We are all familiar with the square, gold-colored folded tweeters in many popular studio monitors. Klaus Heinz, who founded HEDD Audio, spent decades refining the concept into the compact AMT (air motion transformer) designs familiar to studio engineers. HEDD now produces several monitor and headphone models that utilize their advanced, handmade version of this tweeter. Most recently, HEDD debuted their main reference monitor system, the Type 40. This system is unique in several ways, and I have been lucky enough to experience this monitor in a few different studios between Nashville and Los Angeles.
A main monitor is generally defined as a high-output, full-range reference speaker designed to maintain accuracy at the high SPLs required in medium- to large-sized control rooms. Traditionally, mains are soffit-mounted into the front wall or placed several meters from the listening position. However, modern studios have become increasingly reliant on nearfield and midfield monitors, largely for two reasons. First, their cost is considerably lower than high-quality mains, and second, many project studios and small mix rooms are too small or lack adequate acoustic treatment for far-field main systems, which take up a lot of space, require a minimum listening distance of two to three meters, and place greater demands on room acoustics.
A large part of my professional work is installing and tuning monitor systems for studios large and small, so I’ve listened critically to monitors in hundreds of studios, dub stages, and high-end listening rooms over the past two decades. In my experience, many main systems aren't what I would call “reference quality.” They're powerful and loud, meant more to impress clients and provide “vibe” during writing and tracking sessions than for critical mix decisions. Many mixers and mastering engineers I know spend more time working on their trusted nearfields and midfields, which work well in smaller rooms and rooms with less-than-ideal acoustic treatment. However, even these “modest” speakers have rocketed in price, up to the thousands or tens of thousands of dollars. The Type 40 approaches the idea of a studio main somewhat differently. It’s a compact, full-range monitor that can work in small and mid-sized studios, but it can expand for larger stereo and immersive rooms. It also incorporates several features uncommon among studio mains. Obviously, HEDD used their AMT tweeter and included their Lineariser control, but a few more features bear mentioning. They can be configured a few ways, with the simplest being a single Type 40 per channel. Each can be expanded by adding up to three Type 40 XTD subwoofers per main speaker. The main alone is a full-range reference monitor, but the system can grow as budget, room size, or SPL requirements increase. The XTDs can also be configured as a cardioid low-frequency array, which helps reduce room interactions and improve bass definition. The Type 40s are referred to as compact mains due to their size of roughly 18 x 16 x 14 inches. The XTD subs are the same size and typically mount just below the mains in a stacked configuration. My review system did not include the XTDs, though I have listened to a Type 40 system that included one XTD per side.
Unlike most high-output mains, the Type 40 uses a sealed enclosure, with its deep bass extension coming from a long-throw 10.75-inch woofer. The sealed alignment eliminates port noise and resonances and provides controlled bass with a predictable low-frequency rolloff, while HEDD's electronics extend the system to below 20 Hz. The onboard Lineariser processing corrects the system’s phase response for critical listening, and now has two settings; one with alignment of both amplitude and phase and the other with alignment of only amplitude.
The speaker features a vertical D’Appolito configuration of two four-inch midrange drivers flanking HEDD’s latest-generation AMT high-frequency driver. This arrangement provides a wide sweet spot, reduced early reflections from the ceiling and desk, greater midrange efficiency, and a stable, well-defined acoustic center. These 1,300-watt-per-channel monitors provide the same sophisticated control as HEDD’s MKII speaker range, and can be controlled via the CTRL app on an Ethernet network to adjust a 12-band parametric EQ, sleep modes, low-frequency extension, and more. All this can be controlled from the listening position using a Mac or PC.
The most important controls, like Gain, Sensitivity, Bass Extension, High- and Low-Frequency shelving filters, desk-reflection filters, and Lineariser mode, are available via knobs on each speaker’s rear panel. This can be convenient for those who don’t wish to set up the monitors via the CTRL app, but I highly recommend taking advantage of CTRL's power and flexibility.
All told, this system is meant to compete with the top-tier main studio monitors and also support smaller setups and even immersive rooms that require full-range, high-power monitors for all channels. We have HEDD Type 20 [Tape Op #153] and Type 30 [#118] nearfield monitors in our rooms at Chalice Recording, so I was excited to hear the Type 40s in my own environment. I had previously installed a pair of Type 40s with one XTD per side in the large, 1,500-square-foot control room at South x Sea Studios in Nashville. The system sounded as full and powerful as the previous Augspurger mains system in that room.
My mix room is typical of today’s private studios at about 240 square feet. I sit about six feet from my monitors, and I have always used 10- or 12-inch two-way mains for mixing and mastering, often with one or two subs for full bass extension. The three-way Type 40s easily slid into position where my previous two-way mains sat, and I connected both speakers and my computer to an inexpensive Ethernet switch to run the CTRL software. Despite being classified as mains, the speakers felt like the right size in my room.
I spent some time dialing in the physical position of the monitors and my Sound Anchor stands and wound up setting them slightly wider than my previous speakers, with ear height at the tweeters. These monitors focused well at my midfield position, and I used the onboard PEQ to make three tiny EQ changes – each less than 0.4 dB, mainly to soften the highs at my close listening position. The low-frequency extension is impressive. The Type 40 reaches 20 Hz at just -3 dB and can produce greater than 108 dB SPL at 50 Hz with just the mains. Adding the XTDs can push maximum system SPL beyond 120 dB SPL.
The morning after I set up the speakers, I had a mastering session for a jazz album that I had recently mixed. The client and I sat together and sequenced the album, touching up EQ and level differences between the tracks. Not once did I question what I was hearing. The speakers sound extremely detailed and musical, and the stereo imaging is exceptionally precise. Music spreads evenly across – and slightly beyond – the physical locations of the speakers. Transient clarity is startling. There is no question about how much point or click a kick drum has, and cymbals and other transient-rich material are exceptionally clear… not hyped, but crystal clear. It's also remarkably easy to hear digital clicks and pops – the bane of modern mastering engineers.
I also mastered some pop-rock tracks and mixed an indie-folk record on the Type 40s, using my regular headphones as a reference, and I was never surprised by decisions I had made on the speakers. After more than three years sitting in the same room in front of the same monitors, I changed monitors and was working comfortably within a few hours. The ability to use the CTRL software to fine-tune the speakers while sitting at the mix position is something I don’t ever want to lose.
The Type 40s sound powerful but controlled, never even breaking a sweat, with tight, deep, punchy bass, a smooth midrange, exceptional transient clarity, and a broad, stable sweet spot. In a small or medium-sized room, I can't imagine needing a subwoofer simply for bass extension, which is a plus for ease of integration and use of space. At only 16 inches deep, with a wider-than-tall profile and non-reflective black satin finish, the Type 40s don't visually draw attention. Sonically, they perform a similar disappearing act: the sound seems to come from the front of the room rather than from two boxes.
The Type 40 Mains occupy a unique place among main monitors. They’re compact enough to work at midfield distances in a private mix room, powerful and full-range enough to serve as a true main, and expandable with the XTD system for much larger stereo or immersive installations. I expected changing speakers to require a substantial adjustment period. Instead, I was making mix and mastering decisions without thinking about the monitors at all. For me, that's about the highest compliment I can give a reference monitor.