WiiM Ultra Firmware v5.2.730566 Update - Sep 26, 2025

Please review the WiiM Ultra update release notes below. If you encounter any issues, feel free to reach out to us. This firmware update is being rolled out in stages, with devices updating sequentially over the next few days.

5.2.730566 (In Progress)​

Release date:

9 / 26 / 2025

What's New:

1. Smarter VU Meter – More accurate readout of your output levels.
2. Amazon Music – Faster resume after long pauses and improved casting stability from the Amazon Music app.

Bug Fixes:

1. Dolby Audio – Eliminated playback noise and fixed subwoofer no-sound cases.
2. USB Library – Refined image resizing for crisper album art.
3. Pandora – Resolved track skipping after resume and login failures.
4. Alarms – Station-based alarms now trigger reliably.
5. TuneIn – Apple Music radio via TuneIn now resumes after long pauses; reduced radio playback failures.
6. LMS – Correct bitrate display for radio streams.
7. KKBOX – Fixed playback interruptions and corrected bitrate reporting.
8. General – Stability, performance, and other minor fixes.

 

[hgo58]

Leaving some headroom can be done with the WiiM meters now, too.

How can you see the headroom when we don't know where 0 dBFS is on the meter?

 

[Angel]

That doesn't make any sense and you are mixing up dB and dBFS.

It makes perfect sense and you don't understand that by using higher number formats internally, for exmaple 32bit numbers, digital audio processing devices can go significantly over 0dBFS defined by the max level of the 24bit DAC, for example.
Please check my tutorial here:

Post in thread 'Broken VU output amplitude after update'

Sep 14, 2025

What do you mean? The max dBFS value is defined to be 0. There are no positive dBFS values.

You are correct that for transport e.g. by optical SP/DIF or SMTPE the number range is limited to 0dBFS. And anything above 0dBFS of the DAC will cause distortion. Fully agreed.

But of course there are positive dBFS values internaly in digital audio signal processing.
The reason is that for internal digital processing typically number formats with higher dynamic range, i.e. more bits are used than the ADC and DAC have.
I think this is the point where our discussion is centered.

Let's take...

• Angel

 

[Angel]

where 0 dBFS is on the meter?

At "0"

 

[hgo58]

It makes perfect sense and you don't understand that by using higher number formats internally, for exmaple 32bit numbers, digital audio processing devices can go significantly over 0dBFS defined by the max level of the 24bit DAC, for example.
Please check my tutorial here:

Post in thread 'Broken VU output amplitude after update'

Sep 14, 2025

What do you mean? The max dBFS value is defined to be 0. There are no positive dBFS values.

You are correct that for transport e.g. by optical SP/DIF or SMTPE the number range is limited to 0dBFS. And anything above 0dBFS of the DAC will cause distortion. Fully agreed.

But of course there are positive dBFS values internaly in digital audio signal processing.
The reason is that for internal digital processing typically number formats with higher dynamic range, i.e. more bits are used than the ADC and DAC have.
I think this is the point where our discussion is centered.

Let's take...

• Angel

Yes using a 32 bit floating point format for the audio processing, the signal can temporarily exceed 0 dBFS (the maximum level of the 24-bit) without clipping but I don't think the VU meter shows that. On the output we look at the 24 bit format and the same on the input.

 

[Angel]

t. On the output we look at the 24 bit format

I don't think so.
We are looking at the internal number format of the digital signal processing of the WiiM, whatever it may be, and nothing else is available for a digital display meter, with the zero full scale dB reference defined by the ADC or DAC reference max level.

(Edit: Leaving for today, just missed the 3:0 AND 4:0 for FC Bayern while typing ...)

 

[Deleted member 24058]

(Edit: Leaving for today, just missed the 3:0 AND 4:0 for FC Bayern while typing ...)

i am sorry that i did NOT miss the three goals athletico scored against sge

 

[hgo58]

I don't think so.
We are looking at the internal number format of the digital signal processing of the WiiM, whatever it may be, and nothing else is available for a digital display meter, with the zero full scale dB reference defined by the ADC or DAC reference max level.

(Edit: Leaving for today, just missed the 3:0 AND 4:0 for FC Bayern while typing ...)

It would make no sense to show internal signal levels. The input shall be showing the incoming (original) signal with 16 or 24 bits resolution. This shall also be true for the internal ADC output, allowing to see if the analog input is overloaded.

The digital output shall like wise show the 16 or 24 bits signal amplitude on the USB or SPDIF out.

This will all be in dBFS with zero as max value.

Not sure what we can see on the DAC? I don't think we can get anything from the analog output and I guess the internal input to the DAC is 32 bit? So maybe we could see values above the 24 bit 0 dBFS limit in this case?

 

[Angel]

So maybe we could see values above the 24 bit 0 dBFS limit in this case?

I guess so. Neither the analog input before the ADC not it's raw digital interface nor the analog output after the DAC is available for this digital meters (avoiding the word VU). Only the internal number format of the digital signal processing which is fetched from ADC and sent to DAC is accessible.

 

[Kidprofessor]

This update is not available to me yet. Haven't waited this long for a firmware update before

 

[peterh]

This update is not available to me yet. Haven't waited this long for a firmware update before

Same here!

 

[CliffyBC]

Same here!

A bit underwhelming, don't get over excited, nothing in it that makes a great deal of difference (to me anyway.)

 

[peterh]

A bit underwhelming, don't get over excited, nothing in it that makes a great deal of difference (to me anyway.)

I know that, but it is a bit unusual that it takes that long. In the past it took 2 to 3 days after release announcement, but now there are 7 days gone without the update available for my device. @Kidprofessor have you received it meanwhile?

 

[Audiohome]

I got several ultra updates without notifications lately, so maybe you already received it without knowing it.

 

[Kidprofessor]

I know that, but it is a bit unusual that it takes that long. In the past it took 2 to 3 days after release announcement, but now there are 7 days gone without the update available for my device. @Kidprofessor have you received it meanwhile?

Nope

 

[Kidprofessor]

I got several ultra updates without notifications lately, so maybe you already received it without knowing it.

No, mine is showing the previous firmware

 

[slartibartfast]

No, mine is showing the previous firmware

Sometimes updates seem to be withdrawn and reissued under a new ID a short time later.

 

[Mike in NY]

Sometimes updates seem to be withdrawn and reissued under a new ID a short time later.

That did happen this time too, the original version of this update was posted on Sept. 24th and then withdrawn at some point thereafter, and a replacement with a different version number was submitted on Sept. 26th. The release notes were unchanged between the two.

 

[harkpabst]

No, mine is showing the previous firmware

Did you see your hairdresser lately?

If not, it might be time for an appointment. Updates are rolled out based on good looks.

 

[Kidprofessor]

Still don’t have the update

 

[TRex74]

Me too. I've got two Ultras. One was updated a week ago. The other isn't updated yet.