Room correction: very strange Per Channel algorithm and it's respective results

[slartibartfast]

Hi @AlxTMX
Unfortunately, you are not the only one who has experienced this defect.
I also had, and have, it from the first moment with the Ultra connected via USB to my Topping D70ProSabre DAC.
If I use ARC per channel, from L channel the sweep tone starts in the correct way, although it ends in a couple of seconds of “modulated noise,” as you called it. I called it white noise. When switching to the R channel, no sweep tone, only modulated noise or white noise.
Of course, the equalized curve of the R channel is completely meaningless. As you say "huge overcompensated in bass region and depressed in higs".
In my case, given the position of the speaker (rear bass reflex) which is placed in an angle I should have achieved exactly the opposite. Cut bass and increased treble. I tried everything. Rebooting the Ultra; reinstalling the App; I changed from IOS to Android, but the defect is still there.
On the other hand, if I use the ARC per channel with the DAC connected to the Ultra with a COAX cable, everything works at his best. The problem is only with the USB.
I opened two tickets through WHA attaching the log, but I got no response from @WiiM Support or @WiiM Team .
I thought I was the only one with that problem, but now I see that I am not alone. I hope that @WiiM Support or @WiiM Team can solve this annoying problem.

I suppose a workaround would be to use coax for room correction then change back to USB afterwards. Not ideal though.

 

[Maurizio]

I suppose a workaround would be to use coax for room correction then change back to USB afterwards. Not ideal though.

Hi @slartibartfast
Yes, that's what I did, but, as you rightly say, switching cables is far from convenient also because reaching the cables to be switched/reversed is not exactly easy, given how my devices are positioned.

 

[AlxTMX]

Hi @AlxTMX
Unfortunately, you are not the only one who has experienced this defect.
I also had, and have, it from the first moment with the Ultra connected via USB to my Topping D70ProSabre DAC.

Hi, Maurizio. Thank You for your report!
Just tested USB output of my Ultra and I've got the very same result as yours and as mine earlier. So, to summarize, this problem is character for all digital outputs: USB, Coaxial and Opticial. And there is some strange bug at the very end of the Left channel calibration file definitely. It could be very nice if WiiM developers check this.

 

[harkpabst]

Hi, Maurizio. Thank You for your report!
Just tested USB output of my Ultra and I've got the very same result as yours and as mine earlier. So, to summarize, this problem is character for all digital outputs: USB, Coaxial and Opticial. And there is some strange bug at the very end of the Left channel calibration file definitely. It could be very nice if WiiM developers check this.

Did you send feedback through the WiiM Home app? Ideally right after performing such a crippled correction measurement? If not yet then go ahead.

@WiiM Team, @WiiM Support, @RyanWithWiim, I think that this is really important and probably not to hard to fix.

 

[AlxTMX]

Did you send feedback through the WiiM Home app? Ideally right after performing such a crippled correction measurement?

Yes. I've sent feedback. But I'm pretty sure the problem is in the test file and strange calibrating results are only it's consequence.

 

[Wiimer]

Hi, Maurizio. Thank You for your report!
Just tested USB output of my Ultra and I've got the very same result as yours and as mine earlier. So, to summarize, this problem is character for all digital outputs: USB, Coaxial and Opticial. And there is some strange bug at the very end of the Left channel calibration file definitely. It could be very nice if WiiM developers check this.

I compared the three sound files for stereo and L/R RC to look for the problem you found. However, no oddities were found.

Stereo RC File




Left RC File




Right RC File




Can you tell us specifically what is wrong with the L sound file?

 

[harkpabst]

Can you tell us specifically what is wrong with the L sound file?

I think the pattern lies in an external DAC.

 

[AlxTMX]

Can you tell us specifically what is wrong with the L sound file?

Oh, thank You! No, I can see no differences. But the problem is stable, it's always at the same time-code, it's always with the Left one, it's character for all digital interfaces and various WiiM devices. My workaround hints at sinchronization drops down to 44.1 at this moment and remains in this value. And I suspect it could be caused by interference of WiiM digital interface with XMOS 316 interface of the DAC.
I.e. the question is what in this file causes the problem with DAC that is never encountered in real music for years?

 

[harkpabst]

Yes. I've sent feedback. But I'm pretty sure the problem is in the test file and strange calibrating results are only it's consequence.

Yes, of course. But there's nothing the correction algorithm could do if the test signal used for measuring is not what it's supposed to be. Consequently, the measurement results are crippled.

I suspect some incorrect initialisation.

 

[AlxTMX]

So, what should I do You're think?
No one replied me back, no one demanded no additional info for till now. Hope it's due to the Christmas season only
Ps. To be honest, I couldn't find an option to attach logs to the report.

 

[Burnside]

So, what should I do You're think?
No one replied me back, no one demanded no additional info for till now. Hope it's due to the Christmas season only
Ps. To be honest, I couldn't find an option to attach logs to the report.

When you use the feedback section in the app, your logs are automatically sent.

 

[AlxTMX]

When you use the feedback section in the app, your logs are automatically sent.

Thanks!
I'll do it again, hope it could work.

 

[harkpabst]

Thanks!
I'll do it again, hope it could work.

When you send feedback you also receive an email with your ticket number. The email also tells you to reply if you want to be contacted about your ticket. If you don't reply and WiiM have all the information they need to work on the issue they will usually not come back to you directly.

You can always track your tickets from the WiiM Audio Help Center if you log in with your WiiM account:

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

 

[AlxTMX]

Done. Thank You!

 

[Maurizio]

Hi, Maurizio. Thank You for your report!
Just tested USB output of my Ultra and I've got the very same result as yours and as mine earlier. So, to summarize, this problem is character for all digital outputs: USB, Coaxial and Opticial. And there is some strange bug at the very end of the Left channel calibration file definitely. It could be very nice if WiiM developers check this.

I have done other experiments ( COAX-OPT), but the result is still the same. L channel, starts with sweep tone, but at the very end the sweep tone changes to an undefined noise. R channel, no sweep tone, but that indefinite noise from the beginning to the end. At this point I can say that the ARC per channel of the Ultra does not work, all the more so now that I have found that I am not the only one with the problem.
Instead, everything works perfectly with the stereo correction. The Ultra is connected to my Topping D70Pro Sabre external DAC.
I have already opened a ticket through WHA asking to be contacted again, but from @WiiM Team ; @WiiM Support ; and @RyanWithWiim the most absolute silence.
I will open another ticket, although I don't have much hope for an answer/solution.
I wanted to do another experiment ( put the output fixed at 16/48 KHz ), but in doing so I discovered something I hadn't noticed before.
In the sound options, USB does not appear. Coax and OPT appear, where you can adjust the sound quality and a possible fixed resolution, but not USB, even with the Ultra and DAC turned on.
Does anyone have an idea why for USB it is not possible to adjust those parameters? Really strange, at least for me.

 

[AlxTMX]

I wanted to do another experiment ( put the output fixed at 16/48 KHz )

Hi! I see the core components of my DAC are very similar to your one and to many other DACs on our planet nowadays: ES9039Pro as DAC chip and XMOS XU316 as controller. So the results are the same obviously.
One can use any FIXED resolution for SPDIF as a workaround in Per Channel Room Correction process. Then one can switch to maximum, not fixed. There is no an option to lock USB resolution unfortunately and You could think about to change your connection scheme. And I do think to try some USB-I2S converter/reclocker.

 

[s3igell]

@Maurizio @AlxTMX Any updates on this topic?? Any feedback received from WiiM Support via your Support Tickets??

Did either of you successfully perform RC-per-Channel by using the Ultra's DAC (remove your External DAC from the equation)??
While not Optimum, the result should be the same (unless your DAC is truly coloring the output), no??

@Maurizio - you posted "I have done other experiments ( COAX-OPT), but the result is still the same." Were these tests done with Inputs to the same External DAC?? Could the WiiM RC Sweep Signal "artifact" (whatever it is) be triggering your DAC regardless of Input??

 

[AlxTMX]

@Maurizio @AlxTMX Any updates on this topic?? Any feedback received from WiiM Support via your Support Tickets??

Hi. There is no any updates on my ticket till now.
All digital outputs are struggle of this problem. But there is the workaround for Coaxial an Optical ones (not for USB): to lock output at fixed resolution before Per Channel RC measuring session. Then it could be set back to variable resolution.
The internal DAC doesn't suffer of this problem at all. But my external DAC is way better, so I have to put up with this inconvenient.

 

[Maurizio]

@Maurizio @AlxTMX Any updates on this topic?? Any feedback received from WiiM Support via your Support Tickets??

Did either of you successfully perform RC-per-Channel by using the Ultra's DAC (remove your External DAC from the equation)??
While not Optimum, the result should be the same (unless your DAC is truly coloring the output), no??

@Maurizio - you posted "I have done other experiments ( COAX-OPT), but the result is still the same." Were these tests done with Inputs to the same External DAC?? Could the WiiM RC Sweep Signal "artifact" (whatever it is) be triggering your DAC regardless of Input??

With Ultra’s internal DAC no problems, it works fine. Unfortunately no reply to my tickets.
They are ignored . I tried Opt and Coax, same Ultra, exactly same DAC(Topping) and I have not sweep tone but noise. Changing DAC (SMSL) I have the sweep tone.
Note that SMSL mounts an Ess chip, like Topping.
To solve the problem i did measurements, using Ultra and Topping, not in WiiM Home App, but in House Curve. In HC i had the sweep tone and my EQ curve that i copied inside PEQ of WHA.

 

[s3igell]

With Ultra’s internal DAC no problems, it works fine. I tried Opt and Coax, same Ultra, exactly same DAC(Topping) and I have not sweep tone but noise. Changing DAC (SMSL) I have the sweep tone.

So, it appears this is related to WiiM triggering something undesirable in Certain OTHER Maker's DACs. Hard to Debug without the unlikely cooperation of that Competitor's Engineering Team.
How much effort should WiM dedicate to this odd issue versus turning those resources on the long list of other Fixes and Betas and New Features??
Lists that you @Maurizio feature rather prominently...