Naim HDX music server


Let us start with a provocation: despite what manufacturers and press claim, the hi-fi sector does not involve great technological innovations, unless you want to consider it as the attainment of a zero comma something else obtained during the lab measurements. I think that the sole real innovation in the last years has been the availability, on a large scale, of high-resolution files and machines able to read them respecting the requirements needed to define a listening test of audiophile quality.

Well, in the case you are not aware of what I am talking about, I sum up the situation in brief: today the recording of a musical event is a digital process. The modern recording techniques have higher standards of quality than the classic Compact Disc by Red Book Standard, which we have known for more than twenty years. Hence, when we buy a CD we get a “degraded” version of the studio recording, so to assure its compatibility with our home digital players. Here comes out the idea of providing the enthusiasts with the original tracks, in form of digital files, in order to make them appreciate the higher quality. At this point, however, we bump into some problems. In fact, these files are immaterial entities and to acquire, store, classify and play them, you need information science knowledge and a broadband connection to buy legally the digital material on the Internet. Two main consequences follow. One is the trouble for the more elderly hi-fi connoisseurs in using a pc, since they are more accustomed to the electro mechanical technologies. The other, more serious consequence is the slow migration of the enthusiasts from the audio products to those more specifically related to IT and characterized by market logics (trade and distribution), which are totally different and, therefore, disorientating. In this unstable context, which is the role of streaming music today? I think it is reasonable to consider it as a means to "flank" the ordinary audiophile supports (CD and vinyl) rather than a substitute. Let us say that if you do not need room to store your LPs you do not need to digitalize your collection either. In any other case, streaming music serves the purpose of listening to the high resolution files bought on the Net or getting the records from your friend, in this case illegally, in order to value their artistic qualities and maybe purchase them afterwards. Different is the case of someone who starts afresh and in a short time can get a disc collection by simply using the Apple iTunes Music Store, which, make me stress this point, does not offer a very high resolution, unfortunately.

Technical overview

When Naim decided to design the HDX music server, probably the idea was to propose a high-end product capable of moving deftly inside the complex information of the streaming music, to take up what was good in it without showing its technical complexities to the user.

In this reading key, not only the HDX is a very interesting machine but also it is easy to understand the reasons why some choices, at first sight, could seem weird. Which ones? For example, I realized that the poor quality of the transport is because it does not aim at an audiophile purpose but only at the first acquisition phase or at a quick listening test. Another reason is that the user cannot choose by himself the format to write the data into the in-built hard disc. This is anything but a way to simplify things, the target claims. But let us move on and see what the Naim HDX is. We said that it is a music server, a machine capable of managing digital audio files memorized both into the in –built hard disc and into other net storage unities. Obviously, the music server must be connected to the net. For this reason, the Naim HDX presents an Ethernet port which allows the connection to a LAN (Local Area Network) in turn connected to a WAN (Wide Area Network). When the in-built hard disc of one Terabyte runs out of capacity it is possible to store more music into the other storage unities of the LAN, whilst from the WAN (read Internet) the Naim HDX can get the metadata, namely titles, cover images, etc. The connection is very simple to do: just plug the Ethernet socket to the ADSL and, thanks to the DHCP protocol, the machine configures itself immediately.
Now let us talk about something else. How do you “insert” the files into the HDX? There are two ways: the simplest one is the way chosen by Naim and consists in the acquisition of the CDs. This is the ripping procedure. It is automatic and consists in the transcription, bit per bit, of the CD content into the hard disc. The metadata are then coupled with it. In this operation, the HDX is rapid and precise: in five minutes, the disc is copied with the same quality of the original support. The other possibility is the HDX reading the content of external supports like the USB pen drives (as the Italian Fonè label does) or other hard discs which are shared on the local network by the NAS (Network Attached Server) and which are similar but with more capacity. Lastly, there is the possibility of connecting an iPod that can be driven by an interface. Is that all? No, it is not. What we need now is another passage named rendering, which consists in reading the data from the memory unit, interpreting and sending them to a digital-analogue converter. Obviously, the HDX is also a renderer capable of reading the most common digital formats (WAV, AIFF, FLAC, Apple Lossless, OGG Vorbis, AAC, WMA, MP3). It is also a very good D/A converter, which supports sampling frequencies up to 24 bit/192 kHz of depth, capable of presenting at the RCA or DIN provided outputs a signal that can be sent to a preamp exactly as happens with a CD player. Still, there are also digital outputs in the S/PDIF, 75Ω BNC and TOSLINK formats if you want to use a more performing converter like the Naim DAC, maybe with an external clock that can minimize the harmful phenomena of temporal distortion of the jitter.
The HDX is also equipped with a socket to connect one of the two power supply unities, named XPS and 555 PS, which can offer better performances. Finally, very interesting is the possibility of activating up to 6 different simultaneous streams if you have more than one system in different rooms. What does it mean? That the Naim HDX can be a musical store and serves, at the same time, up to six renderers, which are part of other six systems placed in different rooms.


The touch screen on the front panel is fine and easy to read. It allows a quick access to all the functions, even the hidden ones. The remote repeats all the touch screen controls but if you are distant from the device it is not easy to read the display. So, what to do? There are several options: to connect a computer display to the HDX VGA port, to use a PC connected to the local network and with a browser (Explorer, Firefox, Safari, etc.) to point the IP address of the machine that will then show a gigantic video touch screen. Furthermore, you can use a PC application (provided on the installation CD), an iPhone or an iPad which Naim has written a very good App for, to handle its music server via wireless. It is just to be spoilt for choice!

Once you have selected your own system, it is a pleasure to use the HDX device: the research of an artist, a track title, a musical genre is very flexible and with just few clicks you can find the chosen track among thousands. The access is very prompt.
And now let us talk about some listening considerations. The machine is provided with an internal conversion section that uses a Burr-Brown PCM1791A chip and a filtering section based on Burr Brown OPA604 opamps. In short, modern stuff that assures remarkable and fulfilling performances.
In making a comparative AB test between the CD player and the Naim HDX, it has been very difficult to recognise which device was playing!.

You can object that the HDX is very high-priced. That is a fact. Besides, the comparison with solutions for streaming music based on information technology products is somehow penalizing since these ones offer similar performances at lower costs. So, where the Naim HDX could redeem itself and show its real value? In my opinion, in the using experience it can offer. Because it does not need complex IT tweaking and integrates itself perfectly with the other Naim machines.
As I told in the beginning, this is not an exhaustive description of the product but an excursus on streaming music and on the basic characteristics of the machines designed for its fruition. I honestly think that, currently, the Naim HDX music server represents at best a kind of device for the fruition of this new support.





Thank you for the opportunity to comment on your recent review of the Naim HDX. We are pleased that you understood the huge amount of work we had to undertake to get a computer-based device to deliver the sound quality and musical performance we consider essential for a Naim product.
We have two points if we may:
1. The transport mechanism may look basic but it is the best transport for ripping CDs we could find. This along with our ripping software delivers good sounding bit perfect rips every time.
2. The HDX is as you say upgradeable by using a XPS or 555 PS power supply and this brings significant improvements to the performance. Another possibility is to connect a Naim DAC and then later add a separate power supply to the DAC.
Naim Audio

by Massimo
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