Connect Line-out delay (again)

  • 14 February 2018
  • 8 replies
  • 2070 views

I know this subject has been brought up many times but I'd really like to put this to bed once and for all.

I totally understand why delay exists between bonded Sonos elements and 3rd Party components either line-in or line out via Connect. A DJ cannot expect his Pioneer Mixer to output to a Connect, back into the Sonos loop and come out of the speakers without delay - get it!

My use case is - I have an open plan Front Room and Connecting Dining Room. Sonos in the Dining Room and a Connect Driving an AV Amp in the Front Room. Group the Dining Room + Front Room and the delay ranges from an echo in PURE DIRECT mode to a double beat when DSP Stereo processing is active.

Digital Coax, Optical, RCA, different amps with or without DSP processing may have varying results, but it will never cure the problem.

What I can't understand is why Sonos cannot build a user definable delay into the controller to push back the whole Sonos loop to come in-line with the audible output from speakers from a non Sonos amp driven by Connect.

Is it a fundamental technical impossibility or just an Engineering prioritisation or Connect is seen as a marginal product, that this matter hasn't yet been addressed.

If I thought this was on the engineering road-map I'd sit tight. If it wasn't Connect is probably going back to the store as it's not working for my use case. Sorry Sonos, but I love all my Plays and SUB.

Going to post in the BETA forum too to see if anyone listens 🙂

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8 replies


My use case is - I have an open plan Front Room and Connecting Dining Room. Sonos in the Dining Room and a Connect Driving an AV Amp in the Front Room. Group the Dining Room + Front Room and the delay ranges from an echo in PURE DIRECT mode to a double beat when DSP Stereo processing is active.

Addressing just this: Pure Direct should see perfect sync, so it is surprising to read of this echo. One inconvenient way to test this is to drop in another stereo amp in place of the AVR and if the echo disappears, it would say that the AVR is not quite pure in its direct mode. If the echo persists with a stereo amp, it would suggest one caused by a room acoustics response.

An easier test is to move the Sonos unit in the dining room to the front room and see if the echo persists in Pure Direct mode.
Thanks Kumar - sadly the delay is noticeable in PURE DIRECT & no sub and you're right it's a reasonably sized space, so acoustics could be coming into play - even more reason for a bit of offset in the Sonos Loop 🙂

I see you're very active or maybe a Sonos Employee, can't post in the BETA forum as not a selected BETA tester - anything else I could do to raise this with the right people or get an answer to the wider thread.

I'm in software engineering, so I do understand this stuff is often more complex than first meets the eye.
Surprised there's still an issue with RCAs and direct mode. This seems to fix the issue for most. I have an old Onkyo receiver and able to use both 2.1 stereo and direct modes without sync issues but sounds like newer receivers add more delay with processing.

I see you're very active or maybe a Sonos Employee
I'm in software engineering, so I do understand this stuff is often more complex than first meets the eye.

Active yes, employee no.
Perfect sync across all Sonos units is a major USP of Sonos, so they will want to make sure that this isn't lost in pursuit of something that may matter less; in pure direct mode, the echo issue goes away for most people. Add to that the current focus of development resources on getting voice control to be more than a gimmick as well as on staying afloat in the next wave - home automation - being declared priorities by Sonos, I don't expect anything to change in this area.
But Sonos also claims to read and take as feedback every post that is written here; there is that. And, as said somewhere on this site, you can always send an email to their CEO, Spence.
Userlevel 7
Badge +19
Hey Holmesy1. Thanks for posting and welcome to the Community. I'm happy to pass your feedback and request along to the team. Thanks!

...can't post in the BETA forum as not a selected BETA tester...

The first rule of the Beta forum is to not talk about the Beta forum. Just a friendly reminder for if/when that time comes. 😃
@Kieth N what Beta forum? :$
Thank you
Userlevel 3
Seriously sonos... fix the issue.

Please engineer a delay adjustment for the connect... or stop selling it.

Without a delay adjustment, it’s an almost useless product
Also keep in mind that sound travels about one foot per millisecond. In large rooms or open areas the more distant speaker seems delayed with respect to the nearby speaker -- even if both speakers are driven from the same amplifier speaker terminals. In a large orchestra the Bass player on one side feels that the percussionist on the other side is "late", the percussionist feels that the Bass player is "late", and the conductor feels that they are both "on time".

With respect to latency, CONNECT is no different from any of the other players. And, this latency is not always destructive. I know of an outdoor restaurant that has a stage about 70 feet from the seating area. There are speakers around the seating area and a CONNECT is used to bring audio from the stage to the seating area PA system. (There is a CONNECT and a couple CONNECT:AMP's in this system) Alignment is perfect between the direct acoustic energy from the stage and output from the PA system. Without the 70ms latency this system would be an impossible mess.

With respect to an adjustable delay, at some point the delay will become too short to fulfill its original purpose -- to allow some slack time for the system to work around networking issues without needing to interrupt the audio. Any nonzero latency will offend someone. Another issue is compatibility with the older units. This is a pillar of the SONOS philosophy. Even the original ZP100 is still supported, but it does not have enough memory or processor power to fuss with variable delays. If some level of variable delays are added to the newer units, they could not be supported by the ZP100 and it would drop out of sync. The "time align" is within two milliseconds when players are Grouped -- even if you listen all day and into the night.

Actually, variable delays are supported by PLAYBAR, PLAYBASE, and BEAM. There is a 35ms latency between these units and surround speakers. 35ms is OK for the surround link because the surround speakers will be in the same room and the risk of communication difficulties is low. In addition, these units support an adjustment for video lip sync. If the listener Groups these units with regular players scattered about, PLAYBAR, PLAYBASE, or BEAM lip sync should be adjusted to 70ms in order to "time align" with the other players that are using the fixed 70ms latency. These newer units have much more processor power and memory than the ancient ZP100.