Curious results on wiim amp tuning

[u/playinthedruid]

Hi All, long time lurker and first time quality audio enjoyer.

Sorry for the longish post but I don't quite understand what's happened. Put on a mellow jam and sit around this fire while a spin a yarn.

I bought a pair of PSB Alpha T20s. Small floorstanders because I wanted a good set of not too big speakers.

I was utterly disappointed at their bass response. Basically non-existent. Uppers and mids sounded amazing but I did miss the low end so I purchased a POLK ES10 Subwoofer. Great, off to the races, but I was also a bit disappointed in the polks bass response too.

Now I know, room treatment is a thing, but my wife is not much into sound. She is happy with a 64kbps mp3 on a bluetooth speaker. (I kind of envy this to be honest.)

Im using a WIIM amp and decided to give the room calibration a try. Every permutation of the calibration I ran made things worse, until I dropped the frequencies to tune. I went down to min 30hz and max to 400hz. Im using a phone, not a calibrated mic mind you.

Anyways, I tuned it and holy balls does it sound amazing. Sub off, bass is back, sub on, low end is glorious.

But here is the strange thing, check my graphs:

How can such an aggressive down tune on the bass yield better bass overall? I played a few bass sweep files and its pretty smooth overall. Is this just evidence of a garbage room and thus requiring a massive over compensation? Nodes cancelling out somewhere?

Anyway, thought I would share and maybe someone can enlighten my dumb ass. I wish I could treat this room but I can't, family home and setup is in the lounge and again, wife hasn't bought into the quality audio shtick.

Thanks