Announcements:Homework 9: only one third (!) turned it in. EXTENDED to next TuesdayNote: to find frequencies of tones needed in to answer the asignment, either look it up on p. 153 of Backus, or calculate relative to the nearest A (440, 220 Hz etc) using the tempered semitone ratio (1.05946)

Paper outline dueThird exam is canceled (but will provide exam if anybody requests it)

Recitals: Beatriz (trombone) Friday 7:30 St. Frances HouseHelen (viola) Saturday 2:30 St Frances HouseGayle (piano) winner Beethoven Piano Competition D-minor Sonata Op. 31 #2 3:30 Sun MorphyGreg, Daniel (Tuba): Tuba and Euphonium Ensemble 2 pm Sat. Mills Concert Band 2 pm Sunday MillsFriday 7:30 Music Hall acapella concertElise (Bassoon) Saturday May 4 at 1 pm St. Frances HouseAndrea?Others?

Physics 371 April 25, 2002

• Reed Instrum. (summary)

difference cylindrical/conical

what partials in tone?

importance of cutoff frequency

• Bowed String Instruments

construction

rocking motion

plate resonances

“breathing” mode

oboe, bassoon, clarinet

who can bring bassoon?

lowest total bellnote length diam

Clarinet: D3 67 cm 6 cm

Soprano Sax: A3b

69 cm 6 cm

Oboe: D3 64 cm 4 cm

profiles of reed instruments (vert scale enlarged 3-times)

Difference between cylindrical bore and conical bore (same L)

1. cylindrical bore (Clarinet) lower by nearly an octave than conical bore (Oboe) of same length2. Clarinet overblows to the twelvth, Oboe to the octave thus Clarinet needs 7 more tone holes

If Clarinet is a cylindrical closed pipe, simple theorysays there should be only odd partials......

explanation:clarinet differs from simple closed pipe:• has tone holes• has tapered mouth piece• has bell

higher modes are shiftedand broad - see next slide....

for all instruments the spectrum changes as we ascend the scale(high tones - fewer partials)

Clarinet resonance curve(all tone holes closed)

The dots mark all multiples ofthe fundamentalfrequency even if higher modes are shifted, the partials arestill exact multiples since excitation is periodic

2

3

4 5 76

8

frequency (Hz)

Timbre depends on profile of instrument.

example: Oboe and Sax are both conicalreed instruments but

Sax has : (see picture next slide)• large opening angle, large bell -> lower freq cutoff• large tone holes of Sax loud! strong low partials

Oboe has:• small opening angle, small bell -> high freq cutoff• small tone holes soft,

A3b

B3b

Soprano Sax

Saxophoneinstrument designed(rather than evolution)

Construction of a violin

cross section of violin

is there a detectabledifference betweenStrads and other violins?

see papers by Carleen Hutchins

Strads

other old Italian masters

Tuning of the lowest resonances of different violins