Originally Posted by
RMC
A clarification note. In part 1, E-V, Post # 2, I must add the following in order to avoid any confusion.
The paragraph where I quoted E-V concerning "With regards to Subpassband speaker protection...", this should be seen like a "by the way" note on out of LF passband filtering and how E-V suggests to determine such filter's frequency on low-frequency enclosures in general (i.e. 0.8 times Fb or box tuning frequency). This is NOT part of the Step-Down process, because the way the 6 db boost (and cut) filter is designed it already includes subpassband filtering at 12 db/oct., In addition to equalization. No requirement for redundancy then. I should have put that paragraph at the end of my E-V text as a BTW note.
In a spec sheet's section on subpassband speaker protection, E-V mentions "The step-down equalization described in the Step-Down section provides the required protection."
However, In part 3, Stepping-down with a regular equalizer, post # 4, the need for a subpassband filter remains relevant...
Richard