Wired will always sound better, if this is possible I would always recommend it. With that said, the major limitation of wireless systems is wattage. Whether you have a wireless rear speaker kit or a pair of wireless speakers, wattage is usually 20 watts or less per channel. Compared to a modern AVR, this is very low. Before exploring the various options, I would recommend verifying what connections your AVR has. To use them as true “surround” speakers, your AVR needs to have RCA pre-out connectors for those channels. If it does not have that, the situation will be complicated by needing to convert the speaker level outputs to line level.
This would allow you to connect speakers you own. Of course, we also have wireless speakers that have a transmitter that can be used the same way.
There are more costly solutions out there, but these are some basic solutions available at any Best Buy.
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