Method of constructing trumpet or other brass instrument

A method of constructing a trumpet or other brass instrument is disclosed wherein a zone of increased taper is formed on the cylindrical inner surface of the mouthpipe to provide an improved air column between the mouthpiece and valve sections of the instrument. The zone of increased taper is critically positioned along the length of the mouthpipe to coincide with the pressure maximum points of selected notes in the upper octave of the normal playing range of the instrument to yield a chromatic scale that is nominally true to desired pitch.

BACKGROUND OF THE INVENTION 
The present invention relates to a method of constructing brass instruments 
and more particularly to a method of forming the mouthpipe of a brass 
instrument to include a zone of increased taper which significantly 
improves the intonation of the entire upper octave of the instrument's 
normal playing range. (I.e., for purposes of this application, brass 
instruments comprise wind instruments having a cup mouthpiece and a 
cylindrical bore.) 
Although the origins of brass instruments have been traced back hundreds of 
years to man's primitive ancestors, the basic form of the modern valved 
trumpet derived in the early 1800's. Since that time, consistent efforts 
have been made to improve the harmonic or intonation qualities of the 
instrument. To date, most of these improvements have focused upon the 
configuration of the bell portion of the trumpet. 
In relation to the bell portion, it has been found that by flaring the open 
end of the trumpet to increase in diameter as the opened end is 
approached, the frequencies of the lower note resonances are shifted 
upward. Additionally, if the total length of the trumpet is properly 
adjusted for the particular bell shape, the higher note resonances will 
remain unchanged. Thus, with a properly shaped bell portion, the majority 
of note frequencies will be shifted into a form approximating a true 
harmonic series. 
Although these improvements have proven beneficial in their general 
application, there exists inherent limitations in their operation which 
must be constantly corrected during playing by the musician. In 
particular, it is well known that trumpets constructed of conventional 
design fail to provide a chromatic scale that is nominally true to desired 
pitch for the entire upper octave of the instrument. (I.e., from the D 
natural (D.sub.5) above the 4 partial C-natural (C.sub.5) to the A natural 
(A.sub.5) above.) Thus, with a conventional soprano trumpet in "C", the 
E.sub.5 (659 Hz) note is typically flat enough to be audibly detectable in 
many playing situations, whereas the F.sub.5, G.sub.5 (740 Hz) G 
sharp.sub.5 (831 Hz) and A.sub.5 (880 Hz) notes are all very sharp. 
Heretofore, to intonate these upper octave notes in proper pitch, the 
musician would be required to conscienciously correct these normally 
out-of-tune notes by either extending a valve slide and/or false fingering 
of the trumpet valves. 
Additionally, in the conventional trumpet design, the tuning slide is 
utilized to initially tune the instrument to desired pitch, being 
typically pulled outward away from the upper branch through a distance of 
3/8 to 3/4 of an inch in order for the musician to play at a pitch 
corresponding to A=440 Hz (standard orchestration pitch). This extension 
of the tuning slide locally increases the bore of the instrument both in 
the upper and lower branch which flattens certain notes (i.e., the D 
sharp.sub.5 and E.sub.5) on the chromatic scale as well as produces 
turbulence within the instrument. This turbulence adversely affects the 
playability or action of the instrument which must further be constantly 
compensated for by the musician. Thus, there exists a need in brass 
instruments for a construction which corrects the chromatic scale 
throughout the entire upper octave of the normal playing range without 
adversely affecting the action and total resonance of the instrument. 
SUMMARY OF THE PRESENT INVENTION 
The present invention provides a novel construction for trumpets and other 
brass instruments which results in an improved acoustical shape of the air 
column between the mouthpiece and valve section of the instrument. This 
improved acoustical shape comprises a zone of increased taper which is 
precisely located for each particular instrument along the length of the 
mouthpipe and merges smoothly with the main cylindrical bore of the 
instrument. The zone of increased taper coincides with the pressure 
maximum points of the standing waves of selected notes to correct the 
pitch of the notes propogated through the instrument. 
The improved instrument construction of the present invention specifically 
results in improved intonation (i.e., corrected pitch) in the chromatic 
scale from the D natural above the 4th partial (C natural) to the B 
natural and above without adversely altering the remaining playing range 
of the instrument. For example, when the construction of the present 
invention is employed on a soprano "C" trumpet, the 5th partial E natural 
is raised (as compared with conventional trumpet construction) to its 
proper pitch in the tempered scale and the 6th partial G natural is 
lowered (as compared with conventional construction) to its proper pitch. 
Further, the construction of the present invention also raises the 
normally flat E flat note immediately above the 5th partial and lowers the 
normally sharp G sharp and A natural above the 6th partial. As such, the 
present invention provides a brass instrument which is capable of 
intonating a chromatic scale that is nominally true to pitch for the 
entire upper octave of the instrument and thereby eliminates the need to 
consciously employ valve slide extensions and false fingering techniques 
heretofore required of musicians during playing of the instrument. 
Further, the present invention eliminates the manditory incorporation of a 
movable double branch tuning slide with tuning of the instrument being 
accomplished by the position of the mouthpipe. Moreover, the mouthpipe is 
constructed to merge smoothly with the main cylindrical bore of the 
instrument thereby eliminating the zone of locally increased bore 
attendant with the conventional trumpet's tuning slide design.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIG. 1, there is shown the upper and lower branch 1 and 3, 
respectively, of a conventional trumpet. The upper branch 1 is composed of 
a mouthpiece 5, mouthpiece receiver 7, mouthpiece (or leadpipe) 9, and a 
tuning slide receiver 11 which are connected in an end-to-end 
relationship. As is well known, a valve set (not shown) and valve 
extension (not shown) are additionally included to selectively vary the 
effective tubing length of the instrument. Typically, the tuning slide 
receiver 11 is rigidly connected at one end to the mouthpipe 9 (as by a 
solder joint) and slidingly receives at the other end one leg of a tuning 
slide 13 which interconnects the upper and lower branches 1 and 3, 
respectively. The lower branch 3 additionally includes a tuning slide 
receiver 15 which similarly receives the lower leg of the tuning slide 13. 
As will be recognized, by manually sliding the tuning slide 13 toward and 
away from the mouthpiece 5, the effective tubing length of the instrument 
may be varied to properly tune the instrument to a desired pitch. 
Additionally, the extension of the tuning slides forms an upper and lower 
zone of increased bore 17 and 19 on both the upper and lower branches 1 
and 3, respectively, of the instrument, which, as will be explained in 
more detail below, may adversely effect the intonation of the instrument. 
The mouthpiece 5 and mouthpipe 9 are both formed having a tapered or 
conical shaped inner wall 21 and 23 which has been found to yield a 
suitable air column for the intonation of a harmonic standing wave series. 
As is well known, an energy impulse may be created by expelling air under 
pressure through the mouthpiece 5 to produce a vibration. The mouthpiece 5 
and mouthpipe 9 as well as the remainder of the trumpet provides an 
open-ended air column which propogates the standing wave produced by the 
vibration. 
Referring to FIG. 3, the details of the standing wave produced within the 
instrument are illustrated schematically. At point A (corresponding to the 
throat of the mouthpiece 5 in FIG. 1), the expulsion of air by the 
musician generates a compression impulse which moves within the tube 22 of 
the trumpet from left to right. This compression impulse produces a 
displacement impulse D.sub.1 which additionally travels within the tube 22 
from left to right) in a sinusoidal wave configuration. Upon reaching the 
open end B of the air column (representing the bell portion (not shown) of 
the instrument), the displacement impulse D.sub.1 is reflected unchanged 
in the opposite direction (i.e., from right to left), producing a 
reflected displacement impulse D.sub.2. Since the displacement curves 
D.sub.1 and D.sub.2 are mirror images of one another, a standing 
longitudinal displacement wave is produced within the tube 22 of the 
instrument. 
As the displacement waves D.sub.1 and D.sub.2 travel within the tube 22, 
the air molecules of the air column are pulled apart and crowded together 
creating regions of lower and higher pressure, respectively. Thus, a pair 
of pressure waves P.sub.1 and P.sub.2 may be plotted within the air column 
corresponding to the displacement waves D.sub.1 and D.sub.2. 
As shown in FIG. 3, at the open end of the tube 22, the pressure initiates 
at a maximum value PM.sub.1 (i.e., the 1st pressure maximum point) and 
propogates as a sinusoidal wave P.sub.1 through the length of the air 
column having a 2nd pressure maximum point PM.sub.2, etc. Similarly, a 
second sinusoidal wave P.sub.2 propogates through the air column in a 
direction opposite P.sub.1 and following the reflected displacement curve 
D.sub.2. As shown, the pressure curves P.sub.1 and P.sub.2 are out of 
phase with the displacement curves D.sub.1 and D.sub.2 such that maximum 
pressure is developed at points PM.sub.1 and PM.sub.2 corresponding to 
minimum displacement within the tube 22. 
Although for illustration purposes FIG. 3 has been presented with a 
straight cylindrical tube air column configuratiion, the same principles 
apply to conical shaped air columns with the only exception being the 
elongation of the wave series as they expand in an increasing area air 
column. Thus, by propogating the standing wave in a conical shaped air 
column, the location of maximum pressure points PM.sub.1 and PM.sub.2, 
etc., along the air column may be longitudinally expanded or displaced 
along the length of the tube. A more complete discussion of the 
propogation of standing waves through brass instruments is presented in 
the ACOUSTICAL FOUNDATIONS OF MUSIC, 2nd edition, John Backus, 1977, W. W. 
Norton & Company, Inc., the disclosure of which is expressly incorporated 
herein by reference. 
As will be recognized, each note initiated by a musician into the 
mouthpiece 5 of the trumpet will generate a displacement and pressure 
curve series similar to that shown in FIG. 3 with each note having a 
different sinusoidal wave pattern and varying locations of their maximum 
pressure PM.sub.1 and PM.sub.2 and maximum displacement points along the 
air column. 
Based upon this physical relationship of standing waves in air columns, it 
has long been known that by locally increasing the bore (i.e., the 
diameter) of the air column at the location of a pressure maximum point of 
a particular note, the pitch of that particular note or any other note 
having a pressure maximum point at the same location will be lowered. 
Thus, during playing of the conventional trumpet of FIG. 1, the notes 
generated by the musician whose pressure maximum points are located in 
either of the zones of increased bore 17 and 19 will have their pitch 
lowered. In conventional "C" trumpet designs, the particular notes having 
their pressure maximum points PM.sub.2, etc., coincident with the zones of 
increased bore 17 and 19 are the D sharp 5 and E.sub.5 notes. As such, 
these two notes are normally out-of-tune in conventional trumpet designs. 
Thus, heretofore musicians playing a conventional trumpet were required to 
consciously correct the normally out-of-tune notes as by false valving, 
"lipping", or valve slide extension techniques. 
Further, by use of the conventional tuning slide design, a shoulder 27 is 
formed at both ends of the zones of increased bore 17 and 19 by the 
difference in diameters between the tuning slide 13 and the upper and 
lower branch 1 and branch 3 of the instrument. These shoulders 27 often 
disrupt the normal sinuosidal wave of the note propogated through the 
instrument and increase turbulence within the air column which may 
adversely effect the sound of the instrument. 
Referring to FIG. 2, the modified construction of the present invention 
which provides an improved acoustical shape of the air column of the 
trumpet is shown. The construction includes an upper and lower branch 31 
and 33 which are interconnected by way of a conventional tuning slide 35. 
However, in the preferred embodiment, the tuning slide 35, although being 
typically reciprocal, which is desirable for cleaning purposes as in a 
conventional trumpet, is continuously maintained in its retracted position 
during playing such that a continuous bore diameter 34 is maintained at 
its interface with the upper and lower branches 31 and 33. As such, the 
prior art zones of increased bore (17 and 19 in FIG. 1) and the turbulence 
producing shoulders (27 in FIG. 1) are completely eliminated by the 
present invention construction. 
The upper branch 31 is preferably formed as the straight cylindrical 
tubular section 37 which slidingly receives at one end thereof a mouthpipe 
assembly 39. The mouthpipe assembly 39 comprises an elongate tube being 
preferably formed by a mouthpiece receiver section and a bore section 38 
and 40, respectively, which are mounted to one another as by a solder 
joint 42. The mouthpiece 41 is mounted to the receiver section 38 in a 
well known manner and the entire mouthpipe assembly 39 may reciprocate 
within the length of the tubular section 37 and be locked in a desired 
position by a clamping screw 41. 
The mouthpipe assembly 39 includes an internal bore 43 formed in a conical 
or tapered configuration which is maintained in a substantially lineal 
configuration throughout the majority of its length. However, at the 
distal end thereof, the taper of the internal bore 43 is increased to 
provide a zone of increased taper 45. This zone of increased taper 45 has 
been found to correct certain intonation faults in the instrument as will 
be discussed in more detail below. 
To initially tune the trumpet of the present invention to a desired 
orchestral pitch, it is not necessary and actually undesirable to 
reciprocate the tuning slide 35 within the upper and lower branches 31 and 
33 as in the conventional trumpet design, but rather the mouthpipe 
assembly 39 (and thus the mouthpiece 41) need only be reciprocated within 
the tubular section 37. By this reciprocation, the effective length of the 
air column in the trumpet is altered thereby adjusting the overall pitch 
of the instrument. 
The particular location of the zone of increased taper 45 of the present 
invenion as well as the amount or slope of increased taper is critical and 
varies between individual instruments but in all cases is maintained such 
that the zone 45 coincides with the maximum pressure points of the notes 
of the chromatic scale desired to be corrected. In this same regard, the 
taper of the substantially cylindrical bore 43 of the bore section 40 
which is formed similar to the tapered mouthpipe of a conventional trumpet 
must be maintained unchanged to insure that the many desirable pitch 
qualities of the conventional trumpet are retained. 
While being played, the zone of increased taper 45 of the present invention 
functions to selectively increase the bore diameter of the air column of 
the instrument. As such, particular notes having their pressure maximum 
points located within the zone 45 are effectively lowered in pitch. By 
properly positioning the zone 45 along the length of the air column and 
determining the amount of increased slope of the taper zone 45, the pitch 
of multiple notes may be lowered or corrected in varying magnitude. 
With particular reference to a soprano "C" trumpet, the applicant has found 
that the normally out-of-tune upper octave (i.e., from the D natural above 
the 4th partial (C natural) to the A natural above) may be corrected by 
initiating the zone of increased taper at a distance of approximately 2.75 
plus or minus 0.065 inches from the end of the mouthpiece 41. This 
particular location has been experimentally determined to be between the 
2nd pressure maximum points (as shown in FIG. 3) of the A.sub.5 and A 
sharp 5 notes such that the zone of increased taper lowers the pitch of 
the A.sub.5 note without lowering the pitch of the A sharp 5 note which is 
a half-tone higher along the chromatic scale. 
Referring to FIG. 4, the particular construction of the taper within the 
bore section 40 of the mouthpipe assembly 39 for the soprano "C" trumpet 
(as illustrated in FIG. 2) is depicted in graphic form. As shown, the 
radius of the taper increases gradually to form a slight curved line which 
approximates a substantially linear rate (i.e., slope .apprxeq.0.011) to a 
distance of approximately 2.75 inches from the small end of the mouthpiece 
41. From this location (labelled T on FIG. 4) the taper is substantially 
increased (i.e., slope .apprxeq.0.020) through a distance of slightly less 
than one inch (to a position T.sub.1 indicated on FIG. 4). Thus, the 
magnitude of taper in the zone 45 (i.e., from T.sub.1 to T.sub.2) is 
approximately twice the magnitude of taper in the remainder of the bore 
section 40 of the mouthpipe assembly 39. 
The dramatic improvement in the intonation of notes of the upper octave of 
the soprano "C" trumpet by use of the construction of the present 
invention is shown in FIGS. 5, 6, and 7. All test data plotted in FIGS. 5, 
6, and 7 was obtained under tests conducted by carefully blowing the 
trumpet of FIGS. 1 and 2, using a commercial electronic tuning meter to 
determine the pitches produced. 
In these figures, the notes of the upper octave of the trumpet are plotted 
on the horizontal axis of the graph whereas the amount of deviation from 
the true note on a tempered scale is plotted on the vertical axis (being 
represented in hundredths of a semi-tone flat or sharp). Further, since 
the human ear is capable of only differentiating discrepancies in pitch of 
approximately 5/100ths of a semi-tone, the graphs in FIGS. 5, 6 and 7 
include a zone of acceptable deviation in pitch defined by the area 
between the horizontal lines labelled P.sub.1 and P.sub.2. 
In FIG. 5, the data obtained by testing one of the most popular 
conventional design models of soprano "C" trumpets (Bach "large" bore C 
trumpet with 229 bell, manufactured by Vincent Bach Corporation, Elkhart, 
Indiana) is reproduced. For purposes of this series of tests, the 
instrument was tuned to G.sub.4, a tuning which keeps the C.sub.6 note 
comfortably within the limits of audible detectability, i.e., within the 
region between lines P.sub.1 and P.sub.2. 
As shown, the conventional trumpet, although being utilized by many of the 
major symphony orchestras, has substantial intonation deficiences in the 
upper octave that would require conscious correction (as by slide 
extension or false fingering) by the performer. Thus, the E.sub.5 is 
significantly flat enough to be audibly detected in many playing 
situations. Additionally, the F.sub.5 (one-half tone higher) is quite 
sharp, being over 20/100ths of a semi-tone sharper in deviation than the 
E.sub.5. Further, the G sharp 5 and E sharp 5 are extremely sharp, 
approximately 25 to 28/100ths of a semi-tone, respectively. 
In FIG. 6, the data obtained in a similarly conducted test with the same 
model trumpet as FIG. 5 but modified according to the teachings of the 
present invention is reproduced. It is evident from the graph that all of 
the formerly defective note pitches are now substantially in tune with the 
majority of the notes lying between the lines P.sub.1 and P.sub.2. In 
particular, the notes D sharp 5, E.sub.5, F sharp 5, and G.sub.5 are all 
within the limits of human detectability. Further, the notes G sharp 5 and 
A.sub.5 are only 1/100th semi-tone outside the limits of human 
detectability and can be easily lipped into tune with normal fingering and 
without valve slide extension. 
This dramatic improvement in intonation made possible by the modified 
construction of the present invention is graphically depicted in FIG. 7 
wherein FIGS. 5 and 6 are superimposed onto one another. As will be 
recognized, the modification of the present invention has lowered (by way 
of the zone of increased taper 45 in FIG. 2) the G sharp.sub.5 and A.sub.5 
note approximately 27 and 26/100ths of a semi-tone, respectively, and 
additionally has raised (by way of the elimination of the zones of locally 
increased bore 17 and 19 in FIG. 1) the D sharp.sub.5 and E.sub.5 notes 
10/100ths of a semi-tone. Thus, by way of the present invention, a 
chromatic scale that is nominally true to the desired pitch for the entire 
upper octave of the instrument is provided. 
Those skilled in the art will realize that the teachings of the present 
invention, although being illustrated in relationship to a soprano "C" 
trumpet, are additionally applicable to other trumpets such as B flat, D, 
E flat, or F, as well as other cup mouthpiece brass instruments. Further, 
although for the key of C trumpet tested and disclosed herein, the 
beginning of the zone of increased tape is located precisely at 2.75 
inches from the small end of the mouthpiece, other trumpets as well as 
other brass instruments may require a relocation of the zone of increased 
taper to correct the higher octaves which are normally out of tune. In 
this same regard, the amount or magnitude of increased taper of the 
present invention which is illustrated in FIG. 4 may be varied between the 
normal mouthpiece configuration (represented by the dash line in FIG. 4) 
to a line approaching vertical on the graph. In such a manner, any 
particular trumpet may be finely tuned to compensate for the discrepancies 
of the intonation of different instruments to produce a true tempered 
scale for an instrument.