Fear of volume control

I had the same experience the other day. It didn't just sound better because it was louder -- a familiar phenomenon. It evened out the frequencies -- more balance, more "biff", more soundstage. There are those who talk of less, and to them all I can say is, try "more." ;-)

What I been saying. It is not your imagination. Search Fletcher-Munson Equal Loudness Contours. We like to talk about our ears as if they are microphones, and hearing as if it is something that registers on a meter. Not even close. What those curves are showing is graphical proof that we hear low and high frequencies very differently, and this changes with volume.  

Recording engineers know this. If they were to mix a recording at a low volume level they would have to crank the bass and treble, essentially use a Loudness tone control, to make it sound right. Then if you play it loud at home there will be way too much bass.  

They know sometimes the music will be background and played at different volume levels by different people at different times. They cannot mix for all these different volume levels. What to do?

They know the low volume listening tends to be casual background, while the people really seriously into it are gonna play it louder and do nothing but listen. That is the one who will notice. So they mix for that listener. 

What you just did was finally get into the volume zone that recording was meant to be played at. If you listen closely you will find they all do this. Some records really only sound right when played real loud. Because that is how it was meant to be.

See Jim Smith’s excellent book on Getting better Sound - he covers this topic and much more. 
He is avid audiophile, music lover, recording engineer. Beware he is a listen and measure guy and experienced. 

2-3:00 o'clock-okay for few cuts, but just not healthy for long term  hearing, particularly those among us with confirmed damage.

Fun while it lasts though. The opening of Bach's "Toccata and Fugue and Fugue in D minor" or 2nd movement of the Ludwig V's 9th come to mind.

 Really has a lot to do with a lot of things. Using dac as volume control, may be losing bits, volume pots have sweet spots, I'd say every active component within our systems have sweet spots. Still, I'd say its current supplied to loudspeaker and listening room that are main determinates. Higher current delivery to loudspeakers really wakes them up, louder volumes can energize room in pleasing manner. No doubt more efficient hearing at louder volumes. The quality of recording also has great bearing on energizing room, the quality recording has larger sound stage, more dimensional imaging, greater dynamics. Louder volumes only serve to further emphasize these qualities. You know you have a good system when you can play loud and not suffer any costs, other than damaging hearing and pissing off neighbors.