Room correction improvement suggestions

[dominikz]

Hello all,

New WiiM user here, but a long time audio enthusiast.
I've been testing the room correction feature in my Amp Pro and have noticed what I believe are several areas for improvement. Here's a list (though I assume many of these were already requested by other members):

1. Room correction should calculate correction filters for the subwoofer range as well (i.e. below the crossover). This is crucial because the sub fully operates in the modal region where several main room resonances will be.
2. Implement per-channel room correction even when subwoofer output (bass managements) is enabled.
3. There should be separate controls for the positive (boost) and the negative (cut) gain range of room correction filters (currently both are affected by the same control parameter). This way one could allow deep cut filters, but disallow strong boosts - which saves amplifier headroom and avoids temporal ringing, while still providing audibly very good correction results. My proposal is to have boost gain range =0dB and cut gain range =max by default.
4. Implement a PEQ setting import function, which supports EQ files generated in REW. This would significantly simplify manual room correction implementation via REW-generated filters; today the filter parameters need to be manually configured in WiiM which is quite tedious and errror-prone.
5. Implement import of measurement microphone calibration files.
6. Implement import of custom correction target curves.
7. Consider using the built-in microphone of the WiiM Voice Remote in the Room Correction feature - assuming the microphone in the remote is consistent enough between units and has sufficient frequency range.
8. Consider supporting the moving microphone method (MMM) with periodic pink noise for room response measurement, as it is fast and easy to use, gives very repeatable results, and provides a good level of spatial smoothing.
9. Implement the variable smoothing option when calculating filters - i.e. almost no smoothing at low frequencies (1/48 octave below 100Hz), gradually shifting to very high smoothing at high frequencies (1/3 octave above 10kHz). See variable smoothing in REW as an example. I'd also suggest to use variable smoothing as the default smoothing for room correction filter calculation. Variable smoothing enables accurate correction of sharp room resonances in the low frequencies, while at the same time allowing only smooth tone-shaping above the modal region. This reduces the risk of over-correction.
10. Consider limiting the correction range to 20Hz-500Hz by default, but with default boost range =0dB. This should better match the modal region in most residential rooms.
11. Implement simple tone control (individual treble-bass control, or even better a single "slope" control) adjustment that can work even when room correction is active. This could be used to easily tune overall system tonality to taste, or to apply basic on-the-fly correction to bright/dark sounding media content.

Luckily corrections based on the above principles can functionally already be implemented manually with PEQ, but it would be great if a similar correction could be created by using the automated room correction process.

 

[hgo58]

I think it would be a good idea to forward this to @WiiM Team via "Feedback" in the WiiM Home App.

 

[dominikz]

I think it would be a good idea to forward this to @WiiM Team via "Feedback" in the WiiM Home App.

Thanks, I did this already a week or so ago - just thought it might be interesting for the forum as well.

 

[slartibartfast]

Hello all,

New WiiM user here, but a long time audio enthusiast.
I've been testing the room correction feature in my Amp Pro and have noticed what I believe are several areas for improvement. Here's a list (though I assume many of these were already requested by other members):

1. Room correction should calculate correction filters for the subwoofer range as well (i.e. below the crossover). This is crucial because the sub fully operates in the modal region where several main room resonances will be.
2. Implement per-channel room correction even when subwoofer output (bass managements) is enabled.
3. There should be separate controls for the positive (boost) and the negative (cut) gain range of room correction filters (currently both are affected by the same control parameter). This way one could allow deep cut filters, but disallow strong boosts - which saves amplifier headroom and avoids temporal ringing, while still providing audibly very good correction results. My proposal is to have boost gain range =0dB and cut gain range =max by default.
4. Implement a PEQ setting import function, which supports EQ files generated in REW. This would significantly simplify manual room correction implementation via REW-generated filters; today the filter parameters need to be manually configured in WiiM which is quite tedious and errror-prone.
5. Implement import of measurement microphone calibration files.
6. Implement import of custom correction target curves.
7. Consider using the built-in microphone of the WiiM Voice Remote in the Room Correction feature - assuming the microphone in the remote is consistent enough between units and has sufficient frequency range.
8. Consider supporting the moving microphone method (MMM) with periodic pink noise for room response measurement, as it is fast and easy to use, gives very repeatable results, and provides a good level of spatial smoothing.
9. Implement the variable smoothing option when calculating filters - i.e. almost no smoothing at low frequencies (1/48 octave below 100Hz), gradually shifting to very high smoothing at high frequencies (1/3 octave above 10kHz). See variable smoothing in REW as an example. I'd also suggest to use variable smoothing as the default smoothing for room correction filter calculation. Variable smoothing enables accurate correction of sharp room resonances in the low frequencies, while at the same time allowing only smooth tone-shaping above the modal region. This reduces the risk of over-correction.
10. Consider limiting the correction range to 20Hz-500Hz by default, but with default boost range =0dB. This should better match the modal region in most residential rooms.
11. Implement simple tone control (individual treble-bass control, or even better a single "slope" control) adjustment that can work even when room correction is active. This could be used to easily tune overall system tonality to taste, or to apply basic on-the-fly correction to bright/dark sounding media content.

Luckily corrections based on the above principles can functionally already be implemented manually with PEQ, but it would be great if a similar correction could be created by using the automated room correction process.

Good suggestions there. You are right, many have been suggested before but nobody has yet suggested the moving microphone method, that would be a great addition.
Your first suggestion about room correction working for the subwoofer range already exists unless you select per channel room correction.

 

[canard]

It is a nice synthesis of many desirable improvements of what has been pointed out over the months... but it lacks the primary function of adapting the global level to the corrections applied (in the case of "positive" corrections or impact of q in ls/hs)... an autogain..
not just an improvement but a necessity...
(and the relevance of the correction graphs which is false)
;-)

 

[slartibartfast]

It is a nice synthesis of many desirable improvements of what has been pointed out over the months... but it lacks the primary function of adapting the global level to the corrections applied (in the case of "positive" corrections or impact of q in ls/hs)... an autogain..
not just an improvement but a necessity...
;-)

WiiM room correction never uses HS or LS anyway, not sure why.

 

[canard]

WiiM room correction never uses HS or LS anyway, not sure why.

in peq..

 

[slartibartfast]

in peq...

I know but why doesn't room correction try to use HS and LS. When REW uses them it normally defaults to a Q of 0.707

 

[canard]

I know but why doesn't room correction try to use HS and LS. When REW uses them it normally defaults to a Q of 0.707

This is well seen on the rew algorithm side... a lock at 0.7 max is logical at ls/hs....

but there are very high-level skills upstream of rew...it remains a difficult subject.... the "rc"

 

[dominikz]

Your first suggestion about room correction working for the subwoofer range already exists unless you select per channel room correction.

Hm, in my Amp Pro the correction is only calculated above the crossover frequency when the subwoofer is enabled :/
Perhaps Amp Pro didn't yet receive the update?

 

[slartibartfast]

Hm, in my Amp Pro the correction is only calculated above the crossover frequency when the subwoofer is enabled :/
Perhaps Amp Pro didn't yet receive the update?

There is an option to enable in room correction settings to include the subwoofer. Is that enabled?

 

[dominikz]

There is an option to enable in room correction settings to include the subwoofer. Is that enabled?

I had the "Subwoofer Calibration" option enabled but still all of the calculated filters were above the crossover frequency. Perhaps there is some trick with it that I'm unaware of?

Strangely the advice in the RC user guide seems conflicting:

3. Subwoofer Consideration

• If you are using a subwoofer, enable the Subwoofer Calibration setting.
• Check your subwoofer's crossover frequency and ensure the start of the frequency range for correction is above this crossover to avoid incorrect adjustments for your room's acoustics.

How can you calibrate the subwoofer if you are expected to configure the correction range above the crossover frequency?

 

[dominikz]

It is a nice synthesis of many desirable improvements of what has been pointed out over the months... but it lacks the primary function of adapting the global level to the corrections applied (in the case of "positive" corrections or impact of q in ls/hs)... an autogain..
not just an improvement but a necessity...
(and the relevance of the correction graphs which is false)
;-)

Indeed, pregain setting is critical to avoid clipping when positive/boost EQ filters are used.
Automatic pregain compensation would be ideal!

 

[slartibartfast]

I had the "Subwoofer Calibration" option enabled but still all of the calculated filters were above the crossover frequency. Perhaps there is some trick with it that I'm unaware of?

Strangely the advice in the RC user guide seems conflicting:

How can you calibrate the subwoofer if you are expected to configure the correction range above the crossover frequency?

Yup the user guide is wrong. No surprise there

 

[dominikz]

Yup the user guide is wrong. No surprise there

Unfortunately even with the correction range set to 20Hz-400Hz and with Subwoofer Calibration enabled in my tests no filters were calculated by WiiM RC below the crossover frequency (80Hz).
Based on the user guide I assumed this was intentional, but perhaps it is a bug?

 

[slartibartfast]

Unfortunately even with the correction range set to 20Hz-400Hz and with Subwoofer Calibration enabled in my tests no filters were calculated by WiiM RC below the crossover frequency (80Hz).
Based on the user guide I assumed this was intentional, but perhaps it is a bug?

Strange. It works for me with a WiiM Amp.