Isn’t it so that depending on their specs, MOV’s can "clip" those occasional transient peaks of current to your amps so your speakers can not express those flash cymbal crashes for example.
Not even a little bit true. You are confusing current with voltage.
An MOV activates when the (for instance) voltage between neutral and hot exceeds a limit, like 300V. Each MOV sits across a pair of wires and does nothing most of the time. There’s no current, no noise, nothing. It just sits there until a high voltage happens and then it turns into a closed switch.
A huge amplifier, playing at maximum output might cause the voltage to DROP below 120V. We call this sagging. The MOV would be even less inclined to activate with a big amp like that.
By the way, Richard Gray’s devices famously use a resonant tank to stabilize the AC voltage and eliminate noise and are parallel devices. If you don’t want it in line you can plug it into the other AC socket and it will still work. They do an excellent job of eliminating noise and keeping the voltage stable even when your amp is causing the voltage to sag.
Having said all of that, I encourage you to use Furman with SMP. It uses series mode protection instead of MOVs, though they do have an edge case that uses an MOV.
It may help you to understand that having a high voltage at your speaker requires more CURRENT (amps) from the wall which will probably lower the Volts at the wall socket. If an amp played music loud AND raised the voltage at the wall you’d have an infinite power device and not even Elon Musk can do that.
The plethora of things audiophiles do, like run dedicated lines with extra thick wires, use power regenerators and voltage regulators is all to keep the voltage at the AC outlet from sagging.
