Wiim Amp Ultra new subwoofer sync

[slartibartfast]

Update:
So, I submitted a ticket and got back a response from Wiim. According them the culprit is my phone microphone which is not accurate in the lower frequencies. I also shared with them the new measurements results with the mic and waiting for response.
I suspected that also, so I ordered a Dayton Audio iMM-6C microphone and I redone the measurements.

With the mic the sound is totally different what I used to in the lower frequencies. It's less boomy more accurate, put together. Kinda miss more bass sometimes.
The sub speaker sync is went from subwoofer delay to speaker delay. It now consistently measures between 8ms - 10ms delay to the speakers not like before. Also I did measurements with phase 0 and 180 and it was in both cases 8ms to the speakers. Also, I did room correction with 0 and 180 phase but the 0 phase sounded off in the bass. I was listening the same music and with phase 0 the bass sometimes missed, like on and off it was weird. I stayed with 180.
Oh, and the dip around 100hz is less obvious with the 180 phase.

So, currently I'm getting to used the less bass in my system but probably I'll ending up EQ a bit for more bass.
Here are my measurements with the calibrated microphone.

The automatic sub/speaker sync shouldn't give the same delay for 0 and 180 degrees. The original wrongly implemented version also gave the same delay for 0/180 when I tried it when it was first introduced. I have no idea if that was ever fixed.

 

[mosquito007]

The automatic sub/speaker sync shouldn't give the same delay for 0 and 180 degrees. The original wrongly implemented version also gave the same delay for 0/180 when I tried it when it was first introduced. I have no idea if that was ever fixed.

To be fair I honestly don't know what's right or not. I'm newbie
I did a quick sub speaker sync now toggle between 0 and 180 phase in the Wiim app and the results was 8ms to the speakers in both cases.
When I switched the phase 180 in the SVS app and same 180 in the Wiim app then I saw higher 18ms delay to the speakers.
I'm using phase in the SVS app 0 and the room correction was 180 phase in the Wiim app.
I'm not sure this is right but with phase 0 in the Wiim app the bass was off.

 

[juggle]

The image below is a screenshot used in a subwoofer related document titled "Subwoofer Calibration: One-Tap Sync between Main Speakers and Subwoofer at the Listening Position", which is posted on April 15, 2026.



Source: https://faq.wiimhome.com/en/support...akers-and-subwoofer-at-the-listening-position


The red box area looks different from the UI of the WiiM Home App I’m currently running. Do you guys also see the same UI as the one shown in the posted document?

 

[slartibartfast]

To be fair I honestly don't know what's right or not. I'm newbie
I did a quick sub speaker sync now toggle between 0 and 180 phase in the Wiim app and the results was 8ms to the speakers in both cases.
When I switched the phase 180 in the SVS app and same 180 in the Wiim app then I saw higher 18ms delay to the speakers.
I'm using phase in the SVS app 0 and the room correction was 180 phase in the Wiim app.
I'm not sure this is right but with phase 0 in the Wiim app the bass was off.

I believe your results. I am just surprised that WiiM released the feature with an obvious bug. @WiiM Team why is the sub/speaker sync delay exactly the same when the the phase is switched between 0 and 180 degrees?

 

[slartibartfast]

The image below is a screenshot used in a subwoofer related document titled "Subwoofer Calibration: One-Tap Sync between Main Speakers and Subwoofer at the Listening Position", which is posted on April 15, 2026.

View attachment 37213

Source: https://faq.wiimhome.com/en/support...akers-and-subwoofer-at-the-listening-position


The red box area looks different from the UI of the WiiM Home App I’m currently running. Do you guys also see the same UI as the one shown in the posted document?

The subwoofer level is a new feature only available with new firmware presumably.

 

[mosquito007]

I believe your results. I am just surprised that WiiM released the feature with an obvious bug. @WiiM Team why is the sub/speaker sync delay exactly the same when the the phase is switched between 0 and 180 degrees?

Maybe because it's not taking into account the subwoofer phase but I'm just speculating. Who knows.

 

[slartibartfast]

Maybe because it's not taking into account the subwoofer phase but I'm just speculating. Who knows.

That's how it looks but the purpose of the feature is to synchronise the phase of the subwoofer and the speakers at and around the crossover frequency. For example I can get very similar results by delaying the main speakers by 5ms or switching the phase to 180 degrees with no delays so I would expect the automatic sync to produce the same results. If it doesn't it isn't fit for purpose.
When I get the new firmware for the Amp it will be the first thing I test

 

[mosquito007]

That's how it looks but the purpose of the feature is to synchronise the phase of the subwoofer and the speakers at and around the crossover frequency. For example I can get very similar results by delaying the main speakers by 5ms or switching the phase to 180 degrees with no delays so I would expect the automatic sync to produce the same results. If it doesn't it isn't fit for purpose.
When I get the new firmware for the Amp it will be the first thing I test

So we'll wait for the new firmware then. Fingers crossed that'll work better.

 

[slartibartfast]

So we'll wait for the new firmware then. Fingers crossed that'll work better.

The firmware I was talking about was for the WiiM Amp since this feature isn't available for that until the latest firmware arrives. What you can do is report the issue through feedback in the Home app after performing the sync at 0 degrees and 180 degrees. Then WiiM will receive logs and hopefully understand and correct the issue.

 

[DHS]

@moskito007: I‘d like to give you some advises, if I‘m allowed to?
1.) Leave your crossover frequency at 80 Hz, so you get less frequency modulation in the high-lows and mids (Doppler effects) due to the excursion of the main speakers diaphragm. Your ears will hopefully enjoy
2.) Forget the subwoofer sync. stuff, or set it manually. Considering the speed of sound (approx. 3 ms/m), and looking at the distance between your sub and the speakers (approx. 0.6 m), it will result in a delay between the two of about 1.8 ms, correct? You may most likely end up by experimentally trial-and-error somwhere under 3…5 ms. Don‘t forget: the speakers that are closer to your hearing position need delay, because their sound reaches your ears first.
3.) Room acoustic: At 50 Hz, the wavelength is approx. 6 m. Changing the phase by 180 degrees results in a „time shift“ of 10 ms @ 50 Hz, resp. distance of 3 m (half a wavelenghth). Therefore, I assume that room resonances and standing waves are the reasons for erraneous sync. measurements. Perhaps, some small delays (latencies) in the electronics and crossovers may add some extra delay of a few milliseconds? I did not measure it…, normally less than 10 ms I assume.
4.) If your sub is bluetooth type, errors due to latency make things even worse.
My personal conclusion: Sub sync may work in „free air“, maybe in acoustically highly damped, large rooms only.

 

[BMeek]

I'll also keep my proverbial fingers crossed for the new subwoofer adjustments to sort out with pending firmware updates, etc.

Meanwhile, I would make some suggestions regarding your RoomFit settings and use of the SVS capabilities. Your 'lack of bass' sense about your more recent results reminds me that I've often felt the same about listening to music EQed to match the Harmon curve. I know it emphasizes bass, but I can hear said bass better after targeting the B&K curve... I think it's how the Harmon Curve starts sloping rather rapidly down from its elevated low bass around your crossover through 50-200-500Hz where it sorta flattens out. My RoomFit settings changes from default, after receiving guidance from @dominikz, are Freq: 20-500Hz, B&K Curve, Moving Mic, Adv> Variable smoothing. I see you're doing both the L&R channel measurements and that's good - I'm told using just the stereo sweep loses 1-2db of bass in the results.

Also, I found that after my first run through RoomFit, by looking at the major adjustments it attepmts below the crossover, and then create replacement filters for the SVS PEQ slots so that RoomFit can focus on the crossover region up through ~500Hz. On my SB1000Pro, the PEQ function offers 3 EQ filters... In my space, I have huge room-gain with concrete floor and lower wall, so I set the SVS gain to -22 from its default of -10, and I confess I asked Gemini AI (in "Thinking" LLM mode) to calculate the best 3 filters for the subwoofer from the RoomFit L & R-channel graphs and EQ tables:


The results were good for me, as the raw roomfit measurement shows, I'm at about the right sub level and frequency to being with when re-running roomfit to deal with the crossover and mid-bass region. The following graph was assessed at the completion of my last RoomFit run.


I noticed that the uncorrected raw dip at ~140Hz looked slightly worse in the 'actual vs raw', so I edited the resulting RoomFit profile to zero the gain on that ghost-null-chasing boost. The image on the right shows an evaluation of the edits (it doesn't make a raw sweep in that process).

You get the idea. It's surprising to see such low raw bass measurements in your RoomFit graphs - I usually expect heavy room gain with a sub in a corner, but by playing with the SVS volume/gain and PEQ values such that RoomFit only attempts strategic cuts and boosts well within the 10 and -10 boost/cut maximums.