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View Full Version : 2226 to dual 2118 crossover freq



Andreaspaulsen
01-26-2004, 01:17 PM
Hello all.

This is my first post, so please take it easy on me.

OK here goes:

I have on each channel.
1 2226 in 200L sealed boxes sitting soffit mounted in the corner.
2 2118 soffit mounted at 30 angle each in 20L sealed box
1 (NON jbl) stageaccompany 8626 ribbon tweeter.
in a MTM configuration.

using active filtering through a sony srp- f300 digital processor.

Currently Im crossing over between Wof and mid at 120 Hz.
with 12db HP and 24db LP. As I assume the 12 db highpass in conjunction with the 12db natural rooloff would give 24db acoustic HP.

Crossover between mid/tweeter is is standard 24db/ LR filters.

any thought and opinions on a better crossover choice between woofer and mid ?

cheers
andreas

GordonW
01-26-2004, 09:39 PM
I can't see how that could really go wrong. According to my quick look-up, the 2118 should have an f3 in a sealed box, of somewhere around 120-130 Hz or so... so yes, that cascaded with a Q=.707 (ie, Butterworth) second order highpass crossover, should give you darn near a textbook LR (Q=.5) 4th order acoustic highpass overall rolloff on the 2118s.

I also did a plot of available excursion-limited acoustic output on the 2118s... according to my program (BassBox), you should be within 4-5 dB of maximum electrically-limited output power, at 120 Hz as well. With the LR 4th order crossover being 6 dB down at 120 Hz, sounds like you could literally run the 2118s "wide open" at max rated electrical power (100w each) without running into over-excursion. Just about perfect, really.

Assuming the ability to "tweak" the crossover point a bit with the active crossover (to fine-tune the blend between the 2226 and 2118s), I see no reason why not to keep it this way. Should work just fine. Unless you just want to upgrade the electronic crossover to something more 'esoteric' in brand (probably not necessary, unless you're hearing noise or anything), I wouldn't see much motivation to change it.

Regards,
Gordon.

Andreaspaulsen
02-04-2004, 01:46 AM
Thanks GordonW. It looks like I got it right. I use a digital crossover so I am able to tweak to my hearts delight. Currently the only eq im using is a slow rising shelf from 40hz down to give the 2226 a boost.

I have 4 2245, which I hope will play joyfully after a modest refoaming. What about mounting 2 in each of the 200L sealed bass boxes instead of the single 2226. The total Q would en up a bith highish though (around 0.7). However i might be able to eq it to my taste.
the bass bins are inwall mounted in each corner.

Any opinions are well appreciated!

Cheers
andreas