The Esotec System 362 that was delivered to my lab is a 3-way speaker system with passive crossover networks. The system is comprised of a pair of MD 102 tweeters, a pair of MD-142 midrange drivers, a pair of MW172 woofers and a set of X362 crossover networks. I’ll tell you up front, the Esotec System 362 isn’t for the faint of heart in any respect, be it medical or otherwise.

Dynaudio is not shy about their products. Their offerings include a full line of automotive speaker systems, professional speakers systems and some stunning home speakers reaching an impressive climax with their Evidence Master tower speaker set. Just a heads up, the next-step-down Evidence Temptation speaker set is priced at $30,000 USD. The Masters are reported to chime in at $85,000USD. Hmm.. speakers or a Nissan GT-R?

Design
Enough of my rambling, drooling and random sketches of new door panels for my new STi – we need to check these things out. We’ll start with the 1.1-inch MD 102 soft dome tweeter. The tweeter features a coated textile dome that is built specifically for this driver. A neodymium magnet powers the driver, providing a dense magnetic field for the 1.1-inch voice coil. The tweeters also feature a small sealed air chamber behind the driver that is acoustically damped to prevent reflections that could colour the sound. Finally, the voice coil assembly operates in a bath of Ferrofluid. Ferrofluid is a magnetically and thermally conductive liquid that is used to help wick heat away from the voice coil, as well as damp resonances. The result is a very smooth impedance curve. Emilios Mandalios of Dynaudio USA explained that due to the low mass of the moving parts given their larger than average size allows for extended frequency response and excellent response characteristic. Emilios said that the tweeter can handle a dynamic signal of 500W with no compression – that’s very cool! 

The tweeter mounts in a 2.05-inch round cutout and there are large spade connectors on the back via which you make your electrical connections. A threaded 1/2-inch stud protrudes from the rear of the tweeter for mounting purposes. A permanently installed tough domed metal grill keeps foreign objects away from the delicate dome.

Up next are the MD-142 4-inch soft-dome midrange drivers. To the untrained eye, these look like Godzilla-sized tweeters – and in reality, the concept is quite similar. The MD-142s are a sealed back 3-inch midrange driver. The drivers are powered by a dual-magnet motor to optimize efficiency and dynamic capabilities. The cone is a proprietary coated silk and so is the surround. Emilios points out the surround is phase correct to the cone. What does that mean? Since the surround is a moving part, sound will be created by it. The engineers have worked to ensure that this ‘surround sound’ (excuse the pun) adds to the performance of the driver.

The driver is housed in an aluminum housing and it features an integrated mesh grill that protrudes almost an inch. Electrical connections are made via small terminals that are riveted to the side of the housing. You will need to modify your cutout to accommodate these connections.

Next to last are the impressive MSP MW-172 woofers. These are considered 8-inch woofers, and have an outside diameter of 7-7/8-inches. While we are at it, the mounting depth is a hair over 3 inches. The cone and speaker are classic Dynaudio – if you have seen their products before, then these are instantly recognizable. The basket is precision die-cast from aluminum and has a minimalist design with six narrow spokes. There are basically three discs – one for the surround, one for the spider and one at the bottom to which the motor assembly mounts – other than there, there is almost nothing that could cause sound wave reflections. Dynaudio calls this an aerodynamically designed basket, but it is also very rigid and designed not to resonate.

Inside the basket is a vacuum formed cone assembly made from a magnesium silicate polymer for a good balance of damping and strength. The moving assembly doesn’t use a separate cone and dust cap – just a single unit. The result is minimal phase lag and excellent off-axis response. It also minimizes cone resonances, so the impedance curve is once again relatively flat and easy for an amplifier to drive. The MW-172 uses a styrene butadiene rubber surround that is bonded to the cone via a proprietary thermal coupling process. The spider is designed to offer a change in compliance based on excursion for a balance of good dynamics and cone control at high excursion levels. The spider has a diameter of just less than six inches.

The voice coil former is 3-inches in diameter and made from heat treated aluminum. Wrapped around the former are two layers of Dynaudio-proprietary Hexagonal aluminum wire. This allows the wire to nestle closer to the adjacent layer for a tighter winding and stronger magnetic field. The voice coil assembly is coated with a thermoplastic to form a solid mass that helps prevent warping that can occur with conventional designs.

The motor assembly is quite unique on this woofer. Dual high density ferrite magnets are located inside the voice coil winding. A large mesh-protected vent allows air to escape from the inside of the motor structure. The bottom plate actually wraps around the outside of the voice coil and extends up to the top plate. The area outside of this cup and beneath the spider is protected by a half-torus (donut) shaped cloth shroud.

Last but certainly not least are the X362 passive crossover networks. These networks are housed in a fairly conventional ABS plastic enclosure with cooling vents along the top edge. The networks are relatively large with a foot print of roughly 7 by 4 inches. Electrical connections are made via a 10 position gold plated barrier strip. The network design is unique, but undoubtedly was designed based on extensive listening. Attention to detail includes the use of glue to secure the components to the circuit board and a foam spacer between the circuit board and the rear portion of the housing. On one of the networks, the large inductor was a little loose, but nothing an extra shot of glue couldn’t fix.

The tweeter is filtered at 3,500Hz at a 12dB/Octave slope. The midrange is filtered on the bottom at 900Hz and 3,500Hz on the top, both at 6dB/Oct. Finally, the woofer is filtered at 900Hz at 6dB/Oct. All of the components in the network are of excellent quality. The inductors are air core and are mounted perpendicularly to the next adjacent inductor to resist the interaction of their magnetic fields. Two of the capacitors are polypropylene and one is electrolytic. Finally, there are several non-inductive wire wound resistors for various purposes. The midrange and tweeter both have output level adjustments. You can adjust either +2dB or -2dB by simply moving the location of the positive terminal to one of three positions. This gives your installation lots of tuning capability.

I’ll throw in a personal note / suggestion. Passive crossover networks are, even when they are very simple designs, valuable tuning tools. The networks should (must) be mounted inside the vehicle in an easily accessible location. Networks should not be mounted in the door panels as I hear they are so often. Just thought I’d throw that in.

Testing
I started by unpacking the drivers and setting them up for photography. More fantasies about door panels and kick panels filled my head again. But I digress. Once the picture taking was complete, it was time for the driver break-in procedure. I let the woofers break in for 10 hours with a 6.5V 20Hz sine wave. The midrange drivers and tweeters were fed pink noise for 9 hours (while I was work the next day). I used the passive networks when breaking things in, just to ensure everything was ‘comfortable’ before I got started.

I took an impedance and phase sweep of the tweeter and midrange – you can see those graphs as figures 1 and 2. The resonant frequencies were 1,500Hz and 585Hz respectively. Next I took a set of Thiele-Small parameters from the woofers. Figure 3 shows the impedance and phase plot while Figure 4 shows the T-S information. I use a 3 cubic foot sealed enclosure for my testing, as this represents the volume of the average car door quite well.

Figure 4 – Small Signal Thiele-Small Parameters
Fs = 47.9056 Hz
Revc = 3.0252 Ohms
Qes = 0.7125
Qms = 2.944
Qts = 0.5737
Le = 0.3470 mH  (at 1 kHz)
Vas = 25.3667 L   (0.8958 ft^3)
BL = 4.9384 N/A
Mms = 19.0839 g
Efficiency = 0.3773 %
Sensitivity = 87.7669 dB @1W/1m
Sensitivity = 91.9902 dB @2.83Vrms/1m 

I then loaded this information into BassBox Pro 6 and did some enclosure simulations. In my test enclosures which are similar to the average door panel in volume, the predicted F3 was 71.3Hz with a Qtc of 0.553. Just in case you plan on building an enclosure for the driver, a mere 0.6 cubic feet of net air space only raises the F3 to 71.82Hz and the Qtc to 0.707. Just for comparison purposes. The output predicted difference in output at 50Hz between the two enclosures is a mere 1.5dB. Basically, you are welcome to leave these drivers in a relatively infinite baffle configuration. You are only going to need an enclosure if you want to run them hard and/or really deep.

Listening
I installed the woofers in the enclosure with a custom panel that also has room for the midrange and tweeter mounted directly above to keep everything operating on the same plane. Thanks to Mike at DeClara at Hammerhill Sound Ssytems for the new panel – I need to get my own CNC machine! I fed the set from my Clarion DRZ9255 source unit and Arc Audio 2150SE amplifier. I connected the midrange and tweeters to their 0dB setting for the listening. 

As is usually the case here in my lab, the Focal Demonstration Disc 1 was loaded into the player and the system brought to life. I didn’t really focus on the listening at first, wanting simply to make sure that all the drivers were wired acoustically in phase. After letting the disc run through from start to finish, I decided to throw in Holly Cole’s Don’t Smoke in Bed CD just to be different.

First instincts are usually amongst the most important, and with the Esotec set, the first thing I noticed was clarity. Every syllable of every word clearly defined. The piano strings were very clear, including the low notes. Good quality speakers reproduce music as though the instruments were in the room with you and the Esotec 362 set was immediately delivering.

In terms of tonal balance, these are not laid back speakers like my reference LSi9 bookshelves. There is of course nothing at all wrong with that – the balance is very accurate and realistic.

I switched over to Focal Disc 6 (Yes, I do have all of them, why would you even ask?). What was impressively revealing was ‘I Want You’ by Marvin Gaye. The multitude of different voices was all clearly defined and easily discernable from one-another. Clarity and definition continue to be one of the key defining traits of this speaker set.

I was about to write that although this set includes an 8-inch woofer, they don’t play as low as I thought they might. That was until track 11, Audun Kleive’s ‘Never Thought I Would’ began playing. No, the bass didn’t shake me out of my chair or knock things off shelves, but compared to every other set of speakers I’ve had in these enclosure, they got down there are reproduced the funky synthesized bass line solidly. Now, imagine these integrated into the doors of your 6-speed Subaru. The transfer function, combined with the already good extension might almost negate the need for a sub in all but the most enthusiast tracks.

Listening to speakers designed specifically for a mobile application in a lab isn’t always a fair test. How so? Car speakers require different off-axis response characteristics as compared to home audio speakers. That being said, these speakers produced a rock solid image.

Conclusion
I remember the first time I installed a high-end amplifier in my second car. I sat in the garage (engine off) until 2 in the morning listening to all my favourite tracks again – for the first time. I could hear instruments I had never heard before and subtleties of the arrangements like it was the first time. Now, I have had some excellent speakers in the lab over the years, so the experience wasn’t quite as dramatic, but it was immediately reminiscent. 

Why a 3-way set? The answer is detail and clarity. Off-loading the all-important vocals to a high-quality dedicated driver means that they can be reproduced more accurately, while allowing the woofer to go lower without messing up the midrange. In the case of the Esotec 362 set, more speakers is definitely a good thing.

I usually wrap up my reviews with a simple comment about rushing off to your nearest authorized dealer for an audition, but that’s not what Dynaudio or the Esotec 362’s are all about. First you need to check your situation – is your car up to have these speakers integrated into them? You will want custom doors built and either kick panels or A-pillars modified to house the midrange and tweeter. Is the rest of your equipment up to the challenge? And last but not least, can you afford it? The answer to all these is that if you put it all together properly, you are in for a fantastic musical experience, well worth the effort.