PROVED Solution: Successfully connecting Denon AVR PRE OUTS to Sonos INPUTS:.

Sending Sonos output to an AVR is easy. What is next to impossible is the other direction!

I used a Denon X1800H purchased in March 2024 which has Main Zone pre-outs and ZONE 2 Pre outs. Their capabilities differ markedly. Other builds of this exact Denon model do not come with pre outs. Odd but no mattter. Try Crutchfield. This solution will probably work for other Denon AVRs that have Pre outs for ZONE 2 –possibly other AVRS with slight changes as well. And it works for both digital and analog sources into the avr.

Like many of us I wanted to free up the main zone/room’s audio to be heard over my SONOS system so I could play turntable, CDs or live stream concerts from the computer or TV to hear throughout the house, garage etc. Denon however, like so many other AVR brands, make this really difficult. It feels intentional for they expect you to buy Heos speakers --but we already have Sonos!

After a month of research and experimentation, including working with Crutchfield, Sonos and Denon Tech support and studying the unhelpful manual—I stumbled on how to do it well. 

The steps:

1. Go to Denon Setup, then to General, and then to Zone 2 Setup. Select and set the output to Fixed and adjust volume level to at least 60. I find that a good level.
2. Go to Sonos app settings and set your Connect or Connect Amp Line-In Level to Level 8 (you can adjust later to your liking).
3. With chosen source playing to your AVR Main Zone, Press the button labeled Option on the remote. Then using the jog select wheel, press the down button repeatedly until display reads All Zone Stereo. Select it. Your AVR screen will now show All Zone Start. Select it. (Note that you don’t have to go into The Denon main setup on a TV to do this. The Options button is all you need to tie the two zones together.
4. If you have already patched your Zone 2 pre outs to your Sonos Inputs you now have a robust line level into your Sonos line-in unit. You can select Line-In to use Sonos to distribute any source playing to your AVRs speakers, be it digital or analog. Success

*This may sound complicated but with an audio source playing (digital or analog) on the AVR,  I press Option button on the remote and use the jog wheel down button 4 times to select All Zone Stereo. Select again to select Start All Zone. Sonos takes it from here. It only takes seconds and the AVR resets when powered off automatically for regular use with Main Zone alone. I like that feature. I hope this has been helpful. If you try this it seems like a slog at first but it works super easily for you after two practice runs. And you have freed up your AVR to play throughout the house --thanks to SONOS!!!!

NOTES:

1. By selecting Mute on the AVR remote, your Main Zone speakers mute and still the AVR is playing out the AVR pre outs into Sonos. Why is this cool? Because this eliminates hearing the audible delay (echo) between the live Main Zone speakers and the Sonos system. (That is the time needed for Sonos to convert the analog and distribute it digitally over Sonos Net or WiFi.).
2. I have Sonos speakers in my main zone but you don’t need to.
3. Once the Main Zone pre outs are tied to the Zone 2 Pre outs using the Option and select buttons, Zone 2 pre outs are not affected by the AVR Volume control like the Main Zone pre outs are. Also you set the Zone 2 volume to Fixed.
4. If you do not tie the zones together as I described, and only patch your Zone 2 pre outs into Sonos, analog sources are fine but you will only hear digital static when playing a digital audio source which is the majority of your content! However, by selecting All Zones, and Start, Zone 2 plays digital sources!  Main Zone pre outs alone can output digital or analog sources, however, their output level is unusably weak for Sonos to use. It takes a blasting volume on the AVR to be barely audible to Sonos inputs. After much experimentation I resolved this with a small powered mixer which cost $99 but you are left with the audio delay problem and an unnecessary expense.

If you really don’t want to use your Zone 2 pre outs at all (like I did at first) you can go up the same tree I did and get a small powered mixer to amplify the tiny output level Denon assigns to them. They intend for you to wire another amplifier in a different  room here. Why anyone would want to run wires into another room down the hall or in the walls is not clear to me. Especially since as you adjust the volume in the main zone room you are also adjusting the volume in the secondary room! Do not get the puny line level boosters on the market without checking their gain. All were described as 20db gain at most. What you need is 30db gain and this small powered small mixer worked great. It is on Amazon but also sold at same price by many other vendors. You will be constantly adjusting your AVR volume, the Mixer volume, and your Sonos Volume and living with the audio delay. At least the main pre outs output both analog and digital sources.

The Rolls MX44 mixer can do it and was the only one I could find.

https://www.amazon.com/dp/B09ZJBQSWX?psc=1&ref=ppx_yo2ov_dt_b_product_details