Harbeth DPM 1 pro speakers

Description

The Harbeth DPM 1 Pro appears to be the professional, active version of the Harbeth Xpression! DPM1 two-way passive studio monitor. The Xpression! DPM1 was Harbeth's first studio monitor, designed by MD Alan Shaw, targeting private studios and post-production markets. A "Pro" version with auto-sensing electronic speaker protection and LED peak power monitoring was also available. Active versions could be ordered, and the passive DPM1 could be converted for bi-amping.  

• Active Studio Monitor: The "Pro" designation and mentions of "active versions available to order" indicate that the DPM 1 Pro has a built-in amplifier, eliminating the need for an external power amplifier.
• Two-Way Design: It features a two-way design with a separate woofer and tweeter. The woofer in the passive version was a 200mm (8 inch) unit with a synthetic polymer cone, and the tweeter was a 1-inch soft dome Morel unit with ferrofluid cooling. The Pro version might share similar drivers.
• Active Crossover: Being an active monitor, the DPM 1 Pro would have an integrated active crossover network to precisely divide the audio frequencies between the woofer and tweeter before amplification.
• Built-in Amplification: The active design includes dual amplifier packs built into the cabinet's rear to power each driver independently (bi-amplification).  
• Electronic Speaker Protection: A key feature of the "Pro" version is auto-sensing electronic speaker protection to prevent damage from overdriving, often indicated by an LED.  
• LED Peak Power Monitoring: The Pro version also includes an LED to indicate peak power levels, helping users avoid clipping and distortion.
• Nearfield Monitoring: The quoted frequency response and design suggest it was intended for nearfield monitoring in studio environments.
• Cabinet Construction: The cabinet was made from MDF with a textured grey finish and featured rounded corners and a flush-mounted baffle for the drivers to reduce diffraction. It had a slit-shaped bass-reflex port beneath the woofer.
• Magnetic Shielding: The drivers were magnetically shielded, allowing for use near computer and video monitors without causing interference.
• Input Connectors: Active monitors typically offer balanced XLR and unbalanced RCA input options.
• Power Indicator: An orange LED usually indicated that the mains power was active.

Specifications (Based on the passive Xpression! DPM1, active Pro version may differ):

• Frequency Response: 46Hz - 20kHz ±3dB
• Sensitivity: 87dB 1W/1M (passive version)
• Nominal Impedance: 8 ohms (passive version)
• Crossover Frequency: 2.6kHz (passive version)
• Amplifier Power: Likely optimized for the drivers; one review mentions the passive version being tested with a 175W amplifier. The active version would have integrated amplifiers with specific power ratings for the tweeter and woofer.
• Dimensions: 420mm (H) x 255mm (W) x 305mm (D)
• Weight: 12.6 kg (per speaker)