Perhaps not your preferred cable but here's a common sense answer (follow link) to your question. Blue Jeans gets much of it's cable from Belden.
http://www.bluejeanscable.com/articles/inwallrating.htm
I don't know where you live nor do I have any idea about local code but it seems to me that you could use almost any brand of high end cable provided it was contained or shielded like armored Romex.
If you have an electrician and an inspector coming to check on the installation they can provide an answer for where you live.
My personal opinion is there is already such a mass of wire in modern homes a run to a set of speakers is not much concern.
Where I live the inspectors are mostly worried about high voltage and show little concern for burglar alarm, CATV, internet and similar low voltage cable runs.
http://www.bluejeanscable.com/articles/inwallrating.htm
I don't know where you live nor do I have any idea about local code but it seems to me that you could use almost any brand of high end cable provided it was contained or shielded like armored Romex.
If you have an electrician and an inspector coming to check on the installation they can provide an answer for where you live.
My personal opinion is there is already such a mass of wire in modern homes a run to a set of speakers is not much concern.
Where I live the inspectors are mostly worried about high voltage and show little concern for burglar alarm, CATV, internet and similar low voltage cable runs.