Accuphase DG-78 Digital Voicing/Room Equalizer

DG-78 At A Glance

• Function: Three-mode digital voicing equalizer with room-correction measurement and EQ correction — Voicing, Equalizer, and Analyzer modes
• A/D converter: AKM AK5578EN at 352.8 kHz / 32-bit, run in 4-channel parallel per channel
• D/A converter: ESS ES9028PRO, run in 8-channel parallel per channel with MDS++ topology and ANCC noise-and-distortion cancelling
• Signal processing: Analog Devices SHARC ADSP21565KSWZ10 DSP — native processing of input signals up to 384 kHz without down-sampling
• Digital inputs and outputs: HS-LINK, COAXIAL, OPTICAL — up to 384 kHz / 32-bit
• Analog inputs and outputs: LINE and BALANCED on both input and output sides
• User interface: High-resolution color touchscreen with electrostatic touch panel — operated with dedicated stylus pen or finger
• Compatible with: Accuphase digital interface present on DC-1000, DP-1000, DP-770, DP-570S

The DG-78 is Accuphase's room-correction and voicing tool — a self-contained instrument that measures a room's acoustic response, calculates the equalization curve required to compensate for it, and applies that correction in the digital domain at the resolution of the source. The DG-78 is not software running on a computer or inside a streaming endpoint. It is a dedicated audio component with its own touchscreen, its own A/D and D/A converters, its own DSP, and its own analog and digital signal paths — engineered to the same standards as the rest of the Accuphase digital line.

Three modes, separately controlled. The DG-78 implements three categories of operation. Voicing is the fine-grained tonal adjustment across the audio band according to the listener's preference, the source material's character, or the playback context. Equalizer is the room-correction mode — measurement and compensation of the room-induced anomalies in the bass and lower midrange where modal behavior makes the room itself part of the loudspeaker's frequency response. Analyzer is real-time frequency-response monitoring of the system in operation, allowing the listener to verify what the system is actually delivering at the listening position. The three modes are partitioned in the user interface and can be applied together or independently.

Reference-grade A/D and D/A conversion in the correction path. Room correction is only as good as the signal-handling that surrounds it — a low-resolution converter at either end discards the very low-level detail the correction is meant to preserve. The DG-78 uses the AKM AK5578EN A/D converter running at 352.8 kHz / 32-bit, configured in 4-channel parallel per audio channel; on the output side, the ESS ES9028PRO D/A converter runs in 8-channel parallel per channel using MDS++ topology with ANCC noise-and-distortion cancelling — the same D/A architecture used in the DC-500 and DC-1000 standalone digital processors. The correction path is built at reference-grade resolution end to end.

SHARC DSP processing at native sample rate. The Analog Devices SHARC ADSP21565KSWZ10 — the same family of DSP used in professional audio workstations and broadcast equipment — provides the processing horsepower for the correction filters. Input signals up to 384 kHz are processed natively without down-sampling to a lower internal rate. Lower-precision room-correction processors are forced to down-sample high-resolution inputs to match their internal architecture, then up-sample the output again — a process that compromises the very high-resolution material the DG-78 is designed to handle. The DG-78 runs its filter chain at the resolution of the source.

Electrostatic touch panel. The DG-78's front panel is a color touchscreen with an electrostatic (capacitive) touch panel — the technology that powers contemporary tablets and high-end industrial displays. The previous-generation pressure-sensitive panel has been replaced; the DG-78 supports operation either with the dedicated stylus pen or with finger touch for EQ curve adjustment. Frequency-response measurements are displayed graphically; correction filters can be applied, edited, and compared on screen; pattern memories store complete configurations for different sources, different listening positions, or different rooms.

Full digital and analog connectivity. Digital inputs and outputs include HS-LINK, COAXIAL, and OPTICAL — supporting sample rates up to 384 kHz / 32-bit. Analog connectivity includes both LINE (RCA) and BALANCED (XLR) inputs and outputs, so the DG-78 integrates into a fully digital chain, a fully analog chain, or a hybrid system without requiring an external bridge.

Why a dedicated chassis matters. Room correction inside a streaming application or PC-based playback software constrains the listener to whatever bit depth and sample rate the software supports, runs the correction filters on shared computing hardware whose timing and electrical noise are unknown, and ties the correction to a single source. The DG-78 runs its correction on dedicated audio-engineered hardware, in a chassis built to Accuphase's standards for noise rejection and supply isolation, with its own analog and digital input and output paths — and the correction is applied to every source that passes through it, not only to material delivered through a particular streaming application.

Where the DG-78 sits in the line. The DG-78 connects to the rest of an Accuphase chain through the dedicated digital interface present on the DC-1000 DAC, the DP-1000 transport, the DP-770 SACD/CD player, and the DP-570S SACD/CD player — keeping the signal in the digital domain end to end through the correction path. Analog inputs and outputs are also provided for systems built around non-Accuphase digital sources, or for rooms where the correction path is most naturally inserted between a preamplifier and a power amplifier. The DG-78 is engineered for the listener building or refining a reference system whose room imposes a meaningful correction requirement and who wants that correction performed at the same fidelity standard as the rest of the chain.

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