the Volla is 88 db sensitivity
that will give you 98 db with a 10 watt amp, 101 db with 20 watts and some more with 30
which is very loud to my levels
depending on a larger room or you want to give a party with those speakers than 30 watts will not be enough
a hefty power amp may be beneficial for parties and big rooms and large orchestral works with sudden bursts in loudness
On the other hand tube power sounds louder than ss power, and some high end ss amps as well. the RW 30.2 also sounds (much) louder than its 30 watts suggests
normally i listen between 65 and 80 db which to me is loud
here is a reference list i keep for a long time but forgot the source
0-Threshold of hearing
10-rustle of leaves, a quiet whisper
20-average whisper
20-50-quiet conversation
40-45-hotel, theater between performances
50-65-loud conversation
65-70-traffic on a busy street
65-90-train
75-80-factory noise( light/medium work)
90-heavy traffic
90-100-thunder
110-140-jet aircraft at takeoff
110-130-threshold of pain
140-190-space rocket on takeoff