DEEPER BASS, INTRO
I've decided to start a new thread with the information I gathered on Keele/E-V's "Step-Down Mode" and to re-group everything here for convenience purposes for those who may be interested or need it. That info regarding a derivative of the B6 LF alignment may well be relevant even with some JBL drivers (e.g. Lorr Kramer and Greg Timbers did model a classic sixth-order alignment with the 2245H woofer in their famous article "New Lows in home-built subwoofers", 1983, available in the library of this Web site).
Consequently, for better understanding purposes of what will folow, I'm re-posting here to begin with what I previously wrote in two posts in another thread regarding "Step-Down Mode". The latter is sometimes referred to as "approximate B6 alignment " by Electro-voice (THE major user of step-down mode), or "pseudo B6/Quasi B6 (QB6)" by D.B. Keele. Pretty much interchangeable wording.
For those less familiar with the matter, the B6 LF alignment is a filter-assisted vented-box speaker design. This may be the answer for folks who want deeper bass but just can't afford the space taken by a larger enclosure, or when your life partner turns thumb-down on that...
To complement the two re-posts, I'm adding a third contribution here now (scroll down) with regards to the temptation/feasibility of using a regular equalizer to do the job.
Don't forget while reading, Faux = peak-boost frequency of the auxiliary filter needed.
A fourth contribution is in the making, which may well be 4th and 5 th, considering the first draft already written, plus the amount of documents still on my desk...
Richard