Box fb and voltage divider method
Spent a few hours today finding fb of basic 4cu ft box tuned to 40hz built according to JBL enclosure guide. (two 4 by 6.5inch long ports 2226 woofer)
Box has moderate bracing and thick fibreglass on back.
Comes out to 35hz according to my calculations. This is lower then I expected but is this variation usual when performing the test?
I do have a fine tuned frequency generator so can step in 1hz graduations and did roll back and fowards to find what I considered peaks on DVM.
Did plug the ports and sealed with silicone for the sealed test but a small leak would sent the result out the window?
Any tips from those who do this every month or so:)
Dave
2226 is great "Mid-bass" driver!
I use the for home HiFi use and most of my musical material does not require much below the 45hz that the 2226 does well down to.
A sub for the bottom if needed would work well, but not much organ music playing on my system lately.
I am using a Altec 902 driver on 650hz Edgarhorn (round wooden tractix) crossover is at 1.6khz 3rd order for top end, .7 mh coil for bottom end to reduce the rising response between 800hz and 1.6khz.
Sound is decent, not totally hifi of course, but I can always throw a tweeter and sub on it if I feel the need.
Ron