THE VENTURE GRANT AEOLIAN HARP                                  v14


Construction of an Aeolian Harp for Use in Innovative Cross-Disciplinary Teaching: Melodic Music Production in Low Velocity Winds Through  Electronic Regeneration and Amplification Technology.  A Report to the University of South Carolina Office of                                          Sponsored Programs and Research                                                        


                        EXECUTIVE SUMMARY                        

     As can be seen from the

<a href="" TARGET="_blank">photographs</a>   

 , Public Art Sculptor Rodney Carroll[1]  has done quite a remarkable job in creating The Venture Grant Aeolian Harp! This Harp recreates in modern form an ancient musical instrument.[2]  As is true for all Aeolian Harps, the Venture Harp is played by the wind,[3] and makes music that is beautiful, haunting, strange, weird and wonderful!


     The Venture Grant Aeolian Harp was observed to make Aeolian music with wind speeds as low as 5 miles per hour.  This improvement over traditionally  designed Aeolian harps,[4] was  achieved by incorporating the research results of this project into the final design. The Venture Harp has:

1) The longest (8 feet) and largest diameter (0.080 inch) musical wires permitted by budget. 

2)  Aeolian string vibration amplification through the technology of electronic feed back   


       This harp was used as a successful supplement to the principle investigator's  physics classes. (See full discussion below.) Dr. Richard Maltz, Composer and USCA Associate Professor of Music has become interested in Aeolian harp music and a small “Science-Music” collaborative effort has developed. Photographs and a short description of the Venture Grant Aeolian Harp are on my web page. A scientific paper describing the research results of this project is in preparation.2 A patent  declaration  on “Electronic Regeneration Technology” was completed with the USC Office of Technology Transfer.  One commercial company studied (but declined to pursue) the possibility of producing Aeolian harps under a patent based on the research results sponsored by this Grant.


     The  announcements concerning our Aeolian Harp Venture Grant Award received media attention in USC Times and USC Alumnae Magazine.[6]  The “Harp and Camera” theme as well as the plans to develop an Aeolian harp at USCA were featured in the Aiken Standard  newspaper [7]  An Aeolian Harp Writing contest was sponsored at USCA in Fall Semester 1994. Students were invited to examine an operating  (outdoors) experimental Aeolian harp[8]  and  to write an essay or poem about their experience. Winning entries were offered a $25 prize and publication of their entry in “Broken Ink”, the USCA literary magazine. Six entries were received. Because of the high quality of the entries, two poems and one short story were awarded the prizes and publication.[9] 



     The Venture Grant Aeolian Harp stands twelve feet tall, has ten musical strings, and was supported on a sturdy but hollow base in which will be placed the electronic amplifiers, etc.[10]  The longest musical string (wire) was eight feet long !!   The ten strings permit three octaves of musical notes with three strings per octave. The two strings within each octave, will be tuned to the “third” and “fifth” as is done in (similar) notes of a piano. This harp was constructed entirely of stainless steel except for electronic components. See photograph.


     The eye catching shape of the “Cupid’s Bow” that holds the strings, was an artistic form which has been adopted for quite functional reasons: To achieve the octaves musically, the four octave strings need to have lengths  8 feet, 4 feet, 2 feet, and 1 foot.  This series is of course the shape of a mathematical curve called an exponential. So you see, mathematics as well as physics, is very much a part of this harp.


The exceptionally fine work of Mr. Rodney Carroll  is briefly summarized below:

     1)  The harp base is 35% higher than given in the contract. The increased height makes the harp look much better and will serve to discourage  children from attempting to climb on it. 

      2)  The overall height is  20% higher than specified in the contract. This increases the drama of the sculpture. The added height also moves (fragile) electronic pick-ups higher and further away from unwanted public tampering.

      3)  Mr. Carroll gave us an all stainless steel harp. The contract allowed the base to  be a much less expensive painted metal which of course would have been much less satisfactory.

       4) Getting the two and one half inch super-heavy-duty stainless steel pipe to bend, was a monster job! But Mr. Carroll never diverted from achieving the full artistic and scientific requirements of the job. Especially difficult was the requirement to        bend the pipe at a variable rate of curvature.

      5)  Very high quality materials and workmanship throughout. Mr. Carroll provided ample sized material thickness so as to achieve exceptionally high strength as well as well fitting structural components. These are just a few of the examples of the fine craftsmanship achieved in all parts of the finished harp.

      6)  Mr. Carroll had an usually deep understanding of what we were trying to achieve musically, mathematically, and sculpturally.  Mr. Carroll is a true artist. He fully committed himself to this “work”. There are at least five different major places where his artistic sculptural sense came into play and thus achieved a more exciting finished sculpture. Every step of the way, the needed artistic, scientific, mathematical, and musical qualities were spontaneously recognized by Mr. Carroll and  actively “brought-out” in the finished work. A Command Performance!!!                 

      7) Mr. Carroll stated that  we have a $10,000 sculpture. And I believe him.[11]



     Over five months of full time research was conducted with a specially constructed[12]  apparatus wherein Aeolian strings (tight wires) were subjected to steady air flow (wind) created by a small wind tunnel. The wires, hereinafter called strings, were (nearly all) of solid steel cylindrical shape with smooth exterior surface. Diameter of the strings ranged from .008 inches to .073 inches and string active “speaking length” was typically 41 inches. The research effort concentrated on the larger .073 inches size, so as to study Aeolian behavior in the lower speed winds of interest in this study. The resulting lower frequency (lower cycles per second) made it easier to study the regeneration effect without worries concerning the effect of phase delay of amplifiers or electronic transducers used in the experimentation. Regeneration was hard enough to prove successful, with out unnecessary complications.


     The adequacy of the experimental apparatus (and the research procedures) were established by confirming the (already) published results concerning Aeolian phenomenon.


   Additional research established the following results:

  1)  For any given diameter of Aeolian string, there is a definite “threshold wind speed” below which Aeolian vibrations do not occur.  2) The threshold wind speed is an inverse function of string diameter. A lower threshold (wind speed) is achieved with larger diameter Aeolian string. 3) Aeolian string vibration enhancement[13]  is indeed possible through electronic regeneration technology. 4)  The electronic regeneration technology is only successful with wind speeds (approximately) in the range 20 % below through 10 % above the threshold wind speed. 5) With wind speeds ~20 % above threshold values (and larger), the wire vibrations caused by the forces applied through electronic regeneration can be clearly seen, but did not appear to significantly increase (or decrease) the vibration already induced by the Aeolian wind mechanism. This result (#5) was investigated experimentally, but as of this writing, the reason for this behavior is not understood beyond the fact that the Aeolian forces and the feedback forces appear to combine upon the string following the rules of superposition. Although only a preliminary literature search on Aeolian phenomenon has been completed, published articles (seen as of this writing) do not mention the above results. 


The above research results are “built into” the final design of the Venture Grant Harp. It is thus quite gratifying to report that this harp having 1) Regeneration technology, and 2) Very long and very large diameter strings, achieves the following:


 I) The Venture Grant Aeolian Harp was observed to make Aeolian music with wind speeds as low as 5 miles per hour.  This is an improvement over many traditional harps of which this investigator is aware.[14]  At these very low wind speeds the resulting “music”  on the Venture Harp is typically a steady vibration sound around 40 cycles per second corresponding to one of  the lowest notes of a very large pipe organ. At  progressively higher wind speeds, the Venture Harp makes progressively higher (frequency) musical  sounds which are typical of the more traditional Aeolian Harps. 

 II) USCA now has an instrument that successfully achieves two of the major the goals of the Venture Grant  project:

       1)Low wind speed Aeolian music and  consequently

       2) Significant increase in the portion of the time which the Venture Harp actually  

            plays “music”.

 III) There is an additional “BIG WIN” which was not in our Venture Grant                  Application: The Venture Grant Harp is itself a work of art, and carries the creative contribution of a prominent  professional sculptor.


     A scientific paper is in preparation. This paper will report the research results of this project and describe the performance of our Venture Grant Harp. So far as I am aware USAC is the only university/college that has a system similar (in any respect)  to the Venture Grant Aeolian Harp.



 Many of the people who take the time to experience our Venture Harp show interest and pleasure.  However only a relatively small proportion (approximately 1 %) of the people who walk by and  see (or hear) the Harp for the first time show any interest. Evidently the harp will be of fairly low interest for the general public, and a considerable educational effort will be necessary to raise interest beyond what is now “lukewarm” at best. The Venture Harp has been shown to two USCA Physics Classes with a good level of interest and successful physics learning. See paragraphs below which report the Physics Class Response for Spring 1998 and Fall 1998.




     In the Spring Semester 1998, a 40 minute lecture on Aeolian Harp phenomenon was given to my APHY-202 Physics Class. Of the 21 students officially taking this class, 20 students  voluntarily attended the lecture. Eleven students stayed an additional 40 min. after class, for further lecture and demonstration of the new Venture Grant Aeolian Harp.  This shows a considerable interest in these topics since this lecture was  the last class of the semester and by prior announcement was voluntary attendance.

      The lecture concerning the Aeolian phenomenon and the demonstrations of the Venture Harp definitely held the students attention. The students seemed to appreciate learning of the history of the Aeolian Harp. The lecture was 1) well received, 2) gave the students something to think about, 3) clearly stretch the student’s imagination, and 4) extended  strictly scientific lessons (in optics and vibrations) into a lesson in how mankind in history must have been impacted. The students, seeing how  they themselves were impacted by these  physical experiences, could think how these experiences would be received by a pre-scientific humanity. And then they could imagine the changes to civilization (conceptual, psychic, and physical) since Aeolian Harp and the Camera Obscura[15] made their debut during the very formative roots of our ever more rapidly changing scientific and technological civilization.



     In order to expand the Venture Harp audience as much as possible prior to writing this report,  one physics (APHY 201) class period  was devoted to showing our new harp late in the Fall Semester 1998.  The regular classes and labs in Fall Semester physics cover the topics of vibrations, frequency, wave motion, musical sounds, harmonic modes of vibration, and resonance. The demonstration of the Venture Harp was an opportunity to re-view  these topics, prior to the final exam) in an enjoyable  meaningful way and in a new and different context.......all of which promote additional learning.

     The presentation definitely held the students attention. The wind was not very cooperative during that  particular class hour. Several students expressed the desire to hear the harp when an adequate wind was present and thus hear its full range of music sounds.




                                CAMERA OBSCURA AND AEOLIAN HARP



     The Camera Obscura (Giant Pin-Hole Camera) is the most primitive (i.e. the simplest) of all man made optical image forming devices, but never the less, demonstrates all essential physical processes of all image forming optical lenses. Despite, or perhaps because of, its simplicity the Camera Obscura is an excellent way to introduce the principles of optics and optical image formation in a physics class.


     The inspiration  to create the USCA Camera Obscura as a physics teaching tool, came directly from the essay “Harp and Camera”[16], by literary critic, linguist, and philosopher Owen Barfield.  In addition, Barfield's  essay contains a wealth of history and insight [17]

  into our own times and thus is an excellent resource for cross-disciplinary teaching. For example, Barfield describes how  the Camera Obscura was, in the Renaissance, man’s very first optical image   making device. More over, Barfield goes to some length to discuss how the Camera Obscura automatically shows the image in correct “perspective”, an artistic technique which artists had only several decades earlier and with much effort, finally learned how to achieve! Barfield continues by showing how such a technical advance has (has through the centuries) a subsequent impact on mankind’s self-awareness, language, and literature.

     Barfield discusses the Aeolian Harp and the Camera Obscura as metaphors of the human mind (and imagination )  as contained in the literary traditions of the poets of the romantic era especially, Coleridge, Shelley, and Wordsworth.[18] In this context, Barfield discusses  the historical emergence many words such as:  breath  evolved to inspiration;  images  evolved to imagination;  seeing  evolved to insight.[19]  He discusses the emergence of mans first awareness of the Harp and Camera experiences in both the physical and metaphoric sense. Barfield shows how the Aeolian Harp may be a metaphor (indeed symbol) of earlier people’s response to God and nature, whereas the Camera Obscura and its images may be a metaphor (indeed symbol) of modern man’s response to his own self created world: A world having for modern man the apparent absence of God. Moreover, Barfield shows the historical role played by both the Aeolian Harp and (especially) the Camera Obscura in bringing about  our modern form of life and modern thinking. He says we are a “Camera and Image Civilization” and points to the historical Camera Obscura as being midway between 1) our modern perspective  and 2) the God and nature point of view  of ancient people. As indicated herein, I believe the “Harp and Camera” essay provides significant  ideas for teaching and learning in both the Humanities and Physics.


                      OWEN BARFIELD’S  “HARP AND CAMERA” ESSAY

                           INSPIRES CREATION  OF AN  AEOLIAN HARP



     During a subsequent reading of Owen Barfield’s “Harp and Camera” essay, yours truly, in a split second of insight  (or was it inspiration?)........ AHA!.....    I must  construct an Aeolian Harp for my physics classes!


      Besides being an object of history and a significant literary symbol + metaphor, the Aeolian harp is an interesting (and therefore excellent) means to demonstrate the theory of vibrating objects. Easily demonstrated (as mentioned earlier in this document) are wave and harmonic modes of vibration, resonance, feedback regeneration, and wind flow instability. The electronics of the harp offers additional physics lessons involving  photo-optic pick-ups, magnetic forces, amplifiers, and loudspeakers.

      The student first learns about the individual operating parts of the harp. Then the discussion can move up to three distinct topics in system integration: 1) How all the separate components of the harp system work with each other. 2) And then, how the wind, strings, pick-ups, amplifiers, feed back magnetic forces, loud-speakers, work as a combined whole (i.e. a system) to make single musical frequencies. 3) And then, how a linear system, having been shown to work for all individual electrical component parts and play individual musical notes (frequencies), will be able to play complex mixtures of many musical instruments plus voice as an undistorted  algebraic sum of all inputs.



     The Venture Grant Harp and the USCA Camera Obscura, can make for some very exciting teaching possibilities in both physics and the  “Harp and Camera” cross disciplinary topics. I believe USCA now has a significant resource. It remains to be seen how well all of the above ideas actually make a contribution to the process of true and humane learning. 



[1] See Internet for Mr. Carroll's Vita and other related information. <a href="" TARGET="_blank"> View Mr. Carroll's Web Site.</a>

[2] A scientific article for publication plus a list of references to published articles on Aeolian phenomenon is in preparation and will be available upon request.

[3] This harp may also be played by human hands providing opportunities for qualitative scientific experimentation and even a simple musical performance.

[4] Two operating Aeolian Harp sculptures were visited (by Henry Gurr) under the auspices of  this grant: 1) A harp  made by   Mary and Bill Buchen located at “The Wilds”  a wild animal preserve, near Cumberland, Ohio. 2) A harp sculpture made by Rodney Carroll located at one of the Maryland-National Capitol Parks, near Damascus, Maryland. Two other harps thought to exist at the time of our grant writing were found to be unavailable.

[5] As described in a series of letters to Ms. Patricia Hatcher, USC Grants Office, actual construction of the Venture Grant Harp was considerably delayed and funds were combined to make just one harp. During the delay, Aeolian harp research  proceeded on two other Aeolian harps constructed by knowledgeable volunteers. The net result of the delay  is: 1) the creation of a much better Venture Grant Harp and 2)  consequently  this harp provides an advanced platform upon which to conduct further research.

[6] See Appendix  One  for Xerox copies of these articles.

[7] See Appendix  Two  for Xerox copies of these articles.

[8] The expert  assistance of Mr. James Taylor in making this experimental harp is hereby gratefully acknowledged.

[9] See Appendix  Three  for Xerox copies of these winning entries.

[10] See Appendix  Four  for a scale drawing of the design sent to Mr. Carroll.  More specific information concerning the Venture Grant Aeolian Harp will be sent on request.

[11] If necessary this figure could be confirmed by experts at McKissic Museum or elsewhere.

[12] This experimental harp apparatus was designed and constructed by  Dr. Geoffrey King.  Also Dr. King was quick to  recognized that under conditions of resonance, an Aeolian Harp can make excessively loud sounds. His response was to invent, construct, and deliver an electronic “automatic sound level compression” device that would solve the problem! Dr. King’s expert assistance in these and many other areas of this research are hereby gratefully acknowledged.

[13] Enhanced vibration  of the Aeolian string means the string itself has a larger amplitude of vibration (for a

   given wind speed) as a direct result of the applied electronic regenerative feedback.  Regenerative feedback enhanced string vibration is  to be distinguished from “ordinary electronic amplification” such as is achieved  in an electronic guitar. This latter amplification makes larger sound output from a loud speaker, but does not change the amplitude of the guitar string vibration. Ordinary electronic amplification, as well as Aeolian string electronic feedback regeneration  are both employed in the Venture Grant Harp. 

[14]  Although only a preliminary literature search on Aeolian harps has been completed,  most harps of which this investigator is aware, are estimated to have  shorter strings (and smaller diameter strings) than the Venture Harp. Possible exceptions are a 20 foot high harp in Puget Sound, Washington and various harps created by stringing overhead wires, and even overhead electrical power wires. This investigator is aware of only one other person making use of electronic amplification and no other persons using regeneration. Although the Puget Sound Harp uses rather wide flat steel bands, specific emphasis on larger diameter strings is absent in the literature seen. Sounding boards on traditional Aeolian harps are often very, very, inefficient at the low frequencies of large strings. This latter circumstance is where electronic amplification plus feed back regeneration can make a worthy improvement. 

[15]  See the discussion on the last two pages of this document for information concerning the Camera  Obscura. 

[16] Owen  Barfield,  The Rediscovery of Meaning and other Essays  (Wesleyan University Press, Middletown, CN, USA , 1977)

[17] The reader will note herein the natural usage of certain words  to convey ideas (for us) as a modern civilization. Marked with  (italics ) here and below are: inspiration, insight, image, imagination,  perspective, point of view. Barfield shows where and how these everyday, even scientific, words first came into being, and how we have been changed by  our use of science and knowledge which these words have spawned. 

[18] Additional illustrations of the harp/camera confluence may be found in “The Mirror and the Lamp” by M. H. Abrams, Literary Critic.

The reader will note the natural usage of certain words  to convey ideas for us as a “modern” people . Marked with  (italics ) above are: inspiration, insight, image, imagination,  perspective, point of view. Barfield shows where and how these everyday, even scientific, words came into being, and how we have been changed by our own use of science which they spawned. 


Cover Letter for Venture Grant Aeolian Harp Report.

22 February 1999


Ms. Patricia F. Hatcher

Venture Fund  Administrator

Office of  Sponsored Research

J. Byrnes Center

University of South Carolina

Columbia SC 29208


Dear Ms. Hatcher


Enclosed herewith is my Venture Fund Final Report. I trust it is up to the needed standards. Please tell me if I should supply any other information or recompose the documents enclosed. 


I can only apologize for the tardy arrival of these materials to your desk. My mother passed away in mid December 1998, and pressure of immediate duties with her estate put this final report on hold. I am sorry for any inconvenience this may have caused you.


Again, thank you for all your interest, support, and help with  our Venture Grant Harp. It would be my great pleasure to show you what the USC Venture Fund, and the combined will of concerned and dedicated people of the USC System have brought into being!


A really great Venture Grant Harp has finally come forth!!


So far as I am aware USAC is the only university/college that has a system similar (in any respect)  to the Venture Grant Aeolian Harp. 






           Henry S.  Gurr