High Frequencies Cutting Off at 16kHz

[yuki]

First off, as a Japanese speaker with limited English, please excuse any awkwardness in this translation, as I'm relying on translation tools.
I just noticed that the high frequencies abruptly stop at 16kHz. Looking at past measurements, it seems this was already happening back in January. Since I recently got new speakers, I initially thought they were the cause. However, the fact that the roll-off is so precise at 16kHz made me investigate further.
When connecting to my SMSL DAC via Bluetooth, it properly reproduced frequencies up to 20kHz. Similarly, other equipment also played up to 20kHz as long as the Wiim wasn't involved.
The issue is that whenever the Wiim is in the signal chain, regardless of the input or output, the sound cuts off exactly at 16kHz. I've considered various potential causes and swapped out cables, but the problem persists.
Looking back at older measurements, I found that in late November of last year, the system could still reproduce up to 20kHz even with the Wiim in the chain. This suggests that an update between late November of last year and late January of this year might be the cause, or perhaps the Wiim simply failed sometime during that period.
Has anyone else experienced this same issue? I'm looking for any information.

 

[harkpabst]

Welcome, @yuki.

What WiiM device are you actually using and how is it connected in your chain?
What kind of measurements are you performing and using which tools (software, hardware, microphone)?

I never noticed anything similar (doing acoustical in-room measurements with the WiiM Amp, WiiM Amp Pro and WiiM Ultra). I cannot hear 16 kHz anyway.

Edit:
Once I know your WiiM device I might move this thread into the appropriate sub-forum, so it gets more attention from fellow users.

 

[yuki]

I am using a Wiim Pro (model 863a).
Regarding connections, I have tried optical, coaxial, and line outputs, but all of them only go up to 16kHz. The devices I connected to were both a DAC and an amplifier. When I connect directly from my smartphone to either the DAC or the amplifier via Bluetooth (bypassing the Wiim), it plays up to 20kHz. However, when I connect through the Wiim, all connection methods are limited to 16kHz.
The measurements were taken using a microphone to measure the frequency response. After noticing the issue, I measured at a distance of 1 cm from the tweeter, which resulted in a graph showing a very sharp drop-off.
Personally, I can barely hear frequencies around 16.5kHz, which is why I initially assumed the speakers were the issue and didn't pursue it further. For regular music listening, frequencies above 16kHz are mostly irrelevant to me, but knowing they aren't being reproduced is still bothersome.
I'm not very familiar with how to use this forum, so I apologize if I'm posting in the wrong place.

 

[yuki]

I've noticed something new.

I had previously reported an issue where the Wiim was inverting the left and right channels to their support. On November 21st, they replied stating, 'We have added your device to the whitelist for version 4.8.621960.' I then updated, and the left/right channel inversion issue was resolved. The last time I confirmed 20kHz playback was on November 16th, so I now suspect this update is the cause.

 

[harkpabst]

I've noticed something new.

I had previously reported an issue where the Wiim was inverting the left and right channels to their support. On November 21st, they replied stating, 'We have added your device to the whitelist for version 4.8.621960.' I then updated, and the left/right channel inversion issue was resolved. The last time I confirmed 20kHz playback was on November 16th, so I now suspect this update is the cause.

Yes, WiiM do provide special firmware versions to whitelisted devices for various reasons from time to time. It could be the cause, or just a coincidence in time.

I'm sure you did double check all PEQ and GEQ settings, so this is not the issue.

There have been five firmware updates for the WiiM Pro since November 2024, so maybe just updating to the most recent general availability release could fix both issues. If you cannot opt out of the special firmware 4.8.621960 yourself by tapping the version number app, I suggest you sent feedback to WiiM through the WiiM Home app (tab "More" => "Send us feedback") and request to be taken off the whitelist.

I haven't heard of any similar case so far, so I'm running out of alternative suggestions.

Good luck.

 

[yuki]

Thank you.I have already sent feedback regarding this.I believe my device has been updated multiple times since then, but perhaps being on the whitelist makes a difference. I think I will try requesting to be removed from the list.Thank you for the advice.

 

[harkpabst]

OK, so 4.8.621960 is not your current firmware version any more? For certain cases WiiM do provide alternative firmware forks, indeed.

If you know your ticket number (you should have received a pop-up notification and an email containing the ticket number) you can log into the WiiM Audio Help Center ...

https://faq.wiimhome.com/en/support/tickets

... and add further information any time you want.

 

[Wiimer]

First off, as a Japanese speaker with limited English, please excuse any awkwardness in this translation, as I'm relying on translation tools.
I just noticed that the high frequencies abruptly stop at 16kHz. Looking at past measurements, it seems this was already happening back in January. Since I recently got new speakers, I initially thought they were the cause. However, the fact that the roll-off is so precise at 16kHz made me investigate further.
When connecting to my SMSL DAC via Bluetooth, it properly reproduced frequencies up to 20kHz. Similarly, other equipment also played up to 20kHz as long as the Wiim wasn't involved.
The issue is that whenever the Wiim is in the signal chain, regardless of the input or output, the sound cuts off exactly at 16kHz. I've considered various potential causes and swapped out cables, but the problem persists.
Looking back at older measurements, I found that in late November of last year, the system could still reproduce up to 20kHz even with the Wiim in the chain. This suggests that an update between late November of last year and late January of this year might be the cause, or perhaps the Wiim simply failed sometime during that period.
Has anyone else experienced this same issue? I'm looking for any information.

Hi

What sound source did you use for the measurement?

If it is Amazon music for example, it is possible that HD/UHD is turned off in the WiiM app.

I will test this later.

 

[yuki]

Sweep tones

 

[Wiimer]

Sweep tones

Is it a sound file you own, not streaming?

 

[Wiimer]

Sweep tones

No problem with my Pro (FW 4.8.712747).



As already said, it could be your firmware or a device specific problem. (Unless there is a problem with the sound source.)

 

[yuki]

To test all inputs, I tried various methods. They all resulted in 16kHz.

I also tried changing the bit rate and sample rate. I even reset the device to its factory settings. Over the course of four hours, I tried everything I could think of.

I've encountered various bugs in the past, but they have all been fixed so far, which is why I trust their support. However, I thought this forum offered a good opportunity to see if others had similar experiences, so I decided to join.

The images are from November 15th, 2024 and March 31st, 2025.

 

[yuki]

Last week, support asked me to turn off the EQ to see if it improved the issue. I replied that turning off the EQ did not fix it. I also mentioned that detailed information about the problem could be found on this forum.
Today, a week later, I received a response from support, and they asked me the exact same thing: to turn off the EQ to see if it improves the issue.
I am really disappointed.

 

[Wiimer]

Last week, support asked me to turn off the EQ to see if it improved the issue. I replied that turning off the EQ did not fix it. I also mentioned that detailed information about the problem could be found on this forum.
Today, a week later, I received a response from support, and they asked me the exact same thing: to turn off the EQ to see if it improves the issue.
I am really disappointed.

What firmware version is your Pro?

Also, you mentioned that you tried all the inputs on the WiiM, what devices did you connect and test?

The graph that cuts off around 16kHz seems very similar to what you see when you play a lossy file.

 

[Wiimer]

Last week, support asked me to turn off the EQ to see if it improved the issue. I replied that turning off the EQ did not fix it. I also mentioned that detailed information about the problem could be found on this forum.
Today, a week later, I received a response from support, and they asked me the exact same thing: to turn off the EQ to see if it improves the issue.
I am really disappointed.

Could you download the 16/48 sweep tone WAV file from this site to your phone and play it from "My Music" in the WiiM app?

【周波数テストトーン】正弦波(サイン波) Sweep 20Hz to 20000Hz 1min - Useful Sounds Japan

正弦波(サイン波)のスイープ音（20Hz～20000Kz）です。

usefulsounds.jp

This is the result of my test.

 

[yuki]

After updating to version 4.8.712747 and checking again after a week, I can now confirm playback of frequencies above 20kHz on all connections.
The things I did were: upgraded to the beta version and then downgraded to the current version, and reconnected all the wiring due to getting a new TV (incidentally, I'm currently using analog input from the TV's headphone jack to the Wiim, and I was surprised to find that it's properly being AD converted? and the EQ even works). I also moved the Wiim's placement. However, none of these changes seem relevant to the outcome.
I have absolutely no idea what changed, and now, conversely, I can no longer reproduce the previous state that had persisted for three months, even if I try to investigate.
I am grateful for everyone's kind support.
Also, the file you shared played up to 22kHz without any issues. Unfortunately, my ears in my forties can't hear it, but it's important to me that it's being measured, and seeing that gives me peace of mind.

 

[canard]

for info..(we never really knew your capture conditions etc), this kind of problem can happen in certain circumstances with measurements via can if the computer microphone is not properly muted during these....
to check when "weird"...

 

[Wiimer]

for info..(we never really knew your capture conditions etc), this kind of problem can happen in certain circumstances with measurements via can if the computer microphone is not properly muted during these....
to check when "weird"...

From the image in which the OP posted, I think the Spectroid app for Android was used here.

 

[yuki]

for info..(we never really knew your capture conditions etc), this kind of problem can happen in certain circumstances with measurements via can if the computer microphone is not properly muted during these....
to check when "weird"...

I did consider the microphone as a potential issue, but I was able to measure frequencies above 20kHz when the Wiim wasn't in the chain.
By the way, since the TV size changed, I ran room correction, and I was able to confirm a significantly improved high-frequency response in that graph as well. The TV has terrible reflections though...

 

[yuki]

From the image in which the OP posted, I think the Spectroid app for Android was used here.

That's right! I usually connect a microphone to my Android smartphone, which has a headphone jack, and use a 20-20 sweep tone generator that I've had for ages. Thankfully, it looks like it might become 20-22 from today onward.