You have some choices for SPL toys:

A. If you have time and money: https://www.trueaudio.com/rta_abt1.htm

B. If you have less time and money: https://www.amazon.com/Galaxy-Audio-CM13...eter+c+weighted

C. If you have no time and no money and an Android phone - the efficacy of this one is very debatable:
https://play.google.com/store/apps/details?id=com.gamebasic.decibel&hl=en

The cross-over did fail because that one component is on the cross-over and the cross-over needs it to work right otherwise it wouldn't be there and you wouldn't have published this post.

As for the "heating issue", let me tell you how that works. When a difference in electrical potential energy (voltage) is applied to a wire, a portion of that energy causes the electrons within the atoms that constitute the wire to experience a re-distribution. The re-distribution causes one portion of an atom to be electron-rich and another portion to be electron-poor. This re-distribution liberates electromagnetic energy we perceive as light.

The light is liberated from the interaction of two fields - a matter field and a force field. The matter field is the electron-positron field. The electrons we "count" are excitations in this matter field. The force field is the electromagnetic (EM) field. Both fields are states of space. When the excitations (electrons) in the matter field re-distribute, they perturb the EM field giving rise to EM waves. These waves carry packets of energy we count as photons. The waves fall within a frequency band we label as the thermal spectrum.

To sum up, matter jiggles, the EM field that bathes all matter jiggles as well and we perceive the EM jiggling as a change in temperature. In other words, you turned up the volume too much and burned the damned thing out!

House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated