After Invisible Cities Part 2 by André Mehmari and Sergio Reze, ADS founded by Gustavo Cândido, offers us an immersion into a different musical universe with the album Trio Callas – Mozart Brahms Mehmari. The 5.0.4 recording literally places us at the heart of every instrument and every nuance, delivering an exceptionally refined immersive sound experience. This classical album not only allows us to discover another musical style but also to appreciate the richness of spatialization and the depth of the sound. I invite you to explore this album across various playback formats, up to DXD 5.1.4, to fully enjoy every detail and the full dimension of the music.
The Trio Callas, founded in 2021 in Salzburg, is made up of three musicians from diverse cultural backgrounds:
– Lucas Garcia Muramoto (cellist)
– Bella Schütz (pianist)
– Miguel Rocha (violinist)

In less than a year, they won the ProQuartet Prize in Paris and the Bacewicz Competition in Lódz.
Based in Austria, the trio regularly performs across Europe and other continents, including Japan, Canada, and South America. Under the direction of Cibrán Sierra Vázquez at the Mozarteum in Salzburg, they are supported by the “Yehudi Menuhin – Live Music Now” Foundation. The group explores both the classical repertoire and contemporary projects, engaging in innovative collaborations and immersive recordings, such as the album featured in this review.

The album is available for download on NativeDSD in Stereo (DSD64, DS128, DSD256, DXD, WAV 176.4kHz), 5.1 format (DSD64, DS128,DSD256, FLAC 96 kHz) and 5.1.4 (WAV 88.2kHz and Dolby Atmos TrueHD in MKV) formats.

You can find the description of ADS Studio in the review of the album Invisible Cities Part 2.

For this review, you will find 4 versions tested:

• Ed 1: DSD stereo – 2025
• Ed 2: DXD 5.1.4 – 2025
• Ed 3: FLAC 5.1 24 96 – 2025
• Ed 4: MKV Dolby Atmos TrueHD 5.1.4 – 2025

Below you will find the description of the different editions, as well as the measurements of each edition in the following chapters.

The album is composed of 8 tracks:

1. Mozart, Piano Trio in E major, K. 542 – I. Allegro
2. Mozart, Piano Trio in E major, K. 542 – II. Andante grazioso
3. Mozart, Piano Trio in E major, K. 542 – III. Allegro
4. Brahms, Piano Trio No. 2 in C major, Op. 87 – I. Allegro
5. Brahms, Piano Trio No. 2 in C major, Op. 87 – II. Andante con moto
6. Brahms, Piano Trio No. 2 in C major, Op. 87 – III. Scherzo. Presto
7. Brahms, Piano Trio No. 2 in C major, Op. 87 – IV. Finale. Allegro giocoso
8. Mehmari, Portais Brasileiros No. 5 – Rondo

Summary, scoring and Samples

Ed 1: DSD stereo – 2025

Presentation

The DSD64 version is delivered as a stereo DSF file, encoded in DSD64 (2.8224 MHz / 1-bit).

Waveform and Spectrum: DR13

The waveform of the DSD stereo – 2025 shows a high range confirmed with DR13.

The spectrogram below represents the SACD. The yellow arrow shows that the signal rises well above 20 kHz. We also find the characteristic noise of DSD64 beyond 30 kHz (white arrow).

The graph below represents the spectrum of the DSD stereo – 2025.
The spectrum of the DSD stereo version up to 24 kHz. Beyond this frequency, the DSD version shows an increase in noise, characteristic of DSD64 encoding.

Synthesis and listening

The DSD stereo version was encoded from a 2.0 downmix of the DXD 5.1.4 master. Converting a 5.1.4 recording into a stereo version is always a delicate process: some of the spatialization and 360-degree sound field is inevitably lost. However, the original character of the recording is preserved, retaining all the richness of detail and an open, well-balanced stereo soundstage reminiscent of the 5.1.4 version.

Rating:

• Dynamic: ●●●●o (4)
• Bandwidth: ●●●●● (5)
• Restitution: ●●●oo (3.5)

Sample : Mozart, Piano Trio in E major, K. 542 – III. Allegro 1 bits 2822.4 kHz:

Ed 2: DXD 5.1.4 – 2025

Presentation

The DXD version is delivered as a 5.1.4 WAV file, encoded in PCM (352,8 kHz /24 bits). In this DXD format as a WAV file, the album size is massive, reaching 33.7 GB.

Below the spatialization for all tracks. Click on the images to zoom in.

Below the video spatialization for the track : Mozart, Piano Trio in E major, K. 542 – III. Allegro.

Waveform and Spectrum: DR12

The waveform of the DXD 5.1.4 version shows a very good dynamic range confirmed with DR12.

The spectrogram shows that the signal extends up to 88 kHz (yellow arrow), with no musical information present beyond this limit (white arrow). This cutoff is directly related to the 176.4 kHz sampling rate used during the original recording, which defines the maximum usable bandwidth. Consequently, the DXD mastering at 352.8 kHz does not add any additional high-frequency content but merely provides a higher-resolution working format.

The graph below represents the spectrum of the DXD 5.1.4.
The Spectrum of the DXD 5.1.4 shows that the signal extends up to 88 kHz (yellow arrow), with no musical information present beyond this limit (white arrow). This cutoff is directly related to the 176.4 kHz sampling rate used during the original recording, which defines the maximum usable bandwidth. I asked the engineer Gustavo Candido: “why switch to DXD format for mixing and broadcasting when the recording is done at 176 kHz?“, who replied: “In answer to your question, I would say that your observation is correct. Converting files to a higher sampling rate does not create more bandwidth in the frequency spectrum. However, processing files at a higher sampling rate, such as DXD, results in better technical quality in both the mixing and mastering phases, as well as when rendering the master files for delivery to the end consumer. I sometimes use a reverb plug-in and/or an equalization filter to make minor adjustments. Working with these digital tools in oversampling mode reduces or eliminates potential errors, such as aliasing, clipping, and quantization distortion. “

Synthesis and listening

The DXD 5.0.4 version provides access to the sound quality of the album’s original master. It faithfully reproduces all the subtlety and richness of the multichannel recording, while accurately recreating the spatialization captured with a 5.0.4 microphone setup.
This version delivers an exceptionally transparent and precise listening experience, both in terms of tonal quality and the breadth of the soundstage.
This type of recording goes beyond simply capturing the musicians: it also conveys the acoustics and atmosphere of the recording space, giving the listener the feeling of being at the very center of the performance.
Listening to this album in DXD 5.0.4 on a 5.1.4 system provides a truly immersive musical experience.

Rating:

• Dynamic: ●●●oo (3.5)
• Bandwidth: ●●●●● (5)
• Spatialization: ●●●●●●●●oo (7.9)
• Restitution: ●●●●● (5)

Sample : Mozart, Piano Trio in E major, K. 542 – III. Allegro 5.1.4 24 bits 176.4 kHz:

The sample is in 7.1 wav format, if you can not play the sample in your navigator, you can save it, right button menu and “Save Audio As…” and play it with an external player.

Ed 3: FLAC 5.1 24 96 – 2025

Presentation

The FLAC 5.1 version is delivered as a 5.1 FLAC file, encoded in PCM (96 kHz / 24 bits).

Below the spatialization for all tracks. Click on the images to zoom in.

Below the video spatialization for the track : Mozart, Piano Trio in E major, K. 542 – III. Allegro.

Waveform and Spectrum: DR11

The waveform of the FLAC 5.1 24 96 – 2025 version shows a good dynamic range confirmed with DR11.

The spectrogram shows that the signal rises to 48 kHz with no signal above this frequency (white arrow) due to the 96 kHz sampling frequency.

The graph below represents the spectrum of the FLAC 5.1 24 96 – 2025.
The 5.1 is based on a sampling frequency of 96 kHz, limiting the bandwidth to 48 kHz. The LFE channel is not used.

Synthesis and listening

The PCM 5.1 version comes from a downmix of the DXD 5.1.4 master. Although it no longer includes the height channels, it retains the spatial information captured with the 5.0.4 microphone setup.
This downmix inevitably reduces some of the volume and sonic breadth found in the original DXD mix.
However, when played on a 5.1 system, the result remains immersive: the soundstage maintains a convincing sense of depth and space, and the instruments are rendered with a natural presence.

Rating:

• Dynamic: ●●●oo (3.5)
• Bandwidth: ●●●●● (5)
• Spatialization: ●●●●o (3.9)
• Restitution: ●●●●o (4)

Sample : Mozart, Piano Trio in E major, K. 542 – III. Allegro 5.1 24 bits 96 kHz:

The sample is in 5.1 wav format, if you can not play the sample in your navigator, you can save it, right button menu and “Save Audio As…” and play it with an external player.

Ed 4: MKV Dolby Atmos TrueHD 5.1.4 – 2025

Presentation

This version is offered with lossless Dolby Atmos TrueHD encoding, encapsulated in an MKV container for each audio track. This format provides greater accessibility, allowing easy playback using a Dolby Atmos-compatible preamplifier or AV receiver. A sample in MKV format is also available, enabling you to experience the recording in 5.0.4.

To provide more detail about this version, the Dolby Atmos mix was created from a Dolby Atmos ADM master featuring a 5.1 bed and four audio objects assigned to the height channels (more information on Dolby Atmos here). The ADM file faithfully reproduces the master’s tracks but with a reduced sampling rate of 48 kHz.

When playing this Dolby Atmos TrueHD version on a 5.1.4 system, the playback perfectly matches the 5.0.4 channels of the DXD master. However, on a 7.1.4 system, playback does not occur strictly in 5.1.4: the Dolby decoder redistributes the 5.1.4 surround channels across the four surround channels of the 7.1.4 setup to create a more immersive effect—consistent with Dolby Atmos’s original design for cinema. This results in a slightly different spatial rendering in the surround field.

Once the system is reconfigured to 5.1.4, everything returns to normal. This specific behavior of Dolby decoding led to several technical discussions with Gustavo Cândido in order to fully characterize and understand it.

Below the spatialization for all tracks. Click on the images to zoom in.

When played on a 7.1.4 system, the spatial rendering corresponds to the one shown below, as indicated in the description of the MKV version:

Waveform and Spectrum: DR12

The waveform of the MKV Dolby Atmos TrueHD 5.1.4 – 2025 version shows a very good dynamic range confirmed with DR12.

The spectrogram of the Atmos in 5.1.4 version of blu-ray shows that the signal goes down to 24 kHz (yellow arrow) and that there is no signal above this frequency (white arrow), due to the 48 kHz sampling frequency used with Dolby Digital TrueHD encoding (lossless).

The graph below represents the spectrum of the MKV Dolby Atmos TrueHD 5.1.4 – 2025.
The Dolby Atmos is based on a sampling frequency of 48 kHz, limiting the bandwidth to 24 kHz. The LFE channel is not used.

Synthesis and listening

This MKV Dolby Digital version is the easiest to use for achieving 5.1.4 playback. It can be played directly through an audio-video amplifier or a processor capable of decoding this format (see details above regarding 5.1.4 playback in Dolby Digital TrueHD).
In a 5.1.4 configuration, the original recording is preserved; although there is a slight loss of transparency compared to the DXD version, this option allows you to fully enjoy the production work on the album while benefiting from a setup that is simpler to implement.

Rating:

• Dynamic: ●●●oo (3.5)
• Bandwidth: ●●●●o (4)
• Spatialization: ●●●●●●●ooo (7.3)
• Restitution: ●●●●o (4)

Sample : Mozart, Piano Trio in E major, K. 542 – III. Allegro decoded in 5.1.4 24 bits 48 kHz:

The sample is in 5.1.4 wav format, if you can not play the sample in your navigator, you can save it, right button menu and “Save Audio As…” and play it with an external player.

Sample : Mozart, Piano Trio in E major, K. 542 – III. Allegro MKV Dolby Atmos 48 kHz:

The sample is in MKV format, you can save it, right button menu and “Save Audio As…” and unzip the file and play it with an external player and a Dolby Atmos decoder.

Sample 1 Ed 4: MKV Dolby Atmos TrueHD 5.1.4 – 2025

ADS presents a beautiful album by Trio Callas that immerses the listener fully in the heart of the music. The 5.0.4 recording places the listener at the center of the trio, revealing all the richness and depth of the interpretations of Mozart and Brahms. If you have the opportunity, I highly recommend listening to this album on a 5.1.4 system to fully experience the immersive depth of this recording.

Dynamic Range measurements are shown below.

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Measurements

Dynamic Range comparaisons

Dynamic represents the ability to reproduce a wide range of sounds from the softest to the loudest. The target is to compare the dynamics of the music and not of the media (CD, digital files or vinyl).

For our 4 editions reviewed have obtained the following Dynamic Range (DR) :

	DSD stereo – 2025	DXD 5.1.4 – 2025	FLAC 5.1 24 96 – 2025	MKV Dolby Atmos TrueHD 5.1.4 – 2025
Global	DR13	DR12	DR11	DR12
Min	DR12	DR11	DR10	DR11
Max	DR15	DR13	DR13	DR13
Mozart, Piano Trio in E major, K. 542 – I. Allegro	DR13	DR12	DR11	DR12
Mozart, Piano Trio in E major, K. 542 – II. Andante grazioso	DR12	DR12	DR11	DR12
Mozart, Piano Trio in E major, K. 542 – III. Allegro	DR13	DR12	DR11	DR12
Brahms, Piano Trio No. 2 in C major, Op. 87 – I. Allegro	DR13	DR12	DR11	DR12
Brahms, Piano Trio No. 2 in C major, Op. 87 – II. Andante con moto	DR13	DR13	DR11	DR12
Brahms, Piano Trio No. 2 in C major, Op. 87 – III. Scherzo. Presto	DR12	DR11	DR10	DR11
Brahms, Piano Trio No. 2 in C major, Op. 87 – IV. Finale. Allegro giocoso	DR13	DR12	DR11	DR12
Mehmari, Portais Brasileiros No. 5 – Rondo	DR15	DR12	DR13	DR13

As a reminder, the scale goes from 0 to more 20, but the dynamics are considered good from 12, quite good between 10 and 11, and deteriorate below 10.

Detail of the ratings :

• Dynamic :
  1. Significant dynamic compression, DR less than 7
  2. Compression of the present dynamics, DR between 7 and 9.
  3. Correct piece DR >=10
  4. No dynamic compression (DR >12), dynamic rendering
  5. No dynamic compression, high DR and very dynamic sound rendering
• Spectrum :
  1. Spectrum cut and less than 15 khz
  2. Spectrum cut at 15 khz
  3. Spectrum not conforming to the original and cut (not HD) or original but limited bandwidth (but less than 20 kHz)
  4. Spectrum conforming to the original (but not HD)
  5. Spectrum conforming to the original with HD resolution (higher than 24kHz)
• Surface noise (only for vinyl):
  1. Continuous audible noise
  2. Audible surface noise except on passages with a high level of noise
  3. Reduced surface noise, barely audible on low level crossings
  4. Low surface noise, very good quality
  5. Very low surface noise, no defects, almost inaudible on the quiet passages (exceptional disc)
• Spatialization :
  • Between 0 and 5 for 5.1 or 7.1 channels configuration
  • Between 0 and 10 for Atmos configuration (7.1.4)
  • For more information on spatialization, you can read the article describing this parameter here.
• Restitution :
  1. Low quality of the restitution mixing dynamics, clarity, separation of voices and instruments.
  2. Average quality of the restitution mixing dynamics, clarity, separation of voices and instruments.
  3. Quality of the restitution mixing dynamics, clarity, separation of voices and instruments. Good record.
  4. High quality of the restitution mixing dynamics, clarity, separation of voices and instruments. Very high level disc.
  5. Maximum quality of the restitution mixing dynamics, clarity, separation of voices and instruments. Exceptional disc.

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