Vandersteen Quatro Crossovers

It uses the same M5-HP crossover.

I think you will need to do the 1000 hz 1v 100 hz .707v Minus 3 db down test in the manual with these amps if i remember correctly the amps say they are 50 K but you may end up at a lower setting for proper x over point.
Cheers Johnnyr

Can that battery in the M5-HP be easilly replaced by the end user at home, or do they need to be sent back to Vandersteen to be replaced?

((Can that battery in the M5-HP be easily replaced by the end user at home, or do they need to be sent back to Vandersteen to be replaced?))
It should be done by a person that is competent with an Iron you will also need 3M double stick tape and correct size Made in USA wire ties. Vandersteen Audio performs this service very reasonably I would suggest you purchases Two
9V lithium Ion batteries for 10 year lifespan.
Best Johnnyr

((Can that battery in the M5-HP be easily replaced by the end user at home, or do they need to be sent back to Vandersteen to be replaced?))
It should be done by a person that is competent with an Iron you will also need 3M double stick tape and correct size Made in USA wire ties.
This is the last area where you want to be frugal
having an intermittent connection with 9V to ground is not worth taking a chance.
Vandersteen Audio performs this service very reasonably I would suggest you purchases Two
9V lithium Ion batteries for 10 year lifespan.
Best Johnnyr