OK so I need speakers with quite low lower frequency (around 30-40Hz) because I won't have a sub. How are Paradigms 100? I already asked about equivalent Klipsch vs 100's and they're supposed to be better.
I will let others respond to those questions, as I am unfamiliar with the particular speakers you are interested in. But be sure to listen before you buy.
Will they work with Sony str-db830. How do you know when a speaker will work with a reciever?
The important things when matching an amplifier/receiver with a speaker are the impedance of the speaker, the efficiency/sensitivity of the speaker, and the power output of the amplifier/receiver (RMS rating from 20-20,000 Hz @ ?% THD @ the impedance of the speaker). Basically, the impedance of the speaker must not be too low for the amplifier/receiver, and the power must be enough, given the efficiency of the speaker and the loudness one desires. Because of the variability of what one might desire, and how loud a speaker will be is affected by the room and how far you are from the speaker, it is difficult to say how much power is enough. Your best bet on this is to select a speaker you like, and in the stereo shop, listen with a low powered amplifier and then a higher powered one, to see what you think. Keep in mind, your room will be different, so it is usually best to get something that can play louder than you really want, just in case your room is more acoustically "dead" than the room at the stereo shop. It is also good to buy locally from a store with an excellent return policy, just in case you are not happy with it in your home.
The power handling of the speaker is also relevant, as a speaker must be able to handle enough power to play loud enough, given its efficiency. However, power handling ratings are not standardized, and consequently are not generally comparable from one brand to the next. In other words, such ratings are often virtually meaningless.
What cables are the best for floorstanders?
Floorstanders do not require anything different from other kinds of speakers; see:
http://www.roger-russell.com/wire/wire.htm
There is a lot of voodoo nonsense about wires. Don't waste your money on magic wires. But pay attention to the gauge chart at the above link.
What does the -3dB measurement mean? Is it important? Thanks for all previous answers and I'm sorry for asking so many questions but unfortunately I don't know anything...
Take a look at:
http://forum.ecoustics.com/bbs/messages/34579/131062.html
You may wish to do some other searching for information about "frequency response", if the above is not detailed enough for you.
And there is no need to apologize for asking questions. It is the right thing to do when one wishes to get answers. Also, it is a good idea to do some internet searching on one's own, keeping in mind that, along with all of the great and useful information that is available, there is also a lot of misinformation, or, in other words, falsehoods, as any moron with internet access can claim any nonsense they wish online. It is a good idea to look to a variety of sources and to think carefully before making up one's mind, especially if one were researching something controversial.