Reference 3a Dulcet
An IAR Best Buy
This little speaker deserves to become the new world standard for mini-monitors, and an enduring classic for the ages (like the LS3/5A). The Dulcet does everything a great mini-monitor is supposed to do, and does all these things extraordinarily well. And it avoids the pitfalls that ensnare most other mini-monitors.
The Dulcet has absolutely superb stereo imaging, aurally disappearing against a wide and deep projected stage image. It has excellent transparency throughout the spectrum, revealing lots of felicitous musical detail. The midranges are very clear and natural. The trebles are fast, articulate, and at the same time delicate and airy. The natural warmth makes this diminutive speaker sound as though it were 10 times bigger, giving music a rich heft and tone that one hardly ever hears from small speakers. And the bass is totally amazing, with excellent definition, and surprising apparent extension for such a small speaker. The Dulcet has surprising dynamics for such a small system, and a wonderful sense of vivid liveliness that really brings music to life. To cap it all off, integration is excellent, so this speaker sounds seamless throughout its spectral range.
How does the Dulcet get everything so right, when other competing mini-monitors don't? And what are these pitfalls that ensnare other mini-monitors?
Let's start with stereo imaging, and we'll see that other performance factors enter the picture very quickly. High quality imaging should be strength of all quality mini-monitors, thanks to their small size and small frontal area, which virtually eliminate secondary radiation due to cabinet edge refraction, over most of the musical spectrum. Larger speaker systems, with larger frontal dimensions, radiate this delayed secondary energy farther down into the musical spectrum, and with longer delay, which has the unfortunate effect of helping our ear/brain to localize the speaker itself as a hot spot amidst the projected stereo imaging, thereby degrading the believability of the stereo image compared to what is realized when the speaker location aurally disappears.
But most competing mini-monitors don't realize the potential offered by their small frontal dimensions, and therefore don't image as well as the Dulcet. Often that's because the drivers of these other mini-monitors have severe resonances in their non-pistonic breakup regions. When the material of a driver cone resonates, it emits its own spurious sounds, which not only sound ugly and color the music, but also clearly emanate from the driver location, thus allowing you to easily localize the speaker location where this spurious garbage is coming from, and thereby degrading that other mini-monitor's stereo image.
A disappointingly large proportion of mini-monitors have these driver breakup problems. Sometimes it's because the manufacturer buys cheap drivers, trying to meet a budget price point that buyers will still find attractive (people are often reluctant to spend big bucks for a tiny speaker). Sometimes, even if the manufacturer is willing to spend money on high quality drivers, the laws of physics and limits of engineering skill conspire to still impose breakup resonances on the speaker system. That's because a mini-monitor, necessarily a two way system, must stretch the spectral capabilities of both drivers, thus inviting both breakup resonances and also modulation distortion (a situation worsened by the fact that the woofer diameter is so small, hence must make large excursions). The woofer driver usually breaks up throughout the upper portion of its assigned range, thereby degrading the critical midrange of music. And the tweeter usually also has break up problems, often in the form of an obnoxiously sizzly bright resonance peak. Since the tweeter must be more rugged and heavy to meet the woofer in a two way design, this heaviness lowers the frequency of its breakup resonance, thereby making its sizzly presence more audible and more obnoxious (since it affects more of the music). This heaviness also prevents the tweeter from being truly fast, extended, airy, and delicate (a heavy tweeter may be too bright in the mid treble, but it often sounds artificially hard and slow and closed in, because it cannot reach the upper treble at all).
These driver breakup problems in other mini-monitors also have further degrading effects upon your music. They degrade transparency by smearing information over time. This time smearing fills in what should be intertransient silence, and also obscures subtle musical details with lingering hangover energy from a previous louder musical transient that got smeared to later in time by the breakup resonances. These driver breakup problems also color your music, by adding spurious foreign colorations that sound like the material of the cone flexing and vibrating, rather than like the material of the original musical instrument vibrating.
Driver breakup problems also degrade integration, the ability of all drivers in a system to speak as a united, coherent, seamless, single music reproduction entity, so the system brings you all the music with a single voice. In many other systems, the woofer sounds different than the tweeter, so your music is split into two distinctly different personalities for different portions of the spectrum. Driver breakup resonances then compound this dual personality problem into multiple split personalities. Each driver, woofer and tweeter, has a Jekyll personality through the well behaved pistonic lower portion of its share of the spectrum, and then a Hyde personality throughout the misbehaving breakup resonance upper portion of its share of the spectrum. So at this point we see that other mini-monitors often divide the music into four spectral portions, each speaking with a different sonic personality.
Further exacerbating this multiple split personality problem is the fact that some designers of these other mini-monitors feel obliged to compensate for the tiny system's lack of bass by rigging a heavy one note boom resonance at the bottom end of whatever the system can reach (usually in the upper bass). So now we have the music split into five different personalities, with three out of the five being obnoxious to boot. The fragmented music is framed by boomy upper bass at the bottom, and by sizzly bright mid treble at the top.
Other mini-monitors sometimes try to tame their driver problems by using complex passive crossovers, to counteract, compensate for, or mask these problems. But complex crossovers inevitably degrade system transparency, since the parts therein are imperfect, and the more parts there are, the more they will veil the music. Complex crossovers also tend to swallow up system dynamics, absorbing energy (especially from transient peaks) that should be going to the drivers instead. And complex crossovers give your power amp poorer control over the drivers of a speaker system, thereby degrading definition, articulation, and a sense of vivid liveliness that you hear from real live music.
Other mini-monitors are usually not aligned in time, so the tweeter speaks to you before the woofer. This early arrival makes the tweeter's sizzly bright breakup peak sound all the more obnoxious. It also of course harms integration, and degrades stereo imaging.
Other mini-monitors often evince additional colorations from cabinet resonances, which further color and obscure the real music that the drivers are trying to reproduce. Their cabinet panels are small in radiating area, so many designers tend to pay scant attention to bracing, stiffening, and deadening them. But these panels are still larger than the driver cone radiating area, so they can still do sonic damage relative to the driver output.
Well, given all these pitfalls that ensnare other mini-monitors, how does the Dulcet manage to be such an outstanding performer, and in so many areas? Let's start at the end, with the cabinet colorations that plague most other mini-monitors. The Dulcet starts with a rigid cabinet, and then adds Corian reinforcement panels to the enclosure's side panels. Corian is very rigid, heavy, and quite inert. You'll find Corian or similar synthetic stone materials used on some speakers selling for over $10,000. But the Dulcet costs only $1500/pr. That's downright inexpensive for any quality mini-monitor, and to find Corian employed on a speaker at such a price is amazing, testifying to the value of the product itself, and also testifying to the conscientious detailed care lavished on all aspects of the design of the Dulcet.
The Dulcet is also aligned in time, with a sloping front baffle moving the tweeter back to be in alignment with the woofer. This helps system integration, since both drivers can speak to you at the same time. This also means that the Dulcet can reproduce all transients more coherently, instead of as the splattered fragments we hear from other mini-monitors. And this also helps the Dulcet to achieve its superb stereo imaging, since to achieve the utmost in stereo imaging, the subtle sonic cues from hall reflections should be believably integrated and coherent.
Daniel Dehay, who has been the guiding spirit and designer of Reference 3a for many years, is an expert at designing drivers that are efficient and dynamic. He has outdone himself with the tiny new 4 inch woofer he designed for the Dulcet. This driver is not only dynamic, but also remarkably uncolored. Its cone employs polypropylene, already noted for being uncolored and self damping, and then has an added latex coating for further damping control of the cone breakup modes. The result is a driver that sounds incredibly neutral, and free of virtually all the vices discussed above that plague the drivers in other mini-monitors.
In fact, this woofer driver is evidently so well behaved and neutral that it does not require a complex crossover to correct its mistakes, or to tame its misbehavior, or to roll it off at the high end of its passband. Indeed, it does not require any crossover at all. This means that the woofer driver is connected directly to your power amp, without any intervening parts to degrade dynamics, transparency, or intimate control of the driver by your amp. This direct connection (allowed by the woofer driver's inherent good behavior) combines with that good behavior, to give the Dulcet its outstanding transparency, its excellent dynamics for such a small system, and its vivid sense of bringing music to life. This good driver behavior also yields better system integration, since the woofer more seamlessly reproduces its entire assigned spectral range within this two way system. And the outstanding transparency from this driver and its direct connection also further helps achieve the superb stereo imaging, since subtle imaging cues like hall ambience are revealed only by the most transparent systems.
For its tweeter, the Dulcet uses a high quality silk dome tweeter, which has a beautifully delicate, extended, airy sound when reproducing music's trebles. This tweeter's lack of hardness, and lack of any obnoxious misbehavior, means that it too reproduces its entire assigned range with one consistent voice (as opposed to tweeters that breakup into a hard or spitty sizzle for the top part of their range). This tweeter's manners perfectly complement the woofer's smooth, well behaved manners. And this completes the wonderful system integration, since both drivers are uniform in personality throughout their respective ranges, and both drivers also complement each other's manners. Thus, the Dulcet brings you music with one voice, not fragmented into five different voices as some other mini-monitors.
Because both its drivers are so well behaved, the Dulcet neutrally brings you only the music, without added spurious foreign colorations. And the Dulcet brings you more music, because its drivers are not smearing and obscuring musical information (as the misbehaving drivers in other systems do, throughout their breakup resonance regions).
Now let's look at the Dulcet's amazing upper bass, that's amazing both in extension (for such a small system) and in high definition quality. The bass system uses a vented enclosure, which certainly helps bass extension (this system is rated to 48 Hz) and power, but which often degrades bass quality in other small speakers. The Dulcet's vent is unusual, being in the shape of a long spiral tube. This long path vent might afford some damping benefits, almost like a miniature transmission line. Additionally, we suspect that the port tuning is broadband, which usually improves bass quality and bass extension, because it is a lower Q system (see IAR issue 35 for discussion).
Everyone needs a high quality mini-monitor that really brings you the music. Even those of us with larger systems crave better sound for our mini second system in our office or den. There are many competing mini-monitors on the market, some decent, many not. But the Reference 3a Dulcet is the one you want to get. And at $1500/pr it's irresistible
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