please note this website is permanantly "under construction", or possibly not constructed properly in the first place
note also that designs shown,are mostly "under construction" or...
coming soon! 42Hz straight bass horn
download (old school) Jensen imperial horn articles here.
1952 Jensen Technical Bulletin No. 1
1954 AUDIO magazine
Jensen DIY designs
pdf files of largish size but each less than 800KB. They are compressed, so get out your reading glasses.
cardboard speakers
1/2 Scale Jensen Imperial, extra holes for experiments with different throat sizes.
for more info. relating to this prototype press here.
1/2 Scale Jensen Imperial with 80Hz Tractrix Horn
sorry about the crap picture...
"no bass" transmission line
enclosures of this size are quite rigid with no noticable resonances.
white glue (pva?) was used to laminate cardboard.
silicone calking compound (no more gaps) was used to seal the ends of the cardboard. IMPORTANT!
using my favorite cheap Jaycar 5 inch driver.$5 australian
this driver is efficient with a high qts. and a large magnet.
The t-line was tuned to the driver free air resonant frequency of 130Hz and tested with no stuffing.
the enclosure was stuffed and the length tuned by measuring the impedance vs frequency.
the sound was smoother with stuffing but had even less bass
baffle step is an issue as with all enclosures of this size and shape.
"kardboard" karlson
tone was altered by squeezing the slot together.