FWIW, etc., we found that it was much cheaper overall to go to the local industrial electrical supply house and measure the small bulk rolls of wire and de-wind, use the excess for various other apps.
I'll keep that in mind! The other day I compared monster inductor with two different active LPFs and to my surprise the passive bass was more transparent and detailed, though less full-sounding. The driver was a single (presumed) Grundig 12" old ferrite placed over a stuffed steel can, supporting FE108eSigma (itself notch/shelf-filtered with Jantzen copper-foil 1.5mH || Silver ZCap etc) -- combo sounded ethereally realistic / supernaturally natural. Then yesterday I tried supproting my trusted 5" Monitor Audio Studio 2 with same company's later dimples/phase-plug 8" over a can, replacing 8" Jamo subs -- much better (2.2mH || 9mH for 1.8mH) but can't have enough different monster inductors.
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Addendum: 1.05m (total length including slot) quarterwave resonance ~44hz clear/strong down near 40hz; compare 0.85m (half-length frontmost divider) quarterwave ~56hz good to 50hz. These freq are substantially lower than suggested by MJK Table 1 ("redux" formula R^1/4.75) 1:4 tapered-line multiplier-effect yielding ~60hz for 1.05m. Which putatively suggests the final 10% slot-loading port further extends bass over a TL of the same line-taper and total length/volume.
With room-assist plays organ/piano quite loud. Test music tracks original/control for comparison purpose only (track 7 for piano/violin, track 10 for organ/soprano) https://www.bilibili.com/audio/am33116224?type=7 (from thread https://www.diyaudio.com/community/threads/open-wing-headphone-crossfeed-stereo-sound.391630/ )
Thanks for you sharing, I want to try this design but I have hard time reading this plan in dimensions, can you share more details?
Thanks for your interest. The blueprint in post #20 has too much information, too many lengths (mm) marked off. The four vertical dividers are two pieces each (to fit through the driver cutout, but can be one-piece), written as 130/2, 130/2, 150/2, 146/2; the only horizontal "cap" piece is 52. All the rest are braces, but if you look at the first two pictures in post #1, the five pieces shown are basically enough: trapezoid 28-rightangle-204-rightangle-23 (2pcs in the rear); rectangle bottom spacer 51x23; near-trapezoid 168-rightangle-23-170-rightangle-18; 18-rightangle-166-18-rightangle-168. I drew them out on a piece of 8mm MDF and cut them by hand, allowing for saw kerf and just a tad big, to file down for a snug fit. (Additonal bracing to taste.)
You can either: (1) make the cab sides and back (saving the front baffle for last), glue in the braces and (single-piece) dividers from back to front, finally attach the front baffle; or (2) make the cab except for one side, position and glue in the braces and dividers, then attach the final side. Just make sure to leave enough room for the speaker driver magnet.
Does this help?
You can either: (1) make the cab sides and back (saving the front baffle for last), glue in the braces and (single-piece) dividers from back to front, finally attach the front baffle; or (2) make the cab except for one side, position and glue in the braces and dividers, then attach the final side. Just make sure to leave enough room for the speaker driver magnet.
Does this help?