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I-O Data Soundgenic HDL-RAS2T Music Server/Audio File Transport

07-21-2020 | By Wojciech Pacuła | Issue 110

I-O DATA was founded in 1976 in the Japanese city of Kanazawa. I-O Data is one of the largest manufacturers of computer peripherals in this country. In 2016, an offspring brand called  Fidata was founded within company, whose audio files transports / music servers are intended for the "premium consumer market." In 2019, they decided to offer more attractively priced products under the I-O Data brand.

  • O Data Soundgenic HDL-RAS2T is a small device with an USB output. It is an audio files transport and music server in one. This means that it can play files stored on its internal memory, from external drives connected to the USB socket and from pendrives. However, it can also operate as a server - the files are then sent out via the Ethernet (RJ-45) socket and—through a router—they are sent to another files player. However, I believe it's primarily function is that of a music files transport.

Looking at the tested device, the I-O Data Soundgenic HDL-RAS2T, I experienced sort of a déjà vu—which in the Matrix movie was an indication of an error in the system. In this case it is deliberate and purposeful action—the HDL-RAS2T, which we test, looks from the outside and behaves identically to the HDL-RA4TB model, which we tested in February this year (HF | № 190) . The only difference between them is a different type of disc that I-O Data engineers decided to use in each of these models. The previous one featured an HDD (Hard Disc Drive), or mechanical memory, and the new one uses an SSD (Solid-State Drive), or semiconductor memory.

At first glance, this should not matter and both devices should behave identically. In audio, however, everything "matters or sounds," including the type of memory the serves music files for playback. And I-O Data has a lot of experience in this area—they conducted similar tests with high-end devices that they sell under the Fidata brand, with models such as HFAS1-S10U and HFAS1-XS20U. Both of these devices were built to prevent both mechanical and electromagnetic and radio interference. Today, this is the basic task of the engineers developing devices that play music from files. If you do not understand it, then you do not understand audio.


  • O Data designed its first mp3 player already in 2000, and in 2005 released their first DLNA compatible server. In 2012, a project was launched to develop an audio files server. Two years later, a prototype was presented at the Tokyo Audio and Home Theater Exhibition. It took them two more years before final product was ready. The result was the music server and audio files transport in one, the Fidata HFAS1-S10U. SOUNDGENIC HDL-RA4TB was the first product of this type sold with the I-O Data logo. Different brand was used to indicate a different approach to the product, in this case—a much lower final price.

Transport vs player

Let's start with a basic distinction between transport vs player. Let's use an analogy with a two-box CD player—files transport is a module that plays files from mass storage (internal or external), which is connected to an external digital-to-analog converter, usually using a USB cable. The file player is, in turn, a device that outputs an analog signal, i.e. a transport and a DAC in one. It can also feature a built-in storage or an external one.


  • HDD - Hard Disc Drive = a mechanical mass storage device
  • SSD - Solid-State Drive = a solid-state mass storage device
  • NAS - Network Attached Storage = a mass storage device connected via Ethernet
  • DLNA - Digital Living Network Alliance = an international organization of electronics, computer and mobile devices manufacturers
  • UPnP - Universal Plug-and-Play = a network protocol for personal computers and smart and wireless devices
  • LAN - Local Area Network = local Ethernet network; uses RJ-45 plugs
  • RENDERER/STREAMER = player/transport of audio files


As I've already mentioned, the Soundgenic can be used either as an audiophile NAS disk (with a capacity of 2 TB in the tested version) on which one stores music files, or as a transport of audio files ("renderer") with an internal SDD disc, which one connects to an external digital-to-analog converter.

On the internal SSD drive of the reviewed transport one can save music files, both via the home network and directly from a USB stick or a hard disk after connecting them to one of two USB type A (flat) ports on the rear panel. One connects the device with an external D/A converter using a USB cable. For control one uses the Fidata Music App, available for Android and iOS devices.

The I-O Data transport actually supports all types of files available on the consumer market, including WAV, FLAC, AIFF, as well as dff and dsf. This includes PCM files up to 768 kHz and 32-bits, and DSD up to DSD256 (11.2896 MHz) in DoP mode and DSD512 (22.5 MHz) in Direct DSD mode. We can connect to it an external HDD or SSD drive, USB sticks, or play files via an Ethernet connection from an external server.

The device does not work with any of the streaming services such as Tidal, Quobuz, and does not decode MQA files. As I wrote in the HDD version test, as usually, you need to choose your priorities yourselves (quality versus functionality).


The I-O Data Soundgenic HDL-RAS2T is a small device and that's why I placed it on a kind of a anti-resonance and anti-noise protection system. I placed  a passive EMI / RFI Verictum X Block  filter underneath the device and it was placed on three Vibrapod rubber pads. Thanks to this setup device benefited from stability and interference filtering.

The listening session was divided into three parts:

  1. Listening to the transport combined with D/A converters of the Mytek Brooklyn Bridge and Ayon Audio CD-35 HF Edition SACD player,
  2. Comparing the I-O Data player to the player section of the Mytek Brooklyn Bridge, where the Japanese device was connected to the USB input; it was a comparison of files played from the Tidal, as well as from I-O Data itself, which worked as a server,
  3. Comparing the I-O Data player to SACDs and CDs played using the Ayon; the Japanese device was connected to its USB input.

In the center of the system, as in the HDD version test, was the Mytek Brooklyn Bridge audio files player. I connected the tested product to its USB input using the Curious Cables USB. Both devices were connected to the FunBox 3.0 router using Ethernet cables. To the same router I connected the Synology DiskStation DS410j, with four HDD disks, 2 TB each (RAID 1). I separately compared the sound of transport to LPs.


Recordings used for the test (a selection):

  • ANNE BISSON, Blue Mind, Camilio Records CAMUSB141, "Master USB Flash," FLAC 24/96 (2009)
  • BILL EVANS, Bill Evans At The Montreux Jazz Festival, Verve /Universal Music LLC, SHM-SACD (1968/2014) + rip DSD
  • BILLIE HOLIDAY, Body and Soul, PolyGram/Mobile Fidelity UDCD 658, gold-CD (1957/1996) + DSD64
  • DEAD CAN DANCE, Into The Labyrinth, 4AD/Beggars Japan WPCB-10076, "Audiophile Edition," SACD/CD (1994/2008) + rip DSD
  • FRANK SINATRA, Where Are You?, Capitol Records/Mobile Fidelity UDSACD 2109, "Special Limited Edition | № 261", SACD/CD (1957/2013) + rip DSD
  • KRAFTWERK, Minimum-Maximum, Kling-Klang Produkt/EMI 3349962, 2 x SACD/CD (2005) + rip DSD
  • MAÂNOUCHE SWING QUINTET, Montreal Jazz-Up, Fidelio FAMF030, "Master USB Flash," USB Flash, WAV 24/96
  • VANGELIS, Blade Runner, Atlantic Records/Audio Fidelity AFZ 154, "Limited Edition | № 2398", SACD/CD (1998/2013) + rip DSD

I-O Data vs Mytek

Since I already knew the I-O Data player featuring an HDD, what I heard this time did not surprise me: it sounded great. Big, powerful, deep, full, dynamic. There was everything I like in this sound. But, as far as I can tell, the new version goes even further in all these elements. The difference between the SSD and HDD versions is not colossal, it's rather another small step towards refinement. But still, the result is noticeable and definitely appreciated.

Not that something was missing before, but the SSD—and I hear it every time with any device—minimizes something mechanical in the sound. The recordings sound smoother, fuller, are more "relaxed" internally. And thus we get a more natural sound.

A comparison with the file player in the Mytek Brooklyn Bridge confirmed everything I'd heard before. First of all, that Mytek is an excellent D/A converter. With both S/PDIF and USB inputs, it's in a class of its own. But also that its file player, although really pleasant sounding, is just a first step into the world of music files. And finally, that playing files from streaming services, even if they are MQA files, offers worse sonic results than playing the same files from local memory. This is something that I-O Data engineers have no doubts about, but also anyone who takes time to make such comparisons, in good conditions, shall realize what can be achieved by playing files in one or the other way.

I have nothing against streaming, I use Tidal passionately myself. But I listen to it more like to a radio station. And when I want to listen to something from a file, I use a dedicated audio files player. And in this role the tested device comes out great. Its sound is incredibly tangible and dynamic. It's better than files played on most other players and transports, though still not as good as achieved with good CD and SACD players.

This time I was surprised by I-O Data's ability to make small changes in sound pressure and imaging. This is a player that phenomenally showed solo in the Nardis track from Bill Evans's album Bill Evans At The Montreux Jazz Festival (1968). It was powerful, dense, multidimensional, exciting. It "got" under my skin and into my head.

But even more impressive was the way it was presented. The announcement begins the album. Immediately afterwards, there is applause, which is initially monophonic, as if the audience was being recorded with one microphone. But then the sound engineer opens the sliders and the applause becomes stereo, three-dimensional.

In a moment it gets even better. When the double bass enters, it is not located centrally, but it seems that its sound bounces from the side, next to us. This is the case when the instrument is point recorded, but its sound is also caught by another microphone, placed next to a different instrument. It creates an impression of the sound surrounding us. The player in Mytek didn't show it clearly, it just played a double bass. Cool, strong, accurate one, but without the aura around it that I-O Data has recreated flawlessly. For this to work, the device must be truly resolving.

I-O Data vs Ayon Audio

The pros and cons of the I-O Data player/server were even more obvious in the second part of the listening session. I connected it to the USB input of the Ayon Audio CD-35 HF Edition player and compared its sound with the sound of SACDs and CDs. It turns out that even in this combination the Japanese device offers a great tonality. It is low, deep, with a slightly shifted tonal balance towards the lower midrange. It gives the sound seriousness, mass and momentum. With every type of music.

The discs played from Ayon sounded a bit brighter, but not because the player brightened them up, but because it delivered more information at the top of the band. The tested audio files transport warms it and withdraws it up a bit. Not enough to flatten it, but rather so that it sounds like a nice amplifier with EL34 tubes in the output. The recordings are a bit "averaged," that is, they are not as well differentiated as from the discs. But this is normal—it is important that this "averaging" goes in the right direction, towards more pleasant listening experience.

We also get great, low bass from I-O Data. This is what distinguishes this design (as well as Fidata devices) from its competitors. I heard a great double bass, a drum kick, and above all a massive, impressive show of Kraftwerk's music. It was really something! The bass with a smooth midrange and warm treble, with good resolution, mean that even compared to SACD and CD discs the I-O Data was necessarily doomed to loose in terms of sound quality. I would even go as far as to say that I could understand those who'd prefer this type of sound. Not because it is better, but because it is so pleasant.


This small device will be an extremely valuable complement to many audio systems, and maybe even the main source. I see its disadvantages mainly in its functionality—streaming services are nowadays the basic source of music. But if we combine it with some nice "DAC" and "settle on" using a mobile device for streaming, then we will find a good balance. And even more, if we have a Mytek class player—together with I-O Data it should become an extremely functional, great-sounding digital source for the 21st century.

Technical specifications (according to the manufacturer)

  • Data storage: SSD 2 TB
  • Supported file types: wav, mp3, wma, m4a, m4b, ogg, flac, aac, mp2, ac3, mpa, aif, aiff, dff, dsf
  • Sampling frequencies (USB output): PCM: 44.1, 48, 88.2, 96, 176.4, 192, 352.8, 384, 705.6*, 768* (*only wav and aiff)
  • DSD (DoP): 2.8, 5,6, 11,2 MHz
  • DSD (Direct DSD): 2.8, 5.6, 11, 22,5 MHz
  • Resolution: PCM: 16, 24, 32-bit, DSD: 1-bit
  • Supported OS: Windows 10, Windows 8.1, Windows 8, Windows 7, OS X 10.7 - 10.11, macOS 10.12 -10.14
  • Transfer standard: 1000BASE-T/100BASE-TX/10BASE-T
  • LAN interface: RJ45 (with Auto-MDI/MDI-X support)
  • USB ports: USB 3.0 x 1, USB 2.0 x 1
  • Network compatible standard: UPnP AV
  • Power consumption: 7.3 W (on average), 29 W (max)
  • Dimensions (W x H x D, without feet): 168 x 134 x 43 mm
  • Weight: 1.2 kg

I-O Data SOUNDGENIC HDL-RAS2T Music server/audio files transport

Price (in Poland): 5990 PLN




Provided for test by:



Text: Wojciech Pacuła

Images: Wojciech Pacuła

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