Understanding Resonant Heads

C.M. Jones

Well-known member
The resonant head represents a gear dimension that baffles some drummers . Questions such as "Should I use thin or thick resonant heads, single-ply or double-ply resonant heads, clear or coated resonant heads, and muted or unmuted resonant heads?" are quite common. Tuning resonant heads eludes many players as well. Below is a great one-page resource that addresses resonant heads clearly and concisely. I hope you find it helpful:

 

MrInsanePolack

Platinum Member
I've always operated under the concept that the batter gives you your note, the reso give the drum itself its tone, or body if you will. An old jazz guy taught me this long ago.

Crank it up for boing and tune it down for thud.
 

C.M. Jones

Well-known member
I've always operated under the concept that the batter gives you your note, the reso give the drum itself its tone, or body if you will. An old jazz guy taught me this long ago.

Crank it up for boing and tune it down for thud.
The article seems pretty consistent with my tom-reso experience over the years: With the reso tighter than the batter, the tonal bend is upward as the drum sustains and dies out, and with the opposite arrangement, it's downward. Of course, different heads can do different things on different shells tuned by different drummers. And if you add muffling, a whole lot can change. We'll be lost at sea if we board that ship. :)

I think the article is a good introduction to reso heads. I came across it today after a local newbie drummer asked me some reso questions. Rather than send him a lengthy email, I just forwarded the link instead, then thought maybe the forum could use it too.
 

GetAgrippa

Platinum Member
Great article C.M. I’d add with increasing mass of reso head it will take more sound energy to activate it so shouldn’t be as sensitive if playing low volume - adding a coating is still adding mass just different material so alters timbre . Just like wrapping wire around a bass guitar string (lowers pitch). More mass means when it does vibrate it will do so slower at a lower fundamental natural frequency than a thinner head-and because once the momentum of mass gets going it will oscillate longer-sustain. As you increase thickness or add tension it also increases stiffness-so determines pitch. A thicker piece of plastic sheet isn't as flexible as a thin-so it's easy to see a thinner head will oscillate and activate more easily-so we see it's "sensitive". I never tried a coated reso head-seems on a snare it would reduce sensitivity with friction-but that might actually be good (like brushes n coated head). I've always used clear thin resonant heads on snares-and ambassadors on toms. I bet a coated reso head on toms would sound great though-warm the tone/timber

One thing I keep thinking about is besides the sound wave bouncing in the acoustic chamber-where the inner layer circumference and material it is made will impact how the sound waves travel and interfactions of frequencies and pressure/sound waves bouncing back and forth between heads in chamber. I keep thinking when you strike the batter head the energy will travel across head into bearing edge and down shell to opposite bearing edge and reso head initiating it to oscillate 10x faster than the sound wave travels-so pre-activates the head. A steel shell is super stiff so energy will travel faster than wood which has viscoelastic properties. You can increase stiffness of wood making it thicker-so more like steel. But still the velocities will be different between wood and steel for the pre-sound activation of reso head. So does that initial reso head oscillation (in time of activation and phase of oscillation) influence the stiffness of head when the pressure/sound wave hits or is there phase interactions? It would only be initial phase of strike because after that it's just waves bouncing in chamber-but that initial attack of sound. With snares the energy in shell should travel to activate wires too before sound hits heads to interact with wires. Does that create stiffness or phase issues?
 
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C.M. Jones

Well-known member
With snares the energy in shell should travel to activate wires too before sound hits heads to interact with wires. Does that create stiffness or phase issues?
Tuning-wise, and hence tonally, I think the snare drum is a whole different ball game. Any purity of tone we can harness when the snare wires are disengaged is immediately altered (and arguably corrupted) when the wires are activated. The sharp snap arrests our ears, and the tone of the drum itself is competing with other frequencies. This effect is likely relative to the thickness of the snare-side head, the number of snare strands, and the tension of the wires, but it's a powerful element nevertheless.
 
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bongoman

Junior Member
I tune the reso heads on my toms a third or fourth lower than the batter on my mini bop kit, because the down-turning decay makes the toms sound deeper and bigger imo.

I use coated resos for warm controlled sound, and I do not perceive any loss of sensitivity at pianissimo levels.
 

Out of Round

Well-known member
I use coated resos too. I've even used clear over coated when I wanted that clear batter zing, but needed to keep the coated resos on for money and hassle reasons.
 

GetAgrippa

Platinum Member
I was thinking of trying one of the Remo ambassador Renaissance reso heads-it's thin but has a texture. I have a Pearl Steel Sensitone and damn it's loud and a bit abrasive. I'm thinking it's just a tad thicker 3 mil but it's texture so offer some resistance too. Maybe calm it down a bit and darker?
 

C.M. Jones

Well-known member
I was thinking of trying one of the Remo ambassador Renaissance reso heads-it's thin but has a texture. I have a Pearl Steel Sensitone and damn it's loud and a bit abrasive. I'm thinking it's just a tad thicker 3 mil but it's texture so offer some resistance too. Maybe calm it down a bit and darker?
The Renaissance Snare Side would probably darken it somewhat but might also make it boxier, meaning you'd lose some wire response. To calm a lively steel shell, I'd probably put a control ring on the batter. That would lower its tone and tame its ping. Steel lovers might hate that idea though. I'm a wood-only guy who goes for a pretty dry sound.
 

felonious69

Well-known member
What if I want the drum to sound like "Wahahoohahahaa"
You gotta use a Wahahoohahaha pedal.
I got one for sale if ya need!?!?!?
 

cbphoto

Gold Member
For years I’ve used Evans Clear Genera reso (10mil) on my toms. About five years ago I tried Evan clear Reso 7 (7mil) and they reduced resonance (faster decay) but also made the drums sound thin. I probably didn’t trial them long enough; they lasted only a couple weeks. My next set of reso heads will be clear G14 (over coated G14 batter) and I plan on exploring attenuation methods to control the resonance. The heavier heads make the bubinga toms punch harder.
 
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GetAgrippa

Platinum Member
You know this drum head article makes sense for heads-a thicker head once activated will have longer sustain. More mass vibrating has more momentum to last but with mass it will vibrate at a lower fundamental frequency. You can hear the difference from mass effect on drum shell fundamental in videos whacking it-adding mass lower fundamental (watched Andy do it)-add mass on outer shell and it lowers fundamental more with more mass. But the drum shell thickness it's like opposite- thinner shells have more sustain. and lower tone. You would think increasing thickness like adding mass to a shell would make it have more sustain, once the larger mass in motion, and a lower frequency/pitch fundamental. But that's the sound pitch fundamental of the shell and it's the air sound and then how does thickness influence that final sound.

But It makes sense a thinner shell activates more easily but that mass vibrating should have less sustain and a higher fundamental if a mass effect. A thinner shell will have more internal air volume than a thicker shell so that alone will influence a lower tone. The volume differences has to be stiffness of material. Steel is louder than softer metals, woods are anisotropic so react different than metals. So we have material of same properties (wood) just thickness and it's louder and with slight decrease in air volume so a bit higher fundamental. Now the law of Laplace applies to how forces distributed across wall-so as increase diameter at even given pressure wave the tension/stresses on wall increase. If you increase thickness the stress on wall decreases. How stresses distribute is different-thinner shell force uniform but higher stress but as wall thickens stresses decrease overall but on inner circumference greater than out circumference. A drum shell due to bending straight wood into round should compress inner layer I"d imagine so it naturally has stress-then a smaller diameter from a thicker shell would also put lots more stress on innermost layer- though more mass will increase it's fundamental it should also stiffen and tense the wood making a better funnel for energy transfer and more volume and at higher pitched because difference is air volume.

So now sustain-that has to be how the wood dampens or supports the bouncing air volume within the drum. The drum will be oscillating from strike and pressure wave traveling down an undulating tube to an undulating membrane and that pressure wave will bounce off and go back and forth -so longer more sustain. You could get into all kind of phase interactions but I don't think that's it. Since a thinner wall shell has more sustain-the wave bounces back and forth longer. Now the thinner wall has more air volume for lower pitch but more uniform in stresses and easier to activate so the pressure wave bouncing back and forth probably gets a small push from undulating walls -it acts like a Windkessel. A thicker shell will have more of sound wave energy reach head membrane so little energy loss in shell-its louder. The sound wave likely has less sustain because the energy dissipates bouncing back and forth faster in the stiffer tube. Though a thin shell has smaller mass and momentum for sustain but the stresses are more uniform (and higher stresses than a thinner shell) and the wall more easily excites and vibrate from an air pressure wave and undulating shell must phase to support each other for longer sustain. The thicker shell creates a stiff inner collar more energy goes straight to head-so louder but less undulating for any viscoelastic push. You know even light puts pressure/mechanical force on an object as I recollect.

Then we have different woods in different layers effect-so adding more anisotropic effects to shell. And seems like adding a softer wood to innermost layer is a big deal in effects-lower tone. So that most inside circumferential material does have a big effect and support my idea inner layer stiffness could be explanatory-that thickness increases stress and tension on internal wall to reduce wall movement (although total stress is reduced across wall)-if more wood absorbed sound thicker wouldn't be as loud -but it's louder-so seems the internal stiffness a big deal? The thinner wall takes higher stresses, oscillates easier, so will absorb some of energy going to head to reduce volume but the oscillations must phase with bouncing sound waves to add sustain. Now I claim no authority on this subject as a disclaimer I'm just sharing what I'm reading and how I interpret it.
 
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GetAgrippa

Platinum Member
Actually more I think about it the sustain isn’t a Windkessel. It’s much simpler. The force of strike travel down shell and tube, the pressure- wave force is really more compression in direction of grain. A thicker wall will have smaller air volume higher pitch, increase thickness is distributing forces over larger area but is stiff at internal surface- it funnels it down with all force going into head as loud but that strategy is at expense that pressure wave energy goes into head and will quickly dissipate in mass. The thinner shell has larger volume and easily activated with more stress per area going through shell to keep shell resonating so energy loss in shell so pressure-wave loses energy and volume , but the shell oscillates and sympathetic buzz in shell travels into heads as sustain.

I'd imagine it's not thickness that regulates sustain as wall tension. Just thin shells is an easy way to get it-but at expense of volume. I imagine you can get plenty of sustain from a thick wood shell-so a steam bent shell would likely have more sustain than a stave shell of same thickness because it's under tension?? I'd imagine you can get volume like using harder woods without thickness-it's just an easy way to get it. It's all in construction like Andy has been saying for years.

There is so much give and take in every aspect and decision made in a build. I'd think the thicker shell would have a low fundamental (warm and woody) but the drum itself in contrast be brighter (despite the mass) lots of attack (and you could make louder or softer wood choices) but a sustain would be warm and woody in the thicker shells? I don't have a stave kit or solid bent but I'd like to know. I'd imagine they could vary though per build dammit. Course I imagine just make a stave thinner to get the sustain would be a prediction?
 
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GetAgrippa

Platinum Member
Crap re-rings just thought of that. They are there for structure but they will impact sustain I'd bet. Hmmmm that's a tough one-my knee jerk reaction it will increase sustain. But really it depends on shell thickness and size and wood type of re-rings. No matter what I bet it dry out a drum-it prevents deformation, but I bet the sustain will depend on design and wood type of re-ring. So a thin shell is naturally resonate the re-ring might impede motion of shell response so it appears to lose sustain-I think by design and hardness of wood you could overcome that to make it a resonator to return sustain.
The thicker shell is harder to activate so doesn't have a natural sustain, but what energy that does flow it's a lower fundamental long waves travel farther and I think the re-ring stiffness would focus the energy into the re-ring to act like a resonator. The thinner is more tricky my bet because the sustain comes from the shell and the re-ring might impede motion so it would appear to sound like a loss of sustain-but I also think you could design a re-ring that would act like a resonator so sustain maintained and likely this is what generally happens? The dryness likely comes from frequency shift to higher frequency because stiffness and stress increased at that point of re-ring I'd deduce. So generally a re-ring would increase sustain I'd bet but exceptions to rule-and perhaps we can explain why.
 
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