Understood.
Affordable mass produced designs vary with quality in the past and present
Your claiming in the past they did not know about panel resonance.
When a early example clearly shows they did. And use same methods then and today to lower or raise resonance.
If a manufacturer decides to use or not use methods to reduce panel resonance.
It does not change the timeline of well established engineering knowledge.
Basing assumptions on low to Medium cost examples. Is silly.
Looking at horrible plastic portable bluetooth speakers today. Might as well assume modern audio knowledge is absolutely nothing LOL.
