It is far too early to expect to draw final conclusions from
the data so far in, but some useful observations can be made
Dating particular flutes more accurately
Combining the address information provided by Langwill's Index
of Musical Wind Instrument Makers and the serial numbers and
addresses from instruments in the Study, we can interpolate to
find the probable date of any flute for which we have a serial
number. The blue squares are known address changes or flutes
whose dates are known independently. I am indebted to Robert Bigio for the
two final dates.
On the company's productivity
It is also possible to get some idea of the company's rate of
production. We can see it varies greatly:
It is tempting to assume that the introduction of Boehm's 1832
instrument caused the downturn of interest in 8-key flutes from
about that time, but we would need to see sales figures for those
instruments before such a conclusion could safely be drawn.
Indeed, since manufacture by Rudall & Rose of the Boehm
instrument didn't start until 1843, perhaps it was more that a
downturn in interest in 8-key flutes prompted the company to
diversify into other flute types.
It is interesting to note that the Patent Head was patented in
1832 and its manufacture continued until the 60's. Was this an
attempt to win back market share?
Again, it is tempting to see the sharp decline at 1850 as a
result of the introduction of Boehm's 1847 cylindrical flute.
Again an examination of sales figures for the new instrument
would be helpful. It was clearly a period of upheaval for the
company, with the induction of Carte and several changes of
address around that time, in addition to the changes which must
have been necessary to take on manufacture of the far more
On Evidence for Models
Lengths of parts and positions of finger holes appear to vary
very little between instruments throughout the serial number
range. This makes a certain amount of sense - after all the
player's hands define to a certain extent what is possible in
terms of reach. It does suggest that we need to look more
to bore profile and fingerhole sizes to differentiate between
On Finger hole sizes
The right hand finger holes seem to vary the
most, with F# for example varying from around 8 to around 11mm.
Early data seems to suggest strong clusters around 8 and 10mm. These might be our earliest indications of
discrete and popular "models".
Distribution of models
The chart below illustrates how the small, medium and large
holed instruments are distributed with time. Left end starts at Serial No
454, the middle large-hole is No 4260 and the right most flute is 7174.
On body keys
Four distinct key types have been reported so far on the
bodies of the instruments surveyed:
- pewter plugs (# 655)
- saltspoon (well distributed)
- flat disk "keycups" with plain leather "pads"
- dished cups (#4974)
- wide cups with vertical sides and a low domed top
soldered to forged shafts (# 7174)
On footjoint keys
Footjoint keys for C and C# seem usually to involve pewter
plugs closing on metal plates screwed to the wood.
The Eb key varies between the pewter plug variety or being the
same as the rest of the keys on the instrument.
On "unusual" keys
Unusual keys (ie. those not part of the "normal" 8-key
contingent) reported so far include:
- a "Brille" (additional upper C pad operated by
ring keys on the top two holes) (# 2625)
- a double Bb key, operated by both LH thumb and RH
forefinger (# 4795, # 5088)
- nine keys, extending the bottom note to B (# 3312)
- ten keys, extending the bottom note to B and Bb (# 3060)
- a C#/D trill key (#6239)
- a roller on short F (# 605)
- a high E key (# 5356)
On Foot Length
As mentioned above, the lengths of the body sections and placement of finger
holes varies only slightly. A fascinating pattern emerges with the length of the foot
joint however. The earliest
instruments were nearly 150mm, gradually making their way down to around 140mm
by about No 4000 (c1840). They settled in this area until about No 7000
(c1885), whereupon they shortened suddenly to just over 130mm.
Two things are probably happening here. Certainly pitch of the flutes
is increasing. Reduction of "flat foot
syndrome" is probably the other contributor.
On Body Scaling and Embouchure to Hole 1 length
During the period covered, 1820 to the end of the century, pitch rose
dramatically, then dropped as British high pitch was abandoned (apart from by
military bands) circa 1895. We saw that effect in the rapidly reducing
lengths of the foot, above. We might also expect to see this as a
significant shift in lengths of other parts of the flute, such as the distance
between holes 1 and 6, and the distance between embouchure and the first hole.
The data does not yield what we might expect.
In the graph below, the distance between the first and sixth hole is given in
navy. While we might expect it to drop over the period and then recover
somewhat at the end, it generally increases slightly. We'll come back to
We would expect the distance from embouchure to first hole to drop very
markedly in order to accommodate the higher pitch towards the end of the period,
but the data shows only a gentle drift of about 5mm downwards. On the old
rule of thumb, 1mm per Hertz, that suggests only a 5Hz variation in pitch, while
our other studies suggest a greater than 20 Hz variation occurred.
This can probably be explained easily - the very long tuning slides provided
were already capable of covering the full range of pitches likely to be
encountered, so there was no need to reduce the distance between embouchure and
hole 1 when pitch rose - just push the slide in a little more. As we'll
see later, the size of the embouchure hole increases too, which sharpens the
On hole size balance
But it's not so easy to explain away the slight increase in distance from
hole 1 to hole 6 at a time when the pitch is rising and there should be a marked
decrease. What else is going on?
Could Rudalls have used fingerhole sizing rather than fingerhole spacing to
allow for increasing pitch? If so, we'd expect holes at the bottom of the
flute, i.e. holes 5 and 6, F# and E to increase, or holes at the top, holes 1
and 2, C# and B, to decrease in diameter, or a bit of both. It turns out
that all holes increase in diameter over the period, although it gets difficult
to interpret as there are a mix of large and small hole flutes in the earlier
days. To get around that problem, it's safer to look at the ratios
of the hole sizes, rather than their absolute values. When we do
that, in the graph below, we see that the bottom-of-tube holes increase
considerably more than the top-of-tube holes.
In blues, we see the ratio of the diameters of hole 6 and hole 1. In
reds, we see the ratio of holes 5 and 2. The rise over the period
approaches 10%, more than enough to overcome the 2% or so increase in length and
make a longer-bodied flute a sharper flute!
Impact of the shorter foot
But there's also something else that is going to sharpen the low notes of the
flute as the century progresses - the shortening feet we saw up at "On foot
length". The E note in particular (being produced from a very small hole)
is very sensitive to how far away its nearest venting support is. That
venting support will be Eb (if you open that when playing E) or the D hole
(where the C# pad is) if you don't. Both of these move much closer to the
E as the century proceeds. The combination of these various effects
probably explain why the C#-E length had to be increased to prevent E going too
On embouchure size
We can see that the longitudinal length increased from around
11.5mm at the start to between 12 and 12.5 or so after about serial
number 4411. The short axis seems to have generally remained
between 10 and 11mm.
On Best Pitch
[Update: This section needs review in the light of other studies.]
By determining the best pitch of readily available flutes and scaling
it is possible to estimate the design pitch of flutes in the
study. This is the pitch for best intonation, not the highest
pitch available by pushing the tuning slide fully in. It suggests
that, in common with other 2nd generation instruments, they were
intended to work best at low and medium pitches (430 and 445) rather than high
pitch (450-455) as is generally believed. Note the last two
flutes are radically different and follow the tuning of third
generation flutes, which seems appropriate given their very late
This picture is confused however by the issue of flat footedness, and more
work is needed to work out what is really going on.
Coping with change
Now an interesting puzzle presents itself. If the finger holes don't
move, yet the pitch of the instrument changes with the time, how is that
reconciled? As we've seen the foot gets shorter, but that won't have much
impact on the body notes. The graph below gives us some clues ...
Firstly, focus on the flutes with an F# hole of about 8mm. Note that
the B holes are about the same size. Note also that these flutes seem more
popular in the early part of the century.
Now turn to the large hole flutes and we note that the B hole is generally a
mm or so smaller than the F# hole. But look at 7120 and we see it is much
smaller. What will this do?
Increasing holes at the top of the tube will sharpen the upper tube notes in
relationship to the notes lower down the tube. To find the best pitch
again, the slide will have to be compressed. As it has more effect on the
upper tube notes, an extension will be found where the upper and lower tube
notes are once more in tune. That will be at a higher pitch than
before. The flute has been sharpened without recourse to shortening the
body. Some adjustment to the foot length will be required too.
On Bore profile
While the bore dimensions have not been made a formal part of
this phase, some bore information is available. As observed
previously, bore information may be needed to confirm the models.
In the graphs above, the vertical dimension (diameter) has been
wildly exaggerated. The vertical scale has been omitted to
protect the interests of the museums from which some of the data
is taken. Of particular interest are the "back
reamings" at the two junctions between the upper and lower
body and the footjoint. Since these had to be consciously
reproduced on each instrument, we can assume the company regarded
them as significant. What result they produce or were
intended to produce is not clear but may be determined by
[Update: Since the work done on the effects
of thread wrapping (see elsewhere on this web site), it is now safe to
assume that the bumps at the tenons of the flute bores shown are due largely if
not entirely to compression of the bore by the combined action of humidity and
Note that the curve for # 7174 has been left incomplete around
the tenons of the upper body because of recent repairs to
Note the great similarity between the bores of # 5047 and #
5501. This is puzzling as the section lengths and
fingerhole positions are nearly identical, but their fingerhole
sizes are very different. There remains a mystery to clear
Note also the lengths of the bores which relate directly to
the estimated design pitch. The Norman flute is longest, with the 5000 series
instruments about the same, and 7120 the shortest.
On Inheritance and Cross-fertilisation
An interesting question is to what extent the company relied
on the work of previous makers, and to what extent their
instruments were copied by other makers, particularly those who
had been employees. Questions and answers appear together
Influence of previous work of Willis (TBD)
Influence of previous work of Rose (TBD)
Influence on Ingram
Ingram was a former employee of Rudall & Rose.
Examination of a flute made by Ingram indicated no sign of
influence by the company's designs.
Influence on Wylde (TBD)
Influence on other makers of the time
Comparisons of bore data indicate no points of
similarity with Metzler, Pratten's Perfected or B&S flutes.
Back to the
Rudall & Rose Models Study