Consider that the new MacPro comes with monster GPU’s that you (or any other musician/sound engineer) don’t need. It’s a machine designed for 4k video editing, it would be the mother of all exercises in sheer waste to use it for audio.
You can build a PC that matches or exceeds (16-core not available on the MacPro) the MacPro for 1/3 of the price. Of course it will not have the same graphic performance but, once again, you don’t need it.