Wiim Pro distortion on spdif input

[JVN01]

Hi there

Had my Wiim pro for about a week now and I'm interested to hear whether others are seeing any of the same issues.

I'm using it for spdif input from my Samsung TV (for all video streaming platforms like Netflix, etc and DVD/Bluray) and for streaming Amazon and Tidal over wifi, both from within the Wiim Pro app and using Tidal/Amazon connect (which is less reliable ie the Wiim doesn't always appear as an available output device from within the Tidal/Amazon apps, but that's another problem).

Right now my biggest issue is distortion when using the spdif input fed from my Samsung TV which occurs on a regular basis about ever half hour or so. Basically the sound starts to deteriorate over several seconds and then breaks down into heavy metallic digital distortion. Usually opening the Wiim home app and switching to wifi source and back to spdif cures it for half an hour or so.

I raised a ticket and noticed that it is a known issue on the Wiim support site. I then had a message from Wiim during the week saying there was a firmware fix going out (4.8.506254) which should address the issue. This firmware was subsequently installed on my Wiim and it seems like the problem has changed as a result but NOT been fixed, as follows:

Now, every 30 min or so, the sound quality starts to deteriorate over several seconds (firstly becomes more sibilant, then noticeably slightly distorted, but less distorted than before) but now it just mutes completely for a couple of seconds before coming good again for the next 30 minutes or so. It's almost as if the Wiim is drifting out of sync with the spdif input, detecting it and then soft muting for a couple of seconds while it restarts/relocks and then unmutes.

So it seems like Wiim are trying to fix the problem but haven't managed to yet... Which is slightly worrying since spdif input should be relatively simple thing for a box with the processing power of the Wiim Pro to cope with...

Would just be interested to know what other people's experiences are of this problem, and whether anyone has noticed a similar change in behaviour since the recent 4.8.506254 firmware upgrade?

 

[MaxwellsEq]

It's most likely an inaccurate clock or severe clock drift on your TV. If you search on ASR you will find lots of threads of people complaining about changing from DAC A to DAC B has resulted in regular distortion bursts like yours from their TV via the new DAC. They assume the DAC is broken, but what's actually required is a change to the Phase-Locked Loop settings on the DAC to cope with the errored TV output. if the Wiim has a setting to change the PLL, give that a go - it should make the DAC less sensitive to the nonsense coming from the TV.

As a general rule-of-thumb (dangerous, I know), TV sound digital circuits are very cheap. If you have a problem, it's normally safe to blame the TV. Some SPDIF chips (e.g. AK) appear to be more tolerant on default settings than others. Some DACs don't offer the PLL settings and this can limit their use with some TVs.

 

[JVN01]

Interesting comments, can't comment on the accuracy or otherwise of the Samsung TV spdif clock although it's been working perfectly for 4 years with a Yamaha WXC-50 streamer with no issues whatsoever until now. The fact that Wiim acknowledge there is a problem with many Wiim users suggests it's a bit more involved than simply down to the TV being the problem..

 

[MaxwellsEq]

Interesting comments, can't comment on the accuracy or otherwise of the Samsung TV spdif clock although it's been working perfectly for 4 years with a Yamaha WXC-50 streamer with no issues whatsoever until now. The fact that Wiim acknowledge there is a problem with many Wiim users suggests it's a bit more involved than simply down to the TV being the problem..

If you search, you will find other threads where people had a TV that worked fine with an older DAC but not with a replacement one. i.e. it's not just about Wiim. See, for example https://www.audiosciencereview.com/...opping-e70-is-defective-skipping-issue.39507/ The problem appears with TVs because they have extremely cheap (and frequently poor) digital implementations.

In the above thread, @Roland68 mentioned that older DACs with the AK4118 SPDIF receiver were quite tolerant of incoming clock errors. Following the Asahi Kasei fire, this part is no longer available, so all new DACs use a different receiver. Some DACs allow you to adjust the sensitivity of the Phase Locked Loop (PLL) to allow a wider range of inaccurate incoming SPDIF clocks. For those suppliers that don't or can't offer this adjustment, they have no choice but to supply patches until the problem goes away.

 

[Roland68]

If you search, you will find other threads where people had a TV that worked fine with an older DAC but not with a replacement one. i.e. it's not just about Wiim. See, for example https://www.audiosciencereview.com/...opping-e70-is-defective-skipping-issue.39507/ The problem appears with TVs because they have extremely cheap (and frequently poor) digital implementations.

In the above thread, @Roland68 mentioned that older DACs with the AK4118 SPDIF receiver were quite tolerant of incoming clock errors. Following the Asahi Kasei fire, this part is no longer available, so all new DACs use a different receiver. Some DACs allow you to adjust the sensitivity of the Phase Locked Loop (PLL) to allow a wider range of inaccurate incoming SPDIF clocks. For those suppliers that don't or can't offer this adjustment, they have no choice but to supply patches until the problem goes away.

The AK4118 can not only deal with poor signal quality, but also read the data from "manipulated/wrong" data streams.
However, you must also remember that poor signal quality is only part of the problem.
The bigger problem is that additional data (multi-channel, surround information, control information, etc.) is not added according to the 2-channel SPDIF standard.
Therefore, a large part of the problems in TVs with SPDIF and Toslink come in connection with DACs, soundbars, AVRs, gaming consoles and even Sonos devices. It is also amazing how many of these problems are mentioned in connection with LG Oled TVs.

 

[Roland68]

Interesting comments, can't comment on the accuracy or otherwise of the Samsung TV spdif clock although it's been working perfectly for 4 years with a Yamaha WXC-50 streamer with no issues whatsoever until now. The fact that Wiim acknowledge there is a problem with many Wiim users suggests it's a bit more involved than simply down to the TV being the problem..

In my experience, unless the DAC is truly defective, the problem is always the TV.
If the manufacturer of the TV uses cheap components for SPDIF and Toslink (but that's the minor problem) then this can have consequences. But the far bigger problem is adding other data to the signal (multi-channel, surround information, control information, etc.) that does not conform to the 2-channel SPDIF standard. This leads to more or less big problems.

In the meantime I have checked 6 televisions in the circle of friends. Of these, five branded televisions (€1200-4000) could not process the signal via SPDIF and Toslink with a Sony DSC-88. Even an old studio recorder with a simple internal conversion from SPDIF -> i2s could not process the signals.
The SPDIF signal of a noName 55" 4K LED TV purchased in 2017 (i.e. in operation for almost 6 years) could be processed without any problems and without dropouts.

But since the TV is the sacred cow for the users (help, my great TV can't be to blame), you have to scold something, then only the DAC remains.
After all, it can't be the fault of the TV manufacturer who doesn't stick to the (simple) standard for SPDIF.

 

[Rednaxela]

It’s the Wiim.

They offer the input. Not except when it’s a TV.

 

[antcollinet]

Not necessarily.

The PLL of a reciever (which is required to sync to the incoming clock from the sending device) will have a maxmium range of clock "difference" (tolerance) that it can cope with. In a correctly designed device this will fit with whatever standard defines the tolerance of clock frequency for SPDIF type interfaces. Most good desgins will probably cope with tolerances larger than specified.

If a sending device doesn't comply wiht the standard to a degree larger than the reciever can cope with - then the reciever won't be able to adjust it's clock to match the sender and the result will be buffer under or over runs.

The fault lies with the device that doesn't meet the requirements of the standard. TV's seem to be renowned to not work well here. Many topping DACs for example struggle with some brands of TV.

The 30 seconds mentioned in the OP will be the time it takes to get a buffer over/underrun. So in this case the clock mismatch is pretty small. However, if the PLL range limit is limtied by hardware, then no firmware fix will get around this. It seems that what they have done is to detect when buffer under/overrun happens, and then reset the system (half fill the buffer) so that it can continue to run - until the next time.

 

[dpuopolo]

It has happened with my ONN 50 inch TV as well. They did a firmware update that fixes the problem. The firmware date is 1/31.

Hi there

Had my Wiim pro for about a week now and I'm interested to hear whether others are seeing any of the same issues.

I'm using it for spdif input from my Samsung TV (for all video streaming platforms like Netflix, etc and DVD/Bluray) and for streaming Amazon and Tidal over wifi, both from within the Wiim Pro app and using Tidal/Amazon connect (which is less reliable ie the Wiim doesn't always appear as an available output device from within the Tidal/Amazon apps, but that's another problem).

Right now my biggest issue is distortion when using the spdif input fed from my Samsung TV which occurs on a regular basis about ever half hour or so. Basically the sound starts to deteriorate over several seconds and then breaks down into heavy metallic digital distortion. Usually opening the Wiim home app and switching to wifi source and back to spdif cures it for half an hour or so.

I raised a ticket and noticed that it is a known issue on the Wiim support site. I then had a message from Wiim during the week saying there was a firmware fix going out (4.8.506254) which should address the issue. This firmware was subsequently installed on my Wiim and it seems like the problem has changed as a result but NOT been fixed, as follows:

Now, every 30 min or so, the sound quality starts to deteriorate over several seconds (firstly becomes more sibilant, then noticeably slightly distorted, but less distorted than before) but now it just mutes completely for a couple of seconds before coming good again for the next 30 minutes or so. It's almost as if the Wiim is drifting out of sync with the spdif input, detecting it and then soft muting for a couple of seconds while it restarts/relocks and then unmutes.

So it seems like Wiim are trying to fix the problem but haven't managed to yet... Which is slightly worrying since spdif input should be relatively simple thing for a box with the processing power of the Wiim Pro to cope with...

Would just be interested to know what other people's experiences are of this problem, and whether anyone has noticed a similar change in behaviour since the recent 4.8.506254 firmware upgrade?

 

[Overseas]

So Wiim was designed for extra superior quality TV's.

 

[antcollinet]

So Wiim was designed for extra superior quality TV's.

Or - possibly - for TV's (and other devices) that meet standards.

 

[Overseas]

So lots and lots of people, forum included, buy sub-standard TVs from legit LG, Sony etc dealers. Understood.

 

[Kegemusha]

I had an old Plasma TV and now a new one and no issues using spdif to a topping DAC with both TVs.
And from another TV I have an xbox to an old smsl integrated amp and no issues.
Gessing the wiim is the issue, some bug there

 

[MaxwellsEq]

So lots and lots of people, forum included, buy sub-standard TVs from legit LG, Sony etc dealers. Understood.

Yes, that's correct! Probably 99% of TVs never have their SPDIF port used. Home theater users have receivers, TVs etc. All connected via HDMI. Most users simply use the TV as is, or with an HDMI soundbar.

If you're a TV manufacturer, why waste money on a bit that's hardly ever used?

Most TV digital implementations are bad, but only a few people ever discover this.

Roland68 has a SPDIF test set. His posts are worth reading on the mistakes he's uncovered.

 

[IAtaman]

So lots and lots of people, forum included, buy sub-standard TVs from legit LG, Sony etc dealers. Understood.

Why do you sound so surprised - isn't that the whole mission of Amir and ASR, to expose the highly rated brands that sell sub-standard products?

 

[kopczas]

Is it possible to stream dsf files by this device?

 

[phofman]

IIUC the streamer is based on A113X. I could not find online any technical reference PDF of that SoC. It may have a HW asynchronous resampler, based on this in https://fccid.io/2ANOG-A98XX/User-Manual/user-manual-4402900.pdf :

A113X integrates all standard audio input/output interfaces including multiple TDM, PCM, I2S and SPDIF
digital audio input/output interfaces, and 8 channel far-field PDM digital microphone (DMIC) inputs. Audio input
has power detector to wake up from low activity states and hardware assisted synchronization blocks for multiple
room audio applications.

Nevertheless, I would not be surprised if the problem was non-implemented or ineffective asynchronous/adaptive resampling of the incoming SPDIF stream against the output audio device clock.

 

[onlyoneme]

IIUC the streamer is based on A113X. I could not find online any technical reference PDF of that SoC. It may have a HW asynchronous resampler, based on this in https://fccid.io/2ANOG-A98XX/User-Manual/user-manual-4402900.pdf :


Nevertheless, I would not be surprised if the problem was non-implemented or ineffective asynchronous/adaptive resampling of the incoming SPDIF stream against the output audio device clock.

No resampling here. WiiM tries to maintain a bitperfect manner from spdif in to out.

 

[phofman]

SPDIF carries its own clock. Unless the SPDIF-recovered clock is used for the output audio device (i.e. both paths SPDIF -> A113X and A113X -> DAC use just one clock and run synchronously), some sort of adaptive resampling must be employed. If not, any amount of buffers between two independent clocks will over/underflow eventually, causing very similar symptoms to those reported here.

 

[onlyoneme]

I would guess it just uses the incoming clock recovered from the spdif transmission, that's why issues can happen when jitter is too high for example.