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As a trained architect practicing in India's water state of Kerala, it's not only Jacob's personal residence below which manifests a keen sense of clean modern design and décorum. His Rethm speakers, racks and recently even electronics embody the same aesthetic sensibilities.

A single-ended but hybrid version of this amp with transformer-coupled transistor outputs is also available

For the Maarga this means six color schemes. Those combine three metallic paints on the PVC piping—silver, brown or dark grey—with white or dyed ash, sycamore, eucalyptus, stained sapele or dyed carbolo for the veneered cheeks.

Amplitude controls for the on-board bass amps with selectable low-pass filter now sit directly on the foot of the enclosures, adjacent to both the power inlet and—finally conventional—speaker terminals. Floor coupling has been improved too with new metal outriggers whose couplers are adjustable from above. Rethm's signature bullnose terminations for the line-loaded widebanders have given way to heavily perforated flat metal rings for diffraction control.

The narrow but 24kg Maarga enclosure conceals a 2-meter long round cross-section line for its 6-inch rethmic widebander with foam surround and 25mm voice coil. Nested inside this labyrinth within its own 14.75l sealed chamber work two piggybacked 6.5-inch custom paper-cone woofers with equivalent 25mm coils and coated fabric surrounds. The back radiation of the second woofer disperses into the room via the diagonal reflectors. A transistor stereo amplifier delivers 110 watts into each bass driver and occupies its own chamber. Compound system sensitivity is 99dB. That's a function of the widebander. The two paralleled woofers only add to ca. 94dB. Being self-powered of course means they aren't seen by the customer's main amp where 2 watts will be sufficient for the main driver. For this speaker breed the specs get most ambitious with the F3 or -3dB down point in the bass. That's 26Hz. Hello Marcus Miller!

For larger rooms than the Maarga's recommended 40m², the Saadhana triples the woofage with the same 6.5-inchers, ups the sealed chamber dimensions to 18.4 liters, adds a 1.4-meter long bass labyrinth via a second docked enclosure, increases power drive to 210 watts and extends the claimed F3 to a mighty 18Hz. The bigger widebander grows its vc to 32mm Ø and system sensitivity attains a steep 102dB.

"The Maarga amplifier design is push/pull class AB FET. Since it only drives bass, power and control were imperative. The 'finesse' one looks for in the midrange and up for a full-range amplifier was not absolutely critical. That said, I actually heard an identical unit without low-pass filter as main amp. It is a very very good amp which we may sell domestically to customers who want a low-cost transistor amp that still performs above the usual Sony/Onkyo/NAD/Marantz level. It sonically is an overspec'd amp for the duties we are putting it to. Otherwise we did stick to basics ensuring that we deliver good clean undistorted power from 20Hz to 150Hz. We reserve our 'innovations' for the standalone power amplifiers coming out. A lot of work was done on the low-pass filter section however."

How does your driver improve over the Lowther? What did you change to eliminate the  shout - cone material, cone flare, cone thickness, surround material/profile, spider geometry, basket venting, other?

"Did we 'improve' on the Lowther mechanically and/or electrically? I don't know. All I know is that the end product is a lot better than the Lowther when it came to fulfilling my criteria. So I can probably claim that it is acoustically superior. I gave Milind Patel the parameters I wanted. After several two-way discussions he decided on voice-coil size, thickness of voice-coil  wire—which we had to change during R&D to reduce weight—and voice-coil former material (also changed during R&D). We tried  a very nice bamboo pulp paper cone. It sounded good but was a little  too heavy. We then decided to try the same paper we already used on the Trishna unit. That worked perfectly. While the 6-inch driver  fell into place a lot quicker than the 5er, it still took about 3 months of tweaking. This is where most of my contributions came in. I would look at Milind's frequency response curves, give the prototype a listen and make suggestions on what I thought we should do.

Available Maarga color combinations

"I first told him to try several whizzer cone configurations. I finally suggested we try one with a few holes. We started with a 12-hole version, tried a few iterations and ended up with a 6-hole whizzer. We also noticed verifiable differences in response smoothness by varying the shape of the phase plug. You will see that both Trishna and Maarga drivers have uniquely shaped phase plugs. This was another empirical process over several weeks. I would look at the readings, make changes to the plug profile and send the new plugs to Milind for testing. After all of us felt suitably proud of ourselves, I settled down to many days of final break-in and listening."