Revel Concerta2 M16 Bookshelf Speaker Review

Two-way bookshelf speakers using a 6.5” woofer and 1” dome tweeter are one of the most prevalent design types available. Any speaker manufacturer looking to release another speaker in this configuration is going to have to execute it seriously well if they want attention in this crowded market, especially in the sub $1k price range. This is the challenge Revel is attempting to surmount with their Concerta2 M16 bookshelf speakers. Although Revel has demonstrated top-notch engineering in the past, they still have their work cut out for them to stand out in a field of dozens-- if not hundreds-- of similar speakers. So what is Revel bringing to the table to make their bookshelf speakers noteworthy?  Read on to find out...

Appearance

The appearance of the M16 is clean and stylish, almost minimalist. The M16 comes in either white or black with a high-gloss finish. A waveguide on the tweeter is cut to form around the gasket of the woofer in a stylized gelling of the drivers, a nice design touch topped off with no visible screws holding in the drivers. Magnetic grilles do away with the need for visible fasteners on the front baffle which further assists its uncluttered appearance. Only a small logo interferes with these clean lines, but not intrusively. A removable logo with a magnetic hold would have been a neat detail. The front of the speaker is nice enough that it would be a shame to use the grille at all; the M16 looks better without the grille.

The curved sides of the cabinet towards the back are a welcome departure from a simple rectangular box endemic of so many bookshelf speakers. The visual simplicity and high-end gloss finish make the M16 a bookshelf speaker that enhances almost any home furnishings. It fits in perfectly with modern decor, especially with the available white finish, but wouldn’t clash at all with a more traditional interior design.

Cabinet Build Quality 

The M16 looks nice, but how well is it built? A simple knock on the exterior produces a dull thud that gives a sense of solidity, which is a positive attribute in a speaker. The 16 lbs. heft of the M16 also bodes well for the build quality, and although weight alone does not guarantee a good build quality, heaviness bodes well for a better build quality than a lightweight speaker. A stiff and heavy cabinet is needed in order to reduce resonances which can interfere with the sound that is only supposed to be created by the drivers and port. The cabinet exterior walls are ¾” MDF, and a ½” thick window brace is mounted between the tweeter and woofer sections of the cabinet. Revel’s literature on the M16 boasts of using the ‘Kerf Technique’ to bend the sidewalls using perpendicular slots instead of V-grooved joints, and a layer of fiberboard is used to reinforce the internal slotted wall of the cabinet. Stout five-way binding posts ensure a tight grip on the speaker wire, whether using banana plugs or bare wire tips. Altogether the cabinet construction of the M16 is sensible: robustly built and without the overkill construction of extreme high-end speakers which can often multiply the cost for negligible returns in performance.     

Drivers, Port, and Crossover Overview

The 1” aluminum dome tweeter uses a waveguide and an acoustic lens to match the directivity of the woofer in an effort to produce a seamless transition between them. This is in line with the philosophy of many of Harman’s speaker brands, of which Revel is one, that advocates for a uniform off-axis frequency response as well as on-axis response for the best overall soundstage and imaging. The idea behind this design decision is that much of what is normally heard in-room is not direct sound from the speakers to your ears but acoustic reflections off room surfaces and so the off-axis response becomes very important in accurate sound reproduction. The shape and curvature of the waveguide is critical and must be modeled very precisely to match the dispersion pattern of the woofer at the crossover frequency. The waveguide and acoustic lens of the M16 also raises the tweeter sensitivity, especially around the lower frequencies of the tweeter’s band. Boosting sensitivity in this frequency region is a big help, because it is where the tweeter is likely to generate the most distortion, since it is where the tweeter is the most stressed mechanically. 

One innovation in the tweeter assembly itself is Revel’s inclusion of a larger than normal cavity behind the magnet assembly which is also vented. This lowers the tweeter’s mechanical resonance down to 800 Hz from the more typical 1,500 Hz, so there is not a trace of that resonance heard at all.

The bass driver’s cone is made of a Micro-Ceramic Composite (MCC), which is an aluminum layer sandwiched between layers of ceramic. Since sound travels differently between the two materials, the cone construction adds substantial damping over conventional cone materials. Another feature of the driver is the use of an extended pole piece in order to create a more uniform magnetic field in the further reaches of the driver’s excursion. This reduces distortion at higher output levels. Klippel analysis is used to optimize the linearity of the bass driver, and substantially improved linear excursion permitted by the driver’s suspension and also the magnetic fields between the voice coil and magnet.

The crossover network is a nine-element, high-order design. One of its features is compensation for the lower frequency free-space to half-space bump that can occur in bookshelf speakers. The crossover frequency occurs at 2.1 kHz, which is a bit lower than normal for this type of bookshelf speaker but is permitted by the tweeter’s back chamber, which lowers its resonance to 800 Hz, and also its waveguide.

Revel calls the rear-firing port a ‘Constant Pressure Gradient Port’. The idea behind this is that the shape of the interior of the port is such that the change in pressure along the length of the port remains constant. The reasoning for this is at high playback levels ports can produce a noise commonly referred to as ‘chuffing’ when air in the port is pushed too quickly and becomes turbulent. By contouring the port’s shape in a precise way, this turbulence can be reduced by eliminating any points within the port that change the pressure of the air flow.

OK, Enough Technical Description- Let’s Give Them a Listen!

In my approximately 24’ by 13’ listening room, I set up the speakers according to the owner’s manual placement recommendations: equal stand-off distances between the backwall and sidewall, equal distance between speakers and listening position, with tweeter at ear level and the speakers facing the listening position directly. A Pioneer SC-05 receiver was used in ‘Pure Direct’ mode, so no tonal processing would interfere with the speaker’s natural sound, and no subwoofers were there to disguise its low frequency abilities. Speaker distance from listening position is about 8 feet.

First up, was some full orchestral music. If a couple of little bookshelf speakers can convincingly recreate a full orchestra, then we would be off to a good start.

Fantasia on Greensleeves

I purchased this double CD set of English compositions conducted by Neville Marriner and performed by the Academy of St. Martin in the Fields for the tracks of Frederick Delius but was delighted by all the pieces. Sir Neville Marriner and the Academy of St. Martin in the Fields are known for their lush renderings of classical music and exquisite recordings, and Fantasia on Greensleeves is no exception. The Revel Concerta2 M16 speakers brought the soundstage to life; the positioning of the instruments felt authentic (although I must confess here I have not attended one of their performances in the church of St. Martin in the Fields, so I can only guess what it actually sounds like). The timbre of the instruments was reproduced with aplomb by the M16 speakers. I am used to a bit more powerful bass, however, I did switch the subwoofers off. I can hardly expect the two 6.5” woofers of the M16s to match the performance of the four 12” subwoofers that I normally use. With that said, they do have very reasonable bass output considering that they are only a pair of bookshelf speakers. The double bass was certainly present, and the low notes of the cellos left nothing to be desired. In the mids, the violas and violins sailed on with gusto, and were nicely complimented by the woodwinds with their particular tonality, which the M16s nailed. The instrument sections had distinction but performed with unity, although the recording engineer likely had as much to do with that as the speakers. The high pitches were crisp without being overbearing. One trick some speakers often pull to give an artificial sense of detail and ‘air’ is to boost the high frequencies. I did not sense this from the M16s; the recording sounded natural.  

Amadeus: Special Edition

Also performed by the Academy of St. Martin in the Fields and conducted by sir Neville Marriner, the music soundtrack for the film Amadeus remains their most popular recording. The Special Edition is a 24 bit remaster with tracks not included in the original release. I find it to be a great disk set to evaluate speakers with because of the many different types of classical music included, the very high quality of the production, and the wide dynamic range within the recording. The M16 speakers recreated the music of Amadeus very well: the ethereal chorus of ‘Stabat Mater,’ the commanding male vocals of ‘Bubak and Hungaricus,’ the soaring female opera vocal in ‘Sinfonia Concertante for Violin, Viola, and Orchestra,’ the flirtatious interplay between the woodwinds and strings in ‘Don Giovanni,’ among many other delightful moments in this recording. The M16 speakers pivoted nicely from bombast to quietude in the finale from Axur (this fine track composed by Antonio Salieri). As before, truly powerful bass is lacking, but that is to be expected in bookshelf speakers, and I could not fairly hold that against the M16s. I have no real complaints about the execution of the Amadeus soundtrack by the Revel speakers. It was simply a joy to listen to this soundtrack again on the M16s.

Diana Krall - The Look of Love

Yeah, I know, Diana Krall is too-often relied on for demo music for audiophiles, but there is a good reason: Krall’s recordings are superbly produced and sound great. I have to admit to not being a fan of jazz, but the pristine production and vocals can definitely demonstrate a speaker’s strengths and weaknesses.

Since human hearing is so accustomed (‘tuned’, one might say) to human speech and voices, if there is anything even slightly off about a speaker, the vocal region is often where it will first become evident. Krall’s ‘The Look of Love,’ a Grammy winner for best-engineered album, is a great test. The M16 speakers pulled off the entire album beautifully, and I really have nothing to complain about. Through the M16s, you can hear the ‘close miking’ of Diana for an intimate sound. The bossa nova rhythm section and light orchestral accompaniment are reproduced well, but Krall’s voice takes center stage here, as in tracks like ‘I Get Along Without You Very Well.’ The M16s rendering of Krall’s voice was so uncanny that I turned the volume up to make sure it was sounding as good as I thought it did, and, yes, it sounded as good loud as it did at a modest volume. Soundstaging was excellent; vocals and instruments had discrete and natural locations. The soundstage carried over a relatively wide area as well; while the M16s sounded best in the ‘sweet spot,’ the sound was not diminished much by moving in the seats left and right of the center seat. The coverage over a large area was very good, and the off-axis measurements posted further on will explain why this is.

Evol Intent -Era of Diversion

And now for something a completely different. Having seen how the Revels handle delicate timbres and refined soundstaging, I decided to give something on the opposite end of the spectrum a swing, something rambunctious, loud, heavily processed and heavily compressed. Here is where I am forced to turn in my audiophile card, because this sort of thing is more typical of what I'd normally listen to. Era of Diversion by Evol Intent lay in the genre of ‘drum’n’bass’ within electronic music, which is characterized by very aggressive breakbeat percussion, massive basslines, ferocious synth leads, and heavily-distorted voice samples. 

How did the M16s do? I am happy to report they did very well- within their limits. The absence of subwoofers is painfully clear in this genre of music, but again, one has to keep their expectations in check with bookshelf speakers, and even most so called "full-range" tower speakers are left wanting for low frequency power with this type of music. Outside of the bass, the M16s brought snap to the snares, shimmer to the hats, and punch to the kick drums. Sound effects and ambience were rendered uncommonly well, and an unearthly soundstage was conveyed in the lulls between bouts of pounding percussion. At extreme volume levels, well past sane, the M16s can begin to sound congested, but for bookshelf speakers, they did keep their composure at surprisingly high sound pressure levels. Do they rock? Yes, they rock.

Film and Television Content

Let’s turn now to see how the Concerta2 M16s fare with material that marries audio to video. Among the shows and movies I watched with the M16s was the 2012 Bruce Willis movie ‘Looper,’ a time travel tale about assassins who live in the past to dispatch targets sent from the future.

The sound mix for Looper veers from raucous to serene, ranging from scenes of shootouts and fistfights to rural farm life and intimate conversations. The music soundtrack reflects this as well, using simple piano solos, pensive strings, orchestral crescendos, and crunching electronic distortion. Gunshots packed a wallop, with that first ‘shotgun’ blast a particularly startling moment. Since I used a center speaker for Looper, it doesn’t testify to the M16’s strength in carrying dialogue as much, but the music and effects tracks came through with no audible weaknesses in concert with the rest of the speakers. The M16s helped to make ‘Looper’ an enjoyable and engaging film for me. While the M16s are not the kind of speaker I would recommend for a dedicated home theater, in a living space where appearance matters and THX Reference Level SPLs are not needed, the M16s do a fine job.

In my time spent with the M16s, one television show I binged-watched on the recommendation of a family member is FX’s ‘The Americans’.

For those who don’t know, ‘The Americans’ is a cold-war spy drama about a married couple living in a Washington DC suburb in the 1980’s who are secret KGB spies posing as American travel agents. The story mainly concerns the toll that their double life takes on their family and marriage. I used a two-channel mode to watch this using the M16s alone to reproduce the entirety of the audio. The sound mix is dialogue heavy, sometimes backed by a light instrumental score, occasionally punctuated by action scenes, and episodes usually have a popular hit from the 80’s used in a montage sequence.

Dialogue through the M16s was easy to follow, even when mixed in with music and effects noises. The sound mix as recreated by the M16s made for a convincing acoustic environment, but this is as much a testament to the recording technicians and sound engineers as it is the competency of the M16 speakers to reproduce the audio tracks. As with everything else I viewed using the M16s, I have little to complain about. The Americans proved to be an engrossing show, and the M16 was more than up to the task of providing the sound.

Revel Concerta2 M16 Bookshelf Speaker Measurements and Analysis

The Revel Concerta2 M16 speakers were measured in free air at a height of approximately 9 feet and gated at 14 ms. At this window gate, some resolution is lost below 140 Hz, and accuracy is almost completely lost below 70 Hz and so that range should be ignored.

Loudspeaker Test Rig to do full 360 degree outdoor measurements with Revel M16

Revel Concerta2 M16 on-axis response, early reflections, and listening window.

The on-axis response of the M16 speakers is impressively flat for the most part. There is a bit of a bump at 100 Hz, but it is not severe, and since that bump occurs at such a low frequency, any halfway decent room equalization should be able to taper it down for those perfectionists who are worried about it. There are some ripples at 6 kHz and above that are likely anomalies from the microphone stand, and the true response is sure to be flatter than what is depicted in these graphs. The ‘listening window’ curve is an average of the responses out to a 30 degree horizontal angle and 10 degree vertical angle from the speaker’s central axis, and the ‘early reflections’ curve is an average of the angles that are likely to be the first acoustic reflections heard by the listener in a typical room. The significance of the ‘early reflections’ and ‘listening window’ measurements is touched on in Objective Loudspeaker Measurements to Predict Subjective Preferences. The direct axis response and the listening window for the M16s is nearly identical, which indicates this speaker can cover a broad listening area very well.

Revel Concerta2 M16 Bookshelf Speakers unsmoothed horizontal frequency response +/-90 degrees from axis: 3D view

Revel Concerta2 M16 Bookshelf Speakers unsmoothed horizontal frequency response +/-90 degrees: 2D view

The off-axis response follows the shape of the on-axis response for a highly consistent dispersion pattern. As was mentioned before, this all follows Harman’s (Revel’s parent company) design philosophy, which can be roughly summarized that the most preferred sound by most listeners is a neutral on-axis response, with an off-axis response that does not greatly differ from the on-axis, as the reflected sound from the off-axis acoustic radiation should match the on-axis for the most convincing soundstage. This philosophy is backed by extensive research and is not something that some audiophile just mused one day; here is a white paper by Dr. Floyd Toole that discusses these design principles and some of the research behind it. The M16 exhibits a very good on-axis response and a stellar off-axis response.

Revel Concerta2 M16 Polar Map

The above polar map shows the same data as the graphs above it, but in a different manner. The M16 exhibits very good uniformity out to 50 degrees from the main axis. This is a superb showing and goes a long way toward explaining the M16’s realistic and natural sound. What can be seen here was heard in the listening sessions as the M16’s remarkably lucid soundstage. Among the benefits of this kind of performance is the wider area of coverage for a good sound than what is had with many other speakers. This makes the M16s a great choice for situations that need to accommodate a multitude of listening positions, although there are benefits for a single ‘sweet spot’ listening position as well with this kind of dispersion pattern.

Revel Concerta2 M16 Bookshelf Speaker unsmoothed vertical frequency response +/- 90 degrees off-axis: 3D view

The above graph is the M16’s vertical response out to 90 degrees off-axis. This set of measurements isn’t nearly as critical as the horizontal frequency response, so long as it is not completely chaotic and the angles near the main axis are not badly mismatched from the main axis curve. The performance here is pretty good; there is a dip that occurs just under 2.5 kHz between 20 degrees and 50 degrees, which is the lobing effect where the tweeter and wooofer interfere with each other. This is typical for this type of speaker given the driver-alignment and is not a cause for concern. It is unlikely to have any serious audible impact; in fact, there are plenty of speakers whose horizontal dispersion does not measure as well as the M16’s vertical dispersion. Overall, this is an above-average vertical dispersion pattern for this type of design.

Revel Concerta2 M16 Bookshelf Speaker Electrical Impedance and Phase

Revel specifies the impedance of the M16 speakers at 6 ohms nominal. Looking at our impedance measurement, it would be difficult to dispute that rating. The M16s would not appear to present a fairly easy load for the vast majority amplifiers. A low-quality, entry- level AVR might struggle with the low-impedance valley centered around 150 Hz if cranked at loud volumes for long periods, but most receivers and amplifiers will have no problems with these speakers. All of the steep phase changes happen at high impedances and so are not cause for concern. There is nothing to worry about here unless you have a very badly-engineered amplifier in which case it's time for an upgrade.

Revel specifies sensitivity for the M16s at 86 dB for 2.83v at 1 meter, and our testing showed good agreement, 85.5 dB, which is a typical sensitivity for this type of bookshelf speaker. Again, this isn’t a speaker you want to build a THX-certified dedicated home theater around, but most users will probably never put more than 20 watts through these at which point they would be quite loud. However, if your listening position is going to be a more than 15 feet or so from the speakers, and you like to listen at high volumes, you may want to consider something more powerful or at the very minimum bass manage them by adding a powered subwoofer to increase system efficiency and bass extension.

Conclusion

If you have read this review up to this point, you might guess that I liked the M16 bookshelf speakers, and you would be correct. The Concerta M16s are a very well-rounded bookshelf speaker, and I have a difficult time finding any serious shortcomings with them when considering their intended application. If I absolutely have to nit pick, if only for the sake of some balance, I might say that some people would like a choice of wood finish instead of only black and white. But, few people could argue that they don’t look nice, so that criticism doesn’t have any real weight. I could point out that their frequency response isn’t perfect, but it is quite linear for the price, and I would be hard-pressed to name something that has a flatter response while keeping such an excellent dispersion for the same money. There may be bookshelf speakers out there that have more revealing treble, or more powerful bass, or exceed it in some other performance metric, but the M16s do a lot well and for a very reasonable price. 

The M16s are very attractive speakers, and they are also true high-fidelity speakers as can be seen in our measurements.  At $900 a pair, I consider them a good deal for anyone on the market for a solid set of bookshelf speakers, and if you can get them for less, I would consider that a bargain. I began this review by asking if Revel was justified in bringing the M16s to a crowded market of similar speakers, and I will end it by concluding that, yes, these speakers absolutely deserve serious consideration.

Revel Concerta2 M16 Bookshelf Speaker Review
MSRP: $900/pair

HARMAN Luxury Audio Group
8500 Balboa Blvd,
Northridge, CA 91329

www.revelspeakers.com
(Toll-Free) 1-888-691-4171

The Score Card

The scoring below is based on each piece of equipment doing the duty it is designed for. The numbers are weighed heavily with respect to the individual cost of each unit, thus giving a rating roughly equal to:

Performance × Price Factor/Value = Rating

Audioholics.com note: The ratings indicated below are based on subjective listening and objective testing of the product in question. The rating scale is based on performance/value ratio. If you notice better performing products in future reviews that have lower numbers in certain areas, be aware that the value factor is most likely the culprit. Other Audioholics reviewers may rate products solely based on performance, and each reviewer has his/her own system for ratings.

Audioholics Rating Scale

• — Excellent
• — Very Good
• — Good
• — Fair
• — Poor

Metric	Rating
Build Quality
Appearance
Treble Extension
Treble Smoothness
Midrange Accuracy
Bass Extension
Bass Accuracy
Imaging
Dynamic Range
Fit and Finish
Performance
Value