Optimizing Pro-to-Ultra latency for projector & AirPlay issue with Persistent Groups

[eis]

Hi everyone,

I’m looking for some advice on a specific setup involving a WiiM Pro and a WiiM Ultra.

I know this isn't the standard use-case, but I’m trying to use my WiiM Pro as a wireless bridge (transmitter only, no speakers attached) to send projector audio to my WiiM Ultra, and also as an AirPlay receiver (since the Ultra doesn't support AirPlay).

I have two questions:

1. Latency Optimization
Since I'm streaming the projector audio from the Pro to the Ultra, I'm trying to get the latency as low as possible to keep lip-sync manageable.
So far, I’ve set "Group Audio Delay" to "Low" and turned off EQ/volume controls. Are there any other settings or tricks I should check to squeeze out better performance?

2. AirPlay Issue with Persistent Groups
I’ve noticed a strange behavior regarding AirPlay.
When I create a temporary group on the fly, AirPlay works fine—I can cast to the Host device (Pro) and the audio plays correctly on the linked device (Ultra).
However, when I save them as a Persistent Group in the WiiM App, the group doesn't even show up in the AirPlay list on my phone.
Is this a known bug with persistent groups, or is there a workaround?

Thanks in advance for any help!

 

[Wiimer]

Hi everyone,

I’m looking for some advice on a specific setup involving a WiiM Pro and a WiiM Ultra.

I know this isn't the standard use-case, but I’m trying to use my WiiM Pro as a wireless bridge (transmitter only, no speakers attached) to send projector audio to my WiiM Ultra, and also as an AirPlay receiver (since the Ultra doesn't support AirPlay).

I have two questions:

1. Latency Optimization
Since I'm streaming the projector audio from the Pro to the Ultra, I'm trying to get the latency as low as possible to keep lip-sync manageable.
So far, I’ve set "Group Audio Delay" to "Low" and turned off EQ/volume controls. Are there any other settings or tricks I should check to squeeze out better performance?

Hi,

There is likely nothing further that WiiM can do. What is the source being played via your projector?

I use a Fire TV Stick, and its lip-sync feature proved effective. (The TV's lip-sync feature was ineffective.)

2. AirPlay Issue with Persistent Groups
I’ve noticed a strange behavior regarding AirPlay.
When I create a temporary group on the fly, AirPlay works fine—I can cast to the Host device (Pro) and the audio plays correctly on the linked

Persistent groups only appear as devices in Spotify Connect. This is not a bug.
So, please connect to the leader device.

 

[eis]

Thanks for the reply.

Regarding the latency, I guess there isn’t much more I can do on the WiiM side. I use a CCwGTV and AFAIK, it doesn't have a manual lip-sync adjustment feature. I didn't realize that the Fire TV Stick has such feature, so thank you for letting me know! I might consider switching to it to solve the sync issues.

As for the AirPlay grouping, too bad that Persistent Groups are limited to Spotify Connect. I’ve been using the chain link icon to group the WiiM Pro (group lead) and Ultra (follower), which I believe is the method you have mentioned. It isn't persistent so I have to set it up again from time to time. I guess I’ll just have to live with it for now.

Thanks again for your help!

 

[eis]

Just to add some context for anyone interested:

In this setup (S/PDIF → Pro → Grouped to Ultra), the latency is noticeable but within a tolerable range. I went with this Wi-Fi bridge specifically to avoid Bluetooth 2.4GHz interference from a nearby microwave. Hope this helps—if there's anyone else out there trying to do this!

 

[Wiimer]

. I didn't realize that the Fire TV Stick has such feature, so thank you for letting me know! I might consider switching to it to solve the sync issues.

To be honest, it had been quite some time since I last adjusted the lip sync on Fire TV, so I wasn't entirely sure.

Upon checking again, it appears to be working properly.

View attachment 1660.mp4
(Before lip-sync adjustment > Adjusted on FireTV -> After adjustment)



FireTV (HDMI) -> TV -> (ARC) WiiM Amp pro

# The Amp pro is grouped with the Ultra. The group delay is 70ms.

 

[eis]

Thanks a lot for taking the time to test this out for me, I really appreciate it.

I’m still on the fence about buying a new Fire TV Stick, but at least it seems like a much cheaper and simpler option than buying additional transmitters just to reduce the audio lag.
I’ll definitely consider it.

Thanks again!

 

[Burnside]

Persistent groups only appear as devices in Spotify Connect. This is not a bug.
So, please connect to the leader device.

I think that could be more of an airplay restriction - for example, when using Chromecast a group needs to be defined in the Google home group before you can cast to it, but AirPlay 2 or the Apple Home app doesn’t really have a concept of a pre-defined group - you’d think an Apple home “room” might do that, but I don’t see those appear as AirPlay targets.