Clay Vernon
www.ClayVernon.com

This paper was originally written January 14, 2002. It was often the first search result in Google for "Tuning Drums" until about 2006. I revised it in July 2010 as some of the writing was a little sloppy. One can see the original here.

Tuning Drums

Drum tuning is subjective. The same tom may be used equally well on a 4 piece jazz drumset as on an 8 piece hard rock set if it is tuned with heads suited to that particular application. But regardless of how the drum is intended to sound, the problem of not having a standard tuning method still exists.

This paper is divided into two small sections - (1) drum acoustics and (2) tuning method. The first is not necessary to read in order to tune properly, but I feel gives some important information on how membranophones make sound. The second section gives a method for tuning that can be applied to most modern percussion instruments, especially two headed drums.

Any instrument that uses a stretched membrane to produce sound is known as a membranophone. The head of a drum is its membrane. Because most drums have both a batter (top) head and a resonant (bottom) head they are more properly called bimembranophones. A kazoo is also a membranophone because of the small wax paper membrane that vibrates with the player's voice. The next section will not deal with kazoos because they are membranophones that do not require the user to tune the membrane.

Membranophones produce a more complex waveform than chordophones (stringed instruments) or aerophones (wind instruments). It is easy to imagine the air being moved back and forth two-hundred and twenty times per second when one plucks the A string on a guitar, but less simple to visualize the air being moved at the same frequency in a three-dimensional pattern off of a drumhead.

The main reason for this is that a vibrating string strongly resembles the graph of a sound wave. One can see even identify the relative amplitude and harmonic series of a vibrating string just by looking at it. But the best most can do to visualize a vibrating membranophone is to think of bouncing on a trampoline, as in figure 1.

Figure 1

Figure 2

These two figures shows two ways in which a drum head can vibrate. Just like chordophones and aerophones, harmonic frequencies occur here as well. Figure 1 shows what happens when a drum is hit in the exact center. Figure 2 shows what happens when a drum head is struck off-center.

In Figure 1, the fundamental "circular node" of the drum is activated. The energy is tranferred quickly, and there is no decernable tone. One will notice that Figure 2 has more of a "wave" to it. This is the fundamental wave of the drum head. A single "nodal diameter" exists; a single line that (passes lower-left to upper right in this example) does not move.

The more nodal diameters that exist, the more inhibited the membrane's ability to move air. Figure 1 moves a lot more air than figure 2, so that after a membrane is struck in its center it will quickly lose energy. Because Figure 2 is not moving air as efficiently as Figure 1, it will lose energy slower, decay slower and therefore it's responsible for the most musical frequencies of a drumhead heard after the initial attack.

Figure 3

As more tension is applied to a membrane more nodal diameters appear and the membrane's frequency rises. Figure 2 has a frequency 1.593 times that of figure 1. If more tension is applied one gets figure 3's frequency which is 2.135 times that of figure 1. The main tonal modes for a drum are the (1,1), (2,1), (3,1), (4,1) & (5,1) modes. It is not necessary to know this in order to properly tune a drum but it is interesting to know.

Tension is the factor that a drummer gets to control when he/she tunes a drum. The other factors that effect a drumhead's frequency are thickness and diameter. Both of which can be considered when buying or making a drumhead. The thicker a drumhead is, or the larger diameter it has, the lower its frequency will be. This is because when mass is added to a membrane it cannot resonate as quickly. So a 14" head with a thickness of x will have a higher frequency than a 14" head with a thickness of x+100 under the same tension.

Seating the drumhead is the first step in getting a drum tuned. Place the head on the drum and tighten the head to the point that there are no longer any wrinkles in the head. Next follow one of the star patterns bellow to get the head tight without putting too much tension on any one lug. You may hear some glue in the drumhead's rim cracking under the tension. A little cracking is fine, but you should move to the next lug before any major cracks occur.

6 lugs 8 lugs 10 lugs

At this point some people like to crank the drumhead fairly tight and then let it sit over night so that any residual cracks, and thus loosening of the head, will occur before the final tuning.

Dampening the center of the head and listening to the tone of the drum by tapping near each lug will reveal which specific lugs need to be tightened so that only one tone is produced regardless of where the drumhead is struck. Once the head is seated properly, the fine-tuning can occur. Any drum shell will resonate best at some specific frequency. Drum Workshop is the only major manufacturer that currently tunes & marks the drums they sell with the shell's most resonant frequency, but all drum shells resonate best at some frequency. The trick to getting a good drum tone is finding that frequency. Most drummers start with a loose head and tighten it to a point where the drum really sings.

Don't choke! Drums will lose their resonance quicker once their head is tightened beyond their most resonant frequency. If this sort of choking becomes noticeable then loosen the drumhead below the most resonant frequency before snugging it back up. Using this method the lugs will remain tight after you start pounding the drumhead in performance.

This method applies to both the top and bottom heads of a drum. Tuning the bottom head should come first because it is the resonant head that will vibrate in sync with the rest of the drum. Once it is tuned correctly getting a good final tuning on the batter (top) head is easier.

Once a drum is tuned its most resonant frequency there are other things to consider. The most important is "what sort of application the drum will be used in?" Some rock drummers may not like a super resonant tone. In that case muffling is obviously one choice. Another choice is tuning the batter head differently from the rest of the drum. A tighter batter head will produce a frequency that will dip down to the frequency of the less taunt resonant head. A loose batter head will tend to be choked off by the resonant head.

Lastly, both the top and bottom heads can be tuned away from the most resonant frequency of the drum but maintain their relationship to each other. So in this way drums are truly tunable instruments and not really as atonal as they are usually thought of being. If one were to tune a set of drums for use with a concert band the key of Eb might be a good choice because it is a popular key for bands. Perhaps most of the drums could be tuned to Eb and Bb so that songs in Bb had complimentary percussion tunings. But do I tune my drums to a specific key? No. The reason is simple; even if all drums are tuned to a specific key and at their most resonant frequencies, they are still a very transient instrument, and an ensemble will cover up most of their tone, excluding the initial attack. But the option is available. Tuning drums truly is a matter of application and personal choice, but hopefully this short primer will help percussionists provide insightful and stimulating answers to the question of "how did you tune that?"

Becka, Kevin. Advanced Drum Tuning. http://homerecording.about.com/library/weekly/aa081997.htm

Carson, Rob. Drumhead Tuning Tips from Remo. http://www.americandrumschool.com/tuning.html

Mills, Steve. The Art of Drum Tuning. http://people.mn.mediaone.net/sjmills/drum-tuning.html

Russell, Dan. Vibrational Modes of a Circular Membrane. http://www.gmi.edu/~drussell/Demos/MembraneCircle/Circle.html