The Complete Guide To HiFi UPnP / DLNA Network Audio

Intro

The following guide was designed for audiophiles. The guide describes UPnP based home audio reproduction, provides use pro and cons of UPnP, examples, and recommendations for successful UPnP audio implementations.

Overview

Network based audio can be delivered using several different protocols and technologies such as UPnP, DAAP (Apple), and Ravenna among others. UPnP is the most common network audio protocol in use today. It's used in both two channel single room systems and whole house network audio distribution. Ironically UPnP is extremely simple for end users and a bear for product producers. The more one digs into the UPnP protocols the more divergent information with common frustration one finds. This guide will not turn a novice into an expert. I hope it will provide all the information computer audiophiles need to understand and enjoy UPnP based audio playback.

What is UPnP?

Universal Plug and Play consists of several protocols or rules that enable networked hardware devices and software applications to communicate and work together without end user configuration. UPnP devices don't use device drivers, like USB printers and other hardware, for communication and interoperability. Through use of common protocols UPnP devices automatically advertise their services or capabilities enabling auto discovery of devices on a network. UPnP can be seen as a high level framework that has been refined by the UPnP AV architecture for increased performance in audio and video environments.

What is UPnP AV?

UPnP AV is a refinement of the general UPnP protocols. A main goal of UPnP AV is interoperability between controllers and AV devices. For example enabling audio to flow from a NAS to an audio playback device without intervention from a controller. The descriptions below are tailored for computer audiophiles by referencing audio and music rather than all the media types (video, photos, etc…) UPnP AV can accommodate. The UPnP AV architecture specifies three important devices, each with its own services, for audio playback, the Media Server, Media Renderer, and Control Point.

1. Media Server

A Media Server is a device that stores content, advertises the availability of this content for streaming across the network, and enables browsing/searching this content from control points. Media Servers can stream content to multiple devices and be controlled by multiple control points simultaneously. Most UPnP AV Media Servers contain three services, a ContentDirectory Service, a ConnectionManager Service, and an AVTransport Service.

a. Content Directory Service enables a control point to browse the Media Server and view information about available music such as metadata (album title, artist, track name, etc…). This service also identifies the data formats supported by the server for its content. Using this information a control point can determine if the playback divide (renderer) is capable of handling the content.

b. Connection Manager Service is what manages Media Server connections to playback devices (renderers). Through this service a control point instructs a Media Server for its next content delivery to a renderer.

c. AV Transport Service is used by a control point for actions including Play, Pause, Stop, Seek, etc… This service also duplicates itself on the Media Server to enable streaming to multiple playback devices simultaneously.

Example - A very common Media Server for computer audiophiles is a network attached storage (NAS) unit. Synology NAS units ship with a Media Server application. When enabled this application advertises the NAS as a UPnP AV Media Server and allows control points to browse music and stream it from the NAS directly to a UPnP AV playback device. The Synology NAS simply broadcasts on the network that it's available. Other UPnP AV devices can then see information about what it contains, what communication protocols it supports, what type of music it can serve, and details such as album, artist, track, etc…

2. Media Renderer

A Media Renderer is a device that either converts and/or reproduces audio. Computer audiophiles are likely most familiar with renderers as several HiFi companies manufacturer components that render (convert and/or reproduce) audio. A renderer can convert network based audio into another form of digital audio such as S/PDIF and pass this audio along to another non-UPnP AV device or a renderer can convert the network audio into analog for playback. Frequently a renderer is the final device in the UPnP AV chain turning music from streamed content into something audiophiles can hear. Advanced renderers also enable limited control of Play, Pause, Stop, Seek, Volume, etc… Similar to the Media Server a Media Renderer usually contains three services, a Rendering Control Service, a ConnectionManager Service, and an AVTransport Service.

a. Rendering Control Service enables a control point to specify how the renderer operates. This service enables commands such as Volume and Mute.

b. Connection Manager Service, in addition to managing connections to the renderer, enables a control point to read its supported communication protocols and data formats. Using this service a control point can determine what types of music file formats or codecs a renderer supports.

c. AV Transport Service is used by a control point for actions including Play, Pause, Stop, Seek, etc…

Example - The most common Media Renderers for computer audiophiles are made by Linn, Naim, PS Audio, T+A, and other notable HiFi companies. Other non-audiophile type renderers are TVs and game consoles such as Xbox. A Linn DS series renderer accepts music streaming from a Media Server such as a Synology NAS and outputs this music as either an analog or digital signal. Another Media Renderer is the Simple Design Rendu. The Rendu also accepts audi from a Media Server, as directed by a control point, and converts it from Ethernet to S/PDIF output for connection to a DAC.

3. Control point

A pure Control Point simply acts like an air traffic controller viewing planes ready for takeoff and sending them to a destination. A Control Point is often handheld like an iPhone, iPod Touch, iPad, or Android device. Through the Control Point's user interface, usually an app or web page, end users browse Media Servers and select music for playback. The Control Point then instructs the Server and Renderer. Once playback instructions are given to the UPnP AV devices the Control Point isn't part of the device to device communication. In other words, music streamed from a Media Server doesn't flow through a Control Point on its way to the Media Renderer. This is an important piece of UPnP AV as most standard UPnP devices only communicate with a Control Point by receiving instructions rather than taking the next step in communicating with other UPnP devices outside the communication link from device to Control Point. This is also known as out-of-band communication. The following is an example of a sequence of events between a Control Point, Media Server, and Media Renderer. Computer audiophiles will be especially interested in step "i" as it pertains to gapless playback.

a. Discover AV Devices - The Control Point (CP) automatically discovers Media Servers and Media Renderers on the network.

b. Locate Desired Content - The CP browses the Media Server's available music and receives information about the Server's supported protocols and formats.

c. Get Renderer’s Supported Protocols/Formats - The CP asks for and receives the Renderer's list of supported protocols and formats.

d. Compare/Match Protocols/Formats and Check Playability - Information from both Server and Renderer is compared. The CP then selects the protocol and format supported by both devices.

e. Configure Server/Renderer - The CP informs and Server and Renderer about upcoming connections and the protocol & format to be between devices.

f. Select Desired Content - The user via the CP identifies the specific track, album, playlist, etc… to be delivered from the Server to the Renderer.

g. Start Content Transfer - Selected music is sent directly to the Renderer.

h. Adjust Rendering Characteristics - User can select Play, Pause, Stop, Seek, and Volume, etc… via the CP as the music is playing through the Renderer.

i. Repeat: Select Next Content - This is the critical step for gapless playback. The CP uses the command SetNextAVTRansportURI to identify the next track to be sent from the Server to the Renderer. If a Renderer doesn't support SetNextAVTRansportURI it will not support gapless playback as specified by the UPnP Forum.

J. Cleanup Server/Renderer - The CP closes the communication session between devices.

Example - The most common Control Points are Apple (iOS) and Android devices. The Control Point hardware must also feature Control Point software. A common CP app for iOS is PlugPlayer. PlugPlayer can run through the aforementioned steps with a Synology NAS as the Media Server and Linn DS as the Media Renderer. In my explanation of a Control Point I specified a "pure" Control Point. However, apps like PlugPlayer are more just a Control Point. PlugPlayer can also use an iPhone as the Media Server and Renderer. Or, PlugPlayer can use the Synology NAS as the Server and the iPhone as the Renderer.

What is DLNA?

Digital Living Network Alliance (DLNA), like UPnP, is an organization. What computer audiophiles commonly refer to as DLNA is really a set of guidelines, restrictions, or rules for interoperability that are broader but tighter than UPnP. By governing more items on the network the DLNA guidelines create a more restrictive ecosystem. These DLNA guidelines are based on the UPnP architecture v1.0 and UPnP AV. DLNA guidelines identify Device Discovery and Control, and Media Management as key ingredients leveraged from UPnP and UPnP AV respectively. DLNA isn't a subset of UPnP. It mainly differs from UPnP in scope. DLNA's broader scope includes specific file formats or media codecs and content protection. In general a DLNA certified device will work with UPnP devices but not all UPnP devices work with DLNA certified devices. The fact that a device doesn't display the DLNA certified logo doesn't mean it isn't 100% compatible with the DLNA guidelines. Some manufacturers elect not to pursue DLNA certification because of the added cost.

DLNA guidelines separate certified devices into three classes, Home Network Devices, Mobile Handheld Devices, and Home Infrastructure devices. Within the Home and Mobile device class are devices similar to the UPnP AV specified devices. DLNA specifies a Digital Media Server, Digital Media Renderer, and Digital Media Controller nearly identical to UPnP AV's Media Server, Media Renderer, and Control Point. One difference in the Home device class for DLNA is the addition of a Digital Media Player. The DMP functions as a Control Point and Renderer. Both browsing a Media Server and playback are capabilities of the DMP. UPnP AV non-DLNA devices have the same capability but the UPnP Forum doesn't separate the devices into a separate class. The Mobile Handheld DLNA device class includes devices similar to the Home class such as Mobile Digital Media Server and Mobile Digital Media Renderer. The Mobile class also includes a few devices such as an Uploader and Downloader. The capabilities are similar to other devices and cover the Mobile devices, and DLNA Home Infrastructure Devices, in depth is outside the scope of this guide.

UPnP / DLNA In HiFi

UPnP based audio/video has been around for years in mass market products such as TVs and disc players. One of the first HiFi manufacturers to release UPnP products was UK based Linn. In mid 2007 Linn released its Klimax DS network player to a technically unsavvy HiFi marketplace. The original Klimax DS was far from perfect but it was Linn's first network audio product. Plus much of the audio press failed to completely grasp the concept and rated the unit's usability poorly. Since the original Klimax DS release Linn has been on an unwavering UPnP network audio course. Ethernet is Linn's interface of choice no doubt about it. In recent years other HiFi manufactures including T+A, Audio Research, Naim, and dCS to name a few have released UPnP based products. Most manufacturers see UPnP as a good option but not the only option for computer based audio. I think this is the correct approach. UPnP or Ethernet based products aren't for everybody in every situation much the same as USB isn't for everybody all the time. Both interfaces have pros and cons. Neither one will completely kill off the other. UPnP software has slowly improved over the years, but remains far from perfect. Some products install directly on a NAS while others require the Windows operating system on a standard PC. Finding a software solution for a Media Server can be frustrating as each program functions a bit differently and offers different capabilities.

Pros

• UPnP based network audio is a dream come true for computer audiophiles who can't or won't place a music server or computer in their listening environments.
• Aesthetically UPnP renderers such as the Linn DS series and dCS Upsampler look far better in a HiFi rack than any standard computer.
• UPnP renderers and servers connect to networks via varying lengths of ethernet cables rather than USB, FireWire, or Thunderbolt. A single Ethernet cable can typically run 100 meters whereas USB is limited to around 16 feet.
• Noisy network attached storage units / Media Servers can be place anywhere on the Ethernet network eliminating the possibility of noise creeping into the listening environment.
• Playback from a UPnP Media Server to a Media Renderer is less prone to bit transparency issues as it doesn't use audio playback software or an operating system's audio engine for audio output. Thus, output modes like WASAPI and ASIO don't apply to UPnP playback.
• Playback of different sample rates is automatic without the need for additional software as long as the UPnP renderer supports the same rate of the music being played.
• UPnP Media Servers and Media Renderers usually require far less maintenance or zero updating where as computers running jack of all trades software require user attention more frequently.
• Easy to electrically isolate Computer and NAS from the audio playback system.

Cons

• Network must be stable and robust for UPnP to function correctly at all sample rates.
• Learning curve can be steep for users unfamiliar with UPnP terminology and networking.
• An optimized system from network to NAS to Media Server to Media Renderer to Control Point is more likely to require professional setup from dealer than a standard computer based playback system.
• Ideal configurations are much more complicated than the minimum requirements and much more complicated than music servers such as the Aurender or SOtM sMS-1000.
• Ripping CDs in most cases still requires a computer because neither Media Server nor Media Renderer can rip these discs.
• Editing metadata and music library management in most cases requires a computer running the same or similar software one would use for USB based playback.
• Knowledge of network attached storage units and basic file sharing terminology is highly recommended for continued smooth use and operating of the entire system from CD ripping through final playback.
• Troubleshooting issues such as dropouts, pops, ticks, lack of remote control, among others is much more complicated than troubleshooting with a locally attached music server.

Recommendations and Examples

UPnP audio playback requires a Media Server, Media Renderer, and Control Point in addition to a solid network infrastructure. The bare minimum requirements for UPnP playback will not lead to a successful or satisfying UPnP implementation. Computer audiophiles could squeak by with something as simple as a wired PC acting as the Server and Control Point sending audio to the Renderer of their choice. This type of configuration doesn't take advantage of UPnP's capabilities and doesn't invite one to use the system frequently. Stepping up to a high quality wired and wireless network and using separate UPnP devices when needed can increase one's enjoyment of his UPnP based audio system greatly. Selecting solid hardware and software, and configuring both correctly can eliminate most of the ills associated with UPnP audio such as pops, ticks, dropouts and unintended gapped playback. The following non-exhaustive list contains examples of Media Servers, Media Renderers, Control Points, and UPnP software. Readers should keep in mind that Media Servers and Control Points require both software and hardware. In addition, not all hardware and software are compatible with each other due to support for specific operating systems or serving and rendering hardware.

UPnP AV Media Server Hardware

• Synology Network Attached Storage (NAS) - Many NAS units can be UPnP AV Media Servers. I've had great success with Synology hardware and software. Using a NAS as a Media Server enables users to stream directly from the NAS to a Media Renderer. There are caveats to this approach such media servers software's lack of configuration options and possibly more limited support for file formats and navigation menus compared to PC or Mac based Media Server software.
• Apple Macintosh - With the proper software any Mac can be a UPnP AV Media Server. UPnP Software choices for Mac are more limited compared to Windows based PCs.
• Windows based PC - With the proper software any PC can be a UPnP AV Media Server.

UPnP AV Media Server Software

• Synology Media Server built-in application - This application is functional and gets the job done enabling users to stream music directly to HiFi systems. However, it isn't the most configurable, flexible, or thorough server software.
• JRiver Media Center - JRMC is my favorite server software because it's highly configurable, flexible, thorough, and supports more file formats including DSD/DoP/DoPE than most other servers. Plus, JRiver support and responsiveness to feature requests is unmatched.
• Illustrate's Asset UPnP - Asset is my second favorite UPnP software. It doesn't support all the formats that JRMC does and the support, while good, isn't as good as JRiver's.
• MinimServer - This is an upcoming application that was first to support streaming DSD. Installation can be more difficult and frustrating than other UPnP server applications. MinimServer supports more platforms than any other server software. it can be installed directly on NAS units, Macs, PC, and LInux machines. Watch this application in the future for continued improvement. It has great potential.
• Twonky - Twonky has been around for quite awhile but has been complained about for about as long as it has been around. It has improved over the years but remains inferior to other media server applications.
• Linn Songbox - A Linn centric app that works well with Linn's Kinsky Control Point software. Songbox enables easy access to a user's iTunes library when installed on a Mac or PC.

UPnP AV Control Point Hardware

• Apple iOS based devices (iPhone, iPad, iPod Touch) - iOS devices have become a HiFi industry standard for use as Control Points. I use them daily and highly recommend them.
• Android based devices - Android devices have great flexibility and give users great freedom. But, the UPnP AV Control Point application selection is not as large as iOS devices.
• Apple Macintosh - With the proper software any Mac can be a UPnP AV Control Point.
• Windows based PC - With the proper software any Mac can be a UPnP AV Control Point.

UPnP AV Control Point Software

• PlugPlayer - PP has undergone a few updates over the years that have improved its performance and stability nicely. It's still not the most stable app, but it's the most universal UPnP AV Control Point software. It's available for both desktop and mobile platforms.
• Linn Kinsky - Linn centric. Available for both desktop and mobile platforms.
• dCS HD - dCS iPad app works with Vivaldi Upsampler. Available for iOS devices only.
• JRiver Media Center - JRMC is in a unique position because it functions as a Control Point, Media Server, and Renderer if enabled. As a Control Point on the desktop it works exactly like it does when playing music locally to a USB DAC. All the capabilities to edit metadata and curate one's music library are available in JRMC even when used as a Control Point. Here's where things get a little tricky. JRMC can also be controlled by JRemote for iOS. JRemote doesn't become the Control Point rather it's controlling the Control Point. Using JRemote it's possible to send music to multiple zones, control volume and of course select music among many other items. My favorite UPnP AV configuration includes JRemote.
• Bubble DS - Android based Control Point software developed by a Linn DS user. I haven't used this app
• Songbook - Has been around for awhile and has expanded to support Linn, Naim, T+A, and other UPnP hardware. Songbook runs on iOS devices and OS X desktops. Bookshelf Apps, the creator of Songbook, also develops similar apps for HiFi customers in need of custom Control Point software. Many HiFi companies using the Stream Unlimited UPnP platform also use a custom version of this app created by Bookshelf Apps.

UPnP AV HiFi Media Renderers

• Linn - DS Series
• T+A - E Series, HV Series
• Naim Audio - Uniti, ND Series
• Simple Design - Rendu
• Audio Research Corporation - Ref DAC
• dCS Vivaldi - Upsampler
• PS Audio - PWD w/ Bridge PS Audio PWD

A successful HiFi UPnP implementation requires a robust and reliable wired and wireless network. I haven't used all makes and models of routers, switches, and wireless access points but I have used some good and some bad equipment over the years. My recommendations are based on experience with products at home and in an enterprise setting, conversations with colleagues, my understanding of the technology, and countless hours of research. Any or all of my recommended network components can be exchanged for something different easily. I can't say if other equipment will work as well, worse, or better than what I'm using, but I can say there are countless ways to achieve the same goal of a robust and reliable network infrastructure. I've settled on a very good combination of products for my own network that I recommend to nearly all UPnP audio users. I created my network to handle relatively high data throughput and simultaneous multi-zone high resolution audio/video streaming. Here is a list of what I use and why I use it, starting from the Internet and working my way inward.

My Network

• Internet Service - Comcast Extreme 105 Mbps - I live and work on the Internet and want the fastest connection I can reasonably get to save time and not inhibit any online activity I may need to test. Bring on the highest resolution downloads :~)
• Modem - Cisco DPC3000 DOCSIS 3.0 - This modem supports Gigabit speed on both the WAN and LAN ports. It has been very solid. I've never had to reboot the modem.
• Router - Cisco RVS4000 - This router supports Gigabit Ethernet on both the 1 WAN and 4 LAN ports. The web configuration of this router is fairly straight forward with enough features for me to accomplish what I need. I prefer a wired router without wireless capability because wireless is far better implemented by other devices and works better when located based on signal strength rather than proximity to the cable modem.
• Ethernet Switch - Cisco SG200-26 - I like this Cisco switch because it has enough Gigabit Ethernet ports for my network devices, is highly configurable, has a large backplane, and it supports 802.3ad (Link Aggregation Control Protocol). The SG200-26 also works without any configuration when dropped into a network and plugged-in. This switch has a 38.69 Mpps switching capacity and 52 Gbps forwarding performance. This 52 Gbps forwarding performance is equal to the number of 1 Gbps ports x 2 because full duplex 1 Gbps ports are capable of 1 Gbps each way for a total of 2 Gbps. Some switches and many routers have what is called an over subscribed backplane. These switches may feature 26 ports but only offer forwarding throughput of 10 Gbps. It's cheaper to manufacturer a less capable switch and the companies are guessing the average home user won't put much data through the switch at one time. The chances of my network activities maxing out this Cisco switch are very small. But it's nice to know bandwidth isn't a problem if I have an issue streaming audio. I also like the SG200-26's support of 802.3ad (Link Aggregation Control Protocol). This enables me to connect both 1 Gbps ethernet ports from my Synology DS1812+ NAS to the switch and bond them into a single 2 Gbps (4 Gbps full duplex) port. My music servers only support 1 Gbps connections max so they can't take advantage of the additional bandwidth when pulling music from the NAS. However streaming 24/192 audio to five or six zones simultaneously is another story.
• Ethernet Switch - Netgear GS108 - I place this switch right outside my listening room because I don't want to run eight individual Ethernet cables from my main Cisco switch to this area. The GS108 is a great performer. The unit has a fanless design as well. This Netgear switch is connected to the Cisco switch rather than through the Cisco router. I prefer to keep my network traffic on the high speed switches rather than send it through a router with questionable performance capabilities beyond its Internet traffic duties.
• Wireless Access Points - Apple AirPort Extreme & Express- I use two AirPort Extremes in my house and one AirPort Express. The Extremes are set to Bridge mode acting solely as wireless access points with a single Ethernet connection back to my Cisco SG-200-26 switch. I don't believe the wired switching capabilities of the AirPort Extremes are nearly as robust as a Netgear GS108 or Cisco SG-200-26. Apple claims the Extremes have a four port switch, but Apple was unwilling to confirm this in writing or verbally when I asked if it's a true switch or simply a hub. The AirPort Express is configured as a separate wireless network that handles only the traffic from my Dropcams. Each of these cameras sends live audio and HD video back to the Dropcam mothership DVR 24/7/265 and can really slow down a wireless network.

My main UPnP AV devices are the following, in order of preference. I have several other items running on my network for testing, but don't consider them my main devices or applications.

Media Server Hardware / Software

• CAPS Topanga running JRiver Media Center
• Intel Next Unit of Computing (NUC) running Asset UPnP
• Synology DS1812+ NAS running its native Media Server application
• Synology DS1812+ NAS running MinimServer
• Note: It's possible to run several Media Server applications on the same Media Server hardware. My Intel NUC runs Twonky, MinimServer, Asset UPnP, and JRMC without issue.

Control Point Hardware / Software

• Apple iPad running JRemote controlling JRiver Media Center
• Apple iPad running PlugPlayer

Here are four recommended UPnP configurations. Each one has its pros and cons. Users must decide for themselves what level of complexity they are comfortable with and what they want to accomplish with a UPnP based system. Some people prefer simple and stable while others prefer cutting edge even if a few issues arise from time to time. These recommendations have components that can be mixed and matched or combined. I highly recommend readers think about their needs first and foremost before settling on hardware and software devices and applications.

System One

This system is the easiest to use and setup because one computer is the Server, Control Point, CD ripper, library manager, and the network is very basic. The limitations of this system may be lack of disc space that's available to a NAS based system, it requires a powered on computer to steam audio, and may not be able to handle simultaneous high resolution audio streams.

• Media Server - CAPS Topanga running JRiver Media Center and an external USB hard drive for music storage.
• Control Point - JRiver Media Center running on the CAPS Topanga, but being controlled by JRemote on an iPad. It's much easier to think of JRemote running on the iPad as the Control Point, but that's technically inaccurate.
• Media Renderer - Users choice of many HiFi components
• Network - Apple AirPort Extreme connecting to the Internet modem, CAPS Topanga, and Media Renderer via wired Ethernet. The iPad controller connects to the Extreme via WiFi.
• Misc. - The same CAPS Topanga PC can be used to rip CDs and manage the music library using JRMC. One additional note: A recent update to the JRemote application enables an iPad or iPhone to become a lossless Media Renderer by streaming audio from the JRMC Media Server directly to the iDevice without transcoding into MP3.

System Two

This system should be popular with audiophiles seeking to keep a computer out of their listening rooms and powered off much of the time. This is a classic UPnP AV system with clearly defined Server, Renderer, and Control Point for straight forward use an it's fairly easy to understand the concept. The major benefit is no computer required while playing music. All music is stored on an expandable NAS with redundant drives and sent directly to the HiFi Renderer. Limitations of this system are an acceptable network and Media Server software that isn't flexible and doesn't provide a great menu structure for navigation. The Synology Media Server software also doesn't support DSD streaming. Control Point app PlugPlayer can be finicky and require the app and iPad to be on to continue playing audio in the queue.

• Media Server - Synology NAS running the built-in Media Server UPnP AV / DLNA application.
• Control Point - iPad running PlugPlayer
• Media Renderer - Users choice of many HiFi components
• Network - Apple AirPort Extreme connecting to the Internet modem, Synology NAS, and Media Renderer via wired Ethernet. The iPad controller connects to the Extreme via WiFi.
• Misc. - A PC running dBpoweramp for CD ripping and JRiver Media Center for curating the music collection, or a Mac running XLD for CD ripping and JRiver Media Center for curating the music collection.

System Three

This system increases in complexity but also flexibility and network performance. Asset UPnP is a great Media Server application with several configuration options and rock solid performance. This system is better than the previous two systems because of Asset UPnP. Browsing and searching the music collection is nice and quick from an iPad. Asset enables the user to specify several folders to watch for new music added to the collection. I use this feature because I keep all my publicly available music in one folder, my private unavailable music in another folder, and other files for testing in several other folders. Asset watches the two important folders whereas the Synology Media Server app can only watch a single folder. Using the Synology app I would have to select the top most folder. Thus, my library would contain all kinds of test files that are named weirdly or have the same track compressed in every format available. Limitations of this system are the PlugPlayer Control Point app, as compared to JRemote, and no DSD streaming support. Users with Renderers from dCS or Linn could install a custom Control Point app on the iPad to enhance the browsing and selection experience and remove PlugPlayer. However, this is still not as good as JRMC with JRemote. The Netgear switch in this system keep all audio traffic local to the switch without routing through the AirPort.

• Media Server - CAPS Topanga or Intel NUC with a mapped drive to the Synology NAS, running Asset UPnP. Asset is configured to watch the appropriate folders on a Synology NAS.
• Control Point - iPad running PlugPlayer or Custom app from manufacturer.
• Media Renderer - Users choice of many HiFi components.
• Network - Apple AirPort Extreme connecting to the Internet modem and a Netgear GS108 switch. The Synology NAS, Asset UPnP PC, and Media Renderer connect to the GS108 via wired Ethernet. The iPad controller connects to the Extreme via WiFi.
• Misc. - A PC running dBpoweramp for CD ripping and JRiver Media Center for curating the music collection, or a Mac running XLD for CD ripping and JRiver Media Center for curating the music collection. If using a PC the ripping and curating programs can be installed on the Asset UPnP computer.

System Four

This system is exactly what I use most often. I don't believe there is anything related to UPnP / DLNA that I can't accomplish with this system. The network is rock solid and very fast. The CAPS server has plenty of power to handle multi zone playback of high resolution audio including DSD. I stress tested this system using one local USB DAC connection and five UPnP Renderers simultaneously. I successfully played 24 bit / 192 kHz high resolution audio in all six zones without the PC or network hiccuping once. The HiFi renderers included a dCS Vivaldi Upsampler, Linn Akurate DSM, Simple Design Rendu Ethernet DAC, and two Simple Design Rendu Ethernet to S/PDIF converters. Using JRemote on my iPad I was able to select each zone, control music selection and playback, and adjust the volume levels of each zone individually. JRiver can also be set to link two or more zones for playback of the same music in the linked zones. This system has similarities with each of the previous systems, but doesn't compromise at any point. Potential pitfalls with this system are all related to complexity of setup and user knowledge of computers and networking. Once setup the system operates wonderfully. However, if a specific Renderer has issues reproducing audio without dropouts, pops, or ticks it is very helpful to have an understanding of each component in the chain, how the components might effect playback, and how to make configuration adjustments. I much prefer this type of system because I can adjust each piece independently. System one using a single PC and a minimally adequate network is easier to use, but lacks ultimate flexibility and performance. System two using the Synology built-in Media Server app is primitive compared to the flexibility of system four. System three has a very nice Media Server but lacks a great Control Point application because of this Media Server application. System four has it all.