Note that this is a discontinued product. You may want to visit the brand's page here to browse their newer products.
What reviewers think
Bloggers and YouTubers have tried this product—so we've summarized their strongest opinions below. Links to full reviews follow.
Product Strengths
- Creates a big, solid sound with a wide, well-defined soundstage and lots of detail
- Delivers drive and energy behind the music with a solid and full bass
- Presents music with smoothness and gracefulness, especially in the midrange and treble delivery
- Upgradeable with new technologies developed by Metrum Acoustics, such as the Transient DAC Three modules
Product Considerations
- Build quality feels light and less substantial initially, though it is heavier than some competitors
- Lacks DSD processing
Comparisons (according to reviewers)
- Onyx has a smoother and more easy-going sound than Chord Hugo TT2, but the timing is not quite as crisp
- The Onyx has less authority and is a little less detailed than Metrum Acoustics Pavane, but is otherwise very similar
Takeaway: The Metrum Onyx offers a unique blend of smoothness and immediacy. Its full and nicely textured sound makes it a worthwhile consideration for audiophiles seeking a high-performing DAC.
All
Metrum Onyx
reviews

Manufacturer details
- Type: Non Oversampling
- Audio Bit Depth: 24 bits per sample
- Correction Type: Forward (FPGA) corrected
- DACTWO Transient chips per channel: 2
- Power: 15 VA toroidal transformer
- Noise Floor: -145 dB
- Output Impedance RCA: 100 Ohm
- Output Impedance XLR: 100 Ohm
- Total Harmonic Distortion: 0.006% THD
- Sampling rate Optical: 44.1 – 96 kHz
- Sampling rate Coax and AES/EBU: 44.1 – 192 kHz
- Sampling rate USB: 44.1 – 384 kHz
- Dimensions: 290 x 250 x 70 mm
- Weight: 3.1KG
Brand highlights
Taking a step back to look at reviewers' thoughts of the brand's entire lineup—not just this product—what stands out most is the following:
- Metrum products, including those under the Sonnet Digital Audio brand, are designed around the company's proprietary R2R ladder network DAC chips, known as Transient DAC modules, providing a unique approach to digital-to-analog conversion.
- The brand is known for its commitment to non-oversampling (NOS) designs, eschewing oversampling and filtering techniques to preserve the naturalness and musicality of audio signals.
- Metrum implements unique approaches to volume control that maintain signal integrity, utilizing techniques like changing the reference voltage of the DAC modules rather than traditional digital attenuation or analog potentiometers.
Select products
Metrum Onyx
- Positioning: A mid-range non-oversampling DAC designed for home sound systems.
- Description: Uses dual DACTWO chips per channel with parallel FPGA-driven R2R ladder networks for high linearity and clear channel separation. Compared to pricier models like the Pavane and Adagio, it offers solid performance for everyday listening at a moderate budget and suits setups where effective detail and balance are key.
Sonnet Morpheus MK-II
- Positioning: A versatile digital preamplifier DAC suited for integration with sensitive tube designs.
- Description: Adds a -10dB attenuator feature that allows output voltage adjustments, making it flexible for both DAC and preamp usage. Compared to the simpler Onyx and the more feature-rich flagship models, it targets buyers needing adaptable output control for specialized use cases.
Metrum Pavane
- Positioning: A flagship non-oversampling DAC aimed at delivering high-end, refined audio performance.
- Description: Incorporates advanced DAC 2 modules and proprietary forward correction techniques to produce a rich and natural sound with enhanced spatial cues. Compared to the mid-range Onyx and the integrated Adagio, it delivers top-tier sonic detail.
Metrum Adagio
- Positioning: A flagship DAC with integrated volume control that serves as a digital preamplifier for active systems.
- Description: Features dedicated DAC boards with larger, higher voltage transformers and separate toroidal power supplies to maintain low noise and precise volume regulation. In comparison to the Pavane and Onyx, it offers more functionality and controlled performance for users requiring integrated preamp capabilities.
Sonnet Pasithea
- Positioning: A premium DAC and preamplifier built with eight SDA-3 DAC modules for enhanced performance and versatility.
- Description: Delivers improved linearity, lower distortion, and a noise floor markedly lower than the Morpheus by using multiple DAC modules and flexible attenuation options. Compared to all other products in the lineup, it provides superior build quality and maximum sonic resolution in complex and demanding systems.
Our take on the brand
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Used
Metrum
What if you spend more?
Our summary
Product Strengths
- Exemplary build quality, with a chassis milled from a single block of aluminum and high-quality components.
- Delivers a large soundstage with very good imaging and detail.
- Produces a harmonically rich presentation that R2R enthusiasts seek.
- The unboxing experience is premium, with a metal certificate of authenticity and a remote control made from solid metal.
Product Considerations
- The high output impedance (1200 ohms on XLR) might cause issues when pairing with amplifiers that have unusually low input impedance.
- Optical and coaxial inputs might not deliver the same performance as USB and I2S inputs.
- It is DAC-only unit, so it does not have preamp functionality or volume control.
- Spiked feet could scratch surfaces.
Comparisons (according to reviewers)
- Vs Denafrips Ares II: The Harmony DAC has more instrument separation and a little bit more detail through USB or I2S.
- Vs Gustard R26: The Harmony DAC is fuller in the bass and lower mid-range with a warmer presentation and wider soundstage through USB or I2S.
- Vs Denafrips Venus II: The Venus sounds bigger with more tangibility to where performers reside and more space between them.
- Vs Denafrips Pontus II: The Harmony DAC shares similarities but is slightly more resolving and realistic.
- Vs SMSL Raw Pro: The Harmony DAC is more enjoyable to listen to overall, although the Raw Pro is more detailed.
- Vs HIFIMAN EF400 and EF500: The Harmony DAC is an upgrade in detail retrieval, staging, and treble quality.
Takeaway: The Harmony DAC stands out with its build, engaging sound, and focus on providing a high-quality digital-to-analog conversion. Its ability to create a large soundstage and deliver rich detail makes it a solid option for audiophiles looking for an immersive listening experience.
Video review
Our take on the brand
Our summary
Product Strengths
- Musical and natural sound, avoiding harshness or fatigue
- High linearity and a realistic 24-bit dynamic range
- Bit-perfect volume control by varying reference voltage directly from the DAC chips
- Roon Ready, easy to set up and use
Product Considerations
- Does not support DSD playback
- The I2S input uses an RJ45 connector, not the more common HDMI, limiting cable compatibility
- Some reviewers would like a sample rate/bit depth display on the front panel
- Direct-to-amp usage might not sound as good as using a separate preamplifier, depending on the system
Comparisons (according to reviewers)
- Morpheus offers performance equal to Metrum Acoustics Adagio/Pavane without the heavy casing
- Morpheus is better than Metrum Acoustics Onyx or Jade, with more options, expansions, and better build
- Morpheus offers greater apparent resolution and a broader dynamic range than Totaldac d1-tube DAC/Streamer
- Morpheus is better than Denafrips Pontus with soundstage, timbre, tones, and attack, and no listening fatigue on the Sonnet
- Hermes and I2S was simply much better in every way than Primare Prisma NP5 Network Player, where music sounded paler, softer, and less exciting
Takeaway: The Morpheus DAC is a great option for audiophiles seeking accurate, natural, and musically pleasing sound. Sonnet designs deliver high quality sound and could convert even the most stubborn digital skeptics.
Video review
Our take on the brand
Product Strengths
- Natural and engaging sound, praised for its 'non-digital digital sound' and ability to connect the listener to the music's emotive power
- Richness and fullness to the sound, achieving a balance between not being overly warm or rich nor clinical or sterile, offering a natural tonality
- Wide and deep soundstage with precise instrument placement, creating spatial dimensions comparable to higher-priced DACs
- Dynamically lively and snappy, handling complex musical passages without sounding overwhelmed
- High-quality internal parts, robust build quality, and elegant appearance
Product Considerations
- Lacks some of the detail retrieval and resolution compared to other DACs, meaning it may not deliver the same level of micro-textures
- PCM only up to 192k sampling rate, so there is no DSD support
- Some reviewers wished for I squared S and also AESEBU, the XLR input
Comparisons (according to reviewers)
- Vs Mola Mola Tembaki, the Tembaki gave more high-frequency air, clarity and better portrayed the acoustics of the recording venue, but the Aero sounded more humid, with more weight and richness
- Vs Border Patrol DAC, the Aero is more transparent and pure
- Vs Laiv Harmony DAC, the Aero slots in between with a more pleasing and engaging balance between color and resolution
Takeaway: The Linear Tube Audio Aero DAC offers a natural, engaging, and enjoyable listening experience with great soundstage. It brings musical enjoyment for those who prioritize tonality and timbrel accuracy.
Video review
Our take on the brand
What competes at this price?
Our Summary
Product Strengths
- High price/performance ratio
- Heavy power supply (30VA + 44'000µF) adds a headphone amp which can drive 16Ω
- Improved DAC linearity, boosting the converters to top specs
- More articulated transients, more focus, better top-end visibility, and depth specificity
- Unique R2R D/A conversion
- Amethyst features no balanced outputs
Product Considerations
- Volume control covers headfi only, piping directly into a speaker amp runs full throttle regardless of setting, needing a preamp or integrated amp
- Casework makes do without the range toppers' glass lid and massive sides
- Lacks color intensity and has leaner textures compared to some alternatives
Comparisons (according to reviewers)
- Compared to AURALiC Vega, Amethyst has more articulated transients, more focus, better top-end visibility, and depth specificity, but at a lower color intensity and with leaner textures
Takeaway: The Metrum offers great value with its unique R2R D/A conversion and ability to drive headphones, making it a compelling entry-level option from Metrum Acoustics. It provides clear and focused sound, making it a worthwhile consideration for those looking for quality audio.
Video review
Our take on the brand
Our Summary
Product Strengths
- Solid digital sound, good authority, solid bass, and a weighty sound with good scale
- Excellent clarity, very good timing, and a very good soundstage
- Outstanding build quality—solidly made and near indestructible
- Versatile unit that can become the hub of the digital audio world
- Clean and effortless digital processing
- Connectivity options
Product Considerations
- The Lightning DS app is only available for iOS
- The 4-inch non-touch screen is adequate, but not exceptional
- When written instructions feature on the screen, the words can be small and difficult to see
- The alphabetical order of the albums is not followed when used with an external hard drive
- Some reviewers felt a need for a high-end turntable setup, as the analog input feeds directly to the analog output stage—bypassing the digital stage altogether
Comparisons (according to reviewers)
- Vs NAD M10 V2: The Altair offers a step up in sound quality
- Vs AURALiC Aries G1: The Altair G2.1 chassis is a significant upgrade with an internal copper sub-chassis, tuned feet, and a solid steel base
Takeaway: The AURALiC Altair G2.1 is a versatile and well-built streaming DAC preamplifier that offers a clean and detailed sound. Comprehensive features and excellent sound quality make it a great choice for audiophiles looking for an all-in-one solution.
Video review
Our take on the brand
Our Summary
Product Strengths
- Natural and organic timbre with rich and vibrant overtones, offering a remarkable sense of realism
- Stands out as a highly musical DAC within its category, while maintaining an impressively competitive level of technical performance
- Exceptional build quality, made of thick aluminum, ensuring durability and a sleek appearance
- Almost inaudible noise floor, remaining dead silent and free from any hint of distortion
- Wide range of digital inputs, and an integrated streamer, offering versatility and convenience
Product Considerations
- The LCD screen can be difficult to read from a distance greater than 20-30 cm
- The embedded streamer can experience occasional interruptions and buffering issues when streaming high-resolution files
- Some reviewers experienced small hiccups when skipping songs using the internal streamer
Comparisons (according to reviewers)
- Vs Chord Qutest: Has a bigger soundstage, equally sweet highs, much fuller tone timbre and a more muscly bassline—sounding more lifelike
- Vs Ladder Schumann: Gustard R26 hits with more clarity and speed, with a darker background, and an even deeper soundstage
Takeaway: The Gustard DAC-R26 is a musical and technically impressive DAC with excellent build quality and versatile features, including a streamer, making it a great choice for a top-notch audio experience. The natural sound and engaging performance create a lasting impression.
Video review
Our take on the brand
Our Summary
Product Strengths
- The Border Patrol SE-i DAC brings the music naturally, organically, with great coherence and resolution
- It excels in the midrange
- The soundstage is quite large and can be vast, synergy providing
- There is a natural musicality and an organic quality to the music
- This DAC will give the music lover some of the finest reproduction qualities that may be experienced in a digital-to-analog converter
Product Considerations
- It will not play the various high-resolution formats or DSD or DXD or anything above 24/96kHz
- It only converts PCM (pulse code modulation) digital at sampling frequencies of 44.1K, 48K, 88.2K, and 96K
- If one is looking for extreme sonic range, it's best to move on from here
- Synergy with equipment is important to get the best sound
Comparisons (according to reviewers)
- Vs Audio Note CD3.1x/2: The Border Patrol may be a touch more accurate in its midrange response than Audio Note, but this was also highly dependent on the program sources employed
- Vs Prism Sound Callia: The Border Patrol equals the Callia in every way, but its presentation gives out a touch more softness with a little more naturalness in its fundamental tonality and harmonic presentation
- Vs Wyred 4 Sound's 10th Anniversary DAC: The main differences alongside the Border Patrol would be a touch more upper-frequency lift in comparison, whereas the Border Patrol still exudes a more romantic—slightly smoother—sound presentation
Takeaway: The Border Patrol SE-i DAC is great at making music sound natural and draws the listener into the music. It could be perfect for those who enjoy a natural sound and do not need to play super high-resolution files.
Video review
Our take on the brand
Our Summary
Product Strengths
- Drop-dead gorgeous design aesthetic
- Music comes alive, offering a real taste of what reference-quality digital audio can sound like
- Reproduces layers of detail and offers a warm tonal balance, low noise floor, and superb top-to-bottom coherency
- Soundstage is recreated with excellent depth and width, and the imaging is spot on, with musicians and instruments locked firmly in place
- Connected to the Unison Research Triode 25 Integrated Amplifier and Linear Tube Audio MZ3, it was one of the best sounding DAC/amplifier combinations heard in many years, undeniably captivating
Product Considerations
- The display seems half-baked with non-functional bands restricting the functional real estate
- The remote makes a rattling noise, which some may find disconcerting initially, but is by design
- Outputs are extremely hot
- May be overhyped, the sound quality not quite matching up to the hype, or more importantly, matching up to the price tag
Comparisons (according to reviewers)
- Vs SMSL VMV-D1SE: The Spring 3 has better refinement and more of that airy quality on top
- Vs Denafrips Pontus 2: The Spring 3 was a little cleaner in the mid-range, with better bass definition and control, but the Denafrips had a warmer—more full-bodied—presentation and deeper soundstage
Takeaway: The Spring 3 KTE is a beautiful DAC that can bring listeners closer to their music. It may be worth buying to experience high-quality digital audio.
Video review
Our take on the brand
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