LEARNING Audio EQUIPMENT

Shells


Comparing Different Materials

So far in this column, we’ve discussed drumsticks and counterhoops. Now it’s time to dig in and take a look at what we consider to be the heart and soul of every drum—the shell. The shell is the main part of any drum and is really where the sound starts once you hit the head. Whether it’s a wood shell that’s been glued in plies or a metal shell cast in a mold, everything that goes into making a shell has an effect on the sound the drum produces. To answer some questions concerning shells, DB reached out to two specialists in the boutique drum business, Matty Longo of Longo Custom Drums and Curt Waltrip of Joyful Noise Drum Company.

Before we get to specific commentary from Longo and Waltrip, let’s first take a look at the many different materials used to make a shell and the tones that are associated with each. Below is a list of the most common (and some not-so-common) woods, metals, and synthetics used to manufacture drum shells, along with their basic sonic properties.

Wood Types

Maple: Even amount of highs and mids, slightly warm lows. All-purpose.

Birch: Boosted high frequencies, slightly reduced midrange, good low-end punch. Loud and cutting.

Mahogany: Muted highs, smooth midrange, warm/rich low end. Vibrant and resonant.

Walnut: Equal amount of highs, mids, and lows. Big and warm.

Oak: Soft highs, good amount of midrange, slightly warm lows. All-purpose with fairly quick decay.

Beech: Pronounced highs and mids, good low-end punch. Sensitive and focused.

Cherry: Boosted highs, punchy midrange, average low end. Bright and sensitive.

Bubinga: Even amount of highs and mids, rich low end. Sensitive and punchy.

Poplar: Soft highs and mids, boosted low-end warmth. Smooth and eve.

Ash: Pronounced, warm highs and mids, average low end. Throaty and warm.

Exotic woods have been used to make drums for many years. Matty Longo likes to use purpleheart. “It’s a great all-around wood,” he says. “It’s extremely sensitive, with lots of punchy low/mids and excellent presence and cut. The particular lot we’ve been using is at least twenty-five years old and is air-dried.” Curt Waltrip is using some old-growth wood. “Joyful Noise uses reclaimed, submerged old-growth timbers from the Great Lakes as well as wood from Central America for our steam-bent snares and drumsets,” he explains. “Some of the reclaimed, submerged hardwoods we use are flamed red and yellow birch, bird’s-eye maple, quilted maple, blistered maple, and Honduran mahogany.”

The bottom line with wood shells is that with more than 3,300 species of timber out in the wild, the potential for new sounds is almost limitless. Each type of wood produces its own unique sound when molded into a cylinder and made into a drum shell, so it’s best to consider which style of music you play and which type of sound will be the best match. Then zero in on a few specific wood types using the basic characteristics outlined above.

Metals

Steel (carbon): Clear highs, average midrange and low end. All-purpose.

Brass: Open highs, mids, and lows. Musically warm and vibrant.

Aluminum: Crisp highs, warm/open midrange and low end. Colorful and sensitive.

Copper: Muted highs, pronounced midrange and low end. Loud and powerful.

Bronze: Muted highs, powerful midrange and low end. Warm and responsive.

Titanium: Clear highs and mids, boxy low end. Clear and focused.

As with wood types, a seemingly limitless number of metal alloys are available to drum manufacturers. So again, consider your musical and playing style, and use the basic sonic properties of the more common metals to help you decide which alloy would be the best match.

Synthetics

Carbon fiber: Even amount of highs and mids, slightly warm low end. Controlled and dry.

Acrylic: Warm highs, mids, and low end. Powerful attack and presence.

Fiberglass: Even amount of highs, mids, and lows. Controlled and focused.

Synthetics have been used for drum shells for around thirty years, but they haven’t been explored as much as metals and woods. Drums made from synthetic materials generally produce more clean and focused sounds than their wood or metal counterparts, and some are surprisingly versatile. Don’t overlook them as you’re finding your sounds of choice.

Hybrid Shells

A shell that combines wood and acrylic or metal and wood is known in the current market as a hybrid shell. These combinations of materials will produce distinctive sounds, but are they really usable for drum shells? “Just because you combine two unique sonic qualities in materials, that doesn’t mean they will add up well,” Waltrip says. Indeed, some combinations work better than others, and how the hybrid shell is constructed plays a crucial role in the outcome. As Longo explains, “Doing a hybrid ply or stave shell makes a lot of sense because the wood will run the entire length of the drum’s depth. Therefore it’ll have good energy transfer. But when you put a seam in the shell, it’ll impede the shell’s ability to transfer energy.”

The lesson here is that a blind combination of different materials doesn’t necessarily mean the resultant sound will make musical sense. Be mindful of the types of hybrid shells you choose. Make sure the overall tone is true, clear, and musically viable.

Shell Construction

Drum shells are made in many different ways. Let’s use the same outline as we did in the materials section to see how shell construction affects the sound a drum will produce.


WOOD

Plywood: Long sustain with plenty of volume and varying fundamental pitch

Stave: Short sustain and higher fundamental pitch

Steam-bent: Vibrant with long sustain and true fundamental pitch

Solid: Long sustain and higher fundamental pitch

Segment: Short sustain and higher and more focused fundamental pitch


METAL

Cast: Long sustain and higher fundamental pitch

Spun: Vibrant with long sustain and true fundamental pitch

In addition to the ways different materials and construction options affect the sound a drum shell can produce, the thickness of the shell also has bearing on a drum’s overall tone. According to Longo, “The thinner the shell, the lower the fundamental tone. The thicker the shell, the higher the fundamental tone.”

And then there are reinforcement hoops, which many wood models have on the top and bottom of the shell interior. The main purpose of reinforcement hoops is to add strength and stability to the wood, helping thinner shells maintain their true roundness. As drum shell manufacturing has become more technologically advanced, though, the need for reinforcement hoops has less practical use and is employed mostly for tonal effect. “Reinforcement hoops are critical in the tonal character of a drum,” Waltrip says. “The thicker the reinforcement hoop, the more focused or controlled the shell resonance.”

Bearing Edges

Many drummers don’t think about the edges of drum shells in terms of their impact on sound, but they can actually change the timbre quite dramatically. Therefore it’s a good idea to have a handle on different bearing-edge options and how they’ll affect the sound, in order to choose the most appropriate gear for your needs. Also, knowing the general history of how bearing edges have evolved over the last century can help you associate various drum design options with specific sounds and time periods in order to pinpoint exactly what you’re looking for.What You Need to Know About...Bearing Edges

Types of Bearing Edges
Bearing Edges

45-degree. This very common cut features a sharp 1-ply-thick edge that peaks close to the outside of the shell. Sharper bearing edges produce more attack and more sustain, which results in a generally more lively, “modern” sound. The added attack and sustain are due to less of the drumhead film being in contact with the shell.

A sharp 45-degree edge also produces considerably more harmonic overtones, which makes the drum sound brighter. These added overtones make tuning a bit more challenging, due to the shell’s increased sensitivity to minute changes in tension.

Dual 45-degree. This design differs from a standard 45-degree edge in that the peak is moved to the center of the shell and has equal 45-degree cuts made from the inner and outer sides. The difference in sound comes from where the drumhead film contacts the bearing edge. Rather than contacting the head at the collar, which is the part of the head that curves down toward the hoop, a dual edge will meet the head further toward the center, where the film is flat. This results in longer sustain and a wider tuning range.

Roundover. This type of bearing edge is rounded off at the peak, resulting in more head-to-shell contact. Roundover bearing edges were the standard cut until the trend shifted toward sharper edges in the 1980s. Still utilized on many jazz and vintage-style drums today, roundovers tend to provide sharp stick impact and a mellower and warmer overall sound.

A drum will generally sustain a bit less with this type of bearing edge. There are also fewer harmonic overtones present, making for a meatier sound that features more of the fundamental pitch. Think of Ringo Starr or Ian Paice, or even modern players like Glenn Kotche of Wilco or Patrick Hallahan of My Morning Jacket, for examples of a warm roundover drum sound.

Baseball Bat or Extreme Roundover. This type of fully rounded edge was developed by industry giant Johnny Craviotto and is typically used on larger drums. The edge produces the fewest overtones and a fat, punchy sound. While certainly not for every drummer or every musical situation, this style of edge can create some beautiful, vintage-type sounds. The Craviotto Drum Company describes the design by saying, “The baseball bat edge is the ideal choice for drummers looking to replicate the warm tom and resonant bass drum sounds associated with the 1960s. This edge speaks beautifully in mid to low tuning ranges.”

Hybrid. The concept of combining different edges on the batter and resonant sides of drums is a new development in manufacturing. A common pairing would be a roundover edge on the batter side and a standard or dual 45-degree edge on the resonant side. This combination is often used on snare drums to harness the advantages of both types of edges in the same instrument. Some manufacturers are also using this concept because they believe it can maximize the performance of different drum sizes. Pearl’s Reference series, for example, utilizes different bearing edges, shell composition, and thickness as the sizes of the drums increase.

Additional Construction Considerations

Other aspects of a drum’s design will interact with different styles of bearing edges. Though the wood that a drum shell is made of has the most direct impact on the overall sound, bearing edges introduce another important variable into the equation. Common species, like maple, birch, mahogany, and oak, have aural characteristics that we’re all familiar with, but they’re most often cut with sharp bearing edges. What if you combine a long-sustaining wood like maple with a 30-degree roundover edge? This is where you can really start to dig into your customers’ needs. Be sure to ask about their favorite kinds of music, as well as their musical goals, in order to zero in on an ideal sound.

Bearing edges are only one piece of the puzzle when choosing drums to fit certain applications. You’ll also want to consider factors like drum sizes, shell composition, ply configuration (horizontal, vertical, diagonal, etc.), hardware, mounting options, finish type (lacquer versus oil or wrap), and drumheads. Be prepared to experiment with a variety of options, and soon you’ll understand just how different types of bearing edges affect the sound of a drum.

As you can see, there are practically infinite tonal possibilities when you think about all the factors that go into making a drum shell. And that’s before you consider hoop types, drumhead models, snare wire options, bearing edge shapes, and tunings. But using what you’ve learned here—plus what we covered in our counterhoop discussion in the previous issue—you’ll be much better informed when narrowing down the options for the type of drum that will best suit your needs.

Modern Drummer Magazine