My WiiM Pro Plus (+) tests

I'm the opposite. I hope the next product is the WiiM Pro Minus with no ADC, no DAC, no RC, just a basic pure digital transport.

The push for more and more features in an all-in-one will only increase cost and complexity which increases risk in terms of avoiding regressions/bugs.
 
elmoe said:
I'm the opposite. I hope the next product is the WiiM Pro Minus with no ADC, no DAC, no RC, just a basic pure digital transport.

The push for more and more features in an all-in-one will only increase cost and complexity which increases risk in terms of avoiding regressions/bugs.
Click to expand...
I’d have to say - get a Raspberry Pi and a decent USB DAC. Hardware wise it’s as good. Software wise it depends what you install.
 
elmoe said:
I'm the opposite. I hope the next product is the WiiM Pro Minus with no ADC, no DAC, no RC, just a basic pure digital transport.

The push for more and more features in an all-in-one will only increase cost and complexity which increases risk in terms of avoiding regressions/bugs.
Click to expand...
Yes it’s true it will raise the cost but I would rather have them on same box. It’s cumbersome having it separate.
 
Smartplug said:
Look at bluesound node it got sub out.
Click to expand...
I’d rather not. It’s over priced for what it does.
I thought we were talking about a streamer I.e. no DAC but with a USB out. That’s what the post implied. You can’t have a non DAC streamer with a sub out (analogue)
 
onlyoneme said:
At a moment I can tell that my sample unit has an increased space around the coax socket. And a glossy finish of the chassis.

Stay tuned :)




Part 0 - a test gear possibly involved

RME ADI-2 DAC FS, ESS edition
miniDSP Flex, RCA edition
E1DA Cosmos ADC, A grade
PicoScope 4444
Intona 7055-D isolator or ISOUSB211 based one - when needed

and some other less important stuff - powerbanks, Allo Nirvana SMPS, Icron Ranger 2201 USB extender, SPDIF Audio Switch by Beni, etc.


Part 1 - analog output - Pro vs Pro Plus combat

The fight begins. Both devices powered by Xiaomi battery packs, both use the strongest 2 Vrms outputs.
Pro's FW is 4.8.523533.
For the Pro Plus is was 4.8.521533 initially, and later 4.8.523842 with a fix for the reported bug.

Edit: 4.8.524946 has been released to fix locked 16 bit depth output for ADC.

Round 1 - power consumption

The Pro Plus is more power hungry. It needs almost 2.6 W (0.5 A / 5.1 V) when idle with a wired network. It rises to above 4.5 W (0.9 A / 5.1 V) when sine 1 kHz at 96 kHz is played. On the other hand the Pro needs 1.3 W (0.25 A / 5.1 V) and almost 1.7 W (0.32 A / 5.1 V) respectively.

Round 2 - output signal voltage

The Pro Plus real output voltage level is 1.973 Vrms for both channels, for sine 1 kHz at 96 kHz. For the Pro it's slightly unbalanced 2.012 for the left channel and 2.006 for the right channel. Values measured with a multimeter.

Round 3 - REW measurements

My Pro unit measures slightly better on its left channel while for the Pro Plus it's the right one, so better channels are compared unless stated otherwise.
All the measured values are presented as Pro vs Pro Plus.

Sine 1k 48 kHz:

View attachment 1454
View attachment 1455View attachment 1456

Significant 22.5 dB difference in SINAD.


SMPTE 48 kHz:

View attachment 1457
View attachment 1458View attachment 1459

Clear advantage of the Pro Plus but low freq harmonics higher than expected.


CCIF 48 kHz:

View attachment 1460
View attachment 1461View attachment 1462

Another test for intermodulation distortions, this time with a wider bandwidth included in the calculations. Looks like Pro's Achilles heel, it's performance is horrible here. Pro Plus can shine.


Multitone 48 kHz:

View attachment 1466
View attachment 1467View attachment 1468

The test which focuses more on the real life performance. IMD tests issues mentioned before are clearly visible.


DAC filters:

The Pro seems to use a kind of fast linear phase filter with the response as below:
View attachment 1470

The Pro Plus uses rather a fast minimum phase filter:
View attachment 1471

Attenuation of the Pro Plus filter is much more effective (48 kHz):
View attachment 1472


Internal headroom management:

A test to see how the unit can handle intersample peaks. Lets imagine we have a test signal with sample peaks at the max allowed 0 dBFS level, but these samples are not sine wave peaks. On the picture below we can see possible clipping areas if the device cannot provide a sufficient amount of headroom to handle it.

View attachment 1482

To test it I've prepared 4 test signals with sample peak levels from 0 dBFS to -5 dBFS, and intersample peaks from +3.02 dBFS to -1.98 dBFS.

The Pro results:

View attachment 1485

1 and 2 are clipping, 3 and 4 remain the same. Looks like there is no internal headroom or it's just minimal.

The Pro Plus results:

View attachment 1486

Only 1 is clipping. The headroom wasn't big enough to handle +3.02 dBFS peaks, but it's above 1 dB.

Edit:
One more test added for intersample +2.02 dBFS peak:

View attachment 1488

It clips for such level, so the headroom is somewhere in the range 1-2 dB.


Dynamic Range:

It's calculated using a sine 1 kHz signal at -60 dBFS level.

View attachment 1491View attachment 1492

Pro: 44.1 + 60 = 104.1 dB
Pro Plus: 56.3 + 60 = 116.3 dB


Being idle / playing silence:

The noise level when device is doing nothing or when it plays a silence stream - all the samples are zeroed. Also the cases where the PSU used usually impacts measurement plots, especially when the device is idle.

For the Pro idle and silence look different:

View attachment 1495

No idle mode artifacts coming from the PSU, but it's a battery pack used here.

There is no such noise level difference for the Pro Plus, although an alone component appears:

View attachment 1497

The Pro Plus seems to be perfectly muted when playing a silence.


THD vs frequency, sweep -3 dBFS:

A sweep signal can deliver some information regarding the relation between harmonic distortions level and a frequency of the fundamental.

View attachment 1499

A kind of trouble with low frequency distortions is visible here for the Pro Plus. Bad Pro's performance with high frequencies also shown.


Part 2 - a closer look onto Pro Plus analog output

Output voltage levels:

There are 4 output voltage levels available, 2 Vrms, 1 Vrms, 0.8 Vrms and 0.5 Vrms. How does it affect the performance?

View attachment 1503

While the voltage level decreases a SINAD decreases as well (sine 1k 48 kHz).

2 Vrms - SINAD 111.7
1 Vrms - SINAD 109.4
0.8 Vrms - SINAD 107.6
0.5 Vrms - SINAD 103.8

Voltage levels measured by PicoScope using sine 1k 48kHz signal:
1.977
0.990
0.784
0.495

There is a lot of headroom on 1 Vrms output. No clipping at all for intersample peak tests regardless of the signal level:

View attachment 1504


What if I change the power source?

An ordinary Huawei phone charger is the first candidate. Labeled as 2A maximum, is strong enough to power the Pro Plus.
Did I notice performance decrease in my 38 synthetic tests? Not at all.
The Allo Nirvana ultra low noise SMPS is next. No serious improvement again, but at least I've caught a difference:

View attachment 1513

It's a removal of insignificant ultrasonic components in the idle test which is the most sensitive for any PSU changes. That's all.
I can guess that the Pro Plus PSR ratio is high enough to make it quite immune to common SMPS ripples and noise.

I will give the Nirvana SMPS a second chance during listening tests.


Low frequency THD:

A closer look reveals a behavior similar to the infamous ESS hump, more common for implementations of ESS chipsets, where distortions level rises in a specific way:

View attachment 1517

"Better optimized" 1k signal doesn't grow so rapidly:

View attachment 1518

Unexpected behavior of low frequency distortions is also visible on IMD graph below, which uses SMPTE test signal:

View attachment 1519

It should be noticed that although these higher than expected harmonic distortions levels are significant in terms of measurements, their audibility is rather questionable and probably should not bother.



Part 3 - the digital domain

Streaming to digital outputs with bit-perfect capable interface:
The Pro Plus has been connected to RME ADI-2 DAC FS, which will act as the spdif-usb interface to let me analyze the Pro Plus output. All the DSP features of the Pro Plus are disabled.
Nothing unusual here, the Pro Plus is fully digital transparent on both coax and toslink outputs, just like any other WiiM. It also passes all RME bit-perfect tests up to 24 bit depth.

Toslink input to digital outputs with RME ADI-2 DAC FS:

The Pro Plus still connected to RME ADI-2 DAC FS, but an additional device appears here - SMSL PO100 Pro, which acts as the usb-spdif interface to let me feed the Pro Plus.
The Pro Plus is again fully digital transparent on both coax and toslink outputs.

There is also a surprise here. The Pro was suspected to perform a signal reclocking of the input stream to its internal clock, which could result in some unwanted behaviors like clicks and pops. But what do I see in REW when using its generator:

View attachment 1534

An audio chain is:
PC (REW generator) -> usb-spdif -> Pro Plus input -> Pro Plus output -> spdif-usb -> PC (REW capture)
For such scenario the source signal is clocked by usb-spdif interface (PO100 and XMOS clock). There is no discrepancy with the clock captured on the PC, I believe it can be a sign that the reclocking on the Pro Plus wasn't made. The same behavior can be seen with both toslink and coax outputs.
Another possible argument for this assumption is a drift calculation between the input and the output in Multitone Analyzer:

View attachment 1531


I will evaluate this theory later with a different capture interface.


What about the latency between digital input and output?
For 192 kHz signal, the latency measured in Audacity, toslink in -> toslink out, is 44 ms.

View attachment 1533

For toslink in -> coax out, it is 49 ms.

Toslink input to toslink output with miniDSP Flex:

Time to investigate further a possible reclocking behavior on the digital input of the Pro Plus. The Mini will feed the input this time and the Pro Plus is connected to miniDSP Flex via toslink. As the Flex uses ASRC to reclock any input to its own internal clock, it will let me see when the incoming clock varies. So 3 cases to be analyzed:
- Mini connected directly to the Flex
- Mini connected to the Pro Plus which is connected to the Flex
- Pro Plus connected alone to the Flex
I've captured 24 sec audio content, it has been sample aligned at the beginning in Audacity. Results:

View attachment 1552

Mini connected to the Pro Plus behaves like the Pro Plus here. Its spdif stream is reclocked by the Pro Plus and later sent with the clock of Pro Plus. The reclocking can happen on the Pro Plus similar way it's possible on the Pro.


Streaming to digital outputs with ASRC interface:

I haven't observed any significant differences between the Pro and the Pro Plus when connected to miniDSP Flex. For example j-test plot quality looks very similar for both devices, REW:

View attachment 1562

Or in Multitone Analyzer:

View attachment 1563

Probably the digital section of the Pro Plus remains the same, or very similar, to the one of the Pro.



Part 4 - time for a short, analog break, although served in the digital form:


Three devices, two WiiMs, 1 DAC. One of them is the Pro Plus. The analog output was used every time. No mapping to the names included. Have fun :)



Audio test sound source provided by: (C) Maestro Tacky (https://globalaudio.info/page-2358/)
オーディオテスト音源提供：(C)マエストロTacky（https://globalaudio.info/page-2358/）

Pack 1 – Google Drive

drive.google.com drive.google.com

Edit: a new link to the same content but recorded with slightly different, more polished (because I'm Polish ;) ) procedure. Difference between samples from this pack and the previous one should be inaudible.

Pack 1a – Google Drive

drive.google.com drive.google.com



Part 5 - WiiM Pro Plus vs RME ADI-2 DAC FS - analog output performance:

Both devices with left channel, measured again using E1DA Cosmos ADC. ADI-2 unbalanced output level calibrated at 1.977 Vrms to be equal with the Pro Plus level. The Pro Plus presented first with measurements results.

Sine 1k 48 kHz:

View attachment 1622
View attachment 1623View attachment 1624


Sine 12k 48 kHz:

View attachment 1626


IMD SMPTE 48 kHz:

View attachment 1627
View attachment 1628View attachment 1629


Multitone 48 kHz:

View attachment 1631


THD vs signal level for sine 1k, 48 kHz:

View attachment 1632


THD vs signal level for sine 40 Hz, 48 kHz:

View attachment 1633


THD vs frequency for sine, 192 kHz:

View attachment 1635


DAC filters:

"SD Sharp" selected on ADI-2 to match the filter on the Pro Plus.

View attachment 1637



Part 6 - ADC performance:

In one of my comments below:

My WiiM Pro Plus (+) tests

Are the dimensions of the Plus and Plus Pro cases the same?
forum.wiimhome.com forum.wiimhome.com



Epilogue

The main part ends here alhough some supplements may come later. I consider the Pro Plus to be a significant improvement over the Pro for the analog section, despite some downsides related to low frequencies performance or a weaker ADC. If you need a modern device which promises a solid analog performance without a need to use an external DAC, the Pro Plus might be for you. If you don't care about the onboard DAC or ADC, the new model has nothing to offer compared to the Pro. And yes, being comparable even to 500 usd DACs is a bold statement, too bold I would say.

Thanks to the Linkplay team for giving me an opportunity to test the device before its release.
Click to expand...
Hi Onlyoneme,

Thank you very much for your thorough evaluation of the WiiM Pro Plus. We appreciate your insightful feedback and the time you've taken to understand the nuances of our product.

We're pleased to hear that you recognize the significant improvements in the analog section of the Pro Plus. Your point about the low-frequency performance and ADC is well-taken, and we're continuously working to enhance these aspects. As a point of reference, we measured the EVK board from AKM with the AKM4493SEQ which has a similar low-frequency performance as ours. With that being said, we're working on the optimization of this part and will keep the team updated.

We understand that the Pro Plus's value proposition may vary for users depending on their specific needs and preferences. Your perspective on the comparison with $500 DACs is also valuable, and we're always striving to deliver the best possible performance at a competitive price point.

Thank you once again for your review and for your continued support. We look forward to any additional insights you may have in the future.
 
d6jg said:
The inference of the original comment is that that the poster is looking for USB out ie an external DAC.
Click to expand...
And the same time he expects the sub out which makes thinking about the external DAC a bit unfounded.
 
WiiM Support said:
Hi Onlyoneme,

Thank you very much for your thorough evaluation of the WiiM Pro Plus. We appreciate your insightful feedback and the time you've taken to understand the nuances of our product.

We're pleased to hear that you recognize the significant improvements in the analog section of the Pro Plus. Your point about the low-frequency performance and ADC is well-taken, and we're continuously working to enhance these aspects. As a point of reference, we measured the EVK board from AKM with the AKM4493SEQ which has a similar low-frequency performance as ours. With that being said, we're working on the optimization of this part and will keep the team updated.

We understand that the Pro Plus's value proposition may vary for users depending on their specific needs and preferences. Your perspective on the comparison with $500 DACs is also valuable, and we're always striving to deliver the best possible performance at a competitive price point.

Thank you once again for your review and for your continued support. We look forward to any additional insights you may have in the future.
Click to expand...
Thx for your comment, I really appreciate it. And I am delighted that you and your team have been able to once again deliver an extremely competitive product with great customer value.
 
It is good that low frequency distortions can be optimisable , since they could possibly relate to the “tubby” bass that was the only minor complaint in your subjective hearing test you have shared @WiiM Support .However, I have also got my hopes up from the same person (that made the remark about the tubby bass) that said that he/she still preferred it to denafrips ares!
 
Last edited:
With the Pro Plus finally out and in stock in the US, it's time to solve the audio puzzle. Y was the Pro Plus, Z was the Mini, X was my 13 years old DAC.
Who is the winner? ;)
 
So the WiiM Golden Ears award goes to a soon to be 70yr old with hearing aids? Maybe need a better endorsement than that 🤣 🤣
 
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