The RJ is a coaxial-concentric 6th order band pass. The two rectangular regions on the side are horizontally flowing slot ducts leading from the rear chamber of the driver which exit in an area right behind the wierd "lemon" shaped aperture. The output from the slots is then applied to the face of the driver on the "front" chamber. The total output of the slots and the front driver face combine (which is why it is a 6th order band pass - two chambers connected by a duct which then exit through another duct (the aperture). It's tricky describing it in words but perhaps Freddi has a sketch for you.
This is actually a very clever low profile 6th order band pass device. It improves cone loading (for higher SPL before hitting xmax) and makes the minimum excursion coincide with tuning frequency (fb). So the cone excursion goes to a low as bass goes deeper towards fb - lowering HD via less cone movement. I have modeled it in Akabak and it does a lot for adding an extra inch or two to the front of a speaker.
Yes, it seems to have worked out perfectly. The plans drawn by GregB to that scale are good.
I used to use 4-RJ-style vented 18" reflex in my old setup - two 6.4CF - two 8.2CF - if I had understood the loading more then would have tried truncated area aperture but had to get things usable with one build.
I'm surprised with all the stuff built that we don't see RJ type much. btw - the 18" in the larger cabinet sounded somewhat "cardboardy" in that cabinet when used wide range - when it was moved to a Karlson, things improved - go figure
it was interesting to see the vent and speaker sum nice anywhere in the aperture
I'm surprised with all the stuff built that we don't see RJ type much. btw - the 18" in the larger cabinet sounded somewhat "cardboardy" in that cabinet when used wide range - when it was moved to a Karlson, things improved - go figure
it was interesting to see the vent and speaker sum nice anywhere in the aperture
An externally hosted image should be here but it was not working when we last tested it.
I want to try an RJ one of these days. A small one with a Dayton RS100 may be just perfect. Cute 50Hz box with a lemon aperture
I am not sure you can model this in HR - but maybe as a TH with a very strange profile of a constriction (the thin vents) before going back to a sudden expansion to the driver frontside followed by another contstriction or duct leading to the outside. It's a 6th order bandpass.
I use Akabak so many channels connected however you want is not a problem.
I use Akabak so many channels connected however you want is not a problem.
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After extended listening I have to conclude these drivers aren't so easy to use and may require additional components to achieve an acceptable sound - from my perspective they are not recommended for 'normal' use, the FR is too far out of wack. Pitty the initial datasheet wasn't detailed enough to forwarn so I will also avoid buying new drivers from any manufacturer until independent tests and listening impressions are available.
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Fortunately It's not a big deal, I had the box and bought only one driver to try it out. I've now built snd heard three different MA drivers, the best was the 10.3 Pencils but these are large boxes and bass could be stronger given the box size but I'd recommend them. I've yet to hear a full range 4" driver that has passed the test of time, either they fatigue/shout or have no bass. The best is the EL-70 in MLTL boxes but they're obsolete and treble isn't perfect. I'm tempted to get one of those Brazillian drivers you like.
How small can the Karlsonator be made (for the CHN-70) ?
How small can the Karlsonator be made (for the CHN-70) ?
now that's some funky 3D wiring x-man
obviously no curious kids or pets around the system
It sits in my office at work - so no issues there about kids. It is quite the conversation piece though - more people should make amps like this.
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At my work they're used to seeing electronics so I have a spudamp which gets a bit of attention
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