Overview

Previously, I described how you can add Sonos BOOSTs to your Sonos system to extend the range and enhance the robustness of SonosNet, the wireless networking protocol used between Sonos speakers. Starting out, most Sonos customers won’t need one or more BOOST devices. Later, as you expand your Sonos system to more rooms, you should carefully plan your Sonos network layout, just like you should for your WiFi network. BOOSTs are an excellent way to fill in coverage gaps in your Sonos mesh network, without requiring you to connect one or more of your Sonos speakers via Ethernet. BOOSTs create a wireless offload network for Sonos speakers, separate from your existing WiFi network.

In this article, I describe an alternative, more advanced network topology that uses multiple Ethernet-connected Sonos Beam soundbars1 for better Sonos wireless coverage in your home. These best practices are based on my close collaboration with Sonos technical support. This approach:

1. provides significantly greater wired line backhaul to your SonosNet network,
2. shifts the majority of your Sonos speakers to 5Ghz, freeing spectrum in 2.4Ghz for your remaining Sonos speakers, and
3. isolates each room with a Sonos Beam in its own wireless ‘sandbox’

It is also possible to use either the Sonos PLAYBAR or PLAYBASE instead of the Beam, for example in your home theater. However, the Sonos Beam is a much more cost-effective solution, particularly for secondary rooms in a whole home deployment.

SonosNet in 2.4Ghz v 5Ghz Bands

First, a brief overview of SonosNet.2 SonosNet is a proprietary wireless mesh WiFI network that is optimized end-to-end for audio delivery to Sonos devices. Generally speaking, SonosNet 2.0 operates in the 2.4Ghz band. The exception is for 3.1, 5.0, and 5.1 speaker configurations, where Sonos uses the 5Ghz band to distribute audio from the center speaker to the rear satellite speakers and the subwoofer. Each room with a Beam, in effect, becomes its own mini-wireless network. Each Ethernet-connected Beam also serves as a point of connectivity for other rooms lacking Ethernet.

For wireless devices (including Sonos, WiFi, cordless phones), the advantage of using the 2.4Ghz band is that it has longer range. Depending on the size and construction of your home, your wireless signal may have greater resiliency than a 5Ghz signal at equivalent distances. For Sonos, there is also the consideration of backwards compatibility with earlier generations of Sonos speakers.3

However, there are several tradeoffs including:

1. there are only three available clear channels within the 2.4Ghz band,
2. many more  devices (both your own and your neighbors) will default to using the 2.4Ghz band due to range4, and
3. the 2.4Ghz band has a higher noise floor due to bleed over from devices like microwave ovens.

In the 5Ghz band, there are more clear channels and, therefore, fewer devices per band generating traffic. Moreover, with the possible exclusion of DFS and weather radar channels, there tends to be a lower noise floor in the 5Ghz band. For Sonos, the 5Ghz band is therefore ideal for “in-room” audio distribution because range is no longer an issue.5

Our Sonos System’s Original Topology

As your Sonos system gets larger–and particularly if you wish to listen to lossless audio in multiple rooms–available bandwidth becomes a bigger issue when planning your network. You may initially consider lossless audio (such as iTunes’ Apple Lossless and FLAC) limited to the realm of compressed CD rips. However, lossless audio can also include uncompressed analog input on your Sonos Connect:AMP as well as TV sound fed via HDMI into a Sonos Beam. For example, if you wish to listen to the NFL game throughout your house, then your Sonos network topology becomes extremely important due to the lack of audio buffering.

Our home Sonos system consisted of seven Sonos One pairs, one Sonos Connect:AMP, and three Sonos BOOSTS. All eighteen of these devices were running in the 2.4 Ghz band, as depicted below.

	Family Room	Kitchen	Living Room	Garage	Master Bedroom	Guest Room	Office	Gym
Ethernet = 3 BOOSTS	BOOST				BOOST			BOOST
2.4 Ghz = 15 Sonos speakers	One L+R	One L+R	One L+R	Amp	One L+R	One L+R	One L+R	One L+R

Even with three Sonos BOOSTs, we found frequent audio dropouts when streaming lossless audio to more than three rooms (6 concurrent speakers in the 2.4Ghz band). This was the case even though we had an extremely clean RF environment. If you live near a number of neighboring WiFI hotspots or otherwise have 2.4Ghz interference), you may have even less available wireless bandwidth for Sonos.

Our New Sonos Network Using Beams

The solution was two-fold:

1. increase the amount of wired-line backhaul to the Sonos system (before only the BOOSTS were wired); and
2. where possible, shift Sonos speakers to the 5Ghz band (before, everything was in the 2.4Ghz band).

Obviously, each Sonos One was close to a power outlet. Almost none were close to an Ethernet drop.6 However, in the rooms where we had televisions, we already had an Ethernet drop for each smart TV. So, wherever possible, we leveraged these Ethernet drops to add cable pulls for our Sonos Beams.

Now, four rooms have Ethernet backhaul for their center speakers. Each Sonos Beam serves the role of an access point like the old Sonos BOOSTs. Speakers in the same room (e.g. Sonos Ones and SUBs) connect wirelessly via the 5Ghz band to the center speaker. The Ethernet-connected Beams also provide connectivity in the 2.4Ghz band for adjoining rooms with Sonos speakers. That reduces the number of Sonos speakers using the 2.4Ghz band from fifteen to only six. It permits us to add subwoofers to two rooms without impacting system performance. And, it eliminates the need for Sonos BOOSTs in our system (which both add a hop in the Sonos network and count against the 32 Sonos device cap).

	Family Room	Kitchen	Living Room	Garage	Master Bedroom	Guest Room	Office	Gym
Ethernet	Beam				Beam	Beam		Beam
2.4 Ghz = 6 Sonos speakers		One L+R	One L+R	Amp			Beam
5 Ghz = 3+3+2+2+2 speaker systems	One L+R, SUB				One L+R, SUB	One L+R	One L+R	One L+R

• The Sonos Beam in my Office (which lacks an Ethernet drop) connects wirelessly to the Guest Room Beam and then creates a 5Ghz mini-network for the Sonos Ones in the Office.
• The Sonos One left speaker in our Kitchen connects to the Guest Room Beam and direct routes to its paired right speaker in the 2.4Ghz band.
• The Sonos One left speaker in our Living Room connects to the Master Room Beam and direct routes to its paired right speaker, all in the 2.4Ghz band.
• The Sonos Connect:AMP in our Garage workshop is wired into a Sonos BOOST, which then connects wirelessly to the Family Room Beam.

Managed Router Settings

Reducing Multicast Traffic on Your Network (IGMP Snooping)

Sonos is very sensitive to multicast traffic on your network, particularly Google Cast traffic. For this reason, you should enable IGMP snooping for the VLAN used by Sonos. I also recommend segregating other traffic, such as IoT devices to a separate VLAN from your Sonos devices. And, we reduced the number of Google Cast devices on our home network.

Configuring STP

If you are considering a Sonos system similar to ours, then I also recommend that you upgrade your home network to managed network switches. You should configure them for STP (not RSTP). Go to each of the switches in your network, under Spanning Tree, select STP. You should use the following priority: 4096 (for your aggregator switch), 8192 (for secondary switches), or 12288 (for tertiary switches).7 This will ensure a logical loop-free topology, with only one active path on the network between two devices.

Tips

• Be mindful of how you start music playback: for large groups of rooms, always start from an Ethernet-connected Sonos device. Hopefully, Sonos will handle this automatically in the future.
• For lossless encoded music, serve your audio from an Ethernet connected device such as a Mac/PC or NAS.
  • In my experience, Sonos’ Music Library is more limited than Plex for Sonos in terms of functionality. It also requires SMBv1. But, it doesn’t require remote access or NAT loopback like Plex (which present both security and breakage issues).
  • If you wish to play directly from your iTunes library, you can do so via Airplay v2, including lossless audio. If you wish to stream to more than 2-3 rooms, I recommend streaming via Airplay to a room with Ethernet. Then, opening the Sonos app to repeat the stream to all rooms (Party Mode).
• SonosNet is sensitive to outlier devices with poor RF coverage. A single player can impact the overall SonosNet.
  • For example, even though it was 10 feet from a Sonos Boost, our Garage Connect:AMP was dragging down our Sonos system’s performance due to our garage firewall. Our solution was to wire the Connect:AMP into a BOOST, then use the BOOST’s superior wireless connectivity to connect to our Sonos system. The difference was over 20dB!

Updated on August 28th, 2018