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It's taken forever but the RS dipole is finally finished!
I just put up a drawing of the side panel with the layout of the dado cuts but I still need to do a front view. I'll try to get that done eventually. The side view I just added doesn't show much more than the original but I figure ever little bit of information would help and since this drawing already existed, all I had to do was post it.
Behringer Cross-over presets file Click to download the crossover preset file and follow these directions...
For some reason when you download this file it shows up like a graphic image. When I down load it my PC thinks it's a .pcx file and wants to open it with ACDsee. Just ignore all this and use the "load internal presets" on your Behringer external software on your PC. From there you should be able to locate the file where ever you saved it after downloading. Don't use, "load set" because this will not recognize the file. Then use, "recall from internal presets". Select the RS Dipole file. From there you should be able to view the crossover settings and load it to the Behringer.
Go to the manual setup page.
click to see a larger image of the crossover transfer function.
I finally have the cross-over dialed in to a point where I think it's pretty good. I have made some changes from the original plan however and have changes in mind for any future builds. One, I would use the Seas TDFC tweeter next time and two, I have moved the tweeter cross-over frequency from 2160 Hz down to 1600 Hz. This cross-over change seemed to take a slight rough edge out of female vocals etc. Right now I believe this speaker is very close to the Linkwitzlab Orion.
You can download the cross-over preset file above and load it into your Behringer DCX2496. To open the file for viewing on your PC you need to go to Behringer's web site and download the cross-over software. Once you have that you can open the file and view the cross-over and EQ and or you can copy it to a flash card and load it on your DCX2496. You can also connect your PC to the Behringer to load the cross-over. You also want to down load the latest firmware for the DCX. This can be problematic to install or at least it was on mine. Just power it up while holding down the far left button "A" and start the download again and again until it works. In my experience it takes three or four attempts to get the firmware downloaded.
Note that there is a notch at about 46 Hz. This is to remove a room mode peak that will likely be different in your room. Leave this out initially and then add what ever corrections are needed for your room. The near field measurement of the 10" drivers have no indication of an issue at 46 Hz but measured at the listening position the 46 Hz peak was significant. This notch removed it. You could do the same with as simple a tool as a sound pressure meter and a tone generator you can sweep. Just look for excessive peaks at the listening position and notch them out.
There were a lot of changes from the cross-over I had originally posted. As I have mentioned elsewhere on my web site, my brother Marshall and Siegfried are the real knowledge base. I'm just a tinker'er with way more industry standard measurement and design tools than I know how to use. I have recently learned the importance of using a lot of averages and also the change to Praxis provided the use of pink MLS measurement for low frequency. The earlier measurements I had put into LspCAD were wrong and thus the low end response was way off. I believe it is now pretty close and this has resulted in a change of thought on the possibility of a compact dipole woofer being able to keep up with sealed at very low frequency as long as it's given a steep rumble filter. With the current cross-over the RS-10 drivers can be easily bottomed if you turn off the 4th order 25 Hz HP filter and can be bottomed with it on. By the way...a side note...I did distortion measurements on a prototype of the new RS 12 subwoofer currently under development and it promises to be very good! If you want to build this speaker with full range capability then wait and use the high excursion 10" when it comes out later this year. Or, build it as is and build a sealed sub to go with it using the RS subs when they arrive. That's what I'm going to do.
Anyway, the construction of the baffle from a cosmetic stand point is not critical. You can change it anyway you want as long as you don't make any significant change to the width of the baffle or the depth of the upper portion of the baffle. Increases in depth behind the 7" drivers may cause stored energy issues so that 2.5" depth back to the side cut out should not be significantly changed. The total depth of the cabinet can be increased as long as the cut out keeps the 2.5". Increasing the total depth and thus the depth for the 10" drivers will require cross-over corrections but will improve the speakers capability at low frequency.
When I built these, I cut the wires and soldered them to the drivers with the drivers mounted. I then hot glued the wires down nice and neat. Don't do this! Leave a loop so later if you have to replace a driver you don't have to remove the rear grill cloth to get to them. The side trim pieces were attached with those little plastic grill holders. This didn't work, they warp and pop off! If I had left loops I could remove the 7" drivers and reach in to put screws in from the inside but I didn't so I just put screws in at the bottom and just below the upper section. Fortunately that solved the problem. BTW, just a tip on screwing in side trim pieces or side pieces from the inside...knock the tip off the screws with a grinder or belt sander. Especially in the case of something like an Orion you don't want to spend all that time polishing the sides only to put a screw through too far and have it pop out the outside. For holding purposes you want it to go most of the way through but filing off the tip will help prevent damaging the outside surface.
Grill cloth is held in by screen wire tubing as shown above. Additional grooves across the top and bottom will be used to fold the end of the cloth over and attach it.
Right now they just look like a lot of MDF but hopefully they will progress and eventually not look too bad. I will be posting construction photos as I go. I have included one photo next to the Orion for size reference.
I'm in the process of loading and wiring the drivers. I originally only ordered two 7" drivers but the other two should be here tomorrow. Hopefully by tomorrow evening I will have the drivers loaded in the other one and be wrapping the grill cloth. I still need to cut the Cherry trim pieces for the sides and also make the top which I think I will also make in Cherry and the base which will be 1" MDF painted black. After that all I need is some decent weather so I can crank them up in the air and do the measurements for setting up the Behringer cross-over. With any luck they will be playing this weekend.
I'm not good with drawings etc but will try to eventually get more details posted or will try to help anyone that would like to build these. I'm that type that usually has to build it first and then make the drawings but in this case I actually built it based on the drawings above with only a little bit of ad-lib. It's pretty simple to build actually. The whole thing about cutting the front edge of the sides with the dado blade could have gone better. It might make more sense to do that by laminating two half inch pieces so you have a better surface there. Anyway, overall I'm really happy with the way these turned out for both music and Home Theatre. Watching a movie the speakers just disappear!