In Summary

Most engineers understand that quality of their loudspeaker monitoring is only half the story. With a number of options now available to help engineers actually remove the effects of the room itself, here we take a look at some options for speaker calibration in 2024.

Going Deeper

With software technology providing an embarrassment of riches when it comes to the music-making and mixing tools at our disposal, a major hurdle most of us still face in getting our mixes sounding their best is the physical space in which we make them. The compromised acoustics of the average home or project studio has always necessitated acceptance of the fact that what you’re hearing out of your monitors isn’t necessarily true to what’s going into them.

In recent years, however, that disheartening situation has started to change. Thanks to the rise of accessible speaker calibration systems, it really is now possible, to some extent, to counterbalance the dodgy interactions between your speakers and your room using any of a range of software or hardware-based solutions.

What Is Speaker Calibration And How Can It Help Improve The Quality Of My Mixes?

Any loudspeaker in a room will sound different to how it would in a perfectly anechoic space, due to the inevitable effect of reflections and room modes. This can make it difficult to accurately hear and appraise the true sound and nature of your output, resulting in mixes that might, for example, sound great in the studio but be either lacking in or overloaded with bass when played back through other systems.

Purpose-built recording studios and mixing rooms are designed to control such issues as much as possible through carefully considered construction and thorough acoustic treatment, but getting anywhere near the optimum response in the home or project studio can be tricky to say the least. And that’s where speaker calibration comes in. While, of course, it’s not possible to rewrite the laws of physics where room modes are concerned, today’s calibration systems can at least bend the rules significantly to help us get a flatter, more trustworthy response from our studio monitors.

How Does Speaker Calibration Work?

Speaker calibration systems differ in implementation, but one thing they all have in common is the requirement of a point of reference on which to base the all-important room analysis at the heart of the matter. In all cases, a series of sine wave sweeps is played through the speakers and captured via a measurement microphone placed at the listening position to build a snapshot of monitor performance. The resulting profile is compared to a predetermined target profile (a flat response, say, or that of a particular listening environment) to generate an EQ curve that compensates for tonal issues within each monitor channel, and also works to correct the phase relationship between them, thus improving stereo imaging.

What Forms Of Speaker Calibration Are There For Me To Choose From For My Studio?

Although all speaker calibration systems aim to achieve the same thing – improving the accuracy of your monitors by adapting their response to fit the specifics of the room – the technology comes in a variety of different types, from software-only systems, to dedicated outboard and monitor-integrated DSPs. Let’s take a tour…

Software Speaker Calibration

IK Multimedia ARC 4

Landing as an audio plugin that sits across your DAW master, ARC 4 uses a brand-new and “more natural” analysis and correction algorithm compared to previous generations.. IK’s VRM (Volumetric Response Modeling) tech creates a 3D snapshot of the room, identifying the speakers’ response in the space by measuring at several positions around the listening position,

Options for either rapid 7 point measurement or 21 point measurements are available. The longer measurement is suitable for fixed installations and permanent setups, while the shorter measurement is ideal for on-the-go or ad-hoc setups, making it possible to measure the room in minutes.

IK Multimedia claim an “incredibly natural-sounding correction” with ARC 4, which also serves as the place where profiles for ARC Studio hardware correction can be managed and switched.

Key Features And Benefits:

• New analysis app with simplified measurement process.

• Real time spectrum analyzer shows pre-corrected signal.

• 2 phase modes ensure optimum phase coherency.

• PEAK, RMS, LUFS and DR metering at a glance.

• 3D room analysis delivers more accurate, natural sound.

• Improved support for multiple listening setups.

• With 20+ iconic studio monitor profiles to A/B test mixes.

• Dramatically reduce the impact of room acoustics.

• Works with ARC mic or any RTA (measurement) mic.

• Re-sizeable, retina display GUI to fit your workflow.

Sonarworks SoundID Reference

As one of the longer-established software solutions, SoundID Reference is both a standalone app and a DAW plugin. This calibrates both speakers and headphones to deliver what Sonarworks call an “accurate studio reference sound”. With a wide range of intended users, it has been developed for audio engineers, producers, musicians, DJs, composers, sound designers, game developers, and audiophiles.

SoundID Reference also sets out to provide perfect translation across a whole range of real world devices, meaning that even listeners using phones, laptops, or earbuds will hear the mix as intended by the engineer.

One of SoundID Reference’s strengths is the standalone app that handles system-wide audio. Simply by placing the correction downstream of the DAW, users can have all audio hit SoundID Reference including system sound and other apps’ audio.

Key Features And Benefits:

• Accurate speaker measurements and calibration for headphones and stereo or multichannel setups. Over 500+ supported headphone models.

• Software supports speaker setups from stereo, to 5.1. and up to 9.1.6. Atmos rooms.

• Control room favourites such as Mono, Mute, and Left/Right swap.

• Simulate a wide range of listening environments, from a car stereo to a high-end hi-fi system.

• Make custom adjustments to the target curve in real time and manually select the frequency range that the calibration will be applied to.

• Various target modes - select flat to set the frequency response target to be neutral across all frequencies, create your presets or work on Dolby Atmos music target curve.

Genelec GLM Correction System

Moving into deeper territory, Genelec’s GLM (Genelec Loudspeaker Manager) is the company’s room measurement and speaker calibration software. This is designed to work in concert with Genelec’s Smart Active Monitors (SAM) to offer a completely integrated solution from measurement mic to loudspeaker. GLM goes further still by helping you assess physical studio improvements with its unique GRADE Room Acoustic Reports, which include the ability to optimise bass management for compliance with ITU-R BS.1116 recommendations.

GLM integrates with the advanced internal DSP circuitry of Genelec’s SAM Monitors and subwoofers, and GLM 5 software allows you to comprehensively manage monitor behaviour. The initial stage of calibration sees a GLM controller devices analyse the acoustic environment using included reference microphone and GLM interface. The AutoCal 2 algorithm of GLM 5 then optimises each monitor for level, distance delay, subwoofer crossover phase and room response equalisation providing a flat frequency response and neutral listening experience as a base.

Monitor control can come from any MIDI-enabled device, however GLM 5 software requires a GLM controller device to network, calibrate and control Smart Active Monitors. The 9320A SAM Reference Controller provides tactile control of key GLM functionality itself and comprehensive additional monitoring connectivity and alignment.

Key Features And Benefits:

• Automatically adjust in-room frequency response, distance delay and listening level.

• Create and expand systems to suit all types of stereo, multichannel or 3D immersive audio formats.

• Sample room responses in an unlimited number of microphone locations.

• Create a complete analysis of your room and SAM Monitoring system performance in line with best practices, including ITU-R BS.1116 recommendations.

• See in-depth room and system measurements, including frequency response accuracy, early vs late sound at the listening position, time of flight accuracy and early reflection structure.

• Guide decision making for improvements to acoustic treatment, system positioning and bass management.

• Make simple improvements to your listening setup based on accessible and intuitive acoustical advice included in the report.

Hardware Outboard Speaker Calibration

MiniDSP Dirac DDRC-88D

Started back 2009, miniDSP is a technology company focusing on DSP-based systems for audio that prides itself on its ‘agile’ product development philosophy and in-house IP.

The DDRC-88D is the digital I/O version of the now discontinued DDRC-88A. The optional DDRC-88BM software add-on brings additional processing functions including bass management and active speaker implementation. The UMIK-1 calibrated measurement microphone is included in the box.

Dirac Live also corrects the system’s impulse response, which reflects how it responds to sharp transients, such as drums. Reflections, diffraction, resonances, misaligned drivers, etc, combine to smear transients, but this correction makes the real speaker in the room behave much more like the ideal model.

Contrasting with the minimum-phase and linear-phase filters commonly found in audio applications, Dirac Live deploys an analysis algorithm designed to create the optimal correction across the whole listening area, not just at a single point. This is accomplished using mixed-phase filters, which match a desired frequency response and generate a customised impulse response.

You can read Mike’s in-depth run through of the Dirac Live Room Correction System here where he uses the previous analogue socketed DDRC-88A to bend his monitoring into shape.

Key Features And Benefits:

• Processor: 32-bit floating-point Analog Devices SHARC DSP.

• Input/Output resolution: 24 bits.

• Inputs: 4 x Stereo AES-EBU/SPDIF inputs (8 channels).

• Ouputs: 4 x Stereo AES-EBU/SPDIF outputs (8 channels).

• Optional DDRC-88BM plugin for Bass Management + Dirac Live + Active Speaker processing.

Trinnov Audio NOVA

For the uninitiated, Trinnov first made a name for themselves with their enigmatic first generation speaker correction boxes. These were revered by engineers but also loved by artists with deep pockets who just knew that they made everything sound better.

One of the company’s latest offerings is the NOVA, which was conceived to make the company’s Optimizer technology more accessible to music makers thanks to what Trinnov Audio call a “softer” price tag. Smaller than their ‘pro-only’ boxes, NOVA packs a lot into its shallow 1U chassis, which could make it deceptively powerful covering monitoring needs from stereo to 5.1.

NOVA handles analogue and digital signals allowing users to connect, align and seamlessly switch between sources and multiple sets of monitors, regardless of their format or connection. NOVA also flashes Trinnov’s pro credentials with Avid EUCON compliancy and full compatibility with La Remote. Unlike many other systems, it can be set up either as a full monitoring controller or as an inline audio processing toolbox in the loudspeaker path.

As a Dante device, NOVA can be easily connected within an audio network with low latency (down to 250 microseconds for the Dante network, and >25ms for the processing). You can also use NOVA as your main audio interface along with the Dante Virtual Soundcard for direct DAW-to-monitoring integration. Other features include a new modern web interface for the Windows/MacOS/iOS app which automatically finds NOVA on the local network and gives you direct access to its user interface. A new improved measurement microphone rounds off Trinnov’s monitor supercharger.

Key Features And Benefits:

• Trinnov Optimizer Technology.

• Covering monitoring needs from stereo to 5.1.

• New modern web interface for the Windows/MacOS/iOS app.

• Ethernet port:2x Ethernet ports (Dante 16 in/16 out).

• Flexible analogue and digital connectivity.

• New features arriving later in 2024 (as of May 2024).

IK Multimedia ARC Studio /ARC 4

Our next choice caused quite a stir when it came out earlier in 2024. Many reading this will have been aware of much more esoteric systems with prices to match, but IK Multimedia’s recent offering sets out to get in on the action too. As an addition to the ARC ecosystem, ARC Studio is a standalone box that runs profiles that are managed in the ARC 4 software detailed earlier.

ARC Studio does the same job as other loudspeaker correction boxes before it, ARC Studio is different because of its tiny footprint both on the desktop and on your bank balance. Backed with IK Multimedia’s accompanying ARC Analysis and ARC 4 apps, anyone with one of these little gizmos can measure and manage their room’s quirks, before bending signals back into shape through ARC Studio itself. The system isn’t all about ‘just’ correction though; invaluable tricks such as being able to superimpose the sound of well-known playback systems onto the correction is one. Another really neat trick is being able to swing the correction’s sweet spot for the client’s listening position.

It might be no-frills, but that’s the point. For anyone that wants to hear their mix like it is, ARC Studio offers affordable true hardware correction that will never inadvertently feature in your next bounce!

Key Features And Benefits:

• Compact digital room correction processor.

• AKM Velvet Sound conversion.

• 120 dB dynamic range, ultra-low THD and jitter.

• Natural or linear phase correction.

• Set upper/lower frequency correction limits.

• Up to 9 target curves to fine tune the in-room response.

• Improves even untreated or makeshift spaces - generate correction profiles in just minutes.

• Switch sweet spots for clients, test mixes through virtual monitor profiles and common “real-world” playback systems.

• Includes ARC measurement mic and software.

Hardware Onboard Speaker Calibration

Neumann KH 120 II

The first of our two self-correcting loudspeakers adds to Neumann’s growing range of high quality studio monitoring. Not so long ago, their name was more synonymous with high quality studio microphones - that changed with the introduction in recent years of a line of well-regarded compact monitors covering advanced two and three-way designs that hold their own among some of the more established speaker names. The release of the KH 120 II brings some welcome refinements to the company’s popular two-way box.

Building upon the success of its predecessor, the KH 120 II offers improvements in all acoustic parameters for deeper bass, higher SPL capability, and increased resolution. In addition, its internal DSP engine allows for phase linear crossovers and room correction via Neumann’s MA 1 Automatic Monitor Alignment. For aligning surround and immersive setups, a Multichannel Extension for MA 1 is available as a paid extra licence.

According to Portfolio Manager Stephan Mauer “The KH 120 garnered hundreds of 5-star reviews, yet we knew that we could make it even better. For the KH 120 II we’ve developed a novel woofer design that reduces distortion audibly and allows for much higher SPLs. In addition to an exceptionally flat frequency response from 44 Hz to 21 kHz (±3 dB), the KH 120 II also offers a linearized phase response”.

The KH 120 II offers analogue and digital inputs on S/PDIF, and is also available in an AES67 variant with redundant audio network ports making it fully compliant with broadcast standards such as ST 2110, ST 2022-7 redundancy, and RAVENNA. As part of a wider system, KH 120 II AES67 is compatible with DANTE-generated AES67 network streams.

Key Features And Benefits:

• Linear frequency and phase response.

• High-precision drivers, Mathematically Modelled Dispersion (MMD) waveguide.

• Razor sharp imaging due to extremely low tolerances (±0.5 dB).

• Deep low end down to 44 Hz and high SPL capability in a small format.

• DSP engine for outstanding performance and automatic room alignment via MA 1.

• May be combined with other KH line speakers in immersive or surround setups.

• Analog and S/PDIF connectivity, optionally with AES67.

Adam A44H

Our final choice comes from a well-known name in both creator and pro audio circles alike. Turning things on their side, Adam’s horizontally orientated A44H can be mounted above or below a display, or placed on a standard rack shelf thanks to its 19-inch width. This makes it a flexible presence in the control room for music, but equally its symmetrical design means it can be used as a centre speaker in immersive and 3D speaker configurations too.

Dual 4-inch long-throw woofers and the X-ART tweeter deliver a wide frequency range, but most pertinent here is the onboard DSP-based tuning capabilities that enable you to easily tweak the sound to the room.

Using A Control, you can push advanced filters directly to an embedded platform onboard the monitors to help compensate for imperfect room acoustics, and this platform supports filters from industry stalwarts Sonarworks. Using the same SoundID Reference software and a measurement mic detailed earlier, you can create calibration curves specifically for your room and run them directly on the A44H and other A Series monitors. For many, any correction running downstream of the source is preferable, but in the speaker itself negates the need for having to patch ‘through’ an intermediary piece of gear for the shortest of corrected signal paths.

Key Features And Benefits:

• Sonarworks SoundID Reference correction via the A Series platform.

• German Handmade Precision X-ART Tweeter with rotatable HPS waveguide.

• 2 x 4'' Woofer (Multi-Layer Mineral).

• Total Peak Amp. Power: 130 W.

• Frequency Response @ -6 dB: 46 Hz – 45 kHz.

• Max. peak SPL per speaker at 1 m: 103 dB SPL.

Final Thoughts

Ultimately, speaker calibration helps you to trust your monitors and mixing instincts, which in turn enables you to produce better sounding mixes that should translate well on real-world playback systems. As we’ve hopefully shown, whether you’re considering a software or hardware DSP-based approach solution, there’s certainly no shortage of excellent options available.