Lydia Ayers

MIDI to SP MIDI transcoding using phrase stealing

The mobile phone industry has a problem with conversion from MIDI to SP-MIDI, which handles specific polyphonic limits. Simple specific polyphonic reduction algorithms, such as note-stealing, may lose or interrupt important musical information. The authors help resolve the problem with a phrase-stealing algorithm that drops the perceptually least important notes and preserves the most important phrases. Tests show that listeners reacted positively to this solution.

Expressive modeling of Chinese folk wind instruments

Chinese folk wind instruments, including the paixiao, xun, koudi, bawu, hulusi, and lusheng, have distinctive timbres but are less well known than the other Chinese wind instruments. The paixiao (a panpipe) and the xun (ocarina) are ancient instruments. The koudi is a small bamboo whistle/flute, which can play exciting birdlike melodies. The bawu, hulusi, and lusheng have different shapes and playing techniques but have similar embedded metal plate reeds that produce their sounds. This talk will give brief descriptions of the musical and spectral characteristics of these instruments, and then describe the additive synthesis design template used to capture their subtle timbral characteristics using score data in Csound. In addition, the design is expressive and successfully uses spectral interpolation for the idiomatic ornamental phrasing for each instrument. We use a special amplitude/frequency function modulation method to simulate trills, which are also tied to varying numbers of grace notes, as tested ...

Modeling Chinese musical instruments

Chinese instruments include a range of colorful instruments with distinctive characters. For example, the dizi is the most common Chinese flute, and it has a bright buzzing quality produced by a rice paper membrane glued over a hole. This paper describes models for more than 20 Chinese traditional and folk instruments using group additive synthesis with genetic algorithm‐optimized parameters. Other types of Chinese flutes modeled include the xiao (vertical flute), paixiao (panpipes), and xun (ocarina). The sheng is a mouth organ with a ring of bamboo pipes attached to a wind chamber, and dates back to 1500 BC. A folk version of the sheng, called the lusheng, has also been modeled, as well as the bawu and hulusi, folk instruments that sound similar to the clarinet. The player’s mouth completely covers the bawu’s blowhole, which has a vibrating reed cut into a copper strip covering the hole. The hulusi has a playing tube and multiple drone tubes. Several pitched percussion and plucked string instruments hav...

Common tone adaptive tuning using genetic algorithms

This paper introduces a genetic algorithm method for adaptive tuning of chord sequences. The algorithm retains the tunings of common tones from previous chords, and adjusts the tunings of the other notes. The genetic algorithm method avoids problems associated with simpler enumerative, greedy, and distributive tuning strategies. The paper gives results for several musical examples using several different error measures, with extended results for minimizing the worst tuning error among harmonic thirds and fifths.

Synthesising Chinese flutes using Csound

This paper gives brief descriptions of five Chinese flutes: the paixiao, xun, koudi, xiao and dizi, and short musical excerpts with their notation, idiomatic phrasing and typical ornaments. The source material section describes their spectral characteristics. Following a brief description of the previous wavetable synthesis design, an expressive new Csound additive synthesis design used to model the instruments is described. Chinese notation is a convenient Csound pitch input method using Ling Luns tuning. Finally, several excerpts from compositions illustrate applications of the designs.

Comparing the Hawaiian nose flute with the western concert flute

This presentation will compare the spectral and expressive characteristics of the Hawaiian nose flute with the western concert flute. The Hawaiian nose flute is a bamboo courtship flute. This presentation will give live demonstrations on several nose flutes and the western flute, along with brief descriptions of the musical and spectral characteristics of these instruments, and then describe the additive synthesis design template used to capture their subtle timbral characteristics using score data in Csound. In addition, the expressive design successfully uses spectral interpolation for the idiomatic ornamental phrasing for each instrument. A special amplitude/frequency function modulation method simulates the trills, which are also slurred within phrases of varying numbers of notes. [This work was supported by the RGC Competitive Earmarked Research Grant 613505, with special thanks to Rodney ‘‘Kala’’ Willis for making the nose flutes.]

The Woodstock Gamelan

This paper considers the spectral properties of the Woodstock Gamelan, a 3‐octave set of tubular chimes built by Woodstock Percussion in upstate New York. One of the main features of the instrument is expandability, and it includes 75 microtones in the middle octave. The justly tuned instruments of Harry Partch inspired the instrument. The Woodstock Gamelan has two types of aluminum tubes. Racks support the tubes down to Eb4, and these have a vibraphonelike timbre. The larger hanging tubes go down to G3, and have larger diameters than the rack tubes. The sound of the hanging tubes is similar to that of orchestral chimes. The Woodstock Gamelan has five exponentially decaying partials, and their frequency ratios are the same in the low and high registers. The frequency ratios measured were about 1, 2.69, 5.15, 8.38, and 12.08. The ratios are close to the just ratios of 1, 2.667, 5.333, 8.533, and 12. A Csound model for the Woodstock Gamelan has been developed. Listening tests show that the model produces to...

A hybrid additive‐wavetable synthesis model for the horn

Is it possible to synthesize the French horn well enough to pass for the real thing? Most commercial synthesizers and soundcards are limited to producing timbres that are ‘‘horn‐like’’ or ‘‘clarinet‐like.’’ It is much more difficult for a model to be flexible enough to allow different types of articulations, phrasings, and tone colors. This work presents a hybrid additive‐wavetable synthesis model for the horn using genetic algorithm optimization. The parameters for the model include fundamental frequency, overall amplitude, vibrato amount, attack and release times, brightness, and articulation shape. The model gets brighter as the amplitude increases, and the brightness decreases as the amplitude decreases by scaling each partial with a set of exponentially related amplitude envelopes. The model is implemented in the Csound software synthesis language. After implementing the model, several solos and orchestral excerpts that are commonly required in auditions were synthesized. The model is particularly ef...