Both of the responses are the result of L/R measurements and both show the response with both speakers driven. Red is the new algorithm and Blue is the old algorithm that you used. It will be interesting to see your results with the new algorithm.
Managed to do a few tests today. First, I tested to see if my own manual PEQ saved config were negatively affected by re-measuring the response in REW and comparing to saved measurements of the same PEW config from January.
I've asked like four times for this already....and I'm pretty sure I'm not the only one.
At the moment a single control ("Max Gain") controls the allowed amount of both positive and negative gain range in calculated PEQ filters.
Thanks!
I haven't tried remeasuring my saved Stereo PEQ filter yet with the new algorithm. Did you check yours with the previous algorithm and find they were affected? WiiM haven't stayed as much but I assume the extra 3 dB at subwoofer frequencies is the reason L/R correction with sub has been delayed for so long. In your final evaluation it still looks too high to me compared to the target curve and is higher than it was with the previous algorithm. It seems that both the previously saved Stereo responses and the L/R responses have been boosted at subwoofer frequencies compared to the last algorithm. We might find that a flat target curve gives us a B&K result for L/R with sub.Managed to do a few tests today. First, I tested to see if my own manual PEQ saved config were negatively affected by re-measuring the response in REW and comparing to saved measurements of the same PEW config from January.
They match really well when SPL is aligned, so it seems to me in my case the saved PEQs were not negatively affected:
View attachment 17971
Next I also re-ran the individual channel RC with subwoofer active, and got the following results (20Hz-350Hz correction range):
View attachment 17972View attachment 17973
As we can see, the 30-80Hz dip is now gone.
I've validated the results in REW and the individual channel response matches pretty well against the B&K target:
View attachment 17974
Lastly, to illustrate the point from my previous post about the expected +3dB gain in the low frequencies when measuring both L+R channels together (caused by bass frequencies summing like coherent sound sources):View attachment 17975
So to me this all looks to be working well after the latest update of the beta RC algorithm.
Well done @WiiM Team!
P.S. One part of the current implementation of WiiM Room Correction functionality I really dislike is the inability to limit how much PEQ boost is applied.
As you can see in the above measurements, WiiM RC tries to boost a null around 200Hz in the right channel of my system with several positive PEQ filters with up to +6dB gain:
View attachment 17976
This is a serious waste of amplifier power and, given that there's no auto pre-gain, something which could result in digital clipping.
@WiiM Team Is there any chance that we get separate Max Gain controls for positive-gain (boost) vs negative-gain (cut) filters? I'd like to allow -12dB gain for cuts while at the same time completely block boosts (0dB) - and I'm pretty sure I'm not the only one.
At the moment a single control ("Max Gain") controls the allowed amount of both positive and negative gain range in calculated PEQ filters.
Thanks!
The nulls around 200Hz in my system are almost certainly caused mainly by SBIR.
No I haven't, sorry!
I have a different view on this.
Well that depends on how much bass you want, I guess. I personally like matching the individual channels to B&K curve and have the extra +3dB in the summed response.
Ideally the results from a stereo room correction should have a similar frequency response to the L/R + sub results but that 3dB boost prevents it. That 3dB boost was there when WiiM decided to remove the ability to perform Room Correction for L/R + sub so if that boost is still there I don't see why it took so long to reinstate it for this beta as nothing has really changed.No I haven't, sorry!
I have a different view on this.
The response match I get now with WiiM RC is IME comparable to the type of results I get with any other EQ or RC tool I used when doing individual channel correction. If you match individual channels to any target curve in any SW, the summed L+R response will overshoot the same target in the bass frequencies by +3dB.
As I explained previously, this is simply because bass frequencies emitted by multiple loudspeakers sum as coherent sound sources, while higher frequencies sum progressively more like incoherent sources. So this is IMHO perfectly normal.
Further, how would you then adapt the target curve to multi-channel systems, depending on the channel count? You'll get the same +3dB additional bass level for each additional channel playing simultaneously.
This is one of the reasons it is reasonable to align each channel independently to the same target, and accept the way different frequencies sum.
Well that depends on how much bass you want, I guess. I personally like matching the individual channels to B&K curve and have the extra +3dB in the summed response.
I guess ideal would be to have the ability to import custom target curves so people can use what they prefer - or at least to have two variants of the B&K target curve - one that gives you a good match to B&K on individual channels (which we have today), and another that gives you a good match on the summed L+R response.
Thanks; this is really wonderful advice. Now I’m having a hard time figuring out just how to best resolve this SBIR room null. I know that in the past, I had the speakers placed differently and that null either wasn’t there or was much less. Do I have to move them even farther away from that back wall? This would severely intrude into the room in an uncomfortable manner and affect viewing angles for the TV. I wonder if pushing the speakers back would make it worse, or mess something else up. I know I came to settle on this speaker position for a reason, but it has also been a long time since I did it and I’ve forgotten the details of my logic.
Side walls can affect the nulls as well. I have seen nulls appear with both speakers driven which weren't there with either speaker driven independently.
This is just insane.
The better half is usually the main constraint for speaker placement
I usually recommend to read this really nice illustrated loudspeaker/subwoofer placement guide by Genelec.
Thank you so much! I will try both pieces of advice (subwoofer back against the wall, speakers at least 1.3m from the wall) and rerun room correction to recalibrate, and hope that this does it!I usually recommend to read this really nice illustrated loudspeaker/subwoofer placement guide by Genelec.
In short, ideally you'd want to have the loudspeakers about 1,1m away from any walls (as this moves the SBIR dips <80Hz) with the sub right against the wall or in the room corner (which pushes sub's SBIR dips >80Hz). In this way the nulls are out of the operating range of each part of the integrated loudspeaker+sub system and you are ready to use EQ knock down the peaks.
If this is not possible, a good alternative is to push loudspeakers close to the back wall - this moves the main SBIR null to 200Hz or higher, where it is less audibly offending and/or easier to treat acoustically.
As @slartibartfast said, every boundary in the room (walls, floor, ceiling) will cause their own SBIR + and you also get interference caused by room modes. Lastly, the low frequency peaks and dips will shift a bit depending on whether you open or close windows and doors.
Physics is really not making it easy for us...
The apparent 3dB bass boost in combined L+R response compared to individual channel response is simply a result of physics of multiple full-range sound source summation.
No problem at all! I'd be interested to read how it went. Good luck!
Isn't the target curve meant to be the target for the listening position with both speakers playing though?The apparent 3dB bass boost in combined L+R response compared to individual channel response is simply a result of physics of multiple full-range sound source summation.
To be more precise, the bass range of the combined response will be +6dB higher above the individual channel responses, and the high frequencies of the combined response will be +3dB above the individual channel responses - this is expected.
You will see the same effect if you measure with MMM individual in-room responses of any two loudspeakers and compare it to the in-room response measured when both are playing at the same time - even without any EQ applied at all, with no subwoofers or WiiM devices involved.
So the only way to make stereo RC and individual channel RC to produce the same shape of the combined L+R response post-correction would be to use an appropriately modified target with each RC type (i.e. 3dB more bass in the target with the stereo channel RC compared to individual channel RC).
However, I'd actually argue that the current stereo RC results in 3dB too little bass, as IMHO the individual channel bass should be well-matched to the B&K target.
The more you run the more it get complicated. I would probably run multiple test and save them with various names. From there pick what sound best to your ear.
There seems to be an issue where all the L/R PEQ filters sound and measure the same though. Nothing to do with my preference. It seems like the selected filter isn't being applied.
Hi dominikz,doManaged to do a few tests today. First, I tested to see if my own manual PEQ saved config were negatively affected by re-measuring the response in REW and comparing to saved measurements of the same PEW config from January.
They match really well when SPL is aligned, so it seems to me in my case the saved PEQs were not negatively affected:
View attachment 17971
Next I also re-ran the individual channel RC with subwoofer active, and got the following results (20Hz-350Hz correction range):
View attachment 17972View attachment 17973
As we can see, the 30-80Hz dip is now gone.
I've validated the results in REW and the individual channel response matches pretty well against the B&K target:
View attachment 17974
Lastly, to illustrate the point from my previous post about the expected +3dB gain in the low frequencies when measuring both L+R channels together (caused by bass frequencies summing like coherent sound sources):View attachment 17975
So to me this all looks to be working well after the latest update of the beta RC algorithm.
Well done @WiiM Team!
P.S. One part of the current implementation of WiiM Room Correction functionality I really dislike is the inability to limit how much PEQ boost is applied.
As you can see in the above measurements, WiiM RC tries to boost a null around 200Hz in the right channel of my system with several positive PEQ filters with up to +6dB gain:
View attachment 17976
This is a serious waste of amplifier power and, given that there's no auto pre-gain, something which could result in digital clipping.
@WiiM Team Is there any chance that we get separate Max Gain controls for positive-gain (boost) vs negative-gain (cut) filters? I'd like to allow -12dB gain for cuts while at the same time completely block boosts (0dB) - and I'm pretty sure I'm not the only one.
At the moment a single control ("Max Gain") controls the allowed amount of both positive and negative gain range in calculated PEQ filters.
Thanks!
