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.

 

[MrA]

When I purchased my WiiM devices last year I promised myself not to go slip back down the audio forums wormhole (weaned off in 2020) so my comments will be relatively brief/non technical.

Room placement is critical.

In 2012 I started to experiment with digital processing and room correction & within four years had created an extremely complex (& expensive!) multi channel stereo, open baffle, twin subwoofer system. From an initial WTF! moment in 2012 everything progressed incrementally until I decided to go the whole hog & investigate proper room treatment.

As this was in 2019, I have since forgotten or deleted the links I used to calculate correct placements but the 'ideal' result did place the main speakers and listening chair in some less-than-ideal places, even though the overall sound was absolutely incredible. I then had to move things because I and close friends have been having regular 'music nights' (nearly fourty years & counting) so other chairs needed to be accomodated.

Therefore the final compromise resulted in the results below which I still have on file:

Music room dimensions:
H 2380mm
W 3622mm
L 5130mm
38%=1949mm
19%=975mm

Head to rear wall 1.275
Head to front wall 3.763
Speaker to front wall 1.63
Head to ceiling 1.285

Speaker .550
R Speaker to wall .614
L Speaker to wall .604
Chair to tweeter 2.400

In combination with bass traps, wall and ceiling acoustic treatment, rear diffusers and a room also full of 'crap' I managed to turn an environment containing soild walls & floors (and a lot of clutter) into what has and always will remain my 'perfect' audio setup with just the sort of controlled bass resonance that I like whilst retaining incredible deep controlled tight impact.... 'Slam' if you like to call it.

The room party trick for friends and others (including one speaker developer who came to listen) is to play any drum solo at approaching 'real' volume. Transient attack and realism are literally off the scale. Only adjustment of every element in the room finally achieved the result I was after....as well as building a huge pair of open-back speakers, digitally crossed over, fully phase & time aligned drivers incuding to the subs of course!

...back to just listening to music now.

 

[m_sherzod]

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.

12. The possibility to take RT60 measurements so that the listeners know the characteristics of their rooms and on what to work on?

 

[m_sherzod]

When I purchased my WiiM devices last year I promised myself not to go slip back down the audio forums wormhole (weaned off in 2020) so my comments will be relatively brief/non technical.

Room placement is critical.

In 2012 I started to experiment with digital processing and room correction & within four years had created an extremely complex (& expensive!) multi channel stereo, open baffle, twin subwoofer system. From an initial WTF! moment in 2012 everything progressed incrementally until I decided to go the whole hog & investigate proper room treatment.

As this was in 2019, I have since forgotten or deleted the links I used to calculate correct placements but the 'ideal' result did place the main speakers and listening chair in some less-than-ideal places, even though the overall sound was absolutely incredible. I then had to move things because I and close friends have been having regular 'music nights' (nearly fourty years & counting) so other chairs needed to be accomodated.

Therefore the final compromise resulted in the results below which I still have on file:

Music room dimensions:
H 2380mm
W 3622mm
L 5130mm
38%=1949mm
19%=975mm

Head to rear wall 1.275
Head to front wall 3.763
Speaker to front wall 1.63
Head to ceiling 1.285

Speaker .550
R Speaker to wall .614
L Speaker to wall .604
Chair to tweeter 2.400

In combination with bass traps, wall and ceiling acoustic treatment, rear diffusers and a room also full of 'crap' I managed to turn an environment containing soild walls & floors (and a lot of clutter) into what has and always will remain my 'perfect' audio setup with just the sort of controlled bass resonance that I like whilst retaining incredible deep controlled tight impact.... 'Slam' if you like to call it.

The room party trick for friends and others (including one speaker developer who came to listen) is to play any drum solo at approaching 'real' volume. Transient attack and realism are literally off the scale. Only adjustment of every element in the room finally achieved the result I was after....as well as building a huge pair of open-back speakers, digitally crossed over, fully phase & time aligned drivers incuding to the subs of course!

...back to just listening to music now.

Hello! Thanks for sharing your story. I have a very similarly sized room. H 2300mm, W 3600mm, L 4600. It is dual purpose, mainly music and movies (I have a 100 inch projector screen in between the speakers).

I have a situation here, maybe you can give a valuable advice. I have invited a specialist to improve my room sound, we have put large bass traps in 4 corners, covered the walls with and the ceiling with Ecophon panels (https://www.ecophon.com/en/products/modular-ceilings/industry/industry-modus/), the whole floor was already covered with a thick carpet. Also the whole rear wall is one big soft sofa custom made for the room.

We are now planning to put this week vertical slats with 5-10cm gaps between on the side and rear walls for diffusion. However I am already a bit concerned that we have over dampened the room and the slats will not be enough. Although, the task was set clearly from my side to make a lively enjoyable mainly music listening room, not a dead recording studio... Maybe I am making hasty conclusions, but would like to hear from more knowledgeable people before I make even more mistakes... ))

Thanks

 

[pjorgenunes]

Hello! Thanks for sharing your story. I have a very similarly sized room. H 2300mm, W 3600mm, L 4600. It is dual purpose, mainly music and movies (I have a 100 inch projector screen in between the speakers).

I have a situation here, maybe you can give a valuable advice. I have invited a specialist to improve my room sound, we have put large bass traps in 4 corners, covered the walls with and the ceiling with Ecophon panels (https://www.ecophon.com/en/products/modular-ceilings/industry/industry-modus/), the whole floor was already covered with a thick carpet. Also the whole rear wall is one big soft sofa custom made for the room.

We are now planning to put this week vertical slats with 5-10cm gaps between on the side and rear walls for diffusion. However I am already a bit concerned that we have over dampened the room and the slats will not be enough. Although, the task was set clearly from my side to make a lively enjoyable mainly music listening room, not a dead recording studio... Maybe I am making hasty conclusions, but would like to hear from more knowledgeable people before I make even more mistakes... ))

Thanks

From what I read over time, and just to get a reference value:

"
For optimal music acoustics, aim for a reverberation time (RT60) of around 0.3 seconds, which translates to dampening approximately 20-25% of the room's surface area.
"

 

[m_sherzod]

From what I read over time, and just to get a reference value:

"
For optimal music acoustics, aim for a reverberation time (RT60) of around 0.3 seconds, which translates to dampening approximately 20-25% of the room's surface area.
"

my current RT60 is around 0,15 for most of the range and slowly goes up to 0,6 starting from around 60hz to 20hz. The room is very dead, but I am wondering if the slats will help to increase the RT60 up to 0,30-050?

 

[MrA]

My room was extremely dead before I treated it but that has been done selectively based on taking measurements before-after - and listening of course. Triangular bass traps are deep enough to deal with all troublesome peaks, I made them myself.

I still have large areas of wall untreated - using a mirror held by someone else whilst sitting in the listening chair will show first reflection points (walls & ceiling). Likewise, diffusers are only behind the listening chair not continuous. My room has a reverberation time of 0.32 sec and I'm fine with that.

 

[m_sherzod]

My room was extremely dead before I treated it but that has been done selectively based on taking measurements before-after - and listening of course. Triangular bass traps are deep enough to deal with all troublesome peaks, I made them myself.

I still have large areas of wall untreated - using a mirror held by someone else whilst sitting in the listening chair will show first reflection points (walls & ceiling). Likewise, diffusers are only behind the listening chair not continuous. My room has a reverberation time of 0.32 sec and I'm fine with that.

Thanks for sharing. What kind of diffusers are you using?

 

[dominikz]

Hello! Thanks for sharing your story. I have a very similarly sized room. H 2300mm, W 3600mm, L 4600. It is dual purpose, mainly music and movies (I have a 100 inch projector screen in between the speakers).

I have a situation here, maybe you can give a valuable advice. I have invited a specialist to improve my room sound, we have put large bass traps in 4 corners, covered the walls with and the ceiling with Ecophon panels (https://www.ecophon.com/en/products/modular-ceilings/industry/industry-modus/), the whole floor was already covered with a thick carpet. Also the whole rear wall is one big soft sofa custom made for the room.

We are now planning to put this week vertical slats with 5-10cm gaps between on the side and rear walls for diffusion. However I am already a bit concerned that we have over dampened the room and the slats will not be enough. Although, the task was set clearly from my side to make a lively enjoyable mainly music listening room, not a dead recording studio... Maybe I am making hasty conclusions, but would like to hear from more knowledgeable people before I make even more mistakes... ))

Thanks

Side-wall early reflections can actually be quite pleasing if using loudspeakers with smooth and even directivity, as these reflections will extend the soundstage horizontally beyond the loudspeakers and help increase envelopment. Some people might still prefer the presentation you get in acoustically dead rooms.

In any case I'd highly recommend reading at least chapter 7 of "Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms, Third Edition" by dr. Floyd Toole. The whole book is IMHO well worth a read for anyone interested in audio, but this chapter specifically deals with early reflections and basic type of acoustic treatment so might be helpful to your situation.

You might also find this post on loudspeaker placement interesting.

 

[MrA]

Thanks for sharing. What kind of diffusers are you using?

Cut from 2x2" pine using a specific combination of depths (I found DIY instructions to make the attached but no longer need or kept them)

https://www.thomann.co.uk/the_t.aku...Ib-9O09660EgZgOA2dnlmQylSPfZfUcHe0KOfaiBDJWsU