crimping vs soldering

I have read in more than one place crimping connectors on speaker wire is better that solder. Any opinions on this from anyone?
I make no claims to being an electrical engineer, and thus can't state with certainty that one method (crimping) is better than the other (soldering) with regard to preserving the integrity of the audio signal. I have found, however, through my own empirical experience, that doing both ensures that you have an excellent and fail-safe connection.

There is no doubt that having a sound mechanical connection (crimping) is a good starting point. This assumes that the connector itself is of high quality, that the interconnect or speaker wire is clean, and that the crimp is tight. The metal-to-metal connection can be problematical, since metals of two different types can pose electrical interaction problems at their interface.

Because the best crimp can only ensure tight metal-to-metal connection at the actual points of contact, thereby leaving gaps between the wire strands and the connector itself, I think that adding a good solder connection makes a lot of sense. I therefore solder the connections, in addition to having a really tight crimp.

The soldering itself must of good quality (i.e., avoid cold solder joints). I like to use a solder with silver content -- there are several good brands with 4% (or more) silver. The solder must be heated enough to flow smoothly and fill in all the gaps, but you don't want to overload the joint with excess solder (too much solder will only add unnecessary resistance to the flow of electricity). Further, you should use a soldering pencil with relatively low voltage, since using excessive heat will melt the insulation around the wiring, and contribute to oxidation on the wire.

In short, your question is akin to wearing both belt and suspenders. Based on my own experience, a good crimp combined with expert soldering ensures an excellent connection. And, like the belt and suspenders equation, none of my connections have fallen down on the job.

There have been a few threads before on this topic, so you might want to look in the archives. I found one thread from last January that might be a useful starting point for you:
If you use quadutectic solder (contact Cardas Audio for a full explanation)I believe a soldered joint is more like no joint at all. Explore this avenue before you attempt any joinery.
It has always amazed me that people decry soldering when all of our components are full of hundreds of solder joints.
I always solder. (You might have guessed that bit !)
I agree with Seandtaylor99. In my days at Western Electric, I learned that the best connection is a good mechanical joint followed by a properly flowed solder (not too much). Witness all those PCBs with solder. Crimping is fine as long as proper pressure is applied and it not exposed to the elements (solder works well to seal the connection). Just take a look at an outdoor electrical connection via a wire nut (crude mechanical bond), you will find corrosion of the conductors.
Read the Audioquest white paper on cabling which goes in depth regarding this question. A solid cold crimp connection is next-best-thing to a molecular bond (electrowelding, which cannot be done at home) & for additional safeguard against oxidation a followup solder topcoat is advised, although unnecessary if you used a high pressure hydraulic crimper, again not typically found around the house.
I like to do a high voltage electronic weld followed by cryo treatment and my patented magical cable dance to make sure all bases are covered. You cannot go wrong with my method.
Follow Timo's advise an go to Cardas web page, there are lots of information in the FAQ. If you will solder, I recomend the WBT silver solder, it's melts at a low temp so
your cables insulation won't burn.
I don't have an educated opinion, however I read on Jon Risch's Web Site that soldering the spades on his DIY speaker cables can actually degrade the cable's performance.

To get a good solder conection ,you must have a good mechanical conection .so due both :)
Done properly, crimping wins hands down.

That means the correct tool for the crimp and a ratchet type crimp tool (in good condition), so the tool will not open untill enough pressure has been applied.
This produces an air-tight cold weld, which is better than a hot weld unless the hot weld is done under an inert gas blanket, to keep the oxygen away while the metal is hot.

Sorry guys, but solders, even eutectics, do oxidise over time. Thus solder can carry oxidation into a crimp more than would otherwise happen.
When researching crimping for a production line situation, the experts advised against soldering over a crimp.

If you want to seal a crimp (not bad if you want really long term protection) many of the elecrtonic parts warehouses sell products for that purpose. Otherwise nail varnish is a fairly OK substitute, and putting adhesive lined heatshrink over the top helps a lot also.

Just be aware that a poorly done crimp is about as good as a cold-soldered joint.
Lower resistant on crimping, higher on soldering.
More solid & safe connection with soldering and crimping wires might fall and cause a short, short can also damage your system. Cheap solder also degrades sound quality. Use silver 4% solder. If you know you can crimp strong enough, use chrimp, DONT TOUCH THE BARE WIRES WITH YOUR OILY MOISTY HANDS WHILE YOU TRY TO CRIMP THEM, use a pair of gloves! Also dont expouse the bare wire.
Oh also, if you solder, do not over-do it with too much solder, completely melt the solder, try to eliminate fake-solder connection (soldered point which the solder looks like it's melted all the way, but not) it will fall off. and because they are not melted and the connection is bad, hum, buzz, bad sound will also appear..