This is a guide to tone woods for acoustic guitars, before reading this article, please read at least the first few sections of Ultimate Guitar Guide: Tone Woods which does a great job of explaining how important wood is to a guitars tone.
Unfortunately, that guide is also based on electric guitars, has left out many woods such as cedar, koa, spruce...(ect.) that are generally used on acoustic guitars.
This is a bit off the tone wood trail, but the size of the guitar is the most important factor to determining the sound of an acoustic guitars sound. Remember that generally, the bigger the body, the louder the guitar, and more rich bass and midrange tones can be created.
Singe Ought- Written off as "0". This size is the smallest and has very good clarity in the higher registers, the volume is responsive to the touch, but still isn't very loud.
Double Ought- "00" is bigger than the single ought in size, and is also capable of producing a louder sound than the "0". They have great clarity, and also have more bass responsiveness.
Triple Ought- "000" Is even larger and louder than the "0", and "00", giving is more rich bass and midrange tones.
OM and OMC- Stands for Orchestra Model, and Orchestra Model Cutaway. Has a longer Scale than the "000" but is also almost identical in size and tones as the "000"
M- Called "M" or "0000". This size is very clear and well rounded. Able to handle all playing styles well. I recommended this size to beginners, and all others who like a variety of acoustic playing styles.
Dreadnought- "D" The most popular of all acoustic guitar sizes. This size is a lot different from any of the "0's" it is not as well rounded as the "M" or "000", but has a thicker body giving it a lot more of a bass punch to it.
Jumbo- "Jumbo" Popular size with the folks at Gibson. It is what it is called, it is jumbo. Main body size for 12-string guitars, but also commonly found in acoustics. Very loud! with very rich bass and middies. Lacks the clarity you will get from the "0's" type guitars.
Alright, now on to the actual tone woods.
Mahogany- Full midrange with lots of overtones, some top-end clarity but not super clear. Pretty much in the middle of the Deep-Bright spectrum. Good bloom in the midrange. Think good midrange.
Indian Rosewood- Like mahogany, gets more high end sizzle and deeper on the low end. Still has good midrange like mahogany, but what happens when you add more of a broad stretch, you get less of a perception of midrange cause of the more exaggerated lows, and highs. Gives you a bigger sounding guitar.
Brazilian Rosewood- Very expensive, reserved for top dollar guitars only. Delivers a very beautiful warm tone but with good top end like the Indian Rosewood.
Maple- A hard dense wood. Great for a bright sounding guitar. Has longer sustain, and more bite. Less overtone than rosewood or mahogany. Stands out from others. Great wood to use if you play live.
Koa- Has good bright sounds like that of maple, but also has good middies like Mahogany. Great Exotic wood.
Walnut- A good, bright hardwood. Not as bright as maple.
Sitka Spruce- Has a direct punchy sound to it, but tends to lack on the overtones. Used as the top wood for most acoustic guitars. Light weight.
Adironack Spruce- Great tone to it. This wood will not distort you sound if your a heavy picker. Very dynamic, will get as loud as you can strum.
Engleman Spruce- More articulate than the other spruce woods, sounds more broken in than other woods on a new guitar. Great for finger style.
Cedar- Has natural compression to it, so to a certain point your guitar won't get louder ever though you may strum louder. This natural compression is ideal for finger pickers cause of the balanced volume and attack Has a darker tone than spruce. I own a guitar with a cedar top, and love it!
Well that represents most of the guitars you will find in the store, I hope you learned something. Thanks for reading!