The rim is one of the most mysterious parts of a drum kit. Some drummers are not even aware that there are different types of rims, and among those who know something about them, one can often find complete ignorance of the differences between each type of rim.
Why is rim selection important?
Little details lead to big changes. It's like building a car. Each component is meticulously crafted, cleaned and polished, resulting in a gorgeous car...your car.
How do different rims affect the sound of a drum?
The rim controls the overtones that generate the edges of the head. Compared to wood and die-cast rims, stamped rims allow the edges of the head to oscillate more freely, resulting in more sustain, an open, bright and multi-component tone. Molded ones, like wood ones, have more control over the edges of the plastic, as a result, there is some muting effect. The sound becomes tight, focused, with less sustain and more density.
To see this for yourself, hang some kind of rim on your finger and hit it with a stick. You will notice that the diecasts and woods have very little sustain, and the sound is even slightly clunky. But when you hit the stamped rim, you will get a very bright and loud sound, the rim itself will ring like a bell. Together with the head, they affect the overall sound of the drum, regardless of the shell design.
If you are looking for maximum dynamics - lots of sustain combined with an open sound - then stamping is a good choice. On the other hand, if you want a tighter sound, high pitch and little sustain, go for a cast or wood.
A combination of different rims.
There are some peculiarities in such experiments on one drum. For example, I often put a cast rim on the bottom head to control the overtones (coloration) and to some extent the rattle of the small. But on the top head I put stamping to allow the tone to be more varied. Depending on the type of shell, I will use different combinations. Do not forget that sound is a subjective concept. My motto is "If it sounds good to you, then it sounds good."
Rim types and their effect on sound.
Stamped singles (curved once) - very open sound, plastic almost flies, very long sustain.
Stamped trebles - just an open sound, long sustain.
Diecasts - Focused sound, medium controlled head, medium sustain.
Wood - Very focused sound, plastic has very little freedom, very short sustain (depending on the thickness of the rim).
And already in their categories, thin rims lead to greater openness, while thick rims do the opposite.