Intelligent Studio Monitors

Jun 1, 2008 12:00 PM, By Michael Cooper



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Listed alphabetically, here are some current offerings in monitoring systems that provide self-correcting capabilities.

Equator Audio's ( Q Series of self-correcting, bi-amplified reference monitors includes four different satellite monitors — the Q8, Q10, Q12 and Q15 — and a companion subwoofer, the Q18. The satellites all sport custom coaxial designs that time-align their high- and low-frequency drivers. Before each unit leaves the factory, built-in DSP corrects deviations in frequency response caused by minor variances in materials and manufacturing processes. The company also provides two software programs — one included, the other optional — for use with these monitors.

The software requires you to manually enter your room's dimensions and speaker positions, then makes some calculations and automatically applies a combination of parametric and shelving filters to help flatten the response. Only the first harmonic for each of the three axial room modes are corrected by default using fully parametric filters. (This is in addition to applying one shelving filter per monitor to correct speaker-boundary effects.) But the software allows you to multiply the default frequencies by whole numbers (e.g., 2x, 3x or 4x) to correct other harmonics that may be stronger than the fundamental and in greater need of correction.

The optional Secondary Reflection Correction (SRC) package ($495 list, Mac/Win) takes analysis and correction to a much higher level. It's a separate and fully automated DSP program that analyzes collected data using an included calibrated microphone. SRC automatically finds the three worst offending (axial) room modes and applies corrective parametric EQ. Advanced users can edit the filters' settings (including frequencies). Both software packages will by default only treat peaks caused by room modes, but will also allow you to apply boost to notches. Both also allow each speaker to have its own filter settings. (This is especially important for surround setups, as well as stereo setups in an asymmetrical room, as speaker-boundary effects vary with speaker position.)

SRC also automatically identifies and corrects comb filtering caused by secondary reflections, such as those that result from sound bouncing off a mixing console. An adaptive, time-based algorithm (not equalization) treats as many secondary reflections as the software finds. Equator purports that SRC retains a large enough sweet spot so that problems don't occur as you move your head at the mix position.

SRC's networking software can optimize the speakers' combined response for different listening positions, giving your clients seated at the back of the room their own sweet spot. Stereo, 2.1, 5.1, 6.1, 7.1 and 8.2 configurations can be optimized and saved for later recall. You can switch among up to four different saved setups, mixing and matching up to eight satellites and two subs. SRC can also adjust the sensitivity, tone contours (e.g., high-frequency tilt) and speaker grouping (allowing tweaks to groups of monitors at once) for each monitor in the setup. The subwoofer's output can also be delayed to align it with the satellites.

Genelec ( offers two self-aligning, networked systems that are almost identical but work with different monitors. Genelec Loudspeaker Manager (GLM) software works with the DSP chip sets built into the company's 8240A and 8250A satellite monitors, and 7260A, 7270A and 7271A subwoofers. The Small Environments (GLM.SE) DSP system is integral to only the SE7261A sub, but extends its control to up to eight 8130A satellite monitors connected to the sub via single-wire AES/EBU connections.

Both systems use computer-controlled network software packages with nearly identical GUIs. (GLM is Mac/Win; GLM.SE is currently PC-only but will soon also support the Mac.) The systems identify and organize the speakers connected to the network (as stereo or multichannel setups), and control volume, muting and soloing for each speaker. They also include a calibration mic that captures swept test tones produced by the speakers. Genelec's Auto-Cal software routine then analyzes your room's response and automatically equalizes the monitors in the system to correct room modes and speaker-boundary effects. Auto-Cal only cuts frequencies when addressing room modes, leaving notches untouched. The software also adjusts subwoofer phase and sensitivity to integrate the sub optimally with satellite monitors in the system.

The main differences between the GLM and GLM.SE systems are the number and type of digital filters available to them and how many loudspeakers they support. The GLM network can support up to 25 main (satellite) monitors and five subs. The system offers four notch filters, two low-shelving filters and two high-shelving filters for each satellite in the system. Each filter can be independently tweaked to a different setting for each speaker. Thus, each satellite can have four room modes equalized and apply shelving filters to both mitigate speaker-boundary effects (using low shelving) and adjust the balance of bass and highs to taste. A sub under GLM control can have four notch filters and a bass roll-off filter applied to its output (in addition to auto-phase and sensitivity adjustments).

Under GLM.SE software control, each of the SE7261A sub's eight highpass outputs can treat two room modes with notch filters. Located on the 8130's rear panel are manually adjustable DIP switches for controlling analog filters; the switches remain active and can be used with the GLM.SE's digital filters. GLM.SE software also adjusts the sub's phase and level sensitivity for optimal integration with satellites. The GLM.SE software can only address the SE7261A. Both GLM and GLM.SE software can store multiple setups for different listening positions.

You won't have to get out of your chair to correct your room's response using JBL's ( LSR4300 Series studio monitors. The three models in this line — LSR4326P and LSR4328P satellites, and LSR4312SP subwoofer — can all be networked for synchronized control from the mix position. Network control extends way beyond just correcting room modes: Speaker-level calibrations, individual-speaker solo, input source selection and all EQ parameters can be adjusted using the system's included infrared remote control. Or get some exercise and make the adjustments from each speaker's front panel. The included LSR4300 Control Center Software brings all this functionality under Mac/PC computer control.

You can configure up to two LSR4312SP subs and eight satellites — mixing and matching LSR4326 and LSR4328 units — to create a surround monitoring setup. JBL's system will automatically align all of the 4300 Series speakers in your setup so that the sound arriving at your mix position sounds balanced. A setup that includes the LSR4312SP sub provides LFE input, bass management for the satellites, adjustable crossover points, and level and polarity calibrations of the sub with respect to the satellites.

Plug the LSR4300 calibration mic into one of the speakers in your setup, and, at the push of a button, JBL's Room Mode Correction (RMC) system will automatically analyze and correct peaks in frequency response caused by room modes. The system doesn't merely analyze response at a single on-axis point in the room, but takes omni-directional measurements to better match what the engineer hears. Seventy-two measurements are taken, including those of the direct, reflected and reverberant sound fields. Only peaks caused by room modes between 20 and 160 Hz are treated; notches in response are left untouched. RMC can also address speaker-boundary effects, but room modes get priority treatment.

Each speaker — including the LSR4312SP sub — can correct one room mode using a parametric filter set to any of 73 frequencies. Each speaker's filters can be set independently of those for the other monitors in the system. The filters are on 1/24-octave centers and offer Q values from 1 to 16. The LSR4326 and LSR4328 each provide HF and LF shelving filters that can be manually tweaked to tailor spectral balance.


Self-aligning monitors are here to stay and will become more powerful as studio pros become more comfortable with — and enamored by — the technology. However, current systems do have their limitations. Room modes are powerful forces that don't easily yield to equalization. Correcting comb filtering is even more challenging. Even the most intelligent system won't produce a perfectly flat frequency response, but it should be a lot closer than what a standard monitoring setup can provide. The result will be greatly increased accuracy in your monitoring chain that should translate to better mixes. Sure sounds like a smart investment to me.

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