Posts Tagged ‘pitch’

A Reproduction of La Espiral Eterna

Thursday, January 6th, 2011

A Reproduction of La Espiral Eterna is a hybrid algorithmic/organized sound piece with political narrative. I’ve composed it in April, 2010 and revised in December, 2010. It is based on the original composition for classical guitar by Leo Brouwer, composed in 1971, and the guitar recording is taken from the ”Guitar Recital” album by Dmitris Regginos, released in 2004. The piece has been performed at KSU New Music Festival in 28 March 2011 in Kennesaw State University.

A Reproduction of La Espiral Eterna (Revised) by Sertan Şentürk

The piece has a dark, disturbing soundscape aiming to make listeners think by getting sad, helpless, disgusted and shocked either indirectly by the environment they are forced to listen or directly by the meaning of the sounds/voices they hear. Below is a more short text that explains the narrative and the technicality in more insight. I would recommend to read these after listening to the piece as what and how I done in the composition might take away your intimate listening experience.

Narrative Explanation

Taking the side of the weak, “A Reproduction of La Espiral Eterna” expresses the clashes between those in power and those who are oppressed. It acknowledges that the struggle will continue forever; forming an ”eternal spiral”. The piece can be thought to be divided into 9 sections some of which are in contrast with other sections built consistently upon Leo Brower’s composition. The tension in the original composition by Leo Brower is preserved and enhanced with applying intense processing on classical guitar (except the seventh section, which was played very fast and did not need any “touch”) and organizing sound samples throughout the piece.

The first section starts with Subcomandante Marcos’s opening remarks in the First Intercontinental Encuentro Against Neo-liberalism and for Humanity, Chiapas, Mexico, 1996. His speech is reversed in some instances symbolizing censorship, ignorance and misinterpretation of his words by the people with coinciding interests), and implying to the care-free listener that there are some wrong-doings in the world, which do not take place in front of their eyes or they have chosen to turn a blind eye on.

In the second part guitar is accompanied with huge explosions carry on to the and the third section, where weapon sounds and children sounds are used in succession. These sections are literally slams in the face, forming a hysterical situation the listener’s cannot escape of. The third section finishes with the “victory” of the war over innocence, establishing a hopeless state… Fourth section is instrumental and a bridge to the next section, allowing the listeners to take a breathe and assess what they have been exposed to.

Fifth and sixth sections are built around the speeches of political figures. The fifth section consists speeches by politicians such as Truman’s announcement of the atomic bomb dropped on Hiroshima, Netanyahu’s justifications of Israel attacking civilian areas in south Lebanon and Ahmedinejat’s remark stating “there are no homosexuals in Iran”. The speeches create a disturbing blob, aiming to create a negative image on people who abuse power and use any means of justification to oppress people. Note that the piece does not intend to show all the politicians speaking in the fifth section as villains: both Nelson Mandela’s and Evo Morales’ speeches are two good examples of it, which are both a good indication of how two-faced Western Hemisphere democracies can be. The sixth section shows a different side of the influence of power that it can be used to help people rather than oppressing them. The complete list of speakers, the sources and the transcriptions from the audio can be found here.

Seventh and eighth sections are very short and can be thought together and a silent response, a passive resistance to the second part, having the same the tension but refusing to use violence during the progression of piece which is turning against those in power. In this sense, it has a minor flash-forward role to the last section.

Ninth, the last section, is the only section where the guitar recording from the original composition is taken out. Instead the background sound is from a natural, peaceful environment. Now, Subcomandante Marcos’ speech is unaltered and strong, allowing him to make a proper stand next to oppressed. The piece finally reaches its anti-climax, where it is acknowledged that this struggle will continue forever; forming an “eternal spiral”.

Technical Explanation

For Subcomandante Marcos’ speech in the first and the last section, I have used Dan Ellis’ phase vocoder in MATLAB to match the audio duration. The amplitude envelope of the guitar recording is applied to the speech for sound level consistency. I have also pitch tracked the speech in the first part using Arturo Camacho’s SWIPEP and recorded the strength of the fundamental pitch. I have reversed the speech in the intervals where the strength stays less than a definite number for a definite time.

To process the guitar recording taken from the ”Guitar Recital” album by Dmitris Regginos, I am first using a low-pass filter with variable cut-off frequency, which related to the fundamental pitch in that instant. I am using Miller Puckette’s fiddle~ to get the instantaneous pitch in Max/MSP. On top of the original guitar audio, I recorded the downsampled, filtered versions audio and also passed the filtered audio through amplitude modulation and absolute distortion.

I have used Protools as the mixing environment. I have manually mixed and panned the samples and the guitar recordings so they would match the progression I envisioned for the piece. I have taken the samples from freesound and the speeches of the political figures from Youtube.


Monday, January 3rd, 2011

Beatscape is a mixed virtual-physical environment for musical ensembles where sound objects interact with temporal waves to create rhythmic grooves. Musical outcomes in the virtual world are determined by the ensemble’s actions in the physical world. Part of the ensemble manipulates physical objects representing sounds while the other part triggers the sound objects by generating waves with hand gestures.

Me with Akito Van Troyer, Aaron Albin, Brian Blosser and Oliver Jan have built this instrument in Spring, 2010 as our Technology Ensemble project. By a camera, the system detects objects that are put on top a transparent glass table. Each object has a location, a pitch and they’re associated with different sounds. These objects are projected to a screen. However the objects cannot produce any sound by themselves. There are also waves that can be triggered by another player. The waves can be single, repetitive or continuous. Yet again, they too cannot produce any sound by themselves. It is the collision between the objects and the waves that produces the sound. The instrument requires an ensemble that needs active and effective collaboration with each other. We have written a paper about the instrument which appeared in NIME 2011.

The source code can be downloaded at Google Code under the name audio-sketch.

The instrument has been performed twice: the first is in the concert Listening Machines 2010:

…and the second is in FutureMedia Fest 2010.


Joint Recognition of Tonic and Raag in Indian Music

Monday, January 3rd, 2011

Pitch is fundamental to most of the world’s musical traditions and humans utilize a rich set of cognitive representations for pitch processing. For centuries, music theorists have noted that the musical effect of a pitch is in large part determined not by its absolute height but rather by its relationships to other pitches, typically nearby in space and time. Over the past three decades, researchers have established that pitches derive their meaning if large part from their relationship to a tonal center (tonic) and their relative frequency. Moreover, high-level responses, such as emotion, can be related to the tonal properties of the music. Thus, key and mode are fundamental properties of many types of music and have real psychological relevance. For systems that hope to understand aspects of music in order to, for example, provide recommendations, or interact with real performers, such information is critical.

In many non-Western musical traditions, such as North Indian classical music (NICM), melodies do not conform to the major and minor modes, and commonly use tunings that have no fixed reference (e.g. A = 440hz). These characteristics are explained around melodic abstractions (modes) called raags which almost all North Indian classical music is organized.

I, under supervision of Parag Chordia have presented a novel method for joint tonic and mode recognition in NICM from audio based on pitch distributions. To the best of our knowledge, this is the first example of a system that is able to jointly recognize tonic and raag in a fully automatic way. The best results obtained by the system are 95.8% tonic detection and 89.7% raag detection, which are pretty solid results. (more…)