I'm not sure yet.
John K uses a baffle width of about six inches. That width sets his crossover point to something like 1khz, due to the dipole peak.
Something I realized from my last project (http://www.diyaudio.com/forums/multi-way/264680-lx-mini-homage-2nd-try-2.html) was that you need to keep the width of that baffle narrow.
So the baffle width will likely set the crossover point. Hopefully I
can get it down to something like 1khz.
It's hard to predict right now, because the radiation is complex. "The Edge" can sim a baffle, but I am not aware of anything that can easily sim a dipole waveguide.
TLDR: I'll probably run the 12" woofer from about 125hz to 1khz, the mids from 1khz to 2khz, and the tweeter from 2khz to 20khz
I recently hung some old new M&K 5 1/4" peerless drivers in a no baffle frame above 2 10" drivers, with a variety of tweeters. It sounds pretty good from 500 to 5000 hz, even off axis.
You may be able to cross much lower than 1000 hz.
I will try to find his thesis or dissertation on the idea...I don't know which one he wrote this for.
Ended up getting his Ph.D in the field.
Ended up getting his Ph.D in the field.
Note/LX521 have the mids in roughly 120-150mm wide baffle, which means that the get some support from it. Crossing 4-600 and 3-4kHz is possible - with dsp. Passively low end gets difficult.
Upper xo is an interesting issue. because of non-coaxial layout high xo has narrow lobe vertically. I have tried xo 2-6kHz LR4 with my AINOs. Low xo measures smoothest horizontally, but vertically it's valley is smack dab in the tonally very sensitive range. Now I have settled to xo LR4 at 4400Hz (acoustic) I cet very smooth response up to 3,5kHz and piano, violin etc. instruments sound very nice!
Troels Gravesen is a fan of high xo. I can see the point of it when mids are 4"-3"
Upper xo is an interesting issue. because of non-coaxial layout high xo has narrow lobe vertically. I have tried xo 2-6kHz LR4 with my AINOs. Low xo measures smoothest horizontally, but vertically it's valley is smack dab in the tonally very sensitive range. Now I have settled to xo LR4 at 4400Hz (acoustic) I cet very smooth response up to 3,5kHz and piano, violin etc. instruments sound very nice!
Troels Gravesen is a fan of high xo. I can see the point of it when mids are 4"-3"
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Put a slot in front of a woofer to change the radiation pattern. Make it funny shaped to spread out the problems. I'm less than amazed.
Seem like a really interesting idea; I do wonder if it skews phase with its turbulent release of the pressure waves along that long, diffractive edge.
So in essence, this acts like a nozzle, widening the output pattern?
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Yes, the RJ aperture is essentially a double Karlson symmetric about a horizontal plane. The RJ cab is a completely different alignment however and one I have toyed with. I have been developing a model of it in akabak and it may have some promise. It is a 6th order band pass box as the reflex vent feeds into the chamber right behind the aperture. It may have some good cone motion control properties. I have been looking for a suitable full range driver to try it with. It may also work as a sub woofer with a big car audio sub like an Alpine SWR 12D2 which is a fantastic slot loaded band pass sub driver.
Yes, the RJ aperture is essentially a double Karlson symmetric about a horizontal plane. The RJ cab is a completely different alignment however and one I have toyed with. I have been developing a model of it in akabak and it may have some promise. It is a 6th order band pass box as the reflex vent feeds into the chamber right behind the aperture. It may have some good cone motion control properties. I have been looking for a suitable full range driver to try it with. It may also work as a sub woofer with a big car audio sub like an Alpine SWR 12D2 which is a fantastic slot loaded band pass sub driver.
Yes, as I understand.
I am pretty sure that the JBL guys have studied that better than any of us amateurs can. The mask is on the edges and there distance from mask to membrane is short - interferences appear at frequencis above xo. The shape must have been tested for years and the funny shape is functionally most satisfactory. I am sure that it is matched to the horn well. It is not visble, not a "selling argument" like the funny "phaseplugs" that we see in some fullranges. Also the horn has wedges.
I'm really loving the look of the matte black on the curves of the Summa.
My original plan was to ape the look of the Spatial loudspeakers, but I think the curves of the Summa in matte black look superior.
An externally hosted image should be here but it was not working when we last tested it.
My original plan was to ape the look of the Spatial loudspeakers, but I think the curves of the Summa in matte black look superior.
I just ordered a pair of Danley SH50s.
After ordering them, I realized I don't have a way to transport them. They won't fit in either one of my cars. My Summas, at 21" wide, are just small enough to fit in my car. The SH50s are 28" wide.
I live on the second floor, and my Summas are about as much as I'm able to carry up the stairs. The SH50s weight 142lbs. I figured the Summas were about 80lbs.
I put the Summas on a scale, and much to my surprise, they're 121lbs. WOW. That's a big *** speaker.
Hopefully I should be able to haul the SH50s up the stairs, particularly since they have handles. Without a doubt the most difficult part about moving the Summas is that they're shaped like a bar of soap, there isn't ANYTHING to grab onto. I can't count the number of "oh sh1t" moments I've had where I thought I was going to drop them down a flight of stairs.
After ordering them, I realized I don't have a way to transport them. They won't fit in either one of my cars. My Summas, at 21" wide, are just small enough to fit in my car. The SH50s are 28" wide.
I live on the second floor, and my Summas are about as much as I'm able to carry up the stairs. The SH50s weight 142lbs. I figured the Summas were about 80lbs.
I put the Summas on a scale, and much to my surprise, they're 121lbs. WOW. That's a big *** speaker.
Hopefully I should be able to haul the SH50s up the stairs, particularly since they have handles. Without a doubt the most difficult part about moving the Summas is that they're shaped like a bar of soap, there isn't ANYTHING to grab onto. I can't count the number of "oh sh1t" moments I've had where I thought I was going to drop them down a flight of stairs.
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