Why do speakers improve with more powerful amps?

@ricco275 

Yes, sometimes. But ultimately it is the whole system, and really important to have that power paired with the right speakers. 60db is fairly low… I typically listen at volumes I in the low 70’s. But I am using a 70 wpc tube amp. When I had a 350wpc solid state amp I listened about ten db or more higher. There are a lot of variables.

Same amp brand, same board engineering, the bigger amp with the larger power supply and power reserves is going to sound better. That power is always there, at low or high volume.   Push your left finger (speaker) with your right finger (50w amp). Then push it with your right hand's palm (400w amp).   For one you almost always get a better damping factor and bass control. Think about it. and when the going get's tough it's even better.

But, different brands sound different, and quality varies. I recently moved from a 570w/1140w amp to a 160w/?s  watt smaller power amp (although with large supply and capacitance). The Odyssey amp bested my old W4S (decent sounding to me, before...) amp in five very audible ways almost immediately. Stunning. Power had nothing to do with it. The bass got way better too.   :-)

As for why buy low-efficiency speakers, I'll go with @Clearthinker's view on it (grin). Honestly, my ears have never heard a high-efficiency speaker that didn't seem 'in my face' to me,  but that's just my ears...  I'll just plod along with my 85dB Raidho D2s (room equalized flat to 30Hz and smile lots as they play.

Lots of overthinking on this subject but usually, common sense goes a long way. When I purchased my KEF R3 speakers, I had a conversation with a KEF engineer about suitable amps and he pointed me to a blog on their website about power requirements. At its most basic level, choose an amp that is 60 to 110% of the recommended power requirements if published by the speaker manufacturer. Ignore the minimum number because it is usually just enough to get the cones moving.

Narrowed down to those parameters, you can start looking at things like current delivery and such. In a perfect world, and amp just makes a tiny signal louder. What's left is what leads to all the arguments and discussions on forums. We all have to choose our own distortion preference and altered reality.

Having said all that, You can, and many people have filled books with what I don't know or understand about these subjects. 

Among the finest sounding audio systems were those powered by medium powered Class A/B amps such as the classic McIntosh 225 and 240 (for mids alone-McIntosh MC30s).  Generally speaking, low efficiency coupled with low impedance speakers require high powered amps such as most planar speakers to achieve adequate dynamic range.  I had this problem when I owned stat speakers for 20 years.  I have permanently moved to dynamic speakers of medium to high efficiency, despite lower impedance and difficult phase angles because even my medium power amps have great current capabilities and overcome the impedance and phase angle difficulties.  70 Class A tube watts is plenty for my efficient but difficult load (6 12" woofers) speakers in my average size listening room.  35 Class A/B tube watts is plenty for my easier to drive Legacy Signature IIIs in my living room (I auditioned them with a measly 17 watt Sherwood 7100 receiver).  

Funny how whenever I hear Von Schweikert speakers at shows, they have extreme tube power amplification, often with $600K/4 power amps.  Maybe for the huge rooms they play in.  For the typical home listening setting, medium power is required.  As to field coil and other benign speaker power requirements, low power amps will sound best and huge power amps would be energy wasters and possibly blow up the speaker.  

@fleschler

Awesome info above.
I saw your details, incredible wall paneling in your listening room.

Would be cool to see an updated system.