Hafler TRM6 Active Close Field Monitors and TRM 10S Active Subwoofer

Without a doubt, Hafler has come up with a premier monitoring system. One part of the system is the TRM6 (Trans-ana Reference Monitor), a biamplified, two-way close field speaker. The other part of the system is the TRM10S, an amplified 10" vented subwoofer.
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Without a doubt, Hafler has come up with a premier monitoring system. One part of the system is the TRM6 (Trans-ana Reference Monitor), a biamplified, two-way close field speaker. The other part of the system is the TRM10S, an amplified 10" vented subwoofer. Either can be purchased separately or can be set up together as a sub/satellite system. They are recommended for pro studios, digital workstations, broadcast booths and home project studios.
Product PointsApplications: Pro studios; digital workstations; broadcast booths; project studios

Key Features: TRM6: ported 6.5" woofer; 1" soft dome; magnetically shielded. TRM10S: powered; 10" ported woofer; 200 W Class G amp

Price: TRM6: $1,250/pair with a 1-year warranty; TRM10S: $695; TRM12S: $795.

Contact: Hafler at 602-967-3565


+ Accurate, musical sound

+ Deep clean bass from subwoofer

+ Very sharp imaging

+ Very fine detail

+ Adjustable response


- None

The Score: Great-sounding and versatile monitor/subwoofer system is also a good value.

TRM6 Monitor

Each two-way system uses a ported 6.5" woofer with a mica-filled polypropylene cone and an inverted nitrile rubber surround. The tweeter is a ferrofluid-cooled, 1" soft dome unit by Vifa, mounted in a proprietary waveguide. According to Hafler, "A phase lens and axis-symmetric exponential waveguide improve the transition of sound waves from planar to spherical, which results in excellent high-frequency dispersion and coherent on-axis frequency response." Both drivers are magnetically shielded. Crossover is at 3.2 kHz, 24 dB/octave Linkwitz-Riley.

Built into each speaker are two MOSFET power amplifiers. A 50 W continuous amp drives the woofer, while a 35 W amp drives the tweeter. Hafler claims that MOSFETs have several advantages over bipolar transistors: better thermal stability, faster switching speed, lower output impedance and better linearity.

The amplifiers use a system called Maximum Efficiency Heat Sink Application (MEHSA), which is claimed to give up to five times more heat dissipation than standard FET mounting techniques. Hafler's Transðana output configuration provides voltage and current gain at the outputs, requiring fewer gain stages in the amplifier front-end. A front-mounted power switch turns on the amps, and an LED indicates power, clipping, or thermal overload.

Measuring 13.3" high, 8.9" wide and 11.5" deep, the cabinet is solid as a rock and a heavy 23 lb. Cabinet walls are made of 19mm thick MDF lined with damping material. The rear port is a radiused Aerovent, which reduces turbulence. A rubber pad on the bottom controls vibration. The woofer section is stepped out in front of the tweeter section in order to time align the two drivers.

Connectors and a wide variety of DIP switches are located on the rear panel. Inputs are XLR or RCA. One DIP switch sets the input for balanced or unbalanced. Others set the input sensitivity, bass rolloff, bass shelving (up to +/-4 dB), and treble shelving (up to +/-4 dB). There's also a 12 dB/octave subsonic filter which can be set to 30 or 60 Hz. This filter can be used in conjunction with the sub's low pass filter to create a sub/sat system.

Hafler specs the TRM6 frequency response as 55 Hz to 21 kHz +/-2 dB. Peak acoustic output is said to be 119 dB per pair with music at 1 meter. Claimed total harmonic distortion is less than 0.5 percent from 150 Hz to 21 kHz at 90 dB SPL, 1 meter. Input sensitivity is -11 to +4 dBu, and S/N is greater than 100 dB.

TRM10S Subwoofer

Hafler's TRM10S is a powered sub with a 10" ported woofer. (A 12" model, the TRM12S, which goes down to 25 Hz and puts out 115 dB SPL peak, is also available.) The woofer cone is made of cellulose fiber with a Santoprene rubber surround. This driver features a hefty 2" four-layer voice coil on an aluminum former for better heat dissipation.

Damping from the Santoprene surround improves the woofer's low-frequency response. The sub weighs 53 lb and measures 14.75" high, 16" wide and 16" deep.

Built into the cabinet is a 200 W Class G amplifier similar to the MOSFET amp in the satellites. Input sensitivity is adjustable from 160 mV to 5 V unbalanced, or 80 mV to 2.5 V balanced. Thanks to an auto turn-on/sleep mode, the amp turns on when it senses an input signal, and turns off, or sleeps, when the signal is turned off. An LED indicates power-on or sleep mode.

On the sub's rear panel are two balanced XLR inputs (left and right channels), two unbalanced RCA inputs, a gain control with 30 dB range, and a 24 dB/octave low pass filter (variable from 40 Hz to 140 Hz). For flattest system response, the sub low pass should be set to the same crossover frequency as the satellite high pass.

Also on the rear is a 24 dB/octave Linkwitz/Riley low-pass crossover adjustable from 40 Hz to 110 Hz. A phase control (with 90, 180 and 270 degrees phase shift) acoustically aligns the sub with the satellites.

Claimed frequency response is 27 Hz to 110 Hz +/-2 dB. Peak output is said to be 112 dB with music at 2 meters.

The clear and thorough user manuals cover specs, tech features, placement and operation. Unlike most manuals, the Hafler manuals include schematics, block diagrams, component layouts, a parts list and servicing information.

In use

To wire the satellites and sub, I split my mixer's left monitor output to the left satellite and one sub input. Same for the right channel.

I placed the TRM6 monitors as recommended, about 8" from the wall behind them, toed in and oriented vertically. They were 3' apart and 3' from me, on stands behind the console. I raised the midpoint of the speaker to ear height as suggested to get the flattest response. Finally, I adjusted the bass and treble shelving for best sound. In my control room the preferred settings were -4 dB bass shelving and flat high end.

The TRM10S subwoofer was placed under my mixing console, firing downward, several feet from any walls. I set its input sensitivity and low-pass frequency for the best match to the satellites. Here are my impressions of the Hafler system reproducing various instruments:

Piano: Realistic, very low coloration. I can sense the material of which the piano is made; the wood, strings and felt. It's easy to hear changes in timbre vs. key pressure.

Acoustic guitar: Delicate and detailed. Again, there's a sense of the wooden guitar body and metal strings.

Vocal: Smooth, uncolored, not too sibilant. Vocals sound human rather than electronic.

Drums: Natural amount of crispness and impact.

Cymbals: Really sweet. Some of the best I've heard. Flat, extended highs. Gentle on the ears, but not weak in level.

Percussion: Also sweet, not sizzly or harsh. Clean and clear. Well-balanced with other instruments.

Sax: Excellent balance of warmth and breathy edge. Less edginess than most other speakers.

Bass: Very deep and weighty. Clean. Uniform note loudness. A bass drum roll has awesome power.

Electric guitar: Neither puffy nor thin. Lots of bite.

Orchestra: Natural timbres. Realistic and palpable. Transparent.

My own mixes: The Haflers give an entirely new perspective on my mixes. Some of them sound better than when I mixed them - more realistic. Others sound worse - too much bottom in the kick, harsh mids in the snare. This shows that the Hafler system does not add a euphonic coloration to all program material.

Overall, the Hafler system has a smooth, organic, seamless quality. Very musical speakers. I've heard this same sense of wholeness in only a few other superb monitors, such as the Westlake close fields. I like the Haflers' open midrange, which makes many other monitors sound closed-in by comparison. The Haflers sound transparent, with ultrasharp imaging, a good sense of depth, and low fatigue.

The subwoofer's lows are well integrated with the rest of the system. When I turned off the sub and listened only to the TRM6 pair, the sound was basically the same except that the deep lows lost some weight. The bass still was at a good level relative to the rest of the spectrum. It was usable for making mixing decisions. I thought that the TRM6 monitors sounded great by themselves.


The Hafler TRM6 monitors and TRM10S subwoofer form a system that sounds both accurate and musical. In every aspect - transparency, imaging, tonality, distortion - it is in the upper echelon of monitors. Hafler has skillfully engineered a group of speakers that are well worth your attention.