Room Correction for separate channels.......what if?

[Wiimer]

Hi @Smartplug
Good question. I'll tell you my impressions. As I said, the differences between the unequalized sound, the stereo equalization, and the per-channel equalization are very subtle. The sound, compared to the unequalized sound, has not changed totally.This could make me think that RC did a good job. If I had had a completely different sound I would have been wary.
The main difference I found between the Stereo EQ and the Per-Channel EQ concerns the reproduction of the bass. In the stereo EQ, the bass, for me, was perhaps a little too cut compared to the non-EQ sound.
In the per-channel EQ,

I am glad to hear that your attempt went well. Thanks for sharing your experience with us.

BTW, I think I was very wrong about the "Audio Channel" in WHA. To summarize, this setting is totally different from the balance bar.

Stereo: L/R signal out of L/R speakers.
Left Channel: only L signal is output from the L/R speakers.
Right channel: only R signal is output from the L/R speakers.
Mono: Outputs a mono signal from the L/R speakers.

Therefore, it is normal for sound to always come out of both the left and right speakers. Sorry for the mistake.

 

[Emiyanez]

I was reading a bit on the topic and I found this statement from John Mulcahy from REW in the AVNirvana forum:

"As an aside, applying EQ above a couple of hundred Hz is a risky business that can easily do more harm than good, responses can vary a lot over short distances so filters you apply may have a very different effect than you expect just a short distance away from the measurement point. If you do apply EQ at higher frequencies best keeping the filter Q values low and typically best applying the same EQ to both channels (somewhat counter to what you are attempting) as our brains are pretty good at distinguishing the direct sound from the speaker from the contribution of the rooms' reflections (which are included in your measurement) so what you hear is often not what you see on the measurement".

Does this mean that L/R individual adjustment above hundreds Hz are not recommended? Is this true even for on-axis measurements at short distance to correct for speakers inconsistencies?

 

[Smartplug]

I am glad to hear that your attempt went well. Thanks for sharing your experience with us.

BTW, I think I was very wrong about the "Audio Channel" in WHA. To summarize, this setting is totally different from the balance bar.

Stereo: L/R signal out of L/R speakers.
Left Channel: only L signal is output from the L/R speakers.
Right channel: only R signal is output from the L/R speakers.
Mono: Outputs a mono signal from the L/R speakers.

Therefore, it is normal for sound to always come out of both the left and right speakers. Sorry for the mistake.

This was rather surprised as I was expecting right will just output right but sound still produce both speakers. I don’t know who use these features just left or right.

 

[Wiimer]

This was rather surprised as I was expecting right will just output right but sound still produce both speakers. I don’t know who use these features just left or right.

Yes, me too.

However, I feel this makes sense considering the Mono operation. I thought this would be used on the MRM. But in reality, it appears to duplicate the same functionality, since the output channels can be switched on the MRM device card.

Please can someone tell us how to use this?

 

[Smartplug]

Yes, me too.

However, I feel this makes sense considering the Mono operation. I thought this would be used on the MRM. But in reality, it appears to duplicate the same functionality, since the output channels can be switched on the MRM device card.

Please can someone tell us how to use this?

We going to ask the legend @onlyoneme that can give us the answer. Please let us know how to use this feature.

 

[Wiimer]

We going to ask the legend @onlyoneme that can give us the answer. Please let us know how to use this feature.

Or, @harkpabst, @Burnside

 

[Smartplug]

Or, @harkpabst, @Burnside

Hmmm I’m scared he may burn my side just kidding.

 

[onlyoneme]

We going to ask the legend @onlyoneme that can give us the answer. Please let us know how to use this feature.

Please stop calling me like this.

 

[Smartplug]

Please stop calling me like this.

Ok sorry.

 

[Musician]

Hi,

I am also in the process of playing around with L/R PEQ using REW and a calibrated microphone in the process. So far, I have only measured both speakers and the sub separately, adjusted crossover frequency and delay, measured the whole system together from listening position, fitted the curve to Harman in REW and exported the filters from 20-200 Hz into the Wiim App PEQ. I got rid of room resonances and my system never sounded that good.

Next, I would like to experiment with PEQ for L/R. I will proceed as @Musician suggested, making close on-axis measurements of each individual speaker and apply correction from rom 200 to 20000 Hz in order to make both speakers sound as similarly as possible. Then, I will repeat the above mentioned correction.

In summary, I will globally correct for room resonances in the lower frequencies from listening position and I will individually correct above those frequencies using on-axis close measurements for each of the speakers to try to match their sound as much as possible.

Quick question to @WiiM Team, is there a way to listen exclusively to the sub? In order to measure my sub with the crossover active, I had to unplug the speakers from my amp (did not find any other way). Measuring only the speakers with the crossover active was relatively easy by setting the volume of the sub to 0.

If you do this right, the sound will be much better than any automatic room correction program, including Dirak.
The brain/ear always pay more attention for the first arriving sound ( at distances from the speaker more than 1.7 meter, 5 ms ) , above schroeder frequency in the room. Because of this, the on axis sound from the speaker is about 70 % more important compared to the sound reflected from the walls in the room.

This fact ( the precedence effect is very real! ) is often neglected on ASR. This is why you have to measure near the speaker above schroeder frequency to not get a false measurement result.

The microphone and ear/brain is functioning very different after 1.7 meter sounddistance - The mic always takes up all the sound while the brain always selects sounds after 5ms, prefering the first arriving sound and attenuating later arriving sounds as much as 10 dB inside the brain, such as sounds bouncing on the sidewalls.

Below the transition frequency ( same as schroeder frequency ) in the room one can do microphone measurements from the listening position that gonna mirror what the brain hear. But remember the brain sees the room and expect the sound to have some room sound - more bass. This is why we need to apply shelving below 100 Hz, boosting about 6 dB down to 30 Hz.

 

[Emiyanez]

If you do this right, the sound will be much better than any automatic room correction program, including Dirak.
The brain/ear always pay more attention for the first arriving sound ( at distances from the speaker more than 1.7 meter, 5 ms ) , above schroeder frequency in the room. Because of this, the on axis sound from the speaker is about 70 % more important compared to the sound reflected from the walls in the room.

This fact ( the precedence effect is very real! ) is often neglected on ASR. This is why you have to measure near the speaker above schroeder frequency to not get a false measurement result.

The microphone and ear/brain is functioning very different after 1.7 meter sounddistance - The mic always takes up all the sound while the brain always selects sounds after 5ms, prefering the first arriving sound and attenuating later arriving sounds as much as 10 dB inside the brain, such as sounds bouncing on the sidewalls.

Below the transition frequency ( same as schroeder frequency ) in the room one can do microphone measurements from the listening position that gonna mirror what the brain hear. But remember the brain sees the room and expect the sound to have some room sound - more bass. This is why we need to apply shelving below 100 Hz, boosting about 6 dB down to 30 Hz.

Thanks a lot @Musician. I will give it a try out of pure scientific interest and see how it looks and sounds. I have to say that my speakers (ELAC Uni-Fi UF52) measure pretty well above 300 Hz from listening position. Mids are slightly boosted but I think this is the way that Andrew Jones tuned them. I am not planning to correct the speaker's character (which I really like) but rather check inconsistencies between the right and left speakers (levels and different peaks if any).

 

[Musician]

Thanks a lot @Musician. I will give it a try out of pure scientific interest and see how it looks and sounds. I have to say that my speakers (ELAC Uni-Fi UF52) measure pretty well above 300 Hz from listening position. Mids are slightly boosted but I think this is the way that Andrew Jones tuned them. I am not planning to correct the speaker's character (which I really like) but rather check inconsistencies between the right and left speakers (levels and different peaks if any).

Best is to place the speakers symmetrical in the room - every speaker has the same distance to the sidewalls L/R. The difference between different driver are usually no more than 1 dB, making the place where you put the microphone very crititical If you really want to see real differences .

If youre not sitting exactly at sweetspot, you cant correct reflections in a good way ( sound coming from speaker-one wall - listening position ) . Its better using damping material for those.

The lowest three fundamental room resonanses can be corrected successfully ( those resonanses are between wall-wall , roof -floor , wall- wall )
They are all below 80 Hz in a normal rectangular room.

I dont usually correct anything below 35 Hz , its not many instruments having real tones below that frequency ( organs , grand piano, 6 string bass )
—————————

A little OT, but :

Your speakers are ported. With the WiiM you have the opportunity to use high Q high pass shelving at the tuning frequency. This will give you better bass If you try it.
Read more here :

Using high Q shelving to gain 10 Hz in the bass without severe drawbacks

This is a trick thats often used in studios to make the soundmix more fuller and more impressive - the use of high Q shelving function to high pass the signal . This can also be implemented in a ported speaker . And as very few streamers on the market, the WiiM can do this. This can be done...

forum.wiimhome.com

https://audioxpress.com/files/attachment/2721

 

[mz54]

...
Stereo: L/R signal out of L/R speakers.
Left Channel: only L signal is output from the L/R speakers.
Right channel: only R signal is output from the L/R speakers.
Mono: Outputs a mono signal from the L/R speakers.
...

this video highlights the behavior very well

 

[mz54]

...
I'll start by saying I'm totally clueless about EQ. I'm just getting started with RC and I'm experimenting. So don't crucify me or stone me.
I had a crazy idea to try RC per channel and would like to hear from someone who knows about it if it could work.
...

I was about to write the same thing

the photo shows how I proceeded (WiinM Amp with volume 50)
.https://youtu.be/dNdhDCv4mzc?si=Tc_iP6iCpBtoQ7cn&t=33 for balance setup
.https://youtu.be/6TWJaFD6R2s?si=zRzVzZdFiVA-Pk23&t=4 for testing

the first PEQ Stereo measurement served me as a comparison with the same measurement in PEQ L/R mode that I did as described by @Maurizio
Listening impressions:
- without EQ the sound has too much bass and is a little confused
- with RC 03 vol 50 much better but still some more bass on the right
- with RC 06 LR 04 05 optimal bass balance and crystal clear sound

and don't tell me to move the speakers: I had to trade with my wife the purchase of the wiim for that position

 

[MCG555]

I was reading a bit on the topic and I found this statement from John Mulcahy from REW in the AVNirvana forum:

"As an aside, applying EQ above a couple of hundred Hz is a risky business that can easily do more harm than good, responses can vary a lot over short distances so filters you apply may have a very different effect than you expect just a short distance away from the measurement point. If you do apply EQ at higher frequencies best keeping the filter Q values low and typically best applying the same EQ to both channels (somewhat counter to what you are attempting) as our brains are pretty good at distinguishing the direct sound from the speaker from the contribution of the rooms' reflections (which are included in your measurement) so what you hear is often not what you see on the measurement".

Does this mean that L/R individual adjustment above hundreds Hz are not recommended? Is this true even for on-axis measurements at short distance to correct for speakers inconsistencies?

This was my concern too. Also for stereo RC I corrected only up to 600Hz for this reason…

 

[Musician]

This was my concern too. Also for stereo RC I corrected only up to 600Hz for this reason…

Correcting up to schroeder ( 200 Hz in a normal room ) is doable if you always sit in the sweet spot and prefered when using good directivity speakers. The WiiM default is 40-4000 Hz but one can change those frequencies. This is a major advantage.

As always - after the correction, you have to go and change the values manually below 100 Hz * so that you get more bass than the correction program wants ( about +6 dB rising below 100 Hz. ).

*Your eyes and brain sees the room and a total correction in the bass will sound as the speaker is outside playing - very unnatural in a room.
————
In all these cases, you must sit in the listening sweetspot because one meter off , the correction above 80 Hz will show false results - and will sound much worse .
Before any correction, you have to setup the two stereo speakers where they sound the best in your room ( and symmetrical ) because no roomcorrection can save a bad installation. Very important. If you install the speakers symmetrical with the same distance to the side walls theres no need for stereo compensation.

Edit: If you only correct the rooms fundamental resonanses, then set the upper limit frequency span on the ultras room correction to 80 Hz . This corrections will sound better anywhere in the room. Correcting higher in frequency you must sit at the sweet spot .

The default correction in the Ultra is 40-4000 Hz , one can try this before lowering the highest frequency and use 40 - 400 Hz, or 40 - 200 Hz.

WiiM has chosen B/K target as default , in my experience this sounds better than Harman ( also selectable ).

 

[MCG555]

As always - after the correction, you have to go and change the values manually below 100 Hz * so that you get more bass than the correction program wants ( about +6 dB rising below 100 Hz. ).

Not in my case!
For me RC is great to solve room modes problems - and the most problematic are - below 100 Hz. In my case it is around 50 Hz. RC filters this very well out without missing bass…