Power for active crossovers in Active monitors

I am at present using a Phoenix gold automotive active crossover. My amps are still in the audition, alteration stage. I recently purchased two 22-0-22V toroidal transformers for when the times that my amps get mounted inside my monitors. I am contemplating balanced inputs as well as active crossovers. I will need +/-15vdc to +/-18vdc. Should I use a smaller secondary toroid per speaker for this auxillary power?
 
If you'll just be powering opamps with the +/- 15-18 V, i.e. relatively-low total load current, then maybe you could use linear regulators, off of the main power rails. If you use adjustable regulators, you can use 10-22 uF to bypass each adjust pin and get some benefit from that. Maybe use the types that come in a TO-220 case, so they can more-easily be heatsinked.

Otherwise, you could use a small dual-secondary transformer, of any type, and make a small separate power supply.