No substantial difference between SoundTouch 20 and 30?
I have found an exploded view of Bose SoundTouch's insides and was surprised to find out they don't really differ that much except for the 30's subwoofer and "twisted accordion labyrinth" that reflects and amplifies the bass sound. Seems like the most important part - the pair of drivers - is the same in both speakers (probably 2,5").
So am I right in thinking that the only substantial audio difference between SoundTouch 20 and 30 is more bass and higher volume with less distortion thanks to better stability provided by heavier build of 30 (9 kg compared to 20's 3 kg)? Is the sound, especially in middle and higher ranges at lower and middle volume, more-or-less identical thanks to the same pair of drivers or is there something more in the hardware that can't be seen in the pictures?
My theory when deciding to buy SoundTouch 30 III was that even in middle-size room (15x15 feet) it's better to have SoundTouch 30 as a larger speaker will provide clearer sound even at lower volume. Like driving Ferrari at 50 mph is still more comfortable than driving Fiat at that speed even though Ferrari was built for 100+ mph. But now that I saw identical sets of drivers, only play music under 50-60% of the volume and like to lower the bass to -2 or -3, I don't really see a raison d'être for spending more on SoundTouch 30 anymore. Should have bought SoundTouch 20 and save rest of the money for some nice Bose headphones instead? Please argue (everyone, but especially the Bose people)...