Part 2 - 2.1 Stereo Calibration - what am I missing?

[ddude003]

Keith_W, it is OK to agree to disagree... In the last few years traps and absorbers have added features like strike plates, diffusers and tuned membrane so as to not absorb mid and high frequencies...

My bad AOC vs OCA... I am dyslexic after dark... BTY AOC is a sociopathic socialist grifter bartender posing as a politician...

 

[Dave the Rave]

I did some more reading. Archimago's essay was quite revealing. I can see why its hard to correct HF unless we get excellent anechoic measurements of the speakers - something I am too novice to try. Hence his explanation to focus more below the Schroeder frequency range looks appealing.
Below are my tests lately.

1. Avoided any digital corrections above 500h. Just played around with speaker placement again and their mid/high knobs to achieve a flat response. Managed to have decent responses as per pic 1.

2. Since my speakers are 3-way, I wanted to re-evaluate them without the sub. After switching off the sub, the speakers LF measurements showed a flat response but astonishingly provided more coherent listening with the Mids and Highs. Realised I was stubbornly chasing for the Harman target curve cranking up the sub unnecessarily over the years.
However, I did find the speakers could not deliver the consistent LF energy for bass-heavy songs.
So I switched the sub back on and played with all sorts of settings ensuring I get minimal lift from the flat response the speakers provided. I did struggle with the mid-bass being affected when I tried getting better sub contribution.
I achieved the best listening experience when I toned down Bass in my amp (better result for the mid-bass), set my sub as sealed (less peaks and dips), sub at 180 phase and XO where speakers LF response suddenly dropped. See Pic 2 comparing previous and new L+R response below 500h.

3. Finally, I was wondering if I can improve on that using DSP. So I tried GSonic Convolution DSP. Tried both the full range and LF correction filters. From a measurement perspective, they looks good. Pic 3 shows the Left channel changes where essentially the LF is boosted and other ranges corrected marginally addressing the 500h dip with some smoothing above 500h (I used the minimal +3db boost).

Upon listening, the volume went down significantly as expected. The bass correction filters (below100h) was more pleasing. However, over time, I did find it too much hence I went back to setting my system without Convolution.
No disrespect to the advice given here in terms of Convolution success. But maybe since I re-discovered the default nice sound of the full range speakers, I just don't want to ruin it too much (or maybe I haven't mastered the right way to measure and create convolution filters)

Next step is obviously room treatment which is on my list in the longer term.

 

[user44455555]

However, over time, I did find it too much hence I went back to setting my system without Convolution.
No disrespect to the advice given here in terms of Convolution success. But maybe since I re-discovered the default nice sound of the full range speakers, I just don't want to ruin it too much (or maybe I haven't mastered the right way to measure and create convolution filters)

Next step is obviously room treatment which is on my list in the longer term.

the most problem is that your room is not symetrical. you get longer reverb from left side. you can try left and right channel db average so both channels get same EQ. then no phase problems between left and right can happen. use phase linear EQ in bass reduce transients. I think db average sound best

you have a door on left side. maybe you can open the door a little or more and measure and hear again. this work as a huge basstrap. You have maybe luck if it not disturb neighbours. also if you have a wardrobe on left side of the room you can try open it a little and measure and hear again. if it is large and have more depth it have much influnence on sound. also try the generator in REW to play sine tones. then press the note step button and hear the low frequencies. and hear music later. you can do with door open or not and compare too. most important is that it sound good for your ears.if you want not correct so much you can try out difftrent smoothings. try 1/3 then all eq settings are less sharp. I use 1/12 this is less sharp in bass as the Var you use.

I think in rew it is also usefull when can set a % value how much the EQ is used. I use mconvolution in DAW and i do not correct 100%. around 80% i correct. what measure and what hear is diffrent. if you see dips in your FR, play sinus with REW generator best with both speakers and hear how much it differ. play 1 note step above the dip frequency and 1 note step below dip and look how much you need boost so have the opinion it sound same loud. in bass range ears are not so much level sensitive as in other range.

 

[ddude003]

An interesting article... http://archimago.blogspot.com/2026/06/sound-absorption-ikea-mittzon-floor.html