JX92S monitors

[soongsc]

What did you do about BSC? I've got these pretty close to the back wall. I think I could use a little lower ohmage resistor with the 1.5mH inductor. I'm using a 3.9 ohm resistor. I tried bypassing the BSC entirely, but that was not good.

Dave,

Are the inductor and resistor in parallel with each other? This is the way it should be. If you add a 2.2uF in parallel with the resistor and inductor, you might also extend the high end a little more. This parallel circuit would be in series with the JX92s, and the JX92S would be connected inversing the phase. The total efficiency will be reduced by about 4db as the Jordan site indicates.

Also it is best (very important) to use a foil or litz inductor (#14). PP metal foils are best with metalized PP foil following.

Would appreciate to hear how this configuration sounds since I haven't gotton to work on mine yet.

 

[soongsc]

If you want to reduce the 3.9 ohm, maybe a 2 ohme would do if you add about 6.8~10uF in parallel. This configuration might compromise frequencies above 10K to get more efficiency.

 

[Dave Jones]

Update: I wound up reducing the resister to 2 ohms, but I added no cap. The circuit no longer functions as a BSC. It "shelfs up" about 2.75dB from 200Hz downward, while the baffle step is centered around 600Hz. But if you take a gander that the manufacturer's chart, you'll see that there's a dip at 200Hz. The circuit helps with that. I didn't plan it that way, it just worked out. I had glued the coil in so it's never coming out, so I might as well make some use of it in the box.

In the small office where the speakers lived first, there was no need for a BSC after all. In-room response measured dead-flat (Speaker Workshop). I have the speakers at home now where they do need a BSC because they are not up against the wall. (I am going to fix that.) In the meantime, I'm using a graphic equalizer for the BSC - one of Jason's castoffs.