 75 Hz or so. Not too bad considering their small size. As always, you can integrate a sub to fill in the lower couple of octaves if you feel the need.

Comparing the Emeralds side by side to the Dyn's, the bass isn't quite as pronounced. The Emeralds don't have the slam that the Dyn's have got. On the other hand, the bass seems to be a bit more even handed on some music. By that I mean, on classical and jazz as an example, the bass is a bit more true to life on the Emeralds. On Rock I found the bass to be a bit too subdued, in turn that's where a sub integrates nicely. Overall, I feel the bass energy and extension of the Dyn's was better.

Soundstage Depth
Since the Emerald's are slightly recessed in the mid's (again with the woofers down), the soundstage is nice and deep. As I sit here listening to some Coleman Hawkins, At Ease with Coleman Hawkins, Prestige OJC 181 vinyl, it sounds as if pianist Tommy Flanagan is in the next county.

Another really good example is Emmanuelle Axe and YoYo Ma's, Braham's Cello Sonatas. The Dyn's have YoYo about three to four feet behind the plane of the speakers with Emmanuelle placed roughly another five to six feet behind YoYo. When I switch too the Emeralds, YoYo takes a solid three to four steps back placing him about 10 to 12 feet behind the speakers. In turn Emmanuelle seems to appear about 15 or twenty feet back into the stage.

[The soundstage was waaay better defined on the Emeralds]

Soundstage Width
Using Pink Floyds Momentary Lapse of Reason, Track One, the water lapping against the shoreline as a test of soundstage width, on the Dyn's the image appeared about two feet outside of the speaker plane. The Emeralds held about the same position if not just a tad bit closer in. Maybe 6" or so. The main difference between the two, focus. The Emeralds image was sharper.

Though the image focus was in a bit closer in than the Dyn's, the overall virtual stage came across as wider. Why? Well, I can't quite put my finger on it but if I had to guess I'd say it was the near-ultra sonic highs. The air around the instruments and vocals seemed to be helping (not only) better define the performers, but it also gives a virtual presence to the venue.

[the soundstage height was definately taller on the Emeralds]

Soundstage Height
As I listen to the two speakers, The Dyn's have the soundstage tightly focused (vertically) at the plane of the speakers. Though the image does project well above and below the speakers, the main focus is pretty much on axis with the speakers.

The Emeralds take a slightly different approach. The main focus is slightly below the plane of the speakers but the light airy sound of the Emeralds makes for a much taller image. If I had to define it, I'd say it starts at about one foot below the speakers and solidly extends three feet above the speakers.

Imaging and Focus
As I mentioned a little earlier, the Emeralds came really close to disappearing in my room once I had them set up properly. In turn, I was able to get very nice imaging. I got a nice sharp picture of the performers. Occasionally the tweeters would call a bit of attention to themselves but nothing too bad at all. That could easily have been the recordings too.

As I site here listening to YoYo again, I can't help but notice some pretty significant differences in the two speakers approach in the way they present music. The Dyn's are forward and put the performers right in front of you. The imaging and focus is good but, since you are "right there" the image can be little overwhelming at times.

The Emeralds take a far different approach. The Emeralds tend to open up the recording studio or venue. They provide a very open and spacious presentation. The performers take a well defined shape and from in front of you. Plus you (now) begin to see hints of the size and shape of the recording venue.

The Dyn's image tends to be a bit wider and less focused or shapely. Reason? Again the Dyn's are a front row speaker. Ever sit front row center of an acoustic event before? I did just a few short days ago in just such a concert. In fact the performers (James Nacy cello and Jennifer Lim piano) played their renditions of two Braham's Sonatas featured on the YoYo CD I use as a reference. When you are in the front row at a simple piano and cello concerto (or any live performance for that matter) everything gets bigger, bolder and more expressive. The performers are right there in front of you, not off in the distance, even if it's just a few rows away.

Subjective Stuff

Overall Coloration
Generally these speakers aren't very colored at all. On the overly accurate (audiophile) recordings I listened to, the midrange can be a little lean and might not have quite enough color. It seems to be the price we pay for a speaker that is very easy to listen to.

As I mentioned earlier, The Dyn's can add a bit too much midrange color on some recordings. On the other hand the Emeralds are a bit lean in the midrange. Overall, I'd say the Emeralds tend to be slightly less colored than the Dyn's.

Here we have a classic case of a pair of speakers voiced to mid hall. What I mean by that is, the upper midrange to lower treble region is slightly subdued. This places you somewhere near row 15 or so.

Nothing too bizarre about these speakers. They are pretty unpretentious. They play all types of music well.

Miss You
After spending loads of time with the Emeralds and discovering their many strong points, I will definitely miss them. I really like the way they image and the well defined bass. They are definitely a speaker I could live with for a long time.

Objective Ratings




Fit and Finish


Pretty much a wash



Close but not quite up to the Dyn's

Treble - Extension


Nice and airy

Treble - Clarity


Ever so slight edge to the Emeralds

Midrange - Clarity


Both are clean, just presented differently

Bass - Clarity


The side by side was pretty revealing

Bass - Extension


The Dyn's do a great job loading a room

Soundstage - Depth


Much better depth

Soundstage - Width


The airyness sealed it

Soundstage - Height


Definate edge to the Emeralds

Imaging - Focus


Very tight focus and definition

Subjective Ratings

Overall Coloration


Side by side the Emeralds were slightly better



Somewhere around 15th Row



Pretty even speaker

"Miss You" Factor


The Emeralds were very easy to listen to

Here's a Link to the Methodology for my Ratings

[I enjoyed the heck out of these]


When all is said and done, each of the two speakers did a very good job reproducing music. Each one had it's own way of presenting the music. With the Dyn's you had the immediacy and slam of a front row speaker. On the opposite end, the Emeralds gave me a nice relaxed view of the same music. Both are very good in their own rights. It all boils down to your personal preference. Basically, where do you prefer to sit in the concert hall?

Even though I wrote about loads of Jazz and Classical in the direct comparisons, I (personally) found these to be a great match for hard rock. You know the kind I'm talking about. The kind with the screaming, distorted guitars and even louder singers. Head bangers stuff. It all seemed to sound really, really good on these little speakers. Especially when you integrate a sub to fill in the lower end. Everything I threw at the Emeralds sounded pretty darned good. If you're a hard rock fan and can't seem to find a pair of speakers that sound "right" these may just be the ticket. Again, don't mistake what I just wrote, these do all other types of music extremely well. I just happened to find myself listening to more Rock than anything when I was listening to the Emeralds. With their mid-hall presentation, they seemed to take the "edge" off of the harshest music, making it far more listenable.

With most of the mini-monitors, just as these, I'd recommend integrating a sub if you want to hit the lowest octaves. In my system, and especially with rock music, the addition of a sub made it very enjoyable. As I listened to acoustic jazz and classical, I really didn't find the addition of the sub necessary at all.

Here's one last thought about the Emeralds. Mike offers a 30-day, in home, money back guarantee for all of his speakers (less return shipping of course). Personally, I feel this is a big plus. It takes almost all of the gamble out of your speaker purchase. If all you are risking is $50 bucks or so in shipping, the Emeralds are well worth considering.

Thanks/Reference Gear

I'd like to personally thank all of the manufacturers who have made this series of speaker reviews possible. Remember, without these guys, you wouldn't be reading this :-) Surf on into their sites. They all sell affordable gear well worthy of your consideration.

[Click here] for a review of the bigger ACI Sapphire XL bookshelf

Reference Gear


Manufacturer and Model


CD Player

Njoe Tjoeb, Upsampled

Upscale Audio - Kevin Deal

Pre Amp

Korato KVP-20

Korato Group

Audio Switching


NLA – My personal gear


ASKA - Aspen 55 watt Amplifier

Aspen Amplifiers Pty. Ltd.


RAM 301 - 30 watt Modified Jolida

Response Audio - Bill Baker


HH Scott 299A Integrated - EL84 PP

NLA - My Personal Gear


Silver Plated Copper, Teflon Insul

Home Brew

Speaker Cables

Silver Plated Copper, Teflon Insul

Home Brew

Speakers (ref)

Dynaudio Audience 42

Dynaudio USA Michael Manousselis

Speakers (review)

Acoustic Concepts Inc, Emerald LE

ACI Mike Dzurko

Geek Toys

Sencore SP-295c


Manufacturer's Comments

Thank you for the opportunity to respond to your review. It's easy to see that Scott truly enjoyed his time with the Emeralds. This comes as no surprise to us here at ACI. The Emerald is a speaker that consistently surprises people with its simple balance and musicality. Those seemingly basic qualities are not always so easy to attain, but they are what we strive for in each ACI design.

The Emerald's design makes it equally well suited to home theater and high end two channel, and we have found that our customers find it equally adept at both tasks. Neutrality is neutrality, be it in an HT or two channel system. The mid-hall perspective that Scott found is very much in line with our design goals for the Emerald. The recording must always be allowed to be the prime determinant of the listening perspective. The mid-hall leaves the Emerald room to shift the musical portrayal based on the material and the room. Scott said it well when he wrote, "...the Emeralds tend to open up the recording studio or venue. They provide a very open and spacious presentation. The performers take a well defined shape and form in front of you. Plus you now begin to see hints of the size and shape of the recording venue." That's what we hoped he would hear!

Again, thank you for taking the time to review our product and for the opportunity to comment. If any of your readers would like to learn mere about any of ACI's products and our unique "30 Days and You Gotta Love 'em Guarantee" or our industry leading "Total Assurance Guarantee" I cordially invite them to contact me.

I would love to hear from them.
Best regards,
Mike Dzurko - President, ACI - miked@audioc.com - www.audioc.com


© Copyright 2003 Scott Faller - http://www.tnt-audio.com

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