This subwoofer was mainly designed to show what is possible from artisanal aspect – a “money is no object” project without any economical or practice-oriented thoughts. Nevertheless measurement data and sound performance of this woofer also suit this needs.
This woofer is designed as very large vented box assembled with a 21-inch drive unit and without built-in electronics. The woofer is designed for using external amplification and filter electronics.
As long as TSP of the drive unit is fitting with the large enclosure volume any wanted drive unit can be used due to exchangeable mounting torus.
This woofer is made of 5 sheets !! of compreg (2130x1000mm each) – brand name is PANZERHOLZ from DELIGNIT, for example.
This material is basically beech plywood – layers of high quality beech veneers are highly compressed (40 N/sq mm) under heat and by using resins.
For bracing I made an exceptional effortful frame made of high grade aluminium rods, mounted together by using several hundreds of M8 screws and tapped bushings – all high grade stainless steel.
Only this frame has a weight of 110 Kgs.
Using of aluminium rods for bracing is much more efficient in this case (volume to stiffness ratio) than other uusually used materials for bracing. Despite of using aluminium rods for bracing the used rods have to be “massive” because of the high force factors pf the used material for enclosure walls – using of some thin rods would not have any noteworthy effect in this case;-)
All enslosure parts are screwed together by using further several hundreds of M8 screws and tapped bushings made of high grade stainless steel (each 700 pcs of scews and nuts).
Frame and enclosure parts are not glued together because of the different expansion coefficients of aluminium and compreg.
For sealing of all enclosure parts grooves are made to have defined compression for the inlays of the used gasket and to have an optimum and durable force fit.
W = 1206 mm, H = 960 mm, D = 790 mm
Net weight: 440 kg
Due to the heavy weight this woofer is only usable at solidly built basement rooms or ground-level rooms.
Further details and PDF’s also at: www.elodis-subwoofer.com
Due to the heavy and less practice-oriented weight and the high building effort I have discontinued this product.