JBL 308P MkII Studio Monitors (Pair)

JBL 308P MkII Studio Monitors (Pair)

The JBL 308P MkII is an 8-inch powered two-way studio monitor, and this listing is for a pair for stereo monitoring. Each monitor is self-powered and specified individually: an 8-inch low-frequency driver and a 1-inch soft-dome tweeter, each driven by its own 56 watt Class D amplifier. The design draws on technologies from JBL’s 7 Series and M2 Master Reference Monitors, scaled into a monitor intended for music production, broadcast and post-production rooms where imaging accuracy and a broad sweet spot are the priorities.

Per monitor, the frequency response is 45 Hz to 20 kHz within plus or minus 3 dB, with extension to 37 Hz at the minus 10 dB point, giving the pair genuine low-frequency reach for judging bass content without a subwoofer in many rooms. JBL’s Linear Spatial Reference design approach measures the monitor across a full sphere of angles rather than on axis alone, which is why the 308P MkII maintains its balance as the listener moves around a console or desk.

Key features

• Per-monitor bi-amplification: Two 56 W Class D amplifiers, 112 W total per monitor, for the 8-inch woofer and 1-inch soft-dome tweeter.
• Image Control Waveguide: Patented waveguide design for detailed imaging and a broad, room-friendly sweet spot, with 120 degree by 90 degree coverage.
• Measured response: 45 Hz to 20 kHz (plus or minus 3 dB) per monitor, with a 37 Hz to 24 kHz frequency range at minus 10 dB.
• Output capability: 102 dB maximum continuous SPL and 112 dB maximum peak SPL per monitor.
• Slip Stream port: Patented low-frequency port design for controlled bass performance at all playback levels.
• Boundary EQ and HF Trim: Rear-panel controls compensate for placement near walls and for room high-frequency character.
• Balanced connectivity: XLR and 1/4-inch TRS balanced inputs with a plus 4 dBu / minus 10 dBV sensitivity switch and volume control.

Waveguide, transducers and imaging

The Image Control Waveguide is the defining element of the 3 Series MkII design. It shapes the tweeter output so that high frequencies blend with the woofer across a wide listening window, producing a stable centre image and a soundstage that does not shift dramatically with small head movements. The next-generation transducers are engineered for improved linearity and transient response, so percussive detail and low-level ambience are reproduced cleanly. The crossover is set at 1,800 Hz using a 4th-order acoustic Linkwitz-Riley alignment, keeping the handover between the 203 mm woofer and the 25 mm tweeter controlled in both amplitude and phase, and the Slip Stream port geometry reduces air turbulence noise that can mask low-frequency detail at higher levels.

Amplification, output and room controls

Each monitor carries dual integrated Class D amplifiers totalling 112 watts, providing the headroom behind the 112 dB peak SPL rating. Two rear-panel adjustments adapt the monitor to its environment. Boundary EQ applies a low-frequency shelf at 50 Hz with 0 dB, minus 1.5 dB or minus 3 dB settings to counter the bass reinforcement that occurs when a monitor sits close to a wall or on a console surface, and the HF Trim switch adjusts high-frequency output by minus 2 dB, 0 dB or plus 2 dB to suit room acoustics or personal preference. JBL subjects the design to a 100-hour full-power reliability test, and the electronics accept 100 to 240 V AC power.

Connections, cabinet and stereo use

Balanced XLR and TRS inputs, an input sensitivity switch for professional and consumer signal levels, and a detented volume control make integration with interfaces and monitor controllers straightforward. The ported enclosure is built from 15 mm MDF with a matte black PVC finish and an injection-moulded structural ABS baffle. Each monitor measures 419 mm high, 254 mm wide and 308 mm deep and weighs 8.1 kg. As a pair, the monitors form the left and right channels of a stereo nearfield system, and matched additional units can extend the same voicing into surround and immersive monitoring layouts.

For rooms that need an 8-inch monitor with documented off-axis behaviour, serious output headroom and practical placement correction, the 308P MkII pair provides a complete stereo reference built on JBL’s professional monitoring research.