Because there is no analog passthrough.  Everything is digital, including the Port volume control, so there’s no way of bypassing it.  Also, as stated, if you simply want an analog passthrough to your speakers, why bother using a multi-room streamer to accomplish this?  Use an analog speaker, there are thousands of them on the market.  

Which voice assistant are you using?  Amazon Alexa?  If so, then you won’t be able to get them to play in sync as they are not designed for that.  You can have Alexa setup via Alexa groups to always play music on a Sonos speaker(s) rather than it’s own speaker.   That would effectively completely turn off music on the smart speaker with voice assistant, assuming it’s an echo, but still allow Alexa to speak through the echo.

I believe something similar exists for Google Assistant, but I have used GA in quite some time.

edit:

https://support.sonos.com/en-us/article/control-sonos-with-amazon-alexa

https://support.sonos.com/en-us/article/control-sonos-with-the-google-assistant

I think I shall draw a line here and not contribute further.
 

An installer, on these community forums for well over 10 years, doesn’t understand the technology he’s installing and can’t understand what lots of us are telling him. 
 

Either he should get training from Sonos, or take up his issues direct with them. 
 

We on these forums are mere users, not Sonos staff. I think we’ve reached the limit of what we can say; already we’re repeating ourselves.

I’ll probably continue to read this thread, for its entertainment value. But I shall contribute no more. Have fun, folks! 

I agree with @nik9669a.  I’ll only add that the reasons for my irritated replies are twofold:

1. It has been asked and answered dozens, if not hundreds of times before.  The fact yet another poster comes on here and thinks they can outthink or out-argue the previous dozens to hundreds of posts that well and truly answered the question before is frustrating at best, and annoying at worst.
2. The bargaining that ultimately happens in these threads defies all logic and physics.  “Why not just make it zero passthrough for one device”.  Well then, why buy a multi-room device that only streams to one room?  “Well, it should do both” So what happens when the user want to switch from standalone to multi-room on the fly for the same stream?  “Uhh, just make it work!  I need it!!”  <*bangs head*>

@pilot715 

See this for what may be of use as it seems to have for some. Or it may not, it is not a Sonos supported “solution”.

https://en.community.sonos.com/speakers-228992/sonos-5-line-only-no-delay-6872736?postid=16607951#post16607951

That's what I wanted to hear. In this box, everything is assembled around one chip, analog circuits and an audio inputs selector here does not exist in traditional understanding.
The analog audio input is just a bonus.

Unfortunately, I use the local voice assistant Alice by Yandex. Most likely you don't even know about its existence.)))

I’ll be honest, I feel a little sorry for the person who in 2024 calls simple audio streaming “technology” and believes that to understand this "rocket science" you need to undergo training.
My problem is that I was faced with a non-trivial task that I could solve using the analog inputs of a multiroom streamer since they have an autosensor for turning on the audio input. But unfortunately I came across several pitfalls.
Soon I will have opportunity to test Bluesound NODE by audio delay on analog input.
(A very nervous person above, told me that the same thing will happen with Bluesound. We will see) I will certainly report the results in this thread.

Thanks, Kumar I read this thread. If I understand correctly, there will be no audio delay only when the Sonos Port is disconnected from the Internet? This is not my case unfortunately.

Dear Friend. You just don’t understand the difficulties I have to face trying to marry incompatible equipment.
I tried to describe the task above in general terms. I don't think anyone understood it in my broken English.
So just accept it as a fact and stop being so nervous.

ps

If, as you say, this topic has been raised hundreds of times, then the problem still exists and this is not a problem of “stupid” users, but solely the will of the manufacturer, who, for obvious reasons, does not want to complicate production and make its platform more expensive.

ps/ps

If hundreds of people decided to write about this problem, how many people just having read topic with answer and closed the page? Thousands? Who knows?

In the way that is set out, the internet is no longer required by the Sonos device to play music from the net, the internet is instead connected to the other device that is connected to Sonos line in jacks.

I have no idea what you are attempting to accomplish. If you have a control system on site, it’s not so hard to patch around the delay when necessary. In many cases the only hardware required would be an RCA-Y. You may not need a control system, just a change in the system operation. Or adding a single button in your control system might accomplish what you need.

(Against my better judgement):

To the OP, please describe, IN DETAIL, what you are trying to accomplish (use Google translate if you have to).  State the devices you are using, what they are for, how they are connected, and why you wish to do what you wish to do. 

Knock it off with the insulting and demeaning language, the name calling, and the condescending references.  Just list what you are trying to do, because as far as I can see, unless you are trying to install a PA type system for announcements or live music, there is nothing about the delay on a Sonos Line-In which would prevent you from accomplishing you  goals, if you set it up correctly.

I was aware of Yandex, but did not know that they built their own voice assistant.  I guess Alexa and Google Assistant aren’t offered in Russian, so Алиса is your only option.

Hello! I'm trying to create a multiroom system that combines the functions of streaming from a smartphone (airplay) and duplicating sound from a voice assistant (smart speaker with Yandex Alice - the Russian analogue of Alexa, I think).
To do this, I connect Yandex Alice to streamer analog input (in this case Sonos), and a multi-channel amplifier is connected to streamer output. Amplifier connect to ceiling speakers.
I have 4 such zones. Each zone has a smart speaker (1 in the room, second in rack mount. Both speakers combined into one pair), but my client wants to hear sound from smart speaker played through ceiling speakers without losing ability to use airplay function.

The diagrams above do not show smart speakers that are installed in rooms.
Each of them is combined into one pair with smart speakers on this circuit.

Hello everyone, as promised, I tested the Bluesound NODE streamer.
1. It also has a sound delay.
2. It has a delay less than sonos, which is almost unnoticeable. 0.5 ms versus 0.75 ms for Sonos
3. Its main drawback and why it is not suitable for my installation is that Bluesound does not have an autosensor for analog input.

exactly

Yandex smart speakers lineup