We're not arguing about headphones or speakers. I enjoy sharing my impressions with others and learning new things as well. So many awesome posts here!
@mahgister
Thank you for explaining the reasoning behind the concrete slabs. While I have not seen this type of application before, I must say it's a unique way to achieve better performance. Perhaps your application is superior to a common speaker stand. (and also much more cost effective).
High internal loss characteristics may also be improved by added weight (on or below the speaker). Resonance and vibration control could also be positively impacted. I can see how this would help with performance.
Likewise, thank you for your posts. All the best with your system and any upgrades you make in the future...Your posts are appreciated.