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dCS Guide to Streaming

  • Updated

Contents

  1. Streaming using the Built-In Streamer
    1.1. Compatible Products
    1.2. Ways of Streaming Music on a dCS System
    1.3. Do Different Ways of Streaming Sound Different?
  2. Streaming using an External Streamer
    2.1. Synchronous vs Asynchronous Interfaces
    2.2. UPnP Servers
  3. General Streaming FAQs
    3.1. Do I need any special equipment for streaming?
    3.2. Is there a sound quality difference using the same streaming service from different apps?
    3.3. Do I need to change any of the network settings on my dCS product?

 

Internet-based streaming offers convenient access to a vast collection of music – but the wealth of available methods and equipment can be confusing.

In this guide, we offer some tips for listeners looking to stream music with dCS - including advice on how to ensure the best sound and user experience.

 

1. Streaming using the Built-In Streamer

All current dCS product ranges have a streamer built in to one or more of the products. Any dCS product with a Network port can be connected to a network and the internet to stream music from a variety of sources. All of the products listed below have a built-in streamer.

1.1. Compatible Products

The following dCS products have a built-in streamer:

  • Varèse Music System
  • Vivaldi (in the Vivaldi Upsampler Plus, or in the Vivaldi One)
  • Rossini DAC, Rossini Player
  • Bartók DAC, Bartók Headphone DAC
  • Lina DAC X, Lina DAC
  • Network Bridge

1.2. Ways of Streaming Music on a dCS System

dCS supports various ways of streaming - giving you the freedom to stream via various platforms and methods, depending on your preference. To get started, connect your dCS device to the internet using an Ethernet cable (connected to your network router, or via a network switch). You can then stream music in the following ways:

  • dCS Mosaic ACTUS / Mosaic: These are two dCS apps, the former being for Varèse and the latter being for all the other products. Both apps are free and available on both iOS and Android. These provide easy access to multiple streaming services within one app - simply log in with your streaming service account and begin playback. You can learn more about playing music from Mosaic here. They both also provide full control of all settings for the connected dCS product, allowing the settings to be easily customised.
  • Directly from the Spotify, TIDAL or Qobuz apps via Spotify Connect, TIDAL Connect and Qobuz Connect respectively. Using this feature allows you to stream music to your dCS device from within the Qobuz, TIDAL or Spotify apps. The only difference between this and streaming via Mosaic is the user interface - exactly the same content is streamed and in the same way, so the sound quality is identical.
    Note: Spotify cannot be streamed in dCS Mosaic, it has to be streamed directly from the Spotify app via Spotify Connect.
  • AirPlay: This feature allows you to stream any audio from an iOS or MacOS device such as an iPhone or MacBook directly to your dCS device. This method is very convenient, but does not provide the best sound quality, as it is limited to a maximum of 48kS/s and is not lossless.
  • Via third-party apps / services such as Roon, Audirvāna and JPLAY : These allow you to browse and play a combination of locally stored and internet streamed music in one place. All dCS devices listed above are certified for Roon, JPLAY and Audirvāna so will work seamlessly with these platforms. These apps offer the same sound quality as streaming via Mosaic or via a Connect app like Qobuz Connect, provided no features that affect the sound quality (like filters or upsampling) are used.

1.3. Do Different Ways of Streaming Sound Different?

Streaming music from Mosaic, Mosaic ACTUS, Roon, JPLAY, Audirvāna, or via TIDAL Connect or Qobuz Connect will all result in the same sound quality from the same streaming service. So, Qobuz played via Mosaic will have the same sound quality as Qobuz played via Qobuz Connect. The dCS unit still gets the music file from the internet and plays it back directly in the same way – the different app choices you have for playback are just different ways of telling your dCS system to play back the same music. They may provide a different user experience, different ways of searching for music, different ways of displaying that music (and its metadata) to you, but the music itself is the same and is delivered in the same way.

Some of the third-party apps will provide further customisation options for your sound, such as equalisation or external upsampling options. These will affect the sound quality, and their usage is entirely subjective so only you can decide whether they are right for you. Features like external upsampling are largely unnecessary with dCS products which have extremely high quality digital signal processing (DSP) such as upsampling and filtering built in. 

AirPlay will reduce the sound quality, as it is not lossless – some of the data (musical information) is lost before it reaches your DAC. It is a very convenient way to play audio, but for serious listening we would recommend one of the above options. 

2. Streaming using an External Streamer

There are several products available which provide the ability to stream music from the internet or from local storage via a standalone unit or system. Much like the different apps you can use to stream directly to your dCS system, these devices all have different ways of controlling playback, with different apps and interfaces available. 

You may want to use one of these devices if it has a user interface (such as an app) which you enjoy using, or if it offers features such as local storage or being able to stream to multiple music systems simultaneously. 

Given the number and variety of these products and their diverse feature sets and connectivity options, it can be confusing to know the best way to connect one to your dCS system. While it would be a huge task to document the best way of connecting every available device, there are some general best practices. 

As a rule, wherever available, the network connection will consistently provide the highest level of sound quality and the smoothest experience with the broadest support for different sample rates. The reasons we suggest using the network interface are explained in the following sections.

2.1. Synchronous vs Asynchronous Interfaces

dCS devices all offer a variety of different connection types for their digital inputs, and many of the streamers and servers available can connect to a number of the inputs on the dCS device. These interfaces can be broken down into two categories: synchronous (any S/PDIF or AES connections, including TOSLINK optical connections) and asynchronous (USB and Network). 

Synchronous Interfaces

Synchronous interfaces like AES or S/PDIF send the audio samples one after the other in a continuous stream, and at very specific time intervals (such as 1/44,100th of a second apart for CD rate audio). As the audio samples are sent as a continuous stream, data errors are rare but they are possible - if an audio sample is corrupted as it is sent over the cable, it cannot be recovered. 

The AES or S/PDIF signal has a clock signal embedded in it, to tell the receiving device like the dCS DAC how fast to convert samples to analogue. This embedded clock signal is very difficult to recover accurately. A dCS DAC does it very well using specialised hardware and software that is bespoke to dCS, but there is a constant problem with these interfaces that cannot be solved - intersymbol interference. This is a complex topic, but it means that if you can lock both your source device and your DAC to an external Master Clock, you'll get a big jump in sonic performance. 

Better yet, use an asynchronous interface which does not have this problem for the best sound quality. 

Asynchronous Interfaces

Asynchronous interfaces work differently. These are usually the network and USB connections on a dCS product (some older products like Scarlatti had other interfaces like 1394, but for this article we will only be talking about the network and USB connections). With an asynchronous interface, the whole audio track is split up into small ‘packets’ of data. These are put into a sort of digital envelope – referred to as a packet. 

This packet has information written on it specifying some or all of the following: where the packet came from, where it is going, how many packets it is a part of, what order the packets should be put back together in, and a "checksum" (this last one is really important). What this means is that the packets can arrive in the wrong order and at random times, and the receiving device can put them back together in the right order with perfect data integrity. There is no need for an embedded clock signal because of this, so the DAC can replay the audio entirely at its own rate and not worry about how slowly or quickly it is receiving the audio. This completely eliminates intersymbol interference. Adding a Master Clock will still improve sound quality, as it reduces jitter in the DAC (you can read more about this in our Clocking whitepaper here).

The checksum part of an asynchronous interface is really important. This is a mechanism built into the underlying technology that runs the network interface on your dCS product (specifically TCP/IP) that checks to see if the data that the dCS product receives are the same as the data that were sent. If they weren't, the receiving device can ask for that same packet again. This ensures that the data sent are always perfectly received. 

Networked Audio

It is not an exaggeration to say that the whole world runs on TCP/IP. It is the technology that underpins the internet. You trust that if you send a friend £100 via internet banking, they will receive the £100 and data errors won't mean they receive the wrong amount or that it gets sent to the wrong person.

There is a great video made by the "Father of the Internet" Vint Cerf, and Spotify engineer Lynn Root, explaining how TCP/IP and the internet works, which can be found here. 

It should be noted that while network connections do have checksum, USB connections do not, so while the data is asynchronous and will have better clocking performance than synchronous interfaces, the possibility exists that a data error could occur (though in reality this is incredibly rare). 

The network connection is also more consistent in electrical noise control. There is a provision built into the Ethernet specification (the specification that determines how the Ethernet port on a dCS product works), as well as any Ethernet port on any device like switches, routers or streamers & servers work, which says every Ethernet port must have galvanic isolation. This means the input of the port must be electrically isolated from the rest of the product it is feeding. This can be done in a few ways, but the most common method with standard Ethernet ports is to use a coupling transformer. This component isolates the port – meaning there is no direct electrical link between port and product – whilst allowing data to pass through unaffected.

As per the spec, dCS units have coupling transformers for their Ethernet ports, but also feature galvanic isolation for the USB connections. This enhances performance as USB sources can be noisier than network sources, given that isolation is not part of the USB specification. 

Optical Network Connections

It is becoming popular in hi-fi products to have "optical" network connections, which use fibre optics to transmit data instead of copper Ethernet cables. This technology largely stems from industrial environments, where local network signals may need to be run over very long distances (think kilometres) or could be subject to powerful electromagnetic interference from industrial machinery. Over long distances, electrical signals would suffer losses due to the long cable lengths, whereas optical signals do not. 

Manufacturers often claim that optical connections will improve electrical isolation of network components in hi-fi systems. We have seen no conclusive evidence that an optical connection will perform better than a correctly implemented galvanically isolated copper Ethernet connection. However, using optical connections with standard copper Ethernet can present complexities and compatibility issues, which is why we have not introduced them in dCS products.

It is possible to buy optical Ethernet converter devices that convert the copper electrical signal to an optical one, then back again, to be fed into the dCS device. There are a few things to consider with this type of setup:

  1. Each media converter device requires an outboard power supply. These tend to inject a tremendous amount of noise into the power lines and potentially into the DAC, depending on the type of cable used. While providing isolation from the network they still provide a path for noise to enter the system, which could affect sound quality.
  2. Many of these devices have been engineered to support 100Mbit bandwidth. Whilst the network used for streaming audio doesn't require more bandwidth than this, it could pose issues for the underlying network devices managing data flow - this can cause reliability issues for some listeners when streaming
  3. When an Ethernet interface is implemented properly it includes galvanic isolation which will properly isolate network electrical noise from your dCS device. Our devices were designed using very high-quality isolation components and we’ve seen no benefit in adding additional isolation devices to the network connection to a dCS device.

2.2. UPnP Servers

If you wish to play locally stored music from a third-party device via the network connection, this is usually done with a UPnP server. This is a widely adopted standard that allows playback of music files stored on a device on the local network to an endpoint – in this case, the endpoint being a dCS system listed in the Compatible Products section. UPnP is supported by many popular client apps such as Audirvāna and JPLAY, as well as by dCS Mosaic and Mosaic ACTUS.

Third-party streamers and servers often feature options for which UPnP server software is used to send music files from local storage to the dCS device. The choice of software does not have any impact on sound quality, but different UPnP servers may behave differently as there are some inconsistencies in different UPnP servers’ interpretations of the UPnP specification. dCS Mosaic was designed using MinimServer as the UPnP reference, and this is the server we test our products against, so we would recommend using it for the best user experience. 

If the third-party streamer or server offers a choice of UPnP servers, MinimServer should be chosen for a consistent user experience. However, any standard-compliant UPnP server should work.

3. General Streaming FAQs

3.1. Do I need any special equipment for streaming?

No, you do not. One of the benefits of streaming audio is that all the underlying engineering work that has gone into networking and Ethernet over decades means that the standard works very, very well. Issues such as data integrity, noise control, inter-device compatibility and length of cable runs have all been extremely well accounted for. This means that as long as you are using devices which adhere to the correct specifications, they should work correctly. 

There are a few examples of instances where specific types of equipment may cause issues:

Internet Service Provider Routers

Often, the router provided to you by your Internet Service Provider is the cheapest possible device deemed to be fit-for-purpose. These devices tend to work fine in most common use cases, but they often have very limited configuration options. 

It is common to see these routers cause issues with a feature called "multicast" or "mDNS" which streamers and remotes use to advertise their presence to each other over the network.  If service discovery is not working and multicast configuration options are not available, it may be necessary to change the router for one with more configurability. If you aren't confident with what this requires, you should speak to your dealer or to an IT professional for assistance. 

Managed Network Switches

Network switches - devices that sit between a router and end-points like a dCS product and allow for multiple Ethernet devices to be connected easily - come in two variants: managed and unmanaged. 
Managed switches try to determine what packets of data are intended for which connected device, and route them there. This means the data should only be routed to their intended endpoint, and packets of data do not arrive at the wrong place. This is useful for networks with very high volumes of traffic where it is important to optimise flow. However, this is very rarely needed for consumer home networks, and if it was, it would likely be part of a larger network installation performed by a networking professional. 

The network traffic management can again disrupt multicast causing discovery problems with apps. While almost all managed switches will offer settings that enable device discovery, there are simply too many on the market to provide comprehensive set-up advice.

By contrast, unmanaged switches are quite simple , and will do exactly as they are told by the network. For home networks, this means they are extremely reliable, cheaper, and require no setup. Simply connect the router to one port, the connected devices to the other ports, and everything should work with no multicast issues. 

3.2. Is there a sound quality difference when using the same streaming service from different apps?

This question is usually asked when comparing the sound quality streaming the same piece of music from, for example, Qobuz played via dCS Mosaic app and Qobuz via Qobuz Connect in the Qobuz app. When streaming from either of these apps, or through a third-party app like Roon (assuming the third party app is doing no processing like upsampling or EQ) the data the DAC receives are identical. This means there is no sound quality difference between one app and the other. 

Do not worry about trying to optimise sound quality of your system by using one app or another - simply choose the app with the features and interface you like the best, and play from there. You can be confident in the sound quality. 

3.3. Do I need to change any of the network settings on my dCS product?

Within the "web interface" (the page of settings that is shown when you enter the IP address of your dCS unit into a web browser on a device on the same network) there is a tab for Network Settings. These include settings for things called DHCP, DNS servers, setting static IP addresses and NTP servers. 

In most cases, you will not need to adjust these settings. Simply plug the dCS product into the network via an Ethernet cable, open the dCS Mosaic or Mosaic ACTUS app, and it will find the device for you to begin streaming. Changing these settings without understanding what each of them do can cause the network interface to stop functioning correctly, and some settings (such as static IP addresses) can be difficult to fix. 

Unless specifically told to change any of these settings by your dCS dealer or the dCS Support team, leave them on their default values:

  • DHCP: yes
  • Override DNS: no
  • NTP server: pool.ntp.org

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