Review & Measurements: d&b audiotechnik 5D

Introduction

The d&b audiotechnik 5D is a new four-channel, 4 x 600 W power amplifier presented in a compact 9.5" format, specifically designed for fixed installations. It features an integrated DSP system, offering the full range of functions found in d&b's larger models, ensuring seamless integration into the manufacturer's system ecosystem.

The increasing sophistication of multimedia applications has led to more complex fixed installation sound reinforcement systems, demanding higher audio quality, improved operation, and advanced networking. This trend is reflected in d&b audiotechnik's product portfolio, which now includes smaller systems for decentralized applications, conference rooms, houses of worship, and more, alongside their larger PA systems. Consequently, the requirements for matching amplifiers have evolved. Modern amplifiers need to be more than just power output devices; they must offer multiple channels, network control, monitoring, and digital signal input via networks, supported by dedicated configuration software.

While d&b's amplifiers have long offered these features, they were previously limited to larger 2RU, 19" cabinets. The 5D amplifier, a slim 1RU, 9.5" unit, addresses this gap. It provides up to 4 x 600 W output power (depending on the measurement signal) and integrates all the DSP functionalities users expect from d&b's larger models. Notably, the 5D is d&b's first amplifier to include a Dante interface, eliminating the need for a separate audio network bridge for digital signal feeds.

The d&b audiotechnik 5D Amplifier

The 5D amplifier is housed in a compact 9.5" enclosure, with connector plates allowing two units to be combined into a standard 19" rack space. Its front panel is minimalistic, featuring LEDs for power, data, and individual mute/error/signal/gain reduction/overload status for each channel. All controls and monitoring are handled remotely via the R1 software over a network connection.

Internally, the compact enclosure houses two two-channel power amplifier modules, each with its own cooling profile, and a substantial power supply unit. The rear panel is densely populated with connections, including mains input, a fan, four balanced analogue inputs, speaker outputs, four GPI pins, and an error contact, all using Euroblock connectors. An integrated 2-port Ethernet switch facilitates network connectivity, supporting both star and daisy-chain topologies. Remote control is managed via the OCA/AES70 protocol, with the internal microcontroller and Dante interface having distinct MAC addresses and IP addresses.

Software and Configuration

Configuration and control of the 5D amplifier are managed through d&b's R1 software, available for both Windows and macOS. This software is essential for setting up and operating the amplifier, whether for a single unit or complex systems. R1 allows users to create custom interfaces and set operational access levels via passwords.

The R1 software operates in three main modes: Configuration, Tuning, and Show. In the Configuration mode, users can name amplifier channels, assign them to groups, and select specific speaker setups from the d&b library. The Tuning section provides detailed control over each amplifier channel through various tabs:

• General: For input routing, level adjustment, mute, delay, and standard filters (CPL, CUT, HFA).
• EQ: Features an eight-fold filter bank per channel, including shelf, bell, and notch filters, with options for asymmetrical filter shapes. Users can select filter slopes (6 to 24 dB/Oct), gain (-18 dB to +12 dB), and Q values (0.5 to 25).
• Levels: Displays input level, headroom/gain reduction meters, RMS power, and impedance.
• Freq.Gen.: Allows setting test signals like pink noise or sine waves.
• Diagnostics: Provides detailed information for troubleshooting errors.

The DSP handles loudspeaker setup presets, along with filters like CUT (high-pass for subs/tops), CPL (low-shelf for coupling effects), and HFA (high-frequency attenuation). The digital filter processing, particularly near half the sample rate, can lead to curve compression, a characteristic that users should be aware of during setup.

Measurements and Performance

Frequency Response and Damping Factor

Measurements show frequency responses across various loads (2, 4, 8, 16 Ohm) and typical loudspeaker impedances. The 5D exhibits minimal level fluctuations (±0.5 dB) with a 4-Ohm load, and its latency, including the DSP, is a low 1.1 ms. The damping factor measurement displays a typical Class D characteristic, starting high and decreasing with frequency, but remaining adequate for loudspeaker control.

Signal Quality and Interference

FFT analysis reveals the useful signal at 1 kHz and remnants of the PWM switching frequency. Interference levels are low (-68 dBu to -70.5 dBu with A-weighting), resulting in a strong signal-to-noise ratio of 111 dB with analogue inputs, which improves by 3 dB with digital inputs.

Distortion (THD+N)

THD+N measurements show distortion levels generally below -75 dB at 100 Hz and 1 kHz, and around -55 dB at 6.3 kHz at maximum power output into 8-Ohm and 4-Ohm loads. Exemplary distortion spectra at 4x37W output show all components well below -80 dB. THD+N over frequency measurements confirm these results.

Dynamic Intermodulation Distortion (DIM)

DIM100 measurements assess the amplifier's response to transient signals. The 5D demonstrates robust performance, with transient distortions not being significantly pronounced.

Power Output Performance

The amplifier's power output was tested with various signal types (sine, noise, bursts) and crest factors into 8-Ohm and 4-Ohm loads. When all channels are simultaneously loaded, the 5D delivers an average power of 120 W per channel. With a single channel loaded, nearly 250 W is available. The amplifier exhibits significant peak power reserves, capable of handling transient peaks up to 900 W.

Mains Load and Efficiency

Efficiency measurements show good performance, reaching approximately 80% without base load. The amplifier consumes less than 5 W in standby mode and 50 W when idle. Mains load characteristics are favorable, with a power factor of 0.98 and low current distortion (7%), indicating it behaves much like a resistive load on the power grid.

Summary

The d&b audiotechnik 5D is a compact, four-channel amplifier ideal for fixed installations requiring small to medium power. It offers 4 x 120 W continuous power into 4 or 8 Ohms, with peak reserves up to 4 x 900 W, ensuring distortion-free transmission of signal peaks. Its integrated DSP and Dante interface provide advanced functionality comparable to d&b's larger amplifiers. The 5D integrates seamlessly into d&b's workflow and supports other system platforms via plug-ins, making it a versatile and attractive option for planners, especially considering its competitive pricing of €1,900 net plus VAT.