HerHusband wrote:
Absolutely. Just make sure you use plenum rated speaker wires if you
run them inside the walls.

Unless the walls are being used for heating/cooling air passage, this would not
be correct.

From http://www.ecmag.com/section/systems...-vs-non-plenum
In this corner

Plenum-rated cable gets its name from an HVAC term—plenum spaces. The plenum
spaces are those that lie between a drop and standard ceiling (or a similar
version in the floor space) and it is this section where the air in a building
circulates, thus aiding in heating and cooling functions. When no conduit is
used, plenum cable is often required since the cable is considered to be freely
installed.

Plenum spaces allow fire and smoke to travel quickly. By using plenum-rated
cable, the levels of toxicity in the smoke would be lower since plenum cable is
coated with a jacket that is typically made of flame-resistant material such as
Teflon. This special jacketing makes the cable smoke less than regular PVC cable
and the smoke that is emitted is less toxic.

The opponent

Non-plenum cable, which is otherwise known as PVC (polyvinyl chloride) cable, is
the less expensive of the two choices. You are likely to see many projects
stipulating non-plenum to save on costs, since, more often than not, the
decision on the type of cable jacketing is made by the building owner or end
user based upon their circumstances. By contrast, most schools stipulate that
plenum-rated cable be used, mainly due to insurance requirements.

In projects where plenum is not required, non-plenum is nearly ubiquitous. It is
not uncommon for PVC cable to be one-third of the cost of the plenum variety.
But, as more and more businesses are becoming burdened with higher insurance
premiums, some may choose to go ahead and spend the extra money upfront for
plenum in case of fire. By taking such fire safety precautions, companies can
lower their liability, since plenum cable causes less overall physical and
secondary damage.