A horn basically directs acoustic energy in a single focused direction, maximizing the efficiency with which the air mass to moved by acoustic waves is coupled to the driver.  The best thing is to read a good book that covers the basics in simple terms.  I like the explanations in the Radiotron Designer's Handbook and Olsen's Fundamentals of Acoustic Engineering.  You can also try this link: http://www.melhuish.org/audio/horn.html

Adrian

Alex,

the links at the site that Adrian pointed of are way out of date. Look at the “links” section of my site for correct location of Thomas Dunker site. You might also search within this site for Thomas Dunker:

http://www.goodsoundclub.com/Search.aspx?Phrase=Thomas%20Dunker

A few years ago when Thomas said the he is going out of the horn world I pulled some of his writing, preserving it, presuming that he site will go down in future.

You might also, looks at the links section:

http://www.goodsoundclub.com/Links.aspx?Q=Edgar%20Interview

Where you can find a good interview that Bruce Edgar gave to Positive Fedback.

Anyhow, I do not know what kind “basics on horn speakers” you are looking for and how beneficial for you will be Olsens or Radiotron – I have my own reasons to be at doubts…

Nevertheless, if you looking all around reading about horns then I sincerely feel that my site among any other sources that I have seen has the most rational and the most lucid presentation of horn idea. Saying it I am very far from a cheep self-promotion – trust me, my ego is so advanced that I would need way more sophisticated means to advance my self-image. Saying that this site is the location where Sound and Horns are meet each other I testify that this site is the only places where I have any interests to read with blaming the content in ignorance, stupidity or moronity. You might find many positions within this site too opinionated and in a way too dogmatic (mostly from me) but it is only because I care less about the subject of nonfigurative entertaining myself with abstract horns but rather I prefer applied amusement of myself by USING Sound from horns.