When electronics are delivered in this cold weather it is a good idea to let them warm up to room temperature still in the box before opening so you don't get any condensation. I run some tube equipment in a 50F + room sometimes and haven't heard any issues. I don't ever let anything get down to freezing.
Humidity and temperature matters for the sound... if low I will increase the temp and humidity to at least 35% for better sound in my experience. It is better for the cabinets to not be allowed to dry out so much anyway.
There are a few repeats but I thought I'd add the subject to the links. These are some of my favorite threads although I'm missing more than a few. It is no surprise how often Groomlakearea51 shows up!
The $500 Klipschorn Saga.... https://community.klipsch.com/index.php?/topic/98031-the-500-klipschorn-saga
How To: Test & Replace a Heresy-II Driver https://community.klipsch.com/index.php?/topic/98275-how-to-test-replace-a-heresy-ii-driver
KLIPSCH HERITAGE CODES REFERENCE DATA - (V.2 - 8 May 2008): https://community.klipsch.com/index.php?/topic/93433-klipsch-heritage-codes-reference-data-v2-8-may-2008
How to: New Grills, grill cloth, etc... https://community.klipsch.com/index.php?/topic/98877-how-to-new-grills-grill-cloth-etc
Help,I May Need A New Crossover and Cabinet Reglue For A Heresy II, 1986 https://community.klipsch.com/index.php?/topic/98097-helpi-may-need-a-new-crossover-and-cabinet-reglue-for-a-heresy-ii-1986
$200 CORNWALL SAGA - RESCUING ORPHANS https://community.klipsch.com/index.php?/topic/103896-200-cornwall-saga-rescuing-orphans
Re-Veneering question (JoeWoodworker chimes in) https://community.klipsch.com/index.php?/topic/115705-re-veneering-question
I have a Project -- La Scala Restore (Gothover) https://community.klipsch.com/index.php?/topic/117764-i-have-a-project-la-scala-restore
My camera is back... Time for some photos of my La Scala rebuild (jhoak) https://community.klipsch.com/index.php?/topic/110390-my-camera-is-back-time-for-some-photos-of-my-la-scala-rebuild
Rosewood Decorator Cornwall project (rcarlton)
https://community.klipsch.com/index.php?/topic/97138-rosewood-decorator-cornwall-project
https://community.klipsch.com/index.php?/topic/126780-heresy-ii-refurb-and-upgrade-to-hiii/
muel's post in Humidity? was marked as the answer