2021 Cello Wolf Rehabilitator Set

After several years of research including countless iterations of weighted clamps, physics experiments, and many hours of work on lathes and CNC machines, Saddle Rider Music introduces our “2021 Wolf Rehabilitator Set” which includes 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.

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)


Please read through all the following steps before using these wolf control accessories, And don’t forget to check out the interesting Physics Experiments and Research Notes at the bottom of this page!

  1. After removing the magnets from their leather cover, get to know them in a safe space, away from your cello and breakable objects to get a feeling for how they work. When you feel comfortable with them, you can optionally remove the clear rubber shipping bumper — the installation spoon works better without that.
  2. CAUTION! When holding the upper and lower magnets close to one another, every fraction of an inch 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 knock together hard if not held firmly. If you do accidentally connect the back ends, the attraction is very strong — you will need to pry them apart sideways.
  3. 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. 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 securely, 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 positioning magnetic wolf suppressors.
  4. 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 #5 below for reattaching the magnets) or cause other issues.
  5. 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. Holding the magnet top securely, gently place its felt side on the instrument’s top and slide it towards the interior magnet. The interior magnet will then flip into the correct position.
  6. 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 securely, 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 make other sound and response 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. An alternative approach is to start with a clamp as low as possible, right next to the string winding, and move it towards the bridge in small increments until you get the sound and response you prefer. Move the clamps around, try different top and bottom combinations, and see what works best! 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!

Research Notes:

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.