Hoops/Rims
1. Die Cast Hoops: Thicker and stronger then triple flanged stamped hoops with an ability to allow more even tuning of the head and as a result, the head is usually more responsive throughout the tuning range with less varied overtones. As such, may create a slightly drier sound on thin shell, small sized drums due the weight of the rim causing the drum to vibrate less freely. They can also be made out of differing materials such as nickel or aluminum and all aid in changing the sound of the drum.
2. Triple Flanged or “stamped” hoops come in a variety of metals, which affect the tone of the drum. The thinner they are the more difficult they’ll be to tune with. Many drummers prefer these on toms because of the ability to tune “fatter” or “warmer” than with cast. Aluminum makes for a higher pitched tone than does steel and as a result is used on snares quite a bit for a great “crack”. Brass makes the drum more musical and aids in the presence or high-pitched overtones.
3. Wood Hoops have the virtue of being either rigid or flexible, depending upon the manufacturer’s thickness of the hoop. As a result, they can take on the tuning characteristics of a cast hoop if rigid or flanged hoops if thin in construction. However, the rimshot sound is considerably different and acts like an extension of the shell so the drum is usually both more resonant and brighter.
4. Less lugs means fatter tuning and more complex overtones. The longer the interval between lugs the less likely you are to get the head tuned evenly between lugs.
5. A hoop of “rigid” nature results in a head, which can be tuned more evenly between lugs and will accentuate the imperfection in your drum if out of round or bad bearing edges. Sometimes, this causes a drier or more muffled sound as a result of inferior bearing edges.
http://home.earthlink.net/~prof.sound/id13.html
