Why does the Sonos app not have a 0ms delay option for the line-in adapter?

To be fair I’m a new user in the forum and have not been through every thread of the past 2 decades there are regarding line-in adapters, additionally the ones linked in this post doesn’t clearly explain the issue and are just dismissive.

And since there are so many threads bringing up the topic again and again I would conclude there are quite a few people in fact that would appreciate the feature if it were possible.

I’m merely making a suggestion or feature request for the app.  Certainly don’t want any sort of PA//karaoke/DJ system, just the option of the “0ms” delay should I wish to use it with the knowledge that I’m not able to sync with any additional speakers.

Do you mind elaborating what you mean by “stream” - is that the audio signal or WiFi stream to speaker from the Mac/Phone or other service?
Following on from that would you say that is the same as the stream/signal coming from a turntable?
Does this require a buffer as well to play?

Thank you for you feedback none the less.

By “stream”, I mean the digitized stream of the sound coming into the Line-In.  In order to transmit this digitized source to other rooms (or a stereo pair), there must be a buffer built up to allow for synchronization packets to be included and/or missed or corrupted data packets to be resent.  Otherwise, it would be impossible to correct for sync being misaligned or a corrupt/missing packet due to interference or some other network anomaly, and the sound would stutter or dropout.  This is a basic concept of streaming audio.  

This buffer is the same for all Sonos sources (actually for all streaming, period).  However, since a digital file from a server or your local library arrives at the speed of your network, the buffer is built up almost instantly, and there is no perceptible lag between starting the stream and the audio playing.  But a Line-In source is analog, it arrives in real time, so the buffer must be built up in real time.  Hence the 75 ms delay for the Line-In. 

So to eliminate the delay (if it is even possible, it could be baked into the hardware) would mean eliminating multi-room or stereo pairing use, a core concept of Sonos.  You also wouldn’t be able to easily switch between using a standalone speaker configured for no delay and a group of speakers, something you can do easily now with just a click.  So what should be a seamless multi-room experience now becomes one of “You can have no delay, but then you can’t have a stereo pair, or a group.  Or you can have a pair or group, but it will have a delay.  And you can’t easily switch between them in the middle of a song like you can now. Oh and you have to put up with endless warnings and popups if you try to switch.”

Which isn’t seamless at all.

How about this, instead of aggravating things here on the community forum, you submit your suggestion to Sonos directly?

Then you won’t have to listen to folks you obviously don’t care to hear from telling you things you don’t want to hear. The Sonos employee you talk to will happily take down your suggestion and forward it to the folks in charge of suggestions.

Same sort of suggestion for folks trying to help someone who doesn’t want help. Tell them the truth but skip trying to educate the ones not wanting that, just send them off to submit it directly to Sonos. (I’m going this direction from here on out.)

Thank you for the detailed explanation—this makes a lot of sense now.

Just to clarify, I’m not trying to ignore the technical challenges or be difficult; I’m simply trying to gain a deeper understanding of the issue. This way, those of us raising similar points can better grasp what’s happening behind the scenes and avoid misunderstandings.

From what you’ve shared, it seems technically possible to achieve near 0ms delay from an analog source (as is the case with other standalone speakers). However, on a Sonos system, this would mean losing the ability to seamlessly switch between single-speaker playback and multi-room or stereo pairing without interrupting the audio stream.

The closest compromise I could imagine—without resorting to pop-ups or warnings—would be for the speaker or app to detect whether it’s playing through a single speaker or a group. If it’s a single speaker using a line-in analog source (not a network-based source like Spotify), it could default to a “0ms” mode. If the user then switches to a grouped setup, the system could automatically build the buffer in the background and switch over with a brief interrupt in the stream.

That said, I completely understand that this approach likely doesn’t align with the seamless, frustration-free experience that is core to the Sonos ecosystem. It would likely introduce more complexity and potential frustration than the diversity it might offer in functionality.

Thanks again for clarifying this—it’s much appreciated. Your explanation has given me a much better understanding of the challenges and limitations at play here.