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 ...)

 

[Machiavelli]

(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