Tech Focus: Audio Monitoring, Part 3 — Room-Correction Software Aims To Optimize the Environment
Products from a variety of vendors analyze a space and adjust speaker performance
A great speaker can quickly become a mediocre one when placed in an especially challenging space. The audio compartment of a remote-production environment is the ultimate petri dish for this phenomenon, one that becomes even more complex when audio mixes have to move between different spaces and through an assortment of different speakers.
In response, speaker manufacturers have been developing and refining so-called room-correction systems: software that can aurally analyze a particular space’s metrics, such as its size and reflectivity, and adjust the performance of the speakers to that environment.
JBL, Blue Sky, Genelec — all regular components of broadcast-sports remote-production facilities — and other brands have developed these room-correction products. Some began by focusing on LFE correction — JBL’s Intonato 24 system works solely below 500 Hz; Blue Sky’s Audio Management Controller (AMC) traces its beginnings to the company’s now-discontinued Bass Management Controller — but all say they optimize frequency response to that of the spaces they’re used in.
A Growing Product Class
Blue Sky’s eight-channel DSP-based system AMC provides control over levels, balance, mute, selection of house curves, and various other system-configuration settings and supports configurations up to 7.1 surround sound. Any input can be routed to any output, and multiple inputs can be mixed and routed to any outputs. Each channel features 1/3-octave EQ, eight bands of parametric EQ and filters, and variable delay for time alignment. Other features include eight system presets (EQ curves, etc.), lip-sync delay, 7.1 bass management with variable cutoff frequency per channel, and an externally accessible mute input. LFE management is via 10-band parametric equalizer. Digital inputs have a built-in sample-rate converter, which can be bypassed in Pure-Digital mode for 48-kHz/96-kHz operation.
According to Chris Fichera, VP, audio, Group One Ltd., which markets Blue Sky speakers, the AMC is able to be configured for up to 16 channels via specially written software that combines two complete systems as a single array. Those configurations, he says, are already in use for Dolby Atmos monitoring in some broadcast-studio environments. A 5.1+4 configuration for remote-production applications is also available and has been implemented in at least one truck under construction.
“There are still some spacing and positioning issues” for the overhead speakers, Fichera cautions. “But it can be done using our existing [speaker] products. The real question has to do with demand from viewers. Are soundbars going to be enough to jump-start this market for consumers?”
He also wonders how well the A1s, who are the front-line users of monitoring systems, understand and accept self-calibration systems. He includes an initial tuning of those systems for each monitor installation in production trucks, he says, noting that audio engineers often look askance at what some consider electronic artificiality introduced into a monitoring system.
“It’s important that we let them know that there is a [bypass] they can do if they want to,” Fichera says. “But the initial calibration we do is custom for each environment, so it will provide a more accurate monitoring image for them.”
Housed in a 2RU enclosure, JBL’s Intonato 24 Monitor Management Tuning System calibrates and controls up to 24 speakers configured as stereo, surround, or immersive audio systems. Although it’s intended to be used with the company’s 7 Series Master Reference Monitors, Intonato 24 is compatible with other monitors; additionally, Harman’s BLUlink network protocol allows Intonato 24 to be digitally networked with Harman’s Crown power amplifiers. Intonato 24 features internal routing and a mixer to provide monitoring flexibility for a combination of up to 24 analog and digital sources, which can be patched, routed, and selectively monitored via any of the connected speaker or headphone systems. Up to four subwoofers can be assigned as bass-management subs with selectable crossover settings, and the same or different subwoofers can be used to reproduce the LFE channel. Complete configurations — including speaker-setup parameters, EQ, subwoofer settings, input source patching, and downmix preferences — can be stored as profiles and scenes and are instantly recalled, even mid-session.
“The room really doesn’t create problems for monitors above 500 Hz,” asserts Chris Hansen, director, recording, broadcast, and content creation, Harman Professional. “Low frequencies are where the room tends to be in control. If you can solve the low-frequency–management issues, then you’ve resolved most of your room-correction problems. That’s what Intonato 24 does.”
The Genelec Loudspeaker Manager 3.0 (GLM 3.0) software manages connectivity to up to 40 Genelec SAM studio monitors and subwoofers on the Genelec network. The complete GLM control system includes a Genelec measurement microphone and universal microphone holder, a network adapter unit, and the GLM software. Available for both Windows and Mac, the GLM software features adjustment of levels, distance delays, and flexible room-response compensation equalization using Genelec’s proprietary AutoCal automated calibration system. All parameters and settings are stored in system-setup files or saved in each individual studio monitor or subwoofer, in case the GLM network needs to be disconnected.Not every speaker manufacturer is emphasizing automation of near-field monitoring environments, however. Although Meyer Sound’s MAPP XT predictive software and SIM system analyzer are scalable to a near-field environment, Meyer Director, Business Development, John Monitto says the company prefers that it be used to guide users in manually tuning a listening area, rather than letting software do it virtually. Autonomous systems, he cautions, can potentially mistake reflections for source sounds, applying EQ and other processing inadvertently.
“There’s the potential for making the situation you’re trying to correct worse,” he says. “We’d rather provide education on how best to use these types of tools.”
The Next Generation
Yet another class of monitoring-environment–management product has cropped up very recently, adding headphones to the mix. Reference 4 from Sonarworks, which has been aggressive in this new category, puts sound-calibration software and a measurement microphone into a package that can establish consistently flat-frequency response between any brand of speakers and headphones. Calibration of headphones is done using a premeasured profile done in Sonarworks’ facility in Latvia: users simply select their make and model — the company has encoded more than 240 models so far — and the calibration profile is set. Speaker calibration is done by the user with the Sonarworks microphone and measurement software, which captures sound from 37 data-source points and follows a similar process to most other speaker-calibration products.
What’s different here is that Sonarworks SR is designed to align transducers with a common audio reference parameter that the company has developed, comprising patented — and proprietary — sound-measurement technology and DSP. In a broadcast industry that historically looks to AES, SMPTE and ISO for absolute standards, that could be a point of contention. Sonarworks President Martin Popelis notes that the company is “seeking ways to expand it to be a universal standard for audio producers.”
As surround sound has become ubiquitous and immersive sound is increasingly close to a broadcast standard, digital technology is remaking what the speaker is, what it does, how it does it, and where it can do it. In a soon-to-be-world of 5.1+4, perhaps it’s not a moment too soon.
Click here for Tech Focus: Audio Monitoring, Part 1 — Speakers Are Smaller, Lighter, and Proliferating
Click here for Tech Focus: Audio Monitoring, Part 2 — Truck Environment Requires Robust, Full-Range Speakers