Which is best for sound quality? Are they generally just for the convience factor or is bare wire connected into a screw down (gold plated) worse then banana plugs or some other higher end connect?
Bananas for me. Bare wires have a tendency to tarnish more quickly. Proper crimp and solder or high pressure (e.g. QED airloc) bananas help mitigate much of the ageing issues.
"Bare wires have a tendency to tarnish more quickly. Proper crimp and solder or high pressure (e.g. QED airloc) bananas help mitigate much of the ageing issues."
A gas tight crimp is a second best choice. It's just that most people don't have the means to perform a proper crimp.
The issue generally comes down to two things, the quality of the interface between dissimilar materials and the ability of the connection to resist oxidation. On the first, banana plugs fail on all counts. They are a convenience item meant for temporary connections - even though they have become the default connector for most European gear. They present a very small amount of surface to surface contact area between the connector and the jack both at the cable and at the equipment end. Although bananas have been "improved" most still lack the ability to create a gas tight connection with the bare cable and none to my knowledge are gas tight at the equipment end. In most bananas there is simply too much material used for the task at hand, and when dealing with high quality connections the approach is usually one where less is more.
Well made solder connections are excellent for the security of a connection which might be placed under possible stress or for automated manufacturing purposes but the idea of adding tin and lead (even "silver solder" has no more than 4% silver added to the tin/lead amalgam, most is 2% silver) to a high quality connection is against all reason.
If you find your bare cables are oxidizing, look at where you see the oxidation occurring. A proper bare wire connection has the dielectric running right up to the connection point. If the connector allows a gas tight fitting, there should be no oxidation at the actual connection point. In other words, if the connection is gas tight, you can remove the cable from the connector after years of being in position and the point where the connection has been made will still look fresh and clean. If there is oxidation beyond that point, it doesn't matter since the connection has been made in front of the oxidation. If this is the case with your bare wire connection, DM, don't worry. If it is not and you see oxidation at the point where the connection has been made or in front of that point, cut the cable back to clean metal and try again with a better connection. That's an advantage of bare wire, you can always strip it back to get to clean metal.
If you cannot achieve a good connection with bare metal, try a crimped spade lug. You can always clean a spade lug with any conventional cleaner meant for electronic devices. Edison Price sells pure copper binding posts and spade lugs which are the best choice for good sound quality. Since they are not plated, the will ozidize if you do not make a proper connection. On the other hand, plated connectors found on most gear are some sort of visually attractive coating made over a nickel/brass based substrate material. (If I have a choice, I often go with the nickel plated connection rather than add more (very thin) layers of gold plating in between the actual cable and the device I'm connecting to.) Gold plated connectors are done for the visual appeal to the buyer and not for the quality of the connection. Gold slows the oxidation process but also lowers the quality of the connection vs. bare copper to bare copper. If you've made a good connection, oxidation should not be the problem and the beneficial qualities of gold are lost anyway but not the cost.
I have a original pair of Monster Exterminator locking banana plugs from the 1970's that sound quite good and much better than most banana plugs, but, for the most part, gold plated bananas are a waste of money. Avoid connectors, such as bananas, which are dificult if not impossible to clean when the time comes. Bare wire, spades, terminal blocks and binding posts (in that order) all come in ahead of bananas in this regard.
I like the high lead solder treatment on bare ends, as some terminations use flat set screws, others ose points which increase the splay of the conductor.
Tinning the wire, in conjunction with an appropriately sized receiver and fastener work pretty well.
I tin the wires in a modified environment with an inert gas in a confined space, like a small cardboard box and some leftover Argon from the welder.