First, understand that crimping was used for military/aeronautical application during WWII because it was more reliable than soldering under vibration (do speakers vibrate?). In the 1950s it became the standard for automotive electrical systems, same reason.
BUT, the development of reliable crimp connections came from the understanding that ALL good electrical connections require MELTING METAL. In welding, soldering and brazing this is obvious - but the reality is that good screw connections, relay contacts and crimp connections also melt infinitesimal bits of metal to form welds across the junction, called "asperities". This can be from friction, like when you insert an RCA plug or push on a tab like the AMP style connectors as shown in the picture.
For a good crimp connection, you have to squeeze the joint enough to melt metal at the junction between the wire and the tab.. This is quite tricky for insulated terminals as the metal melting force has to be applied through compressed plastic.
OK, so for crimp connections to be good enough for speaker building you need to buy them from a reliable manufacturer, not Chinese no-name or off brands at Home Depot. I buy my connectors and tools from AMP Inc, the inventor of the Quick Connect terminals.
Unfortunately for amateurs, this means a Certified full cycle ratchet tool. I got mine in the '80s and they cost >$200 each back then. They are available through industrial supply distribution.
Once you have a good connection, formed by scraping off the oxide layer on insertion, it is maintained by running enough current through to keep re-welding the junction. If your speaker sits for decades unused, you may have to remove and re-insert the QD connections.
Relay contacts have a minimum current rating because of this phenomenon, and even gold-to-gold contacts will not maintain below 10 micro-amps.
