Not all cardioid subwoofer systems are built the same. Before cardioid boxes were common, system engineers had to manually construct gradient arrays, measure physical cabinet depths, flip polarities, and calculate millisecond delays. It was a time-consuming process that left room for human error. Recognizing this, major loudspeaker manufacturers engineered their own built-in and DSP-driven cardioid sub arrays.
Today, directional low-end is an industry standard in professional touring. Let’s decode how different audio brands approach cardioid technology, their hardware designs, and why they save crews hours of setup time.
d&b audiotechnik: Passive and Active Integration
d&b audiotechnik leads the industry with two distinct approaches: Passive Cardioid and Active Cardioid. Models like the V-SUB and Y-SUB use Passive Cardioid. The cabinet contains a forward-facing 18-inch driver and a 12-inch driver firing backward out of a vented rear chamber. Both drivers are powered by a single amplifier channel. d&b achieves this using an internal passive crossover network and acoustic delay ports. The physical bandpass design naturally delays and phase-shifts the rear driver's output, creating cancellation behind the cabinet from a single speaker cable.
For stadium-level power, d&b uses Active Cardioid (found in the J-SUB and SL-SUB). The flagship SL-SUB contains three drivers (two front 21-inch, one rear 21-inch) and requires two separate amplifier channels from a D80 amp rack. The amplifier handles the complex EQ, phase manipulation, and time delay. d&b also built a feature called CSA (Cardioid Subwoofer Array) into their amplifiers. Stacking three standard B22 omni subs with the middle box reversed and selecting the "CSA" preset instantly applies the factory-calibrated delay, polarity, and EQ needed to optimize rear rejection.
L-Acoustics: Configurable Presets and The Setup Trap
L-Acoustics relies on factory-engineered presets within LA Network Manager. For systems using the KS28, you have two primary preset choices: crossover frequency (60Hz or 100Hz) and directivity (Standard or Cardioid). Crossover points are dictated by your main hang. If flying massive K1 or K2 arrays reaching 40Hz, you select the 60Hz preset. For smaller Kara II boxes, you load the 100Hz preset to support the low-mids.
For cardioid deployments, L-Acoustics supports two primary configurations: blocks of four (three front, one rear) or blocks of three (two front, one rear). The reversed cabinet must be physically aligned with the forward-facing boxes.
The ultimate trap for system techs lies in patching. You must assign the Cardioid Front preset to the forward boxes, and the Cardioid Rear preset to the reversed box. If you accidentally swap these, you create catastrophic phase cancellation in the audience area and amplify low-end firing into the stage. The Cardioid Rear preset mathematically accounts for the physical depth of the KS28 cabinet, applying the precise millisecond delay, polarity flip, and specialized EQ to compensate for wood-shadowing. Furthermore, L-Acoustics supports flown cardioid hangs by reversing every third cabinet and applying these presets, preventing low-end from wrapping around and exciting structural roof reflections.
Meyer Sound: Linear Phase and Processing Control
Meyer Sound focuses on phase accuracy. Unlike other brands, Meyer is strictly a self-powered company; the amplifiers and DSP are built directly into the cabinet (like the 1100-LFC or modern 2100-LFC). Placing the amplifier six inches from the driver eliminates speaker cable damping losses, allowing total cone control. This results in a highly linear phase response and predictable summation.
Meyer systems are controlled using the Galileo GALAXY platform over Milan AVB networks. You construct cardioid arrays in the GALAXY software (Compass) using the PC (Polarity/Cardioid) integration. By inputting the physical cabinet depth (a massive 33 inches for the 1100-LFC) into the GALAXY delay matrix and inverting the polarity on the rear output channel, you get a clean, mathematical null. Because of their linear phase and lack of transient overhang, Meyer subs excel in End-Fire configurations. Engineers can apply micro-delays across arrays to electronically steer the low-frequency wave, widening coverage to hit grandstands or narrowing it to focus on the floor.
JBL Professional: Crown I-Tech HD & Performance Manager
JBL Professional relies on Crown I-Tech HD amplifiers and their control software, Performance Manager. Dragging three VTX B28 subwoofers into a stack on the screen and clicking "Reverse" on the middle box automatically configures the Crown amplifiers with factory-calibrated cardioid settings. JBL's mechanical rigging allows B28s to be flown in cardioid configurations quickly. The factory presets are optimized for broadband rejection, ensuring the stage stays quiet and tonally balanced across the entire 30Hz to 100Hz spectrum.
Martin Audio: 3D Optimization and Hard Avoidance
Martin Audio takes software steering further with their flagship DISPLAY software and SXH218 hybrid horn/reflex subs. Rather than manually choosing standard cardioid stacks or delay times, you load a 3D venue model. You define where the audience sits and where you want absolute silence, such as the stage or a neighborhood noise boundary.
Martin’s software runs complex optimization algorithms to calculate the exact volume, EQ, phase, and delay for every single subwoofer in the array. DISPLAY treats the subwoofers as one giant steered acoustic entity. It might drop the volume of center boxes, delay outer boxes, and shift the phase of specific frequencies on inner boxes to create an acoustic vacuum on stage while maintaining 105dB in the crowd.
(Editor’s note: Go to our interactive Subwoofer Array Calculator to enter your speaker dimensions and check splay mappings. You can also analyze low-end summation and crossovers live using our web-based RTA Spectrum Analyzer).
