Cornet vs. Trumpet

[Gary Morrison]

I have a pretty good feel for the timbral differences between trumpets and
cornets, but it would appear that I'd been told incorrectly about the
physical differences.

I'd been told that the main physical difference between a trumpet and a
cornet (other than the visual shape of the bends in the tubing) was that a
cornet's bore was more gradually conical than a trumpet's. In particular,
I'd heard that the cornet's bore expands conically to a substantially wider
bore at the valves, and then continues to expand toward the bell, whereas
the trumpet's bore is (speaking in first-order approximations) nearly
cylindrical to the valves and begins its conical expansion after the
valves.

I just looked at a cornet and trumpet by the same maker in a local music
store and found that that's not the case, at least for that particular pair
of instruments. So what then are the physical differences?

[David C. Stephens]

A few trumpets have a conical leadpipe (Yamaha Z, for example) and some
cornets are long (Conn New Wonder and Conn Constellation) but they have very
conical bores. Some other cornets (Bach) seem less conical and sound more
trumpet-like, but with an overall, short cornet shape.

Still, the general differences are as you describe. Perhaps you were
comparing two of the exceptions, rather than the normal situations.

Dave

"Gary Morrison" <mr8...@austin.rr.com> wrote in message
news:3CCC3024...@austin.rr.com...

[William E. Graham]

I've been told that a cornet is 2/3 conical, and about 1/3
cylindrical, while a trumpet is 2/3 cylindrical, and about
1/3 conical. But it's pretty hard to see on my horns, too. I
think it would help if I were able to measure the bore
everywhere along the length of the horns, but in fact, I can
only measure it at the valves and tuning slides, which
doesn't tell me the whole story....

"David C. Stephens" <dcs...@swbell.net> wrote in message
news:o9Xy8.28439$ON6.160...@newssvr30.news.prodigy.com..
.

[doctrpt]

The cornet starts with a far smaller shank on the mouthpiece, and a far smaller
opening in the venturi of the leadpipe. At the cluster, the bore differences
are minimal. The bell is generally shorter in length than that of a trumpet,
yet opens to the same throat at the flare. So, the taper is faster on a cornet
than a trumpet.

Over time, makers of trumpets have added more conical sections to make the
instrument have a fuller, more open tone. The bell is also more conical than
100 years ago.

With the advent of twentieth century manufacturing techniques and mechanized
instrument consruction, the cornet has become less conical and the trumpet more
conical.

Also, one has to consider that more and less are relative terms. The
difference between large and medium large bore is .003, to my understanding
less than the thickness of a piece of paper. With that in mind, the venturi on
Bach trumpets goes from .357 (IIRC) to .459 at the second valve for a medium
large bore trumpet, were as the cornet goes from a .250 (again, IIRC) to a .459
for a medium large bore cornet. That is more than double the taper in the same
area of an instrument.

Maybe not obvious to the naked eye, but it is a big difference.