900hz is pushing a DNA360 or DE250.
Mine starts to crap it's pants. The distortion shoots up. Practicality had me at 935hz with it. You can go a bit lower if you need less SPL, or if your horn will provide some loading to help out.
DE550 would be my suggestion, although I never tried it, I am interested. I was asking Tux in email if he used it, I am still looking for someone who has or any real world feedback on it.
You could check out JBL D2, it can handle 900hz, extends up to 40khz with a very clean top and generally low distortion. You just have to use an appropriate horn for it, which might be limiting. I think JBL has some pro audio and studio monitor horns available that match it as replacement parts.
If you don't want to change horns the DE250 /DE500 and DE550 are somewhat proven and affordable IMO. The bigger will match up to the 15" 2226 a little better, if you want to beat on it. Otherwise add a mid.