Dookietwo

Maybe build or buy something like this. https://www.bhphotovideo.com/c/product/726030-REG/Whirlwind_SBNL18442_SBNL18442_SBNL_Series_NL.html/?ap=y&ap=y&smp=y&smp=y&lsft=BI%3A514&gclid=EAIaIQobChMI3PW8h9vy6gIVhL7ICh2BYQONEAQYAiABEgKdk_D_BwE

I might rethink this. What if at some point you don't use the speakers or 1 breaks down and you can't use it for a few shows? I'd go with a true Speakcon snake. Have a stage box much like what is used for a XLR snakes and have that on each side of the stage to plug into. Speakon's selected as needed. Less failure points and can be used for different speakers should you have a failure of some point. Remember the 1588's have some eq adjustments and padding in the passive crossover. Be sure to take a good look at the values and use those as you go to an active crossover. I owned a set of those for some time. Used them both full range and with subs. Honestly if the crossovers in them are still fine I see little advantage of going active between the 2-15's and 2-8/horn section. I found 800 watts RMS at 4 ohms was a good power point to have available full range for them with subs under crossed over around 80hz. Much higher than that and you've taken the advantage of having 2 - 15's for your low midrange away. I was using them for side fill for some time as well.

Nice but this post is 5 years old.. Just saying.

If the stage is high enough place the SP2 upside down on top of the sp1 to better couple the horns. Have the horn drivers inside as close to the same plane up and down as possible. ( Forward to Back )

I had the sp1"split" ( MFx-1 and FH-1 sub) Something that sounded good was FH-1 sub - SP2A-Mfx-1 horn on top. The whole load was 4 ohms and they sounded , for what they were , pretty good. This was in the late 80's , early 90's. Seen in this 1991 brightened picture. The box was a SP1 split by someone and the crossover out to feed to the sub was in the horn box.

With the Dayton Audio DATS V2 you can measure and plot your wide band impedance of your box and get an exact measurement of box tuning. You can guess close ( or be way off...) or put on sign waves and look for least amount of speaker movement at box tuning but this makes it easier. https://www.parts-express.com/dayton...ystem--390-806 With the effort your making to have these boxes you might as well know for sure. Doug

I repaired my Yorkville EF500p volume knob a few years ago. A "helper" moved one and broke it. The horn was supported via a board. with a hole in it the same size as the throat where the horn driver/magnet threaded in. It may work with a bolt on as well. I wouldn't mess with the drivers screws. Hope this picture can give you an idea.