To explain why Sonor favors heavier, more solid drumshells, even in its lighter models, it is easiest to quote Oliver Linknot from anything that was said during our interview, but from what he says in The Drummer's Drum. Research has been carried out at the German Federal Institute of Physics into "how the materials, form and size of a drum interrelate and affect the sound quality of the instrument." It was found that the drumshell doesn't contribute to the sound of the drums. It should be passive. It is the volume of air contained within the shell that reacts with the vibration of the heads to produce the sound. Oliver's conclusions are as follows: "The shell must not vibrate, in order not to deprive vibration energy of the drumhead by its own vibration. The shell must have a high flectional resistance; the higher the flectional resistance, the less chance of the shell producing its own vibrations. The shell must have a great mass, thus making the decay of the drum sound to a large extent independent from the way it is fixed to holders or stands. Furthermore it favors an efficient projection of the fundamental tone." So a drumshell shouldn't vibrate, but once free of vibrations, the thickness of the shell can still affect the sound of the drum. According to Oliver, "The basic frequency will be more muffled when the shell has a thin wall, so that the upper frequencies emerge. The sound seems to be more brilliant and sustaining. Shells with thicker walls and equipped with the same type of heads have the same spectrum of overtones as thin shells. However, the projection of the fundamental tone is better. The sound seems softer and fuller."
According to Horst Link, "The sound of a drum comes only from the heads; the shell only gives the volume of the resonance space. The shell shouldn't take away any vibrations from the reaction of the heads to the space inside the shell. If the shell vibrates, it takes power from this process. The sound of a drum will improve as you put more on a shell-even with weights; you could cover a shell in concrete; it cannot be heavy enough for the ideal projection of the head sound. This is with regard to the basic tone of the head. But we do make tighter drums. This is because the overtones can be an important consideration in the overall impression of the sound. Some people want to hear some overtones, so with the Sonorlite, you get a reduced basic tone with more overtones. It is a livelier, more colorful sound."
Steve Gardner said, "The whole idea of vibrating shells was in somebody's mind. Research wasn't done to see whether a vibrating shell really did give you a better sound. Even this company used to advertise shells as being 'full vibrating,' and it wasn't until somebody said to them 'Hang on a minute. It's only when you stop the shells from vibrating that you put the energy into the head,' that they changed. If you have a vibrating shell, you are taking energy away from the heads, so you lose volume-and more importantly, you lose tunability. You lose the potential of tuning a certain size of drum to its optimum highest pitch or its optimum lowest pitch; you are stuck with this thing that most drums of the '60s had, where you had a set sound that you couldn't get away from. I think that a lot of companies have been having trouble with their power toms. Again, it's all in the mind. Someone has an idea, and goes to the drum company, and says, 'I want a tom-tom this deep.' So the company makes it without doing any research into the way it sounds. Very often, the sound that comes off the bottom head on a power drum is nothing like what drummers think they're getting when they hit the batter head. This company has not only taken note of the research done by the Federal Institute, but it does its own research. If the basic tone of a deep drum is going to be ruined by overtones, Sonor will beef up the shell to counteract it, because Sonor cares about the way its drums sound. As percussion manufacturers, the people at Sonor know that, with a chime bar for instance, it isn't only the note that the bar itself is tuned to that matters, but it is the proportions and material of the sound chamber underneath it which have to project the note accurately. Otherwise, it will sound wrong. All these things are researched and carefully worked out. The same methods are applied in designing drums. The research that has been done, and is still being done, at the Federal Institute wasn't commissioned by Sonor. It is available to everyone, but nobody else has taken it up!"
Oliver Link continued, "We don't want to have a situation where we are telling people that they have to use heavier shells, because it is always the better sound. The reason why we offer so many different shell sizes and combinations of thicknesses is that we want to give the drummer the largest possible choice of sound. Some people want the livelier sound, so we give it to them."
"There is another very important point," Horst Link added, "and that is the bearing edge on the shell. The point at which the head touches the shell is crucial to the sound. It must be absolutely straight, of course, and narrow with as small an amount of shell material touching the head as possible. The type of material used to make the shell is important at this point, too. The difference in sound from shells made of different materials comes mainly from the edge: The harder the edge is, the crisper the sound. So you get a crisp sound from a drum with a metal shell, but you won't get one from a drum made with a soft material. Our drums have got hard, thick shells, but we make sure that the bearing edges are narrow. They are cut at 45 degrees inside and out. Also our shells are slightly smaller than the hoops on the heads, so that the heads 'float,' which means that there is no clogging up of the sound with the hoop rubbing against the shell."
According to Andreas Link, "We used to make thin shells with reinforcing rings top and bottom, but we realize now that there needs to be a free passage of air between the heads on the inside of the shell, and anything close to the heads only serves to block off the sound." Horst Link agrees. "Yes. This point close to the head is where the vibration starts, and if you put an obstacle in the way right next to the head like that . . . ." Andreas Link concluded, "It's the worst thing you can do."
