MartinLogan Brings Back High-End Depth 212 & Depth 215 Subwoofers

Fresh off the heels of relaunching their Grotto subwoofers, MartinLogan has recently brought back their classic Depth subwoofer line, but, like the Grotto subs, these are a major step up from the class of their namesake lineage. That is a big deal since the original Depth subs were MartinLogan’s top dog subwoofer in their time, so to follow that product line, these new subs need to be serious. From what we can see, they definitely look serious; both new Depth subs boast a lot more cone surface area and far more power.

The Depth subwoofer name hasn’t been used by MartinLogan since the “Depth i” sub released back in 2007. That followed the original Depth sub, which was released in 2003. Those subs used three 8” drivers arranged in a triangular opposed mounting configuration, which cancelled cabinet vibrations. Amplifier power rating was 300 watts for the first Depth sub and 350 watts for the Depth i. These new Depth subs are a massive step up. The new subs are called the Depth 212 and Depth 215. The 212 uses two 12” drivers mounted in opposite-facing directions and is powered by a 1.1kW RMS amplifier, and the Depth 215 uses two 15” drivers in opposite-facing directions and is powered by a 2.2kW RMS amplifier. That is a tremendous amount of power as well as cone area, so these subs should pack a mighty punch.

Those who have followed MartinLogan’s subwoofers will note that the new Depth architectures are a lot more like the ‘BalancedForce’ subwoofers that MartinLogan is replacing. It looks to me like since MartinLogan brought back the Abyss line and the Grotto line, why not bring back the Depth name too? All of these subs were contemporaries in their time, so MartinLogan is creating a subwoofer renaissance by not only bringing these lines back but also expanding them with much more powerful versions.

MartinLogan Depth Improvements

The new Depth subs are a lot more than just an amplifier and a couple of drivers in a box. They use MartinLogan’s most sophisticated DSP to control the performance: a 500MHz, 64-bit signal processor that monitors performance in real time and allows users a host of customizations to suit personal preference. Users can access the subs' controls via MartinLogan’s subwoofer control app, but unlike MartinLogan’s other subs, they can also access all of those controls on the subwoofer itself from a touch control LED screen mounted on the front of the sub. The interface can be hidden by a plate for a cleaner appearance. That is a very nice touch and befitting of a premium sub.

As with MartinLogan’s newer subs, the Depth subwoofers support the ARC auto-equalization system that we at Audioholics have had success with in the past. Unlike other MartinLogan subs, the Depth subs include the microphone calibration kit needed to run the calibration routine, so no additional pieces need to be purchased. This makes the Depth subs a great solution for high-end 2-channel systems that have minimal processing, such as simpler setups that use integrated amps.

Another feature where MartinLogan goes all out on is connectivity. Many of MartinLogan’s other subs have RCA inputs and speaker-level inputs, but the Depth has left and right XLR inputs as well as an RCA output. It also has wireless connectivity and comes with a transmitter, so no additional pieces are required to get that going either. The Depth subs are ready to be connected to any system, no adapter needed.

Aside from the sophisticated feature set, the Depth subs are also built and designed to a very high level of quality. The driver cones are made from Carbon Aerocore, a triple-layer of Carbon Fiber, PMI Structural Foam, and Fiberglass, which has a strength-to-weight ratio. That should help increase system sensitivity and optimize cone control. The driver has a lot of venting to reduce thermal compression effects. Venting happens under the spider, through the voice coil, and through the pole piece. The driver also has dual copper shorting rings to help mitigate the effects of induction, which will increase the bandwidth, linearize the response, and reduce distortion. Many drivers use aluminum for this task since it’s cheaper than copper, but copper works better.

The enclosure is built to a high standard using 1” to 3” of paneling. This can be seen in the weight of the units: 127 lbs for the Depth 212 and a staggering 173 lbs for the Depth 215. These things will have the solidity of true luxury products. The dual-opposed mounting of the drivers also helps here since the momentum of the moving mass of each driver will cancel out the other in this configuration. The cabinet should be extremely inert for this reason, and the drivers themselves will not contribute any rocking motion. What little cabinet resonance that will be left should be taken care of by the anti-vibration feet, which should damp any vibration transfer going to the floor. 

The enclosure uses clever design cues, such as the aluminum heatsinks integrated in the aesthetics of the cabinet, so one might not even realize they are functional elements. Speaking of aesthetics, the Depth subs are very nice looking as large subwoofers go. The shape and curved edges of the cabinet give the Depth subs a heightened sense of style relative to most subs - even high-end ones. Subwoofers are essentially just drivers mounted in a box, but the Depth subs get away from that and take on a more interesting geometry. This should help offset their larger size in the ‘spousal approval factor,’ so a large sub might be more palatable for your significant other when it looks as nice as the Depth subs do.  

MartinLogan’s Depth subs have it all: good looks, cutting-edge feature set, high build quality, and potentially outrageous performance. However, a package like that doesn’t come cheap. The Depth 212 clocks in at $5.5k, and the 215 will set you back by $7k. That is a lot of dough, but these are a lot of sub.  We hope to hear them in person to give you a full report, so stay tuned to Audioholics to learn more about these killer new subwoofers from MartinLogan.

Unless otherwise indicated, this is a preview article for the featured product. A formal review may or may not follow in the future.