If you Group Rooms, all members of the Group are time aligned  —when playing music. TV sound, playing through a soundbar, will not be time aligned with other Rooms.

I think I've got them all grouped together but I'll check again.  The port runs all the old speakers in the gym. It sounds like there's an echo because they are so far behind the Sonos speakers.

If you’re playing a music stream, and not a video input, they all should be in sync, as @buzz says.

I'm playing a music stream but they're definitely not in sync.  It doesn't sound like there's any settings I could change to fix it then?

They shouldn’t be out of sync. I’d certainly reboot them, on the off chance that there’s a timing chip that needs to be ‘reset’, but if that doesn’t work, and you’re aware of the timing delay of sound across air (minuscule, but there is some), then I would recommend that you submit a system diagnostic within 10 minutes of experiencing this problem, and call Sonos Support to discuss it.

There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution. Especially if there is some sort of hardware failure. 

When you speak directly to the Support staff, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.

Quick question, though (and I need to go reread the thread), we’re talking about only Sonos speakers, and no others, correct?

Yea, you state ‘Sonos speakers’, so I they should all be in sync. The 75 Ms delay that @buzz and I are talking about is on the digital input, and ‘grouping’ other rooms with that input (traditionally called video).

In order to group rooms, Sonos buffers the analog line in by 75ms, so that if you were playing other speakers in addition to the Sonos, there would be a slight delay. Of course, in order to preserve lipsync, they’re unable to buffer the digital input, so they have to do the ‘buffering’ when it gets expanded to other rooms by grouping. The speakers in the video’s room are all assumed to be on a low latency 5Ghz ‘bonded’ signal, but Sonos can’t guaranty any grouped rooms are on the same low latency setup, so their software ‘demands’ the buffering time. But, for your purposes, this is a moot point, there is no digital input on a Sonos port, only a digital output. Hopefully the explanation will help others who run across this thread, though. 

Thanks for your replies!  I apologize if I haven't accurately described what I've got going on. I'm not tech savvy at all! The port is running an old surround sound system in the basement home gym that are non Sonos speakers.  I have 3 mini subs and 6 era100 speakers, two speakers with each mini sub as a group.  I believe I have them all grouped together, when I'm playing it through the app I have "everywhere" selected.  The sound coming from the existing speakers are delayed compared to the Sonos speakers even though everything is linked together and most of them are in the same area. It's a constant delay.  I think I'll take your advice and contact the tech support and send the diagnostic information and see if there is anything they can do for me. Thanks again for your help though I think this is all a little over my head!

How is the Port connected to the surround sound system? If you’ve connected via a digital coax, then the delay is the processing time of the surround AVR, which Sonos has no control over. 

If you want the Port to be in perfect sync with the other Sonos speakers you need an analogue connection from the Port to the AVR. In that scenario the Port is in control of the processing and should be in perfect sync. 

I've got it connected with standard RCA audio cables....