Use of RCA Y Splitters?

Thanks for all the input. Would there be an issue if the amps were not the same, i.e, not the same power output?

Yes, I was looking at the Audioquest M-22-F/FLX Y-Adapters which appear to do this.

Some other posts suggest that the best method is to use an active crossover which is probably the 100% solution, but wondered if the Y cable solution is "good enough" for most.

Please explain vertical and horizontal bi amping? What if the amps are NOT the same?

Thanks.

No, I was wondering about the effects of bi-amping with two different amps.

Yes, the equivalent impedance as seen by the pre-amp output would be reduced.