Taming wolf notes


Wolf notes are an unfortunate fact of life for cellists, but every year more products are released and new solutions are developed by cellists worldwide. In this article we interview players about their wolf note experiences and publish the results of an experiment with a range of suppressors, followed by a ‘how to’ section on the best way to fit and tune suppressors and how to create a free string resonator.Wolf notes full size

Just as each open string on the cello has its own basic mode of vibration when it is played, so too does the body of the cello. This fundamental mode of vibration in the cello’s body is responsible for the existence of the wolf note, and so the wolf note is an undesirable fact of life for every cellist. To gain an insight into the way different players cope with this problem, we asked some experienced players to share their wolf histories with us. (See below for photographs of the suppressors described in the text.)

Corinne Frost describes the wolf note on her John Lott cello as ‘appallingly bad’. She would prefer not to have to use any suppression but finds it necessary to moderate her wolf just enough so that she can play around it. She has tried a variety of devices in the past, but her current solution is to use two New Harmony suppressors of the lightest possible weight, one on the G string and one on the C. The wolf is worse at times of high humidity and so Corinne fits heavier suppressors when necessary, using just enough weight to make the wolf note manageable. She finds that, with care, she can move the suppressors up and down her Spirocore Tungsten bottom strings without de-tuning them and can fine-tune the suppressors according to the key she is playing in and will occasionally use the suppressors to move the wolf note out of harm’s way (e.g. between E and F). She also finds that slightly different effects can be achieved by rotating the suppressors on the string.

Shaped mute final

Adapted Tourte mute

Nicholas Jones has adapted his shaped Tourte mute to act as a temporary and/or easily adjustable wolf note suppressor (see photo below). His cello has several wolf notes, depending on the weather, and he finds them less troublesome in dry environments such as concert halls. Because Nicholas is determined never to sacrifice sound quality unnecessarily, he relies whenever possible on playing techniques to get around the wolf notes, including squeezing the lower bouts between his knees, stopping free strings to form resonators (see ‘How to’ section below) and rearranging his bowing in order to meet the wolf on a down bow, which offers more control for playing through the wolf note. Nick advises: ‘When testing a suppressor, be sure to assess not just its effect on the wolf note, but also on the general quality of your cello’s sound and response.’

Hannah Roberts also prefers to work around wolf notes. She writes: ‘I have a monstrous wolf note on F, which at its worst resembles a pneumatic drill but at other times is much less potent. I find the unpredictability of it challenging to work with, especially when recording. However, I do not like suppressors as I find they diminish the resonance and sympathetic overtones and I prefer to ‘work round’ the wolf, for example by channelling the balance of weight through the left hand through the centre of the pitch. Although it is often said that the best instruments have healthy wolf notes, I have definitely found that the wolf is worst on my cello when it is out of adjustment or open.’

‘I hate losing all that expensive quality,’ says Raphael Wallfisch on the subject of wolf note suppression and cello sound. Until recently he was using the Güth Wolftöter on his Gagliano cello but has just discovered the new ‘Wolf Tuner’ made by André Theunis. This light-weight (2.8g) solid silver suppressor slips over the string below the bridge like the New Harmony but has a centre of gravity very eccentric to the string and works very well for Raphael.

Adapted Tourte muteIn the past, Ben Davies used a modified round Tourte mute as a suppressor by wrapping rubber bands around the waist of the mute to widen it until it was slightly broader than the gap between the G and D strings; he then wedged it in place and tuned it to the wolf note, finding this easier to use than the traditional brass/rubber or New Harmony suppressors (see photo below). The disadvantage was that using a conventional mute then made the wolf note much worse. On his 17th century Dutch cello Ben avoids the use of suppressors, finding that a fast, narrow vibrato helps to combat the wolf, as does playing closer to the bridge.

After much experimentation, Sue Monks has found that combining a traditional brass/rubber suppressor with a lighter gauge of strings has solved virtually all her wolf note problems, except for the F# on the G string.

Wolf note Theory

The currently accepted explanation of the wolf note is that it is caused by the massive vibrations of the cello body associated with the cello’s simplest and most fundamental mode of vibration or resonance.

When we attempt to bow the cello at or near the note of this resonance (usually between E and G) we get feedback from the intense vibration of the cello body into the strings, disrupting the action of the bow on the string and causing the sound to die momentarily. However, as soon as the vibration dies down, the bow – which is still moving – re-activates the colossal vibration. This cycle of activation and disruption repeats several times per second, producing the oscillating ‘howling’ wolf note.

All wolf note suppressors aim to absorb vibrational energy at the critical frequency and this is why they work best when “tuned” to the wolf frequency. Sometimes the range of affected frequencies is quite broad and the suppressor can be tuned to protect one note or another (eg F or F#). Some playing techniques such as the free string resonator work in the same way, while the technique of squeezing the lower bouts changes the vibrational behaviour of the body of the cello so that it cannot disrupt the bowing action.

Suppressor Trial

John Heley kindly dedicated several hours over two days to help us chase and tame the moderate wolf note ranging between E and F# on his Rubio cello. Our aim was to test a range of devices for their effectiveness as wolf suppressors, while also noting the effect each had on the sound and response of John’s cello. Since each cello is unique, this report does not assess the relative merits of each suppressor, but simply reveals the way John’s cello responded to each device. The results were surprising and very rewarding, which proves the value of patient experimentation!

Status quo When he arrived, John was using a traditional rubber/brass suppressor on his C string which he would regularly adjust to move the wolf note, depending on the key of the piece played and the atmospheric conditions. John uses a very sculptural bow stroke, so the effect of his wolf was minimal using a legato bow. However, the wolf was difficult to control using short, off the string bow strokes which proved problematic, particularly in continuo playing.

Rezx This magnetic suppressor was very effective in quelling the wolf note when fitted at approximately 5 o’clock below the bass f hole but it also subdued the tonal response of John’s A string considerably – this was noticeable as soon as it was removed. The Rezx was admirably easy to fit and adjust which was very helpful in assessing its effectiveness.

Standard suppressor

Standard suppressor

Traditional rubber/brass model (6.5g) There was no negative impact on the tone of the upper register of John’s cello when this model was fitted to the G string and the wolf note was adequately contained. The outcome was better when this model was fitted on the G string rather than on the C string – an unusual outcome, as most cellos seem to respond best to a suppressor fitted on the C string.


New Harmony final

New Harmony

New Harmony (7g) When tuned to a slightly sharp G on the C string the result was dramatic. Instead of quelling the cello’s tone, this 7g device added power and response to the whole instrument, especially from E to F on the C string (almost to excess). John found that the overall response of the cello had improved, especially on the D string. When we tuned the device to F# on the C string, it encouraged an even silkier response on the D string.

New Harmony (11g) When fitted to the C string and tuned to G# this was less effective in suppressing the wolf than the 7g and had no beneficial effect on response. When tuned to F it suppressed the wolf better and also improved the D string response, but not as well as the 7g. Tuned to F# the 11g was not very effective on the wolf and created a good response on the A string but not on the C string.

New Harmony (5g) When fitted on the C string and tuned to E there was an excellent response on the C string (not as over-powerful as using the 7g) and the wolf was well suppressed. When tuned to F, the wolf was completely tamed and John was delighted with the response and tone of the cello in all registers. He described the sound as clearer and more even and the cello also responded well to a very light bow. John decided that he would like to keep the 5g New Harmony fitted to his cello, so the trial ended here. A few days later, John phoned to report that he was still very pleased with the result of our experiment.

Güth Wolftöter This was not as effective as the traditional suppressor and also subdued the cello’s sound to an even greater degree than the Rezx.

Wolf-suppressing techniques

The free string resonator is a very effective – if technically demanding – way to control a wolf note. When you stop the same note as the wolf on a free adjacent string, either one octave above or below the wolf note, the wolf is very successfully tamed.  Josephine Horder uses this technique often on her Panormo cello. In one extreme instance, having no finger available to stop the F on the C string to create a free string resonator, Josephine resorted to stopping it with her chin!

Tune suppressors between the bridge and tailpiece (Traditional, New Harmony, Lup-x and Wolf Tuner) We normally find that suppressors are more effective when fitted to the C string than to the G string. To find the optimal position for the suppressor, first try to identify the central note of your wolf. Experiment with different bow strokes and dynamics to identify the worst note and make a mental note of it. Then fit the suppressor onto the G or C string approximately 4cm below the bridge and bow the short length of string between the bridge and suppressor very close to the bridge, using a light bow pressure.

When you have identified the note this produces, move the suppressor until the bowed string note below the bridge matches the original wolf note (it will be several octaves above the actual wolf note in fact). If the bowed note is too low, move the device towards the bridge; if too high, slide it towards the tailpiece until you have matched the worst wolf note.

Finally, test the wolf note on your cello, also noting the tone and response of your cello across all four strings. A successful tuning will minimise the wolf note while also maintaining the quality of your cello’s sound.

Product details and extended interviews:

Standard suppressor

Standard Suppressor

This standard suppressor has a rubber core, surrounded by a thin metal tube which is held in place by a screw thread fitting and can be fitted to the string below the bridge and adjusted without loosening the string. Some are solid brass, others plated steel. Gewa produce a chrome/gold plated steel version. Supersensitive also produce their own model. In widest circulation are unbranded versions of this model in chrome plated steel or brass, which vary a little in weight and size but tend to have thicker metal tubes and thinner rubber cores than the Gewa. The Gewa model also has a larger string hole, so that it fits more loosely on the C and particularly the G string than the unbranded model. Weights vary from 5 – 6.5g

Lup-x suppressor

Lup-x suppressor

Lup-x  is a circular, solid brass weight in two halves which screw together around the string below the bridge. No rubber core, therefore no damping effect on the string. Standard model is 8g. Violorama will supply adapted versions of the Lup-x at 6g and 10g for a small added labour charge.

New Harmony final

New Harmony

New Harmony A range of solid brass cylinders with curved string grooves available in 3, 5, 7, 9, 11 and 13g.

 Güth Wolftöter

Güth Wolftöter

Güth Wolftöter A sprung, weighted device hung from the A and C strings below the bridge with the colour-indicator facing towards the A string. Available in different weights to match wolf note range: yellow (D-E) green (Eb to F) and blue (E to F#).

Wolf Tuner by André Theunis

Theunis wolf tuner

Wolf Tuner (2.8g) A curved solid silver U-section device which fits below the bridge. For a wolf on F or F# fit tuner on G string about 2cm below bridge and adjust as necessary. For a wolf on E, fit tuner on C string about 4cm below the bridge and adjust.



Rezx Magnet and steel device fitted via the f-hole, allowing easy positioning of extra mass in the area of greatest resonance on the plate during a wolf note. Very quick and easy to fit. Available from the manufacturer in Canada.


Krentz Wolf Note Eliminator

An innovative wolf note eliminator launched in November 2013 by its cellist designer, Dr Kevin Krentz, the Krentz Wolf Eliminator for Cello is a 35g cylindrical polycarbonate capsule about the size of a tube of lip salve, containing a system of highly charged neodymium and ferrous magnets which suspend a magnetic piston inside the capsule. When the cello is played, the magnetic piston oscillates and modulates the vibration of the wolf note without dampening the resonance of the cello.

Krentz eliminator

Krentz eliminator

This device is fitted inside the instrument via the bass sound hole and is held inside the cello front by a small but powerful circular magnet which sits on the outside of the cello below the bass sound hole. Our experiments have found that not only does the device prevent wolf notes with minimal dampening effect, but it can also improve the overall response of the cello.

The external magnet slides easily over the varnish surface, making it possible to experiment freely with wolf note elimination and tonal adjustment and also to ‘park’ the device near the bass corner if it is not needed. The Krentz Wolf Eliminator costs £105 plus £10 special delivery postage and can be ordered from us.  For more information, see http://krentzstringworks.wordpress.com/

Full length interviews:

Nicholas Trygstad, section principal, Hallé Orchestra.

‘I hate using wolf eliminators as I feel that they remove too much of the resonance and overtones. In the past on my Ben Ruth cello I coped through a variety of ways. I found that the most important factor was the quality of contact I had through my bow hold with the string. It was a fine balance between being assertive and sensitive to the cello’s needs. If I was too insensitive and overbearing, the cello would just refuse to co-operate and the wolf would ‘howl.’

The weather does seem to have a huge impact on both my cellos. Damp weather really favours the wolf and dry concert halls favour a more bright, ringing sound. If there is absolutely no way of reasoning the with the wolf I will try to play on a higher string. My wolf (usually on the F, although it does occasionally roam, often asserting itself most violently on an E when I have my mute on) is always at its worst when on the G, rather than the D string. I have had mild success with squeezing the cello between my knees, and if I have to hold a long, sustained note that has a wolf it I will occasionally resort to stopping the octave above or below with my left hand. This kills the overtones but at least spares us the sound of machine gun fire in a magical pianissimo.

I also agree with Hannah that the wolf is usually kept at bay by maintaining the instrument. My Testore had a terrible wolf before I had it restored, but there is almost no wolf now that it is no longer full of open cracks and the arching has been restored.’

James Barralet

‘The wolf note is the natural vibrating frequency of the cello body and it plagues all instruments, regardless of age or value. It is commonly experienced between the notes E flat and F sharp on the G and C strings and also on the D string.

The wolf note on my cello is significant enough for me to try to find a way to reduce it. It is not a screaming machine-gun like you hear on many cellos, but it does make the tone unfocussed, noticeably louder and unpleasant. The wolf is a fickle thing and its intensity, and even the note which it affects, varies depending on a vast range of factors – weather, humidity, temperature, the room in which I am playing, whether the cello has been played a lot recently or not so much, whether there is a mute on the bridge etc etc. This makes it very difficult to find a reliable solution to the wolf problem. I have tried a number of the products available:

The internal resonator – I found this effective at practically eliminating the wolf but it does affect the quality of the sound across the whole cello range, slightly muting it. For me, this was too much of a compromise. (The same effect can be achieved my having a friend press a finger in the right place on the table of the cello. Cheaper but not always practical!)

The traditional metal/rubber device. Ok if you find the right place. After time, the rubber on the inside wears away. Come too close to the bridge and the sound of the whole cello is muted.

New Harmony. More effective than the traditional metal/rubber device in my experience. They come in a pack of varying weights and are easily moved/removed. You find which weights are most effective on your cello and then send back the rest. This is my current preferred solution. I like to have two – one on the C string, one on the G string, both tuning the strings on the other side of the bridge to the wolf note pitch in the hope that they will absorb some of the wolf. It is partially effective. Like the screw up one, come too close to the bridge and the sound of the whole cello is affected.

Other solutions: Adjust the tailpiece so that the strings on the other side of the bridge are tuned to your wolf note. This is actually a very good solution, but very difficult to do without the help of a luthier, and then the pitches on the other side of the bridge do not remain stable. We need a tuneable tailpiece!

One inexpensive solution is to grip the cello harder between the knees when playing your wolf. This disallows the cello body to vibrate as much and mutes the wolf. Another inexpensive solution is simply to know where your wolf is and make allowances for it with your bowing!! Yet another equally inexpensive solution is to stop an adjacent string to the wolf note pitch (or an octave below). eg if you have a wolf on note F on your G string, stop the lower F on your C string while playing the higher F. The C string will absorb the extra frequencies and virtually eliminates the wolf. This is however, rarely a practical solution.

I’m looking forward to the invention of the tuneable tailpiece!’

Hannah Roberts:

‘I have a monstrous wolf note on F, particularly impressive in fourth position on the G string! It varies in it’s intensity, partly depending on factors such as the state of the set-up/adjustment of the ‘cello, whether it is open (in need of gluing), and the type of approach I’m using with the bow and left hand weight. It could be described when at its worst as resembling a pneumatic drill and has been experienced through the ceiling by my husband when he was working in the room below my practice room! At other times it is much less potent, but I find the unpredictability of it awkward and challenging to work with, especially when recording.

I don’t like suppressors, as I find that they diminish other resonances/sympathetic overtones, and prefer to ‘work round’ the wolf. Squeezing the lower bouts with knees can work well, as can being a bit firmer with bow contact. I sometimes liken the wolf to a tiger- if you tickle it it will surely bite you! I also find that the balance of weight through the left hand, channelling it in a centred way through the centre of the pitch helps control/contain the wolf. A fast, lightweight use of the bow elicits more wolf in my experience. And although it is often said that the best instruments all have healthy wolf notes, I have definitely found that the wolf is worst on my ‘cello when it is ‘out of adjustment’ or open.’

Ben Davies used traditional brass/rubber eliminators for some years, but found them awkward to adjust when he wanted to change the position of the wolf. He adapted a Tourte mute as a suppressor by wrapping rubber bands around the waist of the mute to widen it until it is slightly broader than the gap between the G and C strings; he then wedged it in place, tuned to the wolf note, and he found it an effective and easily adjustable eliminator, easier to use than the traditional screw or New Harmony suppressors. Both the weight of the mute on the strings and the slight stretching of the strings by the tightly wedged mute seem to act to suppress the wolf. The disadvantage of this method was that the mute could not be used conventionally and if he did use a separate mute, the wolf became a lot worse. On his 17th century Dutch cello by Cornelius Kleynman, Ben avoids suppressors completely, finding that a fast, narrow vibrato helps to combat the wolf note, as does playing closer to the bridge and bowing in a more focussed way with the bow, using tension in the bow to push the wolf back into the cello.

Corinne Frost

Corinne describes the wolf note on her cello as ‘appallingly bad’. She would prefer not to have to use any wolf suppression but finds it necessary to moderate her wolf just enough so that she can play around it. She found that a resonator dampened the response of the whole cello and she has also experimented with wedging a wine cork under the tailpiece, trying different positions until the wolf was suppressed. She has also used a traditional eliminator, finding that on some days it was advantageous to fit it with the screw facing downwards.

Her current solution is to use two Harmony eliminators of the lightest possible weight on the G and C, moving them according to the weather and the key of the piece being played. She also sometimes turns the Harmony eliminators upside down for a slightly different effect. Corinne is able to move the Harmony eliminators without un-tuning the string, using both hands very carefully on Spirocore Tungsten bottom strings. ‘In some situations I would recommend using an eliminator just to move the wolf out of the way – for example onto a pitch between E and F which isn’t going to bother you!’ Depending on the time of year, Corinne is able to use a lighter weight of eliminator; generally the wolf is worst at times of high humidity.

As she uses mimimal suppression, Corinne also has to work around the wolf. ‘Using a strong left hand can make a difference, and if the weight of one finger is not enough, put two fingers down right next to each other and this will help keep wolf down.’ She is also very careful to maintain an even bow speed, moving the bow slightly nearer to the bridge on a wolf note to stop the wolf kicking in. She also advises a relaxed body: ‘if you are tense, you will lift shoulders, breathe badly and then the wolf will be worse.’

© Sarah Mnatzaganian and Robin Aitchison 2011

Wolf Notes and How to Tame Them (2005 article)

The most common haunt for the seriously inconvenient wolf note is 4th position on the G string, somewhere between E and G. A more ferocious manifestation of this wolf note will appear at the same pitch high on the C string and a milder version may dog you in first position on the D string. If you’re really unlucky, a ghostly wolf can also appear in 4th position on the A string.

Changing the set up of your instrument could be one way to resolve or reduce a wolf note. Generally, the harder the instrument is set up (perhaps with an inappropriately set sound post, a rigid bridge design, a high bridge or high tension strings) the more ‘wolfy’ it will become. Sensitive adjustments to the sound post or bridge can help to minimise a wolf note problem on some instruments without sacrificing the tone and response you are seeking from your cello.

An alternative solution is to fit a wolf note suppressor or resonator to your cello. It is well known that suppressing wolf notes can lead to a reduction in resonance across the whole range of the instrument. However, each cello and cellist is unique and the use of resonators or suppressors is a good solution for many cellists.

We are all familiar with the traditional wolf note suppressor – a rubber tube encircled with brass and tightened onto the string with a small screw – which is fitted to the G or C string between the bridge and tailpiece. To find the optimal position for the suppressor, bow the string between the bridge and suppressor and move the suppressor until the pitch of the string below the bridge matches the pitch of the original wolf note (or its harmonic).

A more subtle answer to wolf note elimination has recently arrived on the scene in the form of the New Harmony range of wolf note suppressors. These are little cylinders of solid brass which fit onto the string by means of a curved groove on one side. The absence of rubber in the design means that there is far less of a dampening effect on the string; the other major advantage is that the suppressors come in a range of weights, (3, 5, 7, 9, 11 and 13 grammes) which allows you to select the lightest weight necessary to control the wolf note, thus minimising undesirable side-effects.

To fit the New Harmony suppressor, just loosen the G or C string and fit the suppressor onto the string between bridge and tailpiece and re-tune the string. Find the optimal position for the suppressor as described above for fitting traditional suppressors.

As an alternative to the on-string suppressor, you could try fitting a Resonator – a small, sprung mass – to your cello front. If you are lucky, you will find a position for the resonator (usually below the f hole on the bass side) which will dramatically reduce the wolf note. The resonator can be fixed to the outside of the cello with harmless putty but if you want to commit yourself long-term you can have the resonator glued to the inside of the cello front. The only drawback is that, once glued in, the resonator can only be removed when the front of your cello is taken off!

For some players, the cost of wolf note suppression is too high in terms of the loss of overall resonance and tone. Here are some tried and tested ways to accommodate wolf notes:

* Experiment with different strings or use a lower tension version of your current strings.

* Experiment with different bows; some bows will, as if by magic, play right through a wolf note as if it were not there.

* Use less bow hair tension.

* Bow more lightly on the wolf note.

* Modify your vibrato to control wolf notes.

* Squeeze the lower bouts with your knees to dampen the cello as you play a wolf note.

© Robin Aitchison and Sarah Mnatzaganian 2005. Published in News for Cellists Spring 2005