Room correction with the lowest entry level equipment and results

[BazsiBazsi]

Dear all,
I've been interested since audio since I was a kid, but low disposable income prevented me going further.
I had many headphones I corrected with reference curves from Oratory or Crin using APO or viper4andoird, but never really went into hifi or home theatre territory. Recently, I've become interested if I could calibrate(or improve) the sound of a cheap speaker system using non reference tools.
So I was looking at my phone at found an interesting app "HouseCurve". I found out that the mics are surprisingly good in this phone (iPhone SE 2022) after many recordings. So I managed to improve the sound of my Genius SP-HF1250B tuning it to the B&K curve. Or at least trying to tune to it with EasyEffects on my Linux desktop. I have a Scarlet Solo 1st gen.
The results were okay, take a look:
Before, pink noise:

After(I switched to sine sweep after I realized that the pink noise measurement is not enough to catch the highs):

The missing parts are clipped. I cannot get it non-clipped even after giving -25 dB preamp. Probably bad speakers or audio interface. While I wrote this I also managed to reduce the highs into an acceptable range and that brought down the brightness and air towards a much more listenable experience. But there are still many deviations from the reference. Considering all I'm especially happy about reducing the triple peaked bass in the original measurement (at 30,60 and ~120 Hz). That was absolutely muddy and booming.
So what do you guys think? Before buying a UMK-1 I wanted to test the waters with this stupid method, and I feel like it's not completely bullshit. It's also a quick way of tuning cars or other basic things that are not a 1k+ sound system setup. I would love a free app that similar to this (can play a tune on an external device, and measure it) and additionally could also generate a correction curve.

 

[staticV3]

Hi @BazsiBazsi! Welcome to ASR.

Nice job with the App! Though I feel like there's still more in it.

For room correction, you ideally want to use the Moving Microphone Method with Pink Noise as the test tone.
House Curve should totally be able to do that, across the entire frequency range.
Perhaps the developer of House Curve, @Greg Wilding, can give you some pointers for better (complete) measurements with Pink Noise

 

[BazsiBazsi]

Thank you for the warm welcome!
I did not expect the creator of House Curve to be a member, but it totally makes sense. For historical accuracy, I set my speakers at 70 dB while using ear protection and fixed the position of the phone while measuring/tuning. I might have to increase the volume, but my equipment is at its limits, have to try out a couple different things tomorrow including the Moving Mic Method.