How much DC is considered safe?

An 8 ohm speaker with 32mV across it would dissipate 128 microwatts or .000128 watts. I think you are safe.

Plato:
In short-0
But-My understanding is that measuring dc with ac present usually results in unreliable readings. Especially true with most garden variety digital meters. Probably not to worry over those readings. Tweeters generally safe from low amounts because of the caps. Do you hear any pops from the woofs when you fire them up?

There are more tech oriented forums than here. As a failsafe try asking your Q at the Asylums DIY page or bottlehead.

The world ain't right when Plato is taken rif from Clueless.

Great parting comment, Clueless :^)! Anyone here monikered Aristotle??? Cheers.