Jordan JX92S + Hi-Vi D10G + passive 1st order crossover?
Jordan JX92S full-range driver
Fs 45 Hz
Vas 15 liters
Hi-Vi D10G woofer
Vas 138 liters
Jordan goes flat down to 100Hz in a small sealed enclosure. The freq curve for the D10G looks like it breaks up around 400Hz. Is two octaves enough overlap for a passive 1st order crossover?
Would this be a reasonable approach?
A second idea:
Since a .7 Q sealed enclosure rolls off at 12dB per octave (is that correct?), let the Jordan do this naturally without any filtering, simply apply a second-order low-pass filter on the woofer. What sort of phasing issues would be presented here?
A number of people use the JX92 in a sealed enclosure and allow that to roll off the bass and have reported good results. On the other hand, a recent thread extolled the virtues of an active crossover at 150Hz and said it made a big difference. The box approach is at least cheap to try and you can add filters later.
Jordan used to recommend a 1st order roll off for their bass drivers, crossing over to the JX92 in a sealed box (with no x/over), crossing at around 110Hz. Although I'm using the 92 full range (down to the mid-30Hz), as an experiment I tried the passive roll off using the inductor value on the Jordan site. Interesting - playing test tones the bass units were still clearly audible up to almost 1kHz (albeit at reduced volume). So if I used a 1st order x/over on the bass, I'd want to add to the rolloff by having the bass units face the floor.
I'd like to build very similar system using JX92S and Seas L22RNX/P which according to simulations make very deep bass. I plan to use it in active system with 1st order crossover at 150-300Hz.
I think that Jordan has to be highpass filtered, because cone excursion goes rapidly up as frequency goes down, so you can easyli exceed Xmax. Vented enclosure for JX would help a little, but not enough. Depends on how loud will you play.
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