Matthew Weigel wrote:
In article ,
"Arny Krueger" wrote:

Matthew Weigel wrote:

It's that the exposed wire oxidizes, and the contact deteriorates.

By definition, exposed wire is not part of the contact between the
connector and the wire.

Yes and no. There is some minimal distance around the exposed wire-
including that part that is the contact- that oxidizes. If the area
of contact is spread out across many threads with small gaps (an
issue with stranded wire that isn't completely locked down), that
minimal distance makes significant inroads on both sides of each
thread, with an end result of greatly reduced contact.

IME if the speaker connector is tightened down proper[u, the
wire surface will still be bright at the point of contact, should
you later disconnect the wire.

Sure. You have to properly connect banana plugs only once, however,
regardless of how many times you might do something that requires you
to disconnect and reconnect the speakers. Spending $15 to reduce
effort over the life of any stereo system I have (the banana plugs are
reusable, not crimped or soldered), the number of times I have to
worry about making solid connections, is very much worth it. At a
guess, anyone who has already bothered to shell out for 12ga speaker
cable won't mind it at all.

The irony is that your typical banana plug does not eliminate the screw
connection, it just changes its form and adds a connector/socket interface
that wasn't there before.

I have a few (dozen) banana plugs in my various audio systems, too. I even
have a few of the high-priced kind that cost over $10. However, I view the
latter as conveniences, not sonic enhancers.

The key to any connection is a solid, so-called gas-tight metal-to-metal
connection. Depending on the exact situation this wothy goal can be achieved
by means that range from wirewrap, to a soldered connection, to a low-cost
banana plug with setscrews, to a high quality 5-way binding post, to a
cheap plated binder-head screw bearing down on twisted stands of wire.