Azryan, I just posted I liked using a meter, I never advocate my cup of tea well blended for all.
I shouldn’t be brave enough post any opinion, as I am skating on the barest base of knowledge in A/V, and don’t I know it! Facts right now tend to slide away from me just as I'm reaching for new ones.
I agree completely with your challenge to think deeply, otherwise I would still be lining up for the latest Bose model demonstration at CC or I’d have my baby sister’s Sony HTIB in my Living Room. Or even more likely, - I’d probably be just rolling my eyes at my guy, saying just drop me at the clothing department if your going to look at those things again! Some part of me in my recent past, dug in my heels, and said, there has to be more to AV than THIS.!!!! I will never understand why I do the things I do, like becoming interested in a subject heavily dependent on knowledge I have no grounding in, - but for me, -‘The journeys the thing’, and unwisely or not I don’t’ have the sense GGM to be intimidated by that intriguing side-trail I see in the road. I was just surprised to read you had never calibrated. One of the first things I ran into was THE GREAT cable/interconnet debate. So typical to me, I said let’s pull out all the cable we can find, cause I want to see for myself.
I did not realize I had put on my flaming party hat, I am now posthaste to the kitchen where the fire extinguisher lives.
You asked: ‘how WRONG were you when you went from ‘by ear’ calibration to trusting the SPL meter results?
For JUST me, very wrong. I’ve always had personal preferences on how a sound system sounds to my ears, yet never bothered to learn, WHY a system sounded better to me?
Since I have not spent years tweaking the nuances of 2 channel, stereo, (CD’s). I was first playing in the DVD boom and bang range of predominately Home Theater type stuff. I think I made a newbie’s mistake of equating all surrounds working noticeably with how riveting or enveloping the movie experience would be.. Therefore I tended to keep pushing the surround db’s up. Many DVD’s really don’t make all that much use of the surrounds, so I’d push and push, and then put in Disc with DTS recorded. Whoop-see, - back to tweaking the other direction, to keep from waking the neighbors with the long distance effects mainly of LF through the mains and the SW.
Over emphasizing my surrounds would periodically land on a serendipitous blend with an individual recording where things opened up and life was good. Unfortunately, 90% of the time, since I did not tweak for every single thing I listened to, I ended up with my levels grossly out of whack.. I thought I was tweaking to an effect which I felt would be pleasing - more surround on movies. After calibrating, very quickly, it was clear…I had destroyed the soundstage for most of my listening.
Even though I had purchased a meter myself before my 950 came, it looked intimidating and I was waiting on my husband to sit down with me on this, I honestly felt at that time, how much difference can calibration ultimately make because I trust my own ears and had vague notions that I could create time delay effects using trim to account for my not so optimum speaker placements and other such thoughts on how to handle aspects and variables unique to my room.
Using my trim this way, for my level of expertise, was heavy handed and grossly inefficient lacking in finesse. Akin to using throttles to bank a plane if you were to lose aileron and rudder control.
Right now I only have my beginner’s ticket and if my plane is in balance (in this instance, calibration)
I need less pressure applied to get movement in any direction I want. You probably don’t need that central fulcrum to start from; since I am not seasoned, - right now I do.

Now If you ever need my expertise, my next classes will be held starting Aug 28, e-mail for scheduling:
A sampling of courses offered this semester:

Topic 1 – The toilet paper roll: Do they grow on the holders?
Round table discussion.

Topic 2 – Loss of Identity: Losing the remote to your significant other.
Helpline support and support groups.

Topic 3 – Is it Genetically impossible to sit quietly as she parallel parks.
Driving simulation included.

Topic 4 – Learning to let go of impossible tasks including keeping flighty brains on serious topics.
Shock Therapy sessions and /or full Lobotomies offered.