Kudos to
@rubato for [finally] getting to the meat of the legit 'wired vs. WiFi' question.
The OP's ask was a straightforward verging on simple 'audio over network' question, the answer to which is "It [USUALLY] makes no difference at all with a reliable connection". The qualifying 'it depends' comes in when your musical goal is whole home networking that
involves speaker groups in overlapping zones.
So, to add meat to
@rubato's excellent point about latency and stability, and to bring this surprisingly lengthy thread closer to my own questions

, I posed a question on this point to Gemini ["Thinking" free LLM] within an ongoing 'Chat' about
my new loft apartment audio project. The LLM's response is pretty good in this case.
[SIDE Note] I sorta apologize for my previous posting of AI drivel (even if it was at least labeled as AI drivel 'for grins'). AI is a tool worth learning to use, and while the previous AI share was Amazon's free-with-Prime LLM (Alexa+ - that I suspect is highly tuned to bolster the user's ego and keep them engaged and I was playing with only because I had just setup Alexa on my phone for the WiiM Ultra Alexa-enable), the following is from Gemini's "Thinking" LLM (with my 'instructions to Gemini' asking for 'zero unlabeled speculation' and in general no bullishit). I always appreciate it when folks posing questions on forums like this do a little research first

. Such research using AI is a many-edged-sword for all us forum participants. Moving on...
PROMPT: "How would the lower latency of wired Ethernet connections to the WiiM Ultra and a WiiM Pro improve upon my current (strong) WiFi-6 connections to the Ultra and a WiiM Mini? Would it make a difference? My goal is uniform and synced sound throughout the high-ceiling apartment and loft."
Gemini's RESPONSE:
Switching from a Wi-Fi 6 connection to a wired Ethernet setup for your WiiM Ultra and WiiM Pro (replacing the Mini) will provide a measurable and audible improvement in synchronization, specifically addressing the "echo" or "drift" often heard when moving between floors.
Jitter vs. Raw Speed
While
Wi-Fi 6 provides high bandwidth, audio synchronization relies on
timing consistency, not raw throughput.
- Ethernet Reliability: A wired connection eliminates jitter (the variance in packet delivery time). In a multi-room group, the WiiM Ultra (Group Leader) acts as the master clock. If the WiiM Mini (Follower) receives packets with even millisecond variations due to Wi-Fi interference, it must constantly adjust its internal buffer, leading to micro-drifts in timing.
- The Apartment Factor: Speculation: In a high-ceiling loft with concrete elements, multipath interference (Wi-Fi signals bouncing off hard surfaces) is common. This can cause the "Follower" device to lose sync packets, forcing a re-sync event that breaks the "uniform sound" goal.
WiiM Pro vs. WiiM Mini: Processing Power
The upgrade from a
Mini to a
Pro is a significant leap in "decoding horsepower" required for stable grouping:
- Processor & RAM: The WiiM Mini utilizes a Dual-Core A7 with 128MB RAM, while the Pro and Ultra use a Quad-Core A53 with 512MB RAM.
- Buffer Depth: The larger memory on the Pro allows for a much larger network buffer. This enables the system to handle network hiccups more gracefully without falling out of phase with the Ultra downstairs.
- Low-Latency Mode: The WiiM Pro and Ultra support a Low-Latency Multi-room (Beta) feature that reduces the grouping delay from ~200ms down to ~100ms. The Mini's hardware is generally excluded from this high-performance sync mode.
Audible Impact on the Stairs
- The "Hollow" Effect: When two zones are slightly out of sync, you hear comb filtering (a "phasey" or hollow sound) as you move between them.
- Wired Sync: Hard-wiring both the Ultra and the Pro allows the system to lock the 48kHz/16-bit multi-room stream with microsecond precision. This ensures that the sound transition on the stairs feels like a single, continuous acoustic space rather than two separate systems fighting for dominance.
| Feature | WiiM Mini (Current) | WiiM Pro (Proposed) |
| Connection | Wi-Fi 6 (Subject to Jitter) | Wired Ethernet (Clock-Locked) |
| Processor | Dual-Core A7 | Quad-Core A53 |
| Buffer Size | 128MB (Standard) | 512MB (Deep Buffer) |
| Sync Stability | Variable | High / Low-Latency Capable |
Speculation: Given your loft's concrete and high ceilings, the
WiiM Mini's smaller internal antenna is likely working harder to maintain the Wi-Fi 6 handshake than the
Ultra, making the Mini the "weak link" in your current synchronization chain.
Would you like me to find the specific CAT6 cabling or shielded RJ45 connectors recommended for your "Apartment" group wiring project?