RE: XB-40 in C: high notes squeaking?
- Subject: RE: XB-40 in C: high notes squeaking?
- From: "Laurent \(Planet Harmonica\)" <laurent@xxxxxxxxxxxxxxxxxxx>
- Date: Thu, 25 Sep 2003 14:03:28 +0200
Many thanks for this very quick and complete answer!
So for people who have not bought the XB-40 yet or would like to buy another
one, which key would you recommend?
>From what I've understood, A, Bb or G seem to be in the good tessitura?
> -----Message d'origine-----
> De : owner-harp-l@xxxxxxxxxx [mailto:owner-harp-l@xxxxxxxxxx]De la part
> de Rick Epping
> Envoye : mercredi 24 septembre 2003 22:30
> A : harp-l@xxxxxxxxxx
> Cc : Laurent Vigouroux
> Objet : RE: XB-40 in C: high notes squeaking?
> -----Original Message-----
> From: "Laurent Vigouroux" <laurent.vigouroux@xxxxxxxxxxx>
> To: "Harp-L" < >; "harponline Timler" mail@xxxxxxxxxxxxx
> Subject: Re: XB-40 in C: high notes squeaking?
> > Is it only a technique problem or can I do some tweaking (gapping?) to
> > improve the response?
> The range of notes easily obtainable on an XB-40 is determined at its
> upper limit by the resonant frequency of the highest chambers relative
> to the frequency of the reeds occupying those chambers. The smaller the
> air space within a reed chamber, the higher its resonant frequency will
> be and the higher pitched will be the reed that can be effectively
> played there. The chambers in the highest holes of the XB-40 have been
> designed as small as possible given the clearance requirements for the
> reeds and valves as well as the requirements of the injection molding
> process by which the comb is manufactured.
> Difficulty begins to arise when the resonant frequency of a reed exceeds
> that of its chamber and the lower frequency of the chamber begins to
> pull the oscillating frequency of the reed downward in a phenomenon
> known as mode locking or frequency pulling. The greater the disparity
> between the frequency of a reed and the lower frequency of its chamber,
> the more difficulty there will be in obtaining good performance. It's
> for this reason that the key range for the XB-40, like that of the
> chromatics, is set lower than that of the standard, single-reed
> diatonics (C/C# is the highest chromatic key while high G is the highest
> diatonic key). The highest reed in a Hohner Richter 10-hole model, the
> g4 reed from hole 10 of a high G harp, would play flat and with some
> difficulty if set over a 270 or 280 chromatic's highest chamber, which
> is larger and has a lower resonant frequency than that of the hole 10
> Richter chamber. The difficulty would be greater still were that same
> reed set over the highest chamber of an XB-40, which is actually a
> double chamber - the inner valve chamber combined with either the upper
> blow reed chamber or the lower draw reed chamber, depending on the
> direction of airflow. While hole 10 in the lower XB-40 keys plays
> easily, the notes in the highest keys, where the resonant frequency of
> the reeds is well above that of the hole 10 chamber, become increasingly
> Technique can to some extent minimize this problem. For high notes on
> harmonicas with small reed chambers, the player's tongue can be
> positioned both forward in the mouth to create a resonant frequency in
> the reed chamber/mouth cavity matching that of the reed being played or
> down and back in the mouth to avail of the higher partials of the full
> vocal tract. On the higher keys of the XB-40 however, the player might
> not be able to position the tongue forward enough to reach the resonant
> frequency of the reed being played, resulting in an unintentional bend
> or a choked note. If the tongue is instead positioned back in the mouth
> to create a fundamental resonant frequency one octave lower than that of
> the reed, the second partial of this larger mouth cavity will then match
> that of the reed and allow it to play. From this position the tongue
> can be shifted upward and forward for a bend. Using this technique, the
> notes in hole 10 on an XB-40 in the key of C are playable though still
> somewhat stiff.
> In short, while the notes in hole 10 on the lower keys are quite
> playable they are unavoidably less so for the key of C and progress
> effectively beyond the practical range in the highest keys of Db, D and
> Best regards,
> Rick Epping
> Hohner, Inc.
> Harp-l is sponsored by SPAH, http://www.spah.org
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