Yellow Spheres and Green Pyramids

A study in relationships to environmental sounds

 

ABSTRACT

We react to the sounds around us in a multitude of different ways and the processes by which we interpret those sounds as pleasurable or annoying vary from person to person. Acoustic parameters such as frequency, amplitude, directionality and fluctuations in pitch are just a few of the elements that are combined into sonic experience that can dramatically change oneÍs perception of their environment or emotional state. The following is an investigation into these sonic relationships though a qualitative research survey and organized into a multidimensional scaling graph. This paper is an explanation of my findings and a proposal for future research. Due to the multifarious nature of the data received I am only able to make a few speculative hypotheses towards the end of this study.

 

METHOD

I gathered the initial data from a Google Docs survey that asked six questions relating an auditory experience to a specific physical reaction. I also inquired about the environment or circumstance that the sound was heard in. The questions asked were:

 

1.     What is a non-musical sound that you absolutely cannot stand?

2.     Under what circumstance did you hear that sound?

3.     What musical based sound do you fined unbearable?

4.     Under what circumstance did you hear that music?

5.     Are there any sounds or a sonic situation you find disorienting?

6.     What non-musical sound you find comforting?

 

110 people participated in the survey whose age ranged from 18 to 64 with a majority between 27 and 36, and 57% female.  Out of the responses received 100% of the participants answered to the Questions 1-4, and 6 and 80% replied to Question 5.

 

I grouped the answers into categories based on how the sound was produced. For example lip smacking and eating were grouped into the larger category of chewing.  I kept each category relating to the questions that were asked separate, so that there are two machine sound groups but one is a ñsoftî machine sound that relates to the question regarding comfort (Question 2) that include fans, washing machines, and refrigerators, while more abrasive machine sounds from the non-musical dislike category (Question 1) include an electric table saw, lawn blower, and vacuum cleaner (Fig1). 

  

In order to analyze the sonic relationships between sounds I gathered WAV audio samples from three websites: freesound.org, sounddogs.com, and findsounds.com and used my own judgment to chose the most appropriate sample based on the quality of the recording and how it best represented the sound I was referring to with little or no other interfering sounds. The categories that were the most successful in obtaining measurable sound files were Questions 1, 5 and 6.  Not all of the sounds from Question 5 could be sampled so I used four of the thirteen sounds listed for this purposes of my study.  The final three categories of sound that I used are; non-musical sounds that people disliked, comforting sounds and disorienting sounds.

 

Each sound was then measured by three acoustic parameters: frequency, fluctuations in pitch, and perceptual loudness. 

 

To measure the frequency and fluctuations in pitch I used the MAX MSP Spectrogram and Sonogram FFT analysis objects.  This allowed me to compare audio samples in a fairly systematic way. I did not use this method to look at amplitude because the sound files were not recorded in a consistent manner and therefore did not represent applicable loudness comparisons.  If there was a decipherable fundamental frequency I used it to base the relationships of the sounds but 95% of the files gathered were non-periodic with lots of noise and pitch fluctuations. Because I used FFT analysis for non-periodic sounds I had to interpret the data by estimating the most dominant frequency band over the duration of the sound file (Handel p.20). 

 

To group fluctuations in pitch I looked at the same sonogram data from the frequency analysis but focused on the movements of narrow frequency bands in relation to the duration of the file.  The perception of loudness is a subjective measure and cannot be universally measured (Plomp & Rasch p.99).  To categorize this information I studied the answers in Question 2 relating the environments in which the sounds were heard and whether the subject was on the street or inside, close to the object or far away. To decipher the loudness for Questions 4 and 5 I had to interpret them the best I could from my own experience with the sounds. This is by no means an absolute calculation and my methods should be kept in mind when observing this data.

 

RESULTS AND ANALISIS

The first graph I made to chart this information was a column graph showing the various levels of acoustic data for each sound and a line graph over it displaying the percentage of people from the study that chose each sound (Fig 2). Unfortunately the bar graph did not show any obvious trend in the data relating a particular aspect of the sound to the percentage data. On completing graphs for each category of sound it became obvious that the information needed to be charted all together into one multidimensional diagram (Fig 3,4).

 

Fig 1

 

non-musicalgraph.jpg

Fig.2 Percent is the percentage of people who disliked that sound the most.

 

 

!!final-no-lines-front-c.tif

Fig 3. The size of each object relates to its percentile value. Yellow spheres are non-musical sounds

that are disliked, green pyramids are comforting sounds and red squares are disorienting sounds.

The X-axis is fluctuation in pitch, the Y-axis is frequency and the Z-axis is perceptual loudness.

 

!!final-no-lines-side-c.tif

Fig 4. View from another angle showing perceived loudness and frequency.

 

 

DISCUSSION

There are many broad relationships that can be inferred from this information.

 

1.     In Fig. 3 the comforting sounds (green pyramids) lie in the right hand field of the graph displaying a quieter perceived loudness than the disliked sounds (yellow spheres).

2.     The largest percentages of disliked sounds (yellow spheres) have a higher frequency than the more evenly dispersed Y-axis comforting sounds (big green pyramids). 

3.     In Fig. 2, more disliked sounds (yellow spheres) are located towards the right of the frame than the comforting sounds displaying the range of fluctuations in pitch as being a more disliked quality than a comforting one.

4.     Three of the largest percentage groupings of the sounds that were designated as disorienting by the survey cohort (big red squares) straddle all three axes almost evenly.

 

Another interesting note is that the sound of fans crosses the exact same place and percentage point for both the comforting category and the disorientating category. In the lower left corner of Fig.3 there is a large pyramid inside of a red square. Thirteen percent of the people surveyed said that they found fans comforting and twelve percent said that they found it disorientating. Further research into this topic would include analyzing sensory dissonance or examining how the fan sound might correlate with issues of attention and habituation.

 

 

FURTHER RESEARCH

This paper is only an initial investigation into how we relate to the sounds in our environment, and how those sounds relate to us. There is so much data from the survey conducted for this project that I was unable to incorporate into this paper. Below is a list of just a few of the things that could be done to improve this study.

 

1. I did not analyze and compare any of the musical data from Question 3 regarding musical sounds that people dislike. Due to the limits of time and the need to thoroughly investigate the individual music tracks in order to group them for study I was unable to include them and any other musical properties that were involved with the survey. I think if this were done there would be some very interesting relationships between acoustic qualities in musical sounds and non-musical sounds that effected people in similar ways. 

 

2. I would have liked to run a second survey that dealt with perceptual loudness. This would involve a controlled study where I would play tracks of sounds for the participants and gather data on how loud the sound felt to them. There are also many other parameters that effect perceptual loudness including pitch, location of the sound in the environment, and the environment itself.

 

3. There are other acoustical features that I was unable to measure, but would be informative for this study. For example ambiguity of directionality directly relates to sounds that have a disorienting effect and sensory dissonance is an aspect of all the sounds mentioned so far. One system to measure sensory dissonance is a MAX MSP object created by CNMAT that focused on roughness, a principal element of sensory dissonance and is based on the work of Richard Parncutt and Ernst Terhardt. 

 

 

CONCLUSION

As the above discussion has shown, individual responses to sounds in the environment are highly variable. This has proven a very challenging subject to incorporate into a study of this nature. In my analysis of the survey data I have attempted to illustrate the relationships that exist between these individual responses and psychophysical qualities of sound. An awareness of the dialogue between the constant stream of uninterrupted auditory information in our environment and our sense of place is an important insight for my work. The most satisfactory feedback I have received from this study so far is from the responses to the survey that stated that this was the first time that the respondents had ever pondered their relationship to their sonic environment. 

 

 

 

 

 

 

 

 

WORKS CITED

 

Handel, Stephen. Listening. Cambridge: The MIT Press, 1989

 

Plomp, Reinier and Rudolf Rasch. ñThePerception of Musical Tones.î The Psychology of Music.

Ed. Diana Deutsch. San Diego: Academic Press, 1999

 

 

 

 

BIBLIOGRAPHY

 

American National Standards Institute, "American national psychoacoustical terminology"

S3.20, 1973, American Standards Association.

 

Handel, Stephen. Listening. Cambridge: The MIT Press, 1989

 

Jarup, Lars dt.al. ñHypertension and Exposure to Noise near Airports: the HYENA Studyî

Environmental Health Perspectives. Vol. 116, No 3. March 2008: 329-333

 

Nevins, Ralph G. ñThe Micro-Environment Creating Comfort in ManÍs Surroundings.î

Transactions of the Kansas Academy of Science. Vol. 71, No 4. Winter, 1928: 451-462

 

Pierce, John R. ñThe Nature of Musical Sound.î The Psychology of Music. Ed. Diana Deutsch.

San Diego: Academic Press, 1999