Unwanted Drum Tones
We often confuse three aspects of drum sounds.
1. Sustain
2. Resonance
3. Unwanted sounds like excessive ring.
Sustain is the duration in which a drum head will vibrate. Adding dampening can cause a drum head to shorten its tone, even limiting it to the resemble the sound of smacking a cardboard box with a stick.
Resonance is the tonal frequency that two objects share, meaning one will vibrate at the same note as the other.
Ring is the high frequency part of the tonal spectrum, as a drum can produce both lower and higher than the entire spectrum of human hearing from 1hz to 50,000hz, the human ear can only hear from 30hz to 20,000hz but the human body feels the initial whack, and the air pressure that hits our body from the drum. Ring occurs when the higher end of the range is louder than the lower end of the range, and a drum fails in its job to percuss if the low end is not as discernible as the high end.
High frequency sounds occur on a drum head near the hoop, and the further towards the center of the drum head, the lower the tone will be produced.
By placing sound dampeners near the edge of the drum head you mute the high frequency vibrations. Modern drum head tech allows you to choose a drum head that will either allow or reject the high frequency tones emitted from the drum head.
Where we can run into problems.
Out of round drum shells: If the diameter of a drum shell determines its general tonal frequency range, then an oval shaped drum shell will have two diameters simultaneously causing the drum to tune to two tones at the same time, which will create a harsh dissonant sound as the two tones fight against eachother. It is possible to tune up the lower frequency up so that both tones match, but it's tedious process and you need a good ear to nail the tone dead one. It's just so much easier to start with a round drum shell, or even a mostly round drum shell, and tune from there.
Out of round hoops: Drum hoops that place emphasis of pressure in one location but not in others while pushing down on a drum head will be very difficult to tune. It's possible to tune up the low side of a misshapen hoop until the low and the high become one tone, but you lose all of your low tuning range, it os simply much easier to start with a in round drum hoop and tune with as little or as much as you desire.
Out of round drum head: Like the hoop, the drum head collar must be excessively tuned on all sides until the tones match up, but you lose all the low frequency tuning range.
Thick drum heads and two ply drum heads: The thicker the material the longer it will vibrate. A thick drum head will sustain much longer than a thin or single ply head. If you tune such a head into a higher tonal range you will also be increasing the sustain of the high frequency as well, which will require ample damping, effectively killing all tone produce by the head. They are much more durable, but the trade off of high tuning a thick drum head is massive ringyness, or when damping will cause the cardboard box dead tone.
Round over bearing edges: Essentially bearing edges determine how much of your drum head is in contact with your drum shell, a round edge will promote whatever tone is fundamental to the drum shell. A thick maple shell and a metal shell will both produce a bright tone, so a rounded edge on either one with have more over tones. However a poplar shell with a rounded edge will promote very low tones
Sharp outer edge bearing edges: The sharp apex and minimal shell contact of a "California cut" ensures that most of the drum shell will not effect your drum tone, and the sound produced is primarily 95% from the drum head.
Some where between a round edge and a sharp edge will produce the perfect tone for your drum, depending on how much of the shell you want in contact, and how much natural damping you want built into the drum.
