Stephen Fox



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The Benade NX Clarinet, Part II:  Development

Stephen Fox

The Benade NX clarinet, originally designed by the renowned acoustician Arthur Benade, will be familiar in name if not in detail to many clarinetists through articles in The Clarinet and demonstrations at the ICA conferences in 1994 and 2000.  More currently, instruments based on this design have begun to be heard in concerts and recordings.  This paper reports on recent progress on the work being carried out since 1998 by the present author aimed at examining the NX from a fresh perspective and developing it into an instrument suitable for series production and for use by musicians in the real world.  (The origins of the instrument and the work of Benade are reported on in Part I of this article.)


In 1998 it was suggested that the present writer contact Benade’s wife Virginia with a view to continuing work on the NX clarinet and bringing it to the next level of development.  Copies of Benade's design notes were obtained and the original NX clarinets (principally the Bb) examined and measured.  The first new generation NX was built in the summer of 1999.  A year of testing and everyday performing led to the recording of a CD of chamber music on this clarinet, following which the first customer instruments were delivered.  Progress to this point was presented in a lecture by the author at the ICA conference in Oklahoma in 2000.  Subsequent work has included the genesis of several clarinet models derived from the original NX or following its design principles in general terms. 

Essential features of the new NX clarinet

The goal of the NX-based instruments built by the writer is to make the essence of the NX - described at length in Part I - accessible and acceptable to players of traditional clarinets.

At the outset, a choice had to be made between using traditional materials and key shapes, or taking the opportunity to redesign the entire mechanism.  An additional possibility would be to use a synthetic body material.  At least for the present, the safe, traditional course has been chosen. 

The central challenge for the maker of a revised NX, one on which success of the entire enterprise rests, is to achieve a bore shape that gives acoustically equivalent results to the original, and furthermore to make it reproducible (at least by the normal standards of hand built instruments).  To this end the main features of the NX bore - cylindrical bore mouthpiece, main bore diameter of 14.65mm, “cavity” upper joint shape, very gradual conical expansion in the lower joint and wide-angle conical bell - have been incorporated into a smoother, more regular shape.

The mouthpieces used so far for the NX have a bore diameter of 15.1 to 15.2mm.  This, coincidentally but somewhat fortuitously, is the same bore as that used for so-called “English bore” clarinets (Boosey & Hawkes 1010 and derivatives).

Keywork:  “simple” and “AHB Replica” versions

A faithful copy of Benade’s original clarinets, with minor mechanical refinements and more professionally executed construction - here dubbed the “AHB Replica” model - is feasible, and a few such instruments have been built.  However, due to the complexity of the keywork (particularly in the register/Bb/trill key area), and certain inherent limitations in the design (see below), a clarinet like this is expected to be of interest primarily to those wishing to pay homage to the memory of Benade and his work.

For an instrument to be used for everyday performing, some simplifications and modifications are in order, at least in the opinion of the present writer and maker.  This leads to what can be called the “simple” model.

In this version, the register/Bb mechanism is separated from the trill keys and moved to the opposite side of the body (the same mechanism as used on the author's other clarinet models).  The trill keys are conventional, with no interconnection and with no separate B natural tone hole (although the second trill hole could, if repositioned and resized, be used to produce B natural rather than Bb, if desired).

The compromises inherent in the original Benade/Jameson left hand second finger mechanism were discussed in Part I of this article.  Briefly, the arrangement produces a decent if rather resistant upper register fork Bb for at least some players, but largely destroys the bridge key Bb fingering, and renders the alternate low Eb fingerings nonexistent.  Further experimentation has failed to solve this problem. 

To address this, in the “simple” NX version the normal Boehm system second finger hole and separate E/B hole are restored.  Attention is still paid to reducing total tone hole volume in this area, however, and the separate left hand Eb/Bb hole is still omitted.  The objections to the alternate Eb/Bb fingerings are thus removed, with no noticeable deterioration of general playing properties.

The low F tuning key is not normally included because it does not seem essential; however, it would be no problem to add such a key (to this or to any other clarinet) if desired.

The bell and lower bore

An unfortunate property of Benade's original NX design is that the altissimo G and surrounding notes do not seem to “lock” into place as well as with French clarinets, being sharper and less stable when conventional fingerings are used.  With familiarity one can learn to deal with this, but it is an obstacle for some players on first playing the instrument.  In order to rectify this, on the new NX clarinets the lower joint is extended, and the conical angle of the bell is reduced slightly.  The vent holes in the bell have also been eliminated.

These modifications also address the tendency on the original NX for the bell notes, particularly bottom E, to "jump out" more powerfully than the other notes of the scale.

Playing characteristics

Being perhaps too close to the NX for objectivity makes it wise to leave judgement of its quality to others.  A few specific comments can be made, however:

The almost parallel lower joint imparts focus and solidity especially to the bottom notes, similarly to a German bore clarinet.  The slight amount of lower joint expansion, however, seems to "open up" the response to a considerable degree.  Due partly perhaps to the greater efficiency of the bell, the tone appears to contain stronger overtones than conventional clarinets.  The result tone could be described as having the purity and focus of the German clarinet combined with the brilliance of the French clarinet. 

The strong tonal character results in a sound which at the same time projects very well through a large orchestra without the player needing to “push”, and blends nicely with a small chamber ensemble without being obtrusive.

Depending on the player’s expectations of resistance in the instrument and reed/mouthpiece setup, some adjustment in blowing style and voicing may be required.  It seems that the NX (in common with modern German bore clarinets) is most happy when played with a moderate strength reed; it will produce the kind of sound that we wish for without the necessity of overpowering the instrument with a hard reed.

A significant observation, which has made independently by a number of listeners and players of the NX, is that the tone of this clarinet is very “vocal”, as if the player were “singing” (figuratively speaking) through the instrument, much more than is the case with conventional clarinets.  Precisely what this means in physical terms is yet to be determined, but a plausible hypothesis would be that a greater degree of subconscious cooperation - more specifically, matching of acoustical impedance - between the instrument and the player’s vocal tract is both encouraged and required by the NX.  Players whose approach to tone production makes their vocal tracts too inflexible to allow sufficient adjustment would thus be the ones who have trouble getting good results from the NX.  This matter needs further investigation, however.

The stipulation of using the correct mouthpiece bore is crucial.  Attempting to play the NX with a conventional mouthpiece will lead to sharpness throughout most of the range (particularly on the throat tones), flatness on the high notes, and generally poor playing qualities. 

Since it is fairly simple to ream out any mouthpiece to the correct bore, and since similar mouthpieces made for English bore clarinets are available from several makers in the U.K., anyone seriously interested in giving the NX clarinet a fair trial would have no trouble acquiring a suitable mouthpiece.  Nevertheless, this requirement most likely erects an insuperable barrier to the NX ever reaching wide popularity, at least in North America; the practice of changing mouthpieces very frequently, and the inability or unwillingness of mouthpiece suppliers on this continent to offer ready-made cylindrical bore mouthpieces, will doom to marginal status any clarinet which does not use a “normal” French-pattern mouthpiece.

Derivative instruments

Subsequent to and in parallel with development of the NX clarinet as described above, the basic NX design elements of bore shape, bell shape and register/Bb key arrangement have been incorporated into a number of other clarinet models of various tonalities.

The Nexus clarinet is an adaptation of the NX to be used with a conventional mouthpiece.  The principal difference from the NX is the main bore size; it has what is probably the smallest bore of any Bb or A clarinet of the modern era, at 14.2mm.  The resulting clarinet has a character recognizably akin to that of the NX, with perhaps a slightly more incisive tone and somewhat more blowing resistance.

Scaling down the NX concept to clarinets in Eb and D has produced successful and popular instruments. 

A question that is sometimes asked is whether NX design ideas could be adapted to the basset horn and the alto and bass clarinets.  Since the larger clarinets (especially with extended range to bottom written C) need a strictly cylindrical bore, and since - with the exception of some poorly designed basset horns - they already incorporate a register/throat Bb mechanism with separate holes for each function, there seems to be nothing specific in the NX design that could be applicable to instruments of this type.


It needs to be made clear that, although the present writer is in the business of building and selling clarinets, the primary purpose of the NX project has been to assess the potential value to performers of the NX design as objectively as possible.  (The writer’s unwillingness to endorse an unequivocally glowing endorsement of the NX, posted elsewhere on the internet, has been disconcerting to one particular customer!)   The evidence of performing and recording, and the testimony of customers who have purchased NX clarinets, indicate that it is indeed a viable design, though the mouthpiece requirement is a significant obstacle.  The NX clarinet and its offspring are now at the point where they can be sent out into the world for the musical community to assess their value and significance in the evolution of the clarinet.