Imersiv D-1 HDR-A Multi-Path DAC

MY TAKE: The imersiv D-1 is represents a most significant advance in digital-to-analog conversion. The measurements are extraordinary. More importantly, what you hear confirms them. This is not incremental progress — it is a genuine paradigm shift, and I am thrilled to offer it.- Galen Carol

Some products come along that demand you sit up and pay attention — not because of clever marketing or flashy aesthetics, but because they represent a fundamental rethinking of how something works. The imersiv D-1 is that product for digital audio.

Imersiv is the consumer-facing brand of Millennia Media, a company with 35 years of pro audio heritage built on an almost fanatical commitment to accuracy and neutrality. Millennia’s preamplifiers are the leading choice for Hollywood film scores, classical music recordings, and major broadcast events including the Grammys and Oscars. Their LOCi phono preamplifier was designed under contract for the U.S. Library of Congress. With over 50,000 recording channels in use worldwide, if you listened to music or watched a film today, chances are good you heard a Millennia recording. This is not a boutique startup making bold claims — this is a company whose work has shaped the sonic fabric of modern culture, now turning its full attention to the DAC.

Paradigm Shift -

Welcome to the most significant audio breakthrough since digital conversion. Delivering noise, linearity, and dynamic range performance so advanced that modern test equipment cannot measure it. Imersiv HDR-A is a revolutionary new multiple-path audio architecture, poised to fully re-imagine the way we capture and deliver sound, from microphone to power amplifier, and everything in-between.

At the heart of the D-1 is what Millennia calls HDR-A — High Dynamic Range Audio — a triple-patented, multi-path architecture that took founder John La Grou over a decade to bring to fruition. The concept is elegantly analogous to HDR photography, in which multiple stacked exposures are intelligently combined into a single image. Here, multiple stacked audio levels are summed into a single audio file — one low-level path covering 0–90dB of dynamic range, and one high-level path covering 80–180dB — with a sophisticated DSP crossfade invisibly managing the transition between them.

The result is a DAC that operates at extraordinarily low distortion across its entire dynamic range, not just at the top. At low signal levels — where standard DACs exhibit their worst waveform distortion — the D-1’s multi-path HDR-A architecture routes signals through a fresh DAC core optimized specifically for that range. Single-path waveforms at these levels are jaggy and noisy; we hear this as poor image definition, atmospheric collapse, and a blurring of complex timbres. The D-1’s low-level signals remain pure and natural, even far below the threshold of human hearing.

The specifications are unlike anything else on the market. The D-1 achieves a broadband noise floor of just 40 nanovolts — approximately 40dB lower, or 100 times quieter, than today’s finest competing DAC designs. The D-1’s self-noise actually sits 25dB below what the leading test equipment, such as the APx555B, is even capable of measuring. True dynamic range comes in at 28 bits, or 168dB — a figure that renders today’s best single-path converters unable to compete, on paper or in practice.

Realization -

Perfecting HDR-A took over 10 years of continuous research and development. The graph shows how it works.

Path 1 is an audio signal with 90dB of dynamic range, from 0dB to 90dB. Path 2 is an audio signal with 100dB of dynamic range, from 80dB to 180dB. When paths 1 & 2 are combined, the resulting dynamic range is 180dB, from 0dB to 180dB. That’s multi-path high dynamic range audio.

Multi-path HDR-A offers two major advantages over traditional single-path methods. First, it significantly reduces noise and distortion (THD+N). The imersiv D-1 achieves a remarkable 40 nanovolts of broadband noise, which is around 40 dB lower — 100 times quieter — than today’s best DAC designs. In fact, the D-1’s self-noise is 25dB below the measurement capability of today’s leading test equipment, such as the APx555B (see FAQ).

The second advantage is untethered headroom. HDR-A technology allows us to boost high-path headroom to any level without affecting our quiescent self-noise. The D-1 provides +22dBu (10 volts) of ISO-free* headroom while maintaining its profoundly low 40nV self-noise floor. This results in a true broadband, unweighted linearity and dynamic range of 28 bits or 168dB.  (*inter-sample overs or inter-sample peaks)

Multi-path is the next design standard of audio architecture, from microphone to power amp, and everything in between.

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Purity -

Acoustic recording engineers — whether in film scoring, classical music, jazz, or other genres — understand that spatial information is conveyed in the quiet moments:  in the space between notes;  in the subtle decay of a piano chord just before it fades from perception;  in the brief instant a note is first struck, before it reaches its peak. Quoting one of today’s top recording engineers, “On the music side, everything in the quiet neighborhood is where we get the ‘life’ and spatial cues in a recording. Distortion of lower-level partials is the very first casualty of any acoustic recording.”

Extraordinarily pure low-level audio is a key reason why HDR-A topology delivers improved spatial and timbral realism compared with legacy single-path DACs. When audio levels drop below a certain threshold, HDR-A begins processing in a new DAC core — with dramatically lower distortion+noise (THD+N) performance.

See diagram. Compare a low-level, perceptible sine wave on the D-1 multi-path DAC versus a high quality single-path DAC. Single-path waveforms are jaggy and noisy. We hear this as poor image definition, atmospheric collapse, and a blurring of complex timbres — while HDR-A “new core” signals remain pure and natural, even far below the limits of human hearing.

Pro Proven -

Over forty Grammy-winning / plantinum recording engineers and film composers evaluated the imersiv D-1 DAC for one year. The results were unambiguous:

“a revelation”

“I went into shock”

“the clarity is incredible”

“this DAC is astonishing”

 “unbelievably pure and clear”

“this will be the industry standard”

“like switching from 35mm to IMAX”

“the client thought he was hearing a 3D mix”

“works magic with metal and dense material”

“I can hear the space between the instruments”

“like hearing my music library for the first time”

Reviews - 

Audio Xpress https://audioxpress.com/news/imersiv-d1-multi-path-digital-to-analog-converter-completes-32-bit-audio-chain Jan Didden Dec 2023

Audio Xpress https://audioxpress.com/article/aes-show-2024-ny-personal-highlights Roger Shively Oct 2024

Positive Feedback https://positive-feedback.com/show-reports/the-2024-aes-show/ Frank Doris Nov 2024

Positive Feedback https://positive-feedback.com/reviews/hardware-reviews/imersiv-d1-dac/ Bob Katz Dec 2024

Gearspace AES 2024 Show Report https://gearspace.com/board/showpost.php?p=17296758&postcount=76 David Rick Jan 2025

Tape Op Magazine https://tapeop.com/reviews/gear/166/d-1-multi-path-dac/ Larry Crane Apr 2025

Audio Xpress https://cc-webshop.com/collections/latest-editions/products/audioxpress-november-2025-pdf Stuart Yaniger & Oliver Masciarotte Nov 2025

Create the Future Design Contest (SAE Media) Create the Future Design Contest 2025 GRAND PRIZE in the CTF Design Contest, over 630 entries from the world's top inventors, 54 judges. Nov 2025

Recording Magazine https://www.recordingmag.com/imersiv-d-1-dac/ Paul Vnuk Jr. & Justin Perkins Dec 2025

Twittering Machines https://twitteringmachines.com/review-imersiv-d-1-dac/ - Michael Lavorgna Mar 2026 "If you want to hear the best sounding stand alone DAC I’ve heard, you need to listen to the Imersiv D-1. No ifs, ands, or buts."

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Pedigree -

Built upon 35 years of innovation in pro-audio design and U.S.-based manufacturing, the imersiv D-1 embodies a heritage of excellence that has shaped the sound of our era’s most celebrated recordings. Millennia’s 2019 induction into the NAMM Technology Hall of Fame acknowledges our lasting influence and commitment to redefining professional audio. We adhere to aerospace-grade design, build, and QA standards, required by our esteemed clients — ranging from classical music recording engineers, broadcast engineers for major events like the Grammys and Oscars, and film scoring stages from Hollywood to Mumbai. It’s no surprise that pre-owned Millennia products consistently achieve top resale value within their professional categories.

Deeper Dive -

Join John La Grou and the imersiv design team for a short video tutorial (below). You will discover the inner workings of HDR-A D-to-A conversion and how it achieves 28-bits of dynamic range and linearity. You’ll also learn how multi-path architecture can be applied to every link in the audio signal chain, from microphones to power amplifiers, and everything in between.

Imersiv Multi-Path HDR-A Full Tutorial Video

Imersiv HDR / HDR-A Comparison Video

Specifications -

Supported Input Format: 32kHz to 384kHz up to 32-bits. 1xDSD, 2xDSD, 4xDSD, Dante Digital
Inputs: 1x USB (B) 32-bit, 1x AES XLR, 3x SPDIF BNC, 1x Toslink,1x Dante (option), XLR Analog
Outputs: +22dBu diff-bal (9.75Vrms) max. Zero Inter-sample overs. 1.8 ohms Z
Level Control: 0.1dB or 1.0dB per step, selectable,154dB range (-130 to +24dB)
Manual Alignment: To 0.01dB left + right matching
Display Monochrome OLED: 256 x 64
Front Panel Switches: Input, Setup, Select, Filter, Mute
Remote Control: IR, 27 functions, 4 reserved, 2 AA batteries required
Powering: 90-240V 50-60Hz
Power Use: 15 Watts nominal
Chassis: Dimensions 8.6”W x 16.3”D x 3.2”H (218W x 414D x 81H mm)
Weight: 7 pounds 7 oz (3.4kg)
Shipping Dimensions: 21” x 21” x 8”H (53 x 53 x 20 cm)
Shipping Weight: 13 pounds (5.5kg)
Included Accessories: Power Adapter,IEC Power Cable, Remote Control,2 AA Batteries, Quick Start Guide, BNC to RCA, Adapters (3)
Temperature Range:: 32°F to 104°F (0°C to 40°C)
Humidity Range: 35% to 85% RH, non-condensing
Frequency Response: 20Hz – 20kHz +/-0.1dB
THD+N at 1kHz: (22kHz BW) 0.0002% at +22dBu
THD+N at 20kHz (80kHz BW) 0.0005% at +22dBu
Self-Noise:20Hz-22kHz bandwidth -146dBu unweighted (calculated)
Dynamic Range: 168dB (28-bits)
Signal-to- Noise Ratio: 168dB (28-bits)
Linearity 168dB (28-bits)
Crosstalk: Better than -120dB at 1kHz
Headphone Output: 32ohm to 600ohm 2.8W max
DC Offset: 20uV max quiescent
Digital Filter: 6 selectable variations, see user guide
Polarity Flip: 180 degrees
Mute: Output Relay
Resampling: 192kHz
Calibration: See user guide
NOTES Performance specifications are broadband & unweighted. 

Specifications subject to change without notice,