Virtually all cellos have them, yet they are mysterious creatures that lurk in the shadows, waiting for just the right weather (or phase of the moon?) to pounce on their unsuspecting prey — usually the night before an important concert or audition! They howl! They scratch! They drag cellists to unwanted pitches sharper or flatter than the desired target! These furry friends are full of mischief!
But in our enlightened age, we don’t want to eliminate wolves. We just want to tame them, and harness that mischievous energy for good! In fact, wolf tones are very powerful notes (i.e. frequency resonances) on an instrument. When these frequencies are played, they send the body of the instrument and bridge into such commotion that they knock the bow out of contact with the string, causing a repetitive gurgling sound, or worse.
After years of research by Cornell University cellist John Haines-Eitzen involving countless iterations of weighted clamps, physics experiments, and many hours of work on lathes and CNC machines, Saddle Rider Music has updated our “Wolf Rehabilitator Set” to include the following array of wolf-taming tools in a boxed set. If you have already purchased the set, please jump to the INSTRUCTIONS section below.
Wolf Rehabilitation Set for Cello
UPPER LEFT: Close up photo of three weighted “button” clamp combinations. Their patent pending design features fully interchangeable tops and bottoms, allowing incremental weights ranging from 4.7 to 7.3 grams. By balancing most of the weight towards to top of the string, these clamps control wolf tones more effectively than traditional “wolf eliminators.” The brass and two different types of stainless steel bottoms offer three choices for each of the three sizes of top (nine combinations in total). Attaching the buttons to the G or C string allow many frequency options to control wolf tones and manage an instrument’s tone and response.
UPPER RIGHT: Complete contents of the set. The set contains a patent pending safe installer for magnet-style wolf tone resonators, a magnetic wolf tone resonator with high quality wool pads, carefully selected for tone, 3 surgical stainless steel button tops with incremented weights, 3 button bottoms (bell brass, surgical stainless steel, knife-blade stainless steel — each with a different hardness to vary response and sound as desired)
LOWER LEFT AND RIGHT: Packaging, including a leather safety cover for the magnetic wolf tone resonator.
Please use caution when handling the magnetic resonator, and read all the safety instructions below before unwrapping it from the leather cover! These magnets are very strong, and can fly out of your hand with great force if you don’t hold them firmly! The Saddle Rider kit has a number of safety features including the thick leather magnet cover and the clear rubber bumper (for shipping and initial newbie handling). The patent pending installation spoon makes putting the magnet resonator into an instrument easy and safe, but be careful to follow steps below. REMEMBER: Please read through all the following steps before starting the process!
- Handle the magnets in a safe space, away from your cello and breakable objects to get a feeling for how strong they are. When you feel comfortable with them, take the clear rubber shipping bumper off — the installation spoon works better without that. You may need to use your fingernail to remove the thin layer of adhesive tape that held the bumper to the magnet.
- CAUTION! As strong as these magnets are with the felt or safety bumper, they’re much stronger without any barrier. When holding the upper and lower magnets close to one another, every fraction of an inch exponentially increases the force of attraction, so hold the two parts FIRMLY, and keep them 12 or more inches away from each other when not attached, felt-to-felt. The back ends (without felt) can slam together hard if not held firmly, and may chip. If you do accidentally connect the back ends, the attraction is very strong — you will need to pry them sideways to get them apart.
- To install: Put the cello on its back on a table or sofa, and insert the large magnet into the installation spoon, felt side up (after removing clear shipping bumper). Insert the spoon and magnet into the C-string side F-hole, and turn until the felt can be pressed securely against the inside of the top of the cello. With the interior felt placed securely against the inside of the cello, use your other hand (12 inches or more away from the interior magnet!) to place the small magnet, felt down, onto the top of the cello. While holding it firmly, slide it until the two magnets hold fast to each other, through the top of the cello. Position the magnets as desired for sound and wolf control. For sound adjusting tips, check out YouTube. There are many videos about the “Krentz Resonator” or other magnetic wolf suppressors, discussing adjustments which also apply to Saddle Rider brand magnetic resonators. Saddle Rider videos on the topic will be coming in the near future.
- CAUTION! If using a magnetic resonator with an old cello or any instrument that may have repaired cracks with cleats on the inside of the top, be sure to consult with a luthier before installing the magnets. Bumping the magnet into cleats can disengage the bottom from the top (see tip #5 below) or possibly even knock a cleat loose, if it isn’t glued well.
- In the unlikely event that the interior magnet does lose connection with the exterior one, turn the cello so that the interior magnet is resting against the inside of the instrument’s top. Reach under the inverted cello to place the felt side of the exterior magnet against the instrument’s top, as far as possible from the interior magnet. Then, slide the exterior magnet towards the interior magnet — the felt side of the interior magnet will flip into its correct position inside the cello for use or removal.
- TO REMOVE THE MAGNETIC RESONATOR: Place the cello on its back, as in step 3, and slide the exterior magnet until the edge is against the F-hole. Insert the installation tool and cup the interior magnet with it. While holding both the tool and the outer magnet firmly, one in each hand, slide the outer magnet 12 inches or more away from the inner magnet and remove it from the surface of the cello. Then remove the interior magnet from the F-hole using the installation tool.
Button Clamp Instructions
Using button clamps to rehabilitate wolf tones, or to center the bass tone and response of a cello, or to make other desired tonal adjustments, is an art as much as a science. A good starting point is to try one of the three clamps below the bridge on the G string at a point where plucking the string afterlength sounds at the same pitch (albeit in a higher octave) than the wolf tone. This will often (but not always) be the best position for wolf control. Putting a clamp on the C string instead of the G string can sometimes sound smoother — a generalist approach — while targeting a specific problematic frequency can sometimes work better on the G string. To every rule, there are lots of exceptions, and there is no shortcut to trying all 9 combinations (3 tops x 3 bottoms) in many of positions on the G and C string. Just move them around, follow your intuition, and see what works best! Don’t expect to put one clamp in one spot on one string and have it work perfectly forever. Weather changes, and you’ll get a sense of what works best depending on your instrument’s mood du jour. After getting the hang of it, the process takes seconds and requires very little thought. Experience will allow you to pick the right button combination just like a golfer grabs a sand wedge or a 5-iron depending on the task at hand. About half the time, I use no wolf rehabilitator on my cello, but when I need one, I’m glad to have a number of options to choose from!
And logic doesn’t always rule. For instance, you might think that the lightest possible clamp that effectively controls a wolf is always best. Not necessarily true! Sometimes, a 4.7 gram option will control a wolf just fine, but a 6 gram option may give your cello more power, especially when used on the C string! There are many variables, infinite variables, actually, and what works best is often not what one expects.
Here is a link to one of the best articles I’ve seen explaining Frequency Resonances, which cause wolf notes on a cello: https://community.sw.siemens.com/s/article/Natural-Frequency-and-Resonance
Check out the world’s most expensive wolf suppressor! A four million dollar sphere hanging like a pendulum in a skyscraper in Taipei: https://www.treehugger.com/watch-giant-tonne-ball-steel-absorb-force-typhoon-4857270
Below are two of the many physics experiments I used in designing the Saddle Rider Wolf Rehabilitators set:
Imagine stringing a rubber band between two nails and tuning it to “A=220 Hz.” Pluck it for a lovely twang which dissipates pretty quickly. Now, imagine pinching a one-gram fishing sinker onto the middle of the rubber band and plucking. What happens? Most peoples’ intuition tells them the weight will deaden the sound of the rubber band and shorten the duration of time it resonates when plucked. But that intuition is wrong! The pitch drops and but the rubber band resonates significantly longer and with greater amplitude. Now, imagine taking a pair of pliers and pinching a half-inch long piece of wire to the rubber band, and pinching the same fishing sinker to the end of the wire, so it’s suspended a half inch below the rubber band. What happens when you pluck the rubber band now? It stops resonating almost instantly! The reason? Because the fishing sinker forms a pendulum that swings opposite to the rubber band action, dampening the rubber band just like two sound waves, 180 degrees out-of-phase, cancel each other out.
By carefully designing the asymmetry of a button clamp wolf rehabilitator, it is possible to achieve the an effective balance between muting extreme frequency resonances or “wolf tones” (when the pendulum action kicks in), and enhancing the less extreme resonances (when the whole clamp, wire, resonating string assembly work together as one system), as in the case of normal, non-wolf, notes. To find the correct balance points for the wolf rehabilitator set, I started with symmetrical, oversized, button clamps and lathed them down in dozens of iterations until I found the optimum balance points for each top and bottom. The 4.7 to 7.3 gram incremented range of the Saddle Rider Wolf Rehabilitator set is what seems to be the sweet spot for most cellos, except for the occasional instrument that responds better to the included magnet-style resonator.
Another sample experiment:
Not long ago, a client sent me a Krentz Resonator that he was abandoning in favor of button-style wolf suppressors. During shipping, the plastic piston tube became disconnected from the main body of the magnet, offering a great opportunity to perform some experiments! Right off the bat, I noticed that the 3/4 inch primary Neodymium magnet and the 1/4 inch button (also a Neodymium magnet), sounded pretty decent on my cello – better, I thought, than a complete Krentz resonator that I had tried at an earlier time. To confirm my intuition about this, I re-attached the plastic tube/piston assembly, and compared. It did, indeed, mute the cello a little more than the magnets, without the tube, and didn’t seem to control wolf tones any better. This led to another question: How does the piston assembly sound, when suspended between two magnetic fields in reverse polarity — as the Krentz is constructed — compared to flipping the piston 180 degrees so it sticks to the tip magnet in a fixed position, and no longer is free to act like a piston? When I compared the two positions, I couldn’t hear a discernable difference. (i.e. the piston does operate as a mass, helping control wolf notes on some cellos and muting others, but the advertised “piston action” is undiscernible to my professional cellist’s ears).
Moving on to the next subject of inquiry, I investigated the felt pads on the magnet where, from a physics standpoint, most of the “piston” or “out-of-phase frequency modulation” (if I may coin a phrase) actually occurs. The felt pads, testing confirmed, really do make a significant difference to both the sound and the wolf controlling properties of the magnets. The Krentz design has centered in on some pretty well-functioning felt pads, as well as an overall mass in the ballpark of what my experiments showed worked best. It weighs 35 grams in total, which is a bit heavy, but still okay. I found a 25 gram total mass sounded better (i.e. a 3/4 inch base magnet and 1/4 inch top magnet, identical to the Krentz weight without the piston assembly), and controlled wolf tones just as well. Further, I found that a 35 gram magnet assembly (1 inch base magnet with the same 1/4 inch top magnet) sounded and performed virtually identically to the Krentz (also 35 grams), provided that the characteristics of the felt pads were the same. Using lighter magnets, surprisingly, didn’t necessarily lessen the tone filtration, and, less surprisingly, didn’t control wolf tones as well. Small changes to the thickness, hardness , and material of the pads solicited significant changes to the magnets’ performance, so experiments with those variables formed the bulk of my research into magnet resonators.
I found that magnetic resonators can definitely control wolves, as can button-style fixed-contact point wolf rehabilitators. The magnets are a more extreme approach, and less targeted to specific frequencies. Both methods require adjustment and experimentation to optimize an instrument’s tone and response. Some cellists like the way the magnets “firm up” or “focus” the bass register of an instrument. I found that using button-style clamps on a cello C-string can have a similar effect with less frequency filtration. In the end, it’s a very personal choice, and one that tends to change with the weather.