Acoustic treatment

Thanks theaudiotweak… But my result obtained only with water are enough for the day and extraordinary... I am very pleased already, the helmhotz resonator are not snake oil,pricing sometimes is, ideas are often implemented with very low cost and sufficient good result... I will not purchase audiophile resonators, I am proud of my cheap ones and astounded... Perhaps I will try olive oil some day to comes thanks Tom for the idea... Thanks also to Geoff for his impulse and astute observations...

Just finished my bass traps and installed them. All I can say now is that I'm a believer! 

     Using large, expensive and butt-ugly bass traps always seemed analogous to opening windows in mid-winter to control the heat in your house.  Better to control it at the source, right?
      Like turning down the thermostat to reduce the heat or use a 4-sub DBA system to optimize your room's bass response and sell your bass traps.

Tim

Many older theaters were designed with a combination of bass traps,diffusers,resonators,and pillars(aka tube traps) incorporated into the structure. They have incredible acoustics.The DBA system and room treatments can work well together.

Check this out:https://www.psiaudio.swiss/avaa-c20-active-bass-trap/
It looks to me like an expensive alternative to the DBA system