Anyone have experience building and designing a Vocal studio in your home/garage?
My partner is entering the Voice acting industry and has expressed interest in working from a home studio.
A vocal booth is MUCH easier to construct than a larger recording space.
Grab a bale of Roxul Safe N Sound batts. Build a basic structure to hold them, maybe even just attach them to a booth made of 2" pink EPS or blue EPS.
Get one of those mic-isolating things to shield the mic, a variant of this:

As important as acoustic isolation is, electric noise is critical too. Use a quality mic preamp and/or interface with good S/N ratio. Prefer a mic with higher output (look at the sensitivity spec).
Ensure you have very clean power running your interface/computer, etc. I'm not sure a Furman is anything beyond an overpriced surge suppressor, but some kind of power management/filtering/UPS etc might be a good idea of your local power is bad.
(Most rack noise issues are caused by other items within the rack-- just breaking down the items and getting them out of the rack will often fix noise issues).
Finally, you'll want to spend some time figuring out which mic is most complementary to the natural timbre of aspiring voice actor. Many mics will sound "good" but people with particularly sibilant or darker-timbred tones will definitely want to avoid particularly bright or warm mics.
If you have a sibilant-voiced person, don't overlook a ribbon like the Royer R121. They are a famous ability to tame harshness (like trumpet brass) while still having amazing clarity.
If you have a person with a naturally warm and less detailed voice, don't be afraid to go as far as a small diaphragm condenser. There are many compelling options now from relatively new companies (Lauten audio, Austrian Audio, etc).