What the "Audio Solution" concerns, we (at work) got three of them.
One is a testsetup for resonance circuits, checking and adjusting coils.
Got a Sinewavegenerator, a 1400W PA-Amplifier and a Pre-Resistor on the output to make sure, the amp won´t be damaged if the coil is getting saturated.
Second is a setup for checking inverters, same as before but with transformer for galvanic isolation on the output and no pre-resistor.
The third is somekind of special...
It uses three "High-End" PA-Amplifiers with 2.5KW each, driven by a 3-Phase sine with free adjustable frequency, delivers up to 135Vrms/phase on 4 Khz...
I have some doubts about using a really cheap Class D amp for this purposes, but I can´t put it in the right words actually.
Must think about it.