Issues with the LS and HS in PEQ?

[Wiimer]

I'm off today, so I'm testing the WiiM pro and Mini with MRM. So, I seem to have found some issues with PEQ.

I used LS and HS on PEQ to connect the Pro to the main speakers and the Mini to the subwoofer to set up the crossover.

However, when LS and HS are set to their maximum values, they produce loud noise and distortion at nearby frequencies.

After repeated testing under different conditions with a measuring microphone, we found that this problem occurs on all WiiM devices. (MRM is irrelevant.)

I'll post the results here to explain the issue to the support team.

First, the LS has a gain of 0 dB. Look at the red graph. It is almost flat and does not have a volume above -5 dB. At this time, there is no problem with the sweep sound that can be heard in my ears.


Next, LS was set to "100Hz/-5dB/Q24" and a swept tone was played. Then, around 135Hz, the volume increases and distortion occurs.



If I change the frequency of the LS, the problem will occur at a frequency slightly above the set value in the same way. (When LS is "200Hz/-12dB/Q24", it will be distorted at 270 Hz.)

Also, I think the blue circled area represents that the LS is not working effectively.



HS has the same problem.



These issues are occurring on all of my devices (WiiM amp/WiiM Pro/WiiM Mini). I don't think it's an external factor, as each of them has a different amp or speaker to connect to.

I'd be happy if the @WiiM Team would look into this.

Also, I would be happy if everyone here would do a similar test. It should be easy to hear in your ears.

Thank you.

 

[harkpabst]

Shelf filters (or shelving filters) are not really the appropriate tool to mimic high-pass and low-pass filters, for a start. I suppose it's the very high Q value producing the artifacts in the end. I tend to think that these high values are not useful anyway, so should be avoided, if this is enough to fix the problem.

A higher Q will just mean a steeper slope (potentially more difficult to integrate perfectly), not a higher attenuation.

Apart from these general thoughts I still haven't performed any measurements on my WiiM Amp.

 

[Wiimer]

Shelf filters (or shelving filters) are not really the appropriate tool to mimic high-pass and low-pass filters, for a start. I suppose it's the very high Q value producing the artifacts in the end. I tend to think that these high values are not useful anyway, so should be avoided, if this is enough to fix the problem.

A higher Q will just mean a steeper slope (potentially more difficult to integrate perfectly), not a higher attenuation.

Apart from these general thoughts I still haven't performed any measurements on my WiiM Amp.

Thank you.

I think I understand what you said, but the fact is that lowering the Q value doesn't make the issue go away. (The higher the gain or Q, the more pronounced issues.)

Also, since the WiiM Team recommends using the Mini as a sub-out, it would be preferable if this problem did not occur.

 

[Wiimer]

Hi, @WiiM Support, @WiiM Team,

Is this normal?
(Ticket number: 501786 )


PEQ: FLAT



PEQ
LS: F 200hz / G -12dB / Q 5
HS: F 1kHz / G -12dB / Q 5



PEQ
PK: F 200hz / G -12dB / Q 24



Setting the PK to "-12dB / Q24" does not cause any problems. Distortion occurs only on LS and HS.

 

[WiiM Support]

Hi, @WiiM Support, @WiiM Team,

Is this normal?
(Ticket number: 501786 )


PEQ: FLAT
View attachment 6225


PEQ
LS: F 200hz / G -12dB / Q 5
HS: F 1kHz / G -12dB / Q 5
View attachment 6226


PEQ
PK: F 200hz / G -12dB / Q 24
View attachment 6227


Setting the PK to "-12dB / Q24" does not cause any problems. Distortion occurs only on LS and HS.

Hi Wiimer,

Thanks for your testing. I'll forward your results to our Eng. team for further review. Please stay tuned!

 

[Wiimer]

Hi Wiimer,

Thanks for your testing. I'll forward your results to our Eng. team for further review. Please stay tuned!

Thank you so much.

 

[canard]

Hi Wiimer,

Thanks for your testing. I'll forward your results to our Eng. team for further review. Please stay tuned!

small ps will you make a peq with left and right separated?

 

[dimezis]

I think Q > 1 is broken for shelf filters.
Try using Q < 1 for now.

 

[steadyshot]

High q is a narrow filter intended to correct with accuracy ,room or speaker resonances (peaks or dips ) that is very specific frequencies .I would probable use high q with peak filter not low pass or high pass. That is my impression at least

 

[harkpabst]

High q is a narrow filter intended to correct with accuracy ,room or speaker resonances (peaks or dips ) that is very specific frequencies .I would probable use high q with peak filter not low pass or high pass. That is my impression at least

Yes, but I'm the absence of liww-pass and high-pass filters we are talking about shelf filters here. There is not "wide" and "narrow" with shelf filters, but only steeper or less steep slope and ... overshooting.

After thinking about it one more time, I think we are reall seeing just the amount of overshoot you should expect from a high Q shelf filter. It shouldn't be used like that for the given purpose.

 

[Wiimer]

Yes, but I'm the absence of liww-pass and high-pass filters we are talking about shelf filters here. There is not "wide" and "narrow" with shelf filters, but only steeper or less steep slope and ... overshooting.

After thinking about it one more time, I think we are reall seeing just the amount of overshoot you should expect from a high Q shelf filter. It shouldn't be used like that for the given purpose.

Can you tell me a bit more about overshoot?

Is the peaks and distortions that appear in my graph an overshoot, and does this mean that the shelf filter is working properly?

What I want to know is, is this normal behavior or is there something out of the ordinary?

Thank you.

By the way, support team contacted me and said they were working to resolve this issue. (I couldn't tell if this was boilerplate or not. )

 

[harkpabst]

The jriver wiki has some information on this:

Parametric Equalizer - JRiverWiki

wiki.jriver.com

From my point of view, shelf filters are implemented correctly for Q > 1, but this type of filter is just not useful for what you are trying to achieve. OK, this must have been the 3rd time or so I said this. I promise I won't repeat it again.

 

[WiiM Support]

Hi, @WiiM Support, @WiiM Team,

Is this normal?
(Ticket number: 501786 )


PEQ: FLAT
View attachment 6225


PEQ
LS: F 200hz / G -12dB / Q 5
HS: F 1kHz / G -12dB / Q 5
View attachment 6226


PEQ
PK: F 200hz / G -12dB / Q 24
View attachment 6227


Setting the PK to "-12dB / Q24" does not cause any problems. Distortion occurs only on LS and HS.

Hi wiimer,

Consider adjusting the Q value of your LS/HS to a smaller figure, like 0.25, instead of 5. A Q value of 5 doesn't produce the typical low shelf or high shelf effect needed to boost or cut your low (low shelf) or high frequencies (high shelf). Refer to the figure below for a clearer understanding:

 

[Steve Woodhouse]

Hi wiimer,

Consider adjusting the Q value of your LS/HS to a smaller figure, like 0.25, instead of 5. A Q value of 5 doesn't produce the typical low shelf or high shelf effect needed to boost or cut your low (low shelf) or high frequencies (high shelf). Refer to the figure below for a clearer understanding:

View attachment 6269

A Q of 1.0 is required for 2 LS filters for these headphones (see PEQ towards the bottom of Post 1):

Sennheiser HD650 Review (Headphone)

This is a review and detailed measurements of the Sennheiser HD650 open back headphone. I purchase mine back in 2017. It costs US $400 with free shipping as of this writing from Amazon. My sample is near new because I don't use it everyday (due to high noise level, I have to wear closed back...

audiosciencereview.com

 

[Wiimer]

@harkpabst, @WiiM Support,

I'm shamed..
Thank you for telling me until understood.

However, I'm hardheaded guy, so I tried to compensate for the overshoot with a PK. Whether this is practical or not, the results were not bad at ALL.


Main Speaker / PEQ: Flat (without SW)



Main Speaker
WiiM's high pass (Cross: 100hz)
PEQ: Flat
(without SW)


Main Speaker
PEQ: LS100Hz G-12 Q5 / +PK
(without SW)


This is roughly adjusted with the tablet's built-in microphone.

 

[harkpabst]

However, I'm hardheaded guy, so I tried to compensate for the overshoot with a PK.

With the shelf filter's Q below 1 there shouldn't be any overshoot.

 

[Wiimer]

With the shelf filter's Q below 1 there shouldn't be any overshoot.

Yes, I'll try that too.

@WiiM Support,
By the way, if We need to use a shelf filter in Q<1, why not set an upper limit more low? I think this could break the speakers.

 

[Wiimer]

small ps will you make a peq with left and right separated?

@canard.

Did you see this?

10 PEQ Beta test (Bug Report)

Android 10 PEQ beta testing. WiiM amp firmware V 5.0.614351. Save the initial screen as flat, adjust one band, and then turn it off to change the sound. (It should be back to flat, but it's not.) Specifically, the volume of the sound that is higher than the adjusted frequency will be lower...

forum.wiimhome.com

Finally, the stereo PEQ that we have been waiting for will be realized.

Please smile and rejoice once in a while.

 

[canard]

wait and see ;-)
(feedback on pec beta, eq, and the positive gain gestion aspect? ;-) )

 

[WiiM Team]

I'm off today, so I'm testing the WiiM pro and Mini with MRM. So, I seem to have found some issues with PEQ.

I used LS and HS on PEQ to connect the Pro to the main speakers and the Mini to the subwoofer to set up the crossover.

However, when LS and HS are set to their maximum values, they produce loud noise and distortion at nearby frequencies.

After repeated testing under different conditions with a measuring microphone, we found that this problem occurs on all WiiM devices. (MRM is irrelevant.)

I'll post the results here to explain the issue to the support team.

First, the LS has a gain of 0 dB. Look at the red graph. It is almost flat and does not have a volume above -5 dB. At this time, there is no problem with the sweep sound that can be heard in my ears.
View attachment 6208

Next, LS was set to "100Hz/-5dB/Q24" and a swept tone was played. Then, around 135Hz, the volume increases and distortion occurs.
View attachment 6209


If I change the frequency of the LS, the problem will occur at a frequency slightly above the set value in the same way. (When LS is "200Hz/-12dB/Q24", it will be distorted at 270 Hz.)

Also, I think the blue circled area represents that the LS is not working effectively.
View attachment 6210


HS has the same problem.
View attachment 6211


These issues are occurring on all of my devices (WiiM amp/WiiM Pro/WiiM Mini). I don't think it's an external factor, as each of them has a different amp or speaker to connect to.

I'd be happy if the @WiiM Team would look into this.

Also, I would be happy if everyone here would do a similar test. It should be easy to hear in your ears.

Thank you.

This bug on the Android app would not turn the band off; we will fix it in the next app version.