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Notes & Lines

Notes & Lines discusses the intersection of math, science, and technology with performing and visual arts. Topics include bizarre instruments, technically-minded musicians, and cross-pollination of science and art.

Acoustic Guitar Tonewoods

Posted July 26, 2014 12:00 AM by cheme_wordsmithy

I remember the day I received my acoustic guitar, and played it for the first time. In the moment, it seemed produced the most beautiful sound I had ever heard from an instrument of its kind. As my ears became attuned to more guitar music, I came to realize that the tonal quality of mine was nothing special. That realization drove me to delve deeper into the realm of acoustic guitar sound, and would help me find the right build for my next guitar a few years later.

As an amateur whittler and wood-worker, the beauty of wood is one of the reasons I think the acoustic guitar is such a neat instrument. Apart from maybe the body shape, the wood choice is the single most critical factor in determining the guitar's sound. What's more, different wood types can be chosen for each of the guitar's main body parts (top, back, sides, and bracing) to create a unique blends of look and tone.

Because wood comes from trees, which are living organisms, no two pieces are identical - each cut will have its own unique characteristics based on grain pattern, size, etc. A luthier (guitar-maker) must assess these characteristics to determine the musical quality of the wood piece for guitar building. Velocity of sound is perhaps the most important, and is a measure of how fast the wood transmits received energy. In other words, when you pluck a string, how will the wood respond to the energy of its vibration. Wood with a higher velocity of sound will generally have more colorful, lively, and accurate tones.

Characteristics like velocity of sound will vary by cut, but are also largely inherent in the wood based on its type (stereotypes of a sort, if you will). Different types of guitar woods (tonewoods as they are called) have different tonal qualities. The best tonewood for each musician will thus vary based on their playstyle. Here is an overview of some of the woods commonly used in guitar-making:

Spruce - Spruce is the acoustic guitar standard for soundboards, and comes in a number of species (Sitka being most commonly used). Spruce is a rigid, lightweight softwood with a high velocity of sound, and strikes a good balance of response for lighter and heavier playing styles.

Cedar - Cedar is a softwood with a balanced warm sound, and has a rich and quick response favorable to lighter playing styles.

Mahogany - As a topwood, mahogany (a hardwood) has a relatively low velocity of sound and high density, giving it a very mellow, warm, somewhat "punchy" sound suitable to country-blues music.

Koa - Koa is a hardwood similar to mahogany, with a solid tone throughout, with heavier emphasis on the mid-range.

Maple - Maple has a high degree of internal dampening and lower velocity of sound. This gives a heavy emphasis on the high range and a very bright tone, that contrasts well with the warm nature of finger-picking.

Rosewood - Rosewood is known for its high response rate, with a darker tone throughout most of its range, and a strong bottom end. It's broad range gives it presence in any style of music, finger-picking or pick-style playing.

The complexity of tonewoods goes well beyond this overview, as their are many more in this list I did not mention. In addition, the back, sides, top, and bracing on a guitar can all be made of different woods to create unique varieties of sound.

I'd be interested to hear what you fellow musician and/or woodworker CR4ers have to say. Do you own or have you ever made a wooden instrument? By sound or by application, do you have a favorite type of wood for your instrument?

Sources

Sweetwater.com

Davesguitar.com

Pantheonguitars.com

Tonewood Data Source

14 comments; last comment on 08/06/2014
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For Love of the Index

Posted May 09, 2014 12:00 AM by Hannes
Pathfinder Tags: books index indexing

If you're a literate human who's a (diligent) knowledge worker or (diligent) student, chances are you've used an index this week. Or at least you did, back when you had routine physical contact with printed books. You might not think of it on a regular basis, but most of those indexes (not indices; those are the financial tools) were created by a freelancer who specializes in reading book manuscripts really closely and mapping their contents. Book indexing is an old-school craft: some professionals still use a pencil and paper to organize headings and topics before working them into index format.

I considered starting a freelance indexing firm myself during the dark days between grad school and professional success. That is, until I envisioned the sleepless nights over 36-hour turnarounds and the increasing eyeglass prescriptions and headaches caused by daily manuscript reviews. I'm retrospectively happy I avoided this career path and its idiosyncrasies, beginning with the big one: the unreasonable, nearly unmanageable deadlines.

In an industry known for tight deadlines, indexing is the last step in the publishing process: the author completes the manuscript, the editor corrects it, the author rewrites, the editor edits again, and off it goes for an index. All an indexer really needs is a completed manuscript to do his or her job, but that 600-page manuscript is probably two weeks delayed already, resulting in a 48-hour deadline (and two sleepless nights). The index might be complete when the publisher announces that pages have been cut or added; in that case, it's now useless and has to be rewritten on an even tighter deadline. I'm imagining stuff like this might occasionally happen on engineering projects too, yes?

Technological development stresses this industry out, as it's done for many antiquated professions. E-books and digital prints are becoming more common, with most reader software incorporating some form of full-text search. Heck, everybody knows how to CTRL+F these days. Authors and publishers are becoming dubious of paying freelancers (typically $3 to $6 per indexed page) and instead are using proprietary software to scan their manuscripts and generate an instant index in a matter of minutes; and it's more or less free. By all indications the profession may be imploding: the U.S. government-backed basic indexing course (which was curiously run by the Department of Agriculture for over 35 years) will cease to exist after September 30th of this year, although in fairness this seems to be part of a larger scale-back of older USDA distance education programs.

Manual indexing is still an extremely useful and necessary practice despite its faults. As hashed to death in previous blog posts, indexers (and humans in general) can do what automated systems can't: they can really and truly think. Indexing is a precise, strategic craft which involves planting markers - Hansel-and-Gretel-like breadcrumbs - where readers are likely to find them. Indexers use tools such as cross-references, see's, and see also's to anticipate user needs and point queries in the right direction. Since the vast majority of freelance indexers are library school-trained individuals who longed for an entirely different form of tedium, indexers are pretty adept at (and usually enjoy) making stuff findable and helping users find it.

Indexes help users find correct topical information at high speeds; you're not just CTRL+F'ing (this post has now officially graduated from PG to PG-13) for individual terms, but instead are finding the knowledge you need. Sure, you may have to turn a few pages (or, in the case of e-readers, scroll a bit), but if the index is good and you have a vague idea of what you're looking for, you'll pick it out. Even if you don't know what you're looking for or at, there's still hope: indexes were the original semantic search engine. Confused about references to Eric Arthur Blair in a text about 20th-century British writers? The index can quickly assure you that you're in fact reading about Orwell, George. Finding references to Cristobal Colon in Spanish primary sources? See also Columbus, Christopher.

While it briefly attracted my attention as a career, indexing wound up in the junk bin alongside my aspirations to become a musicology professor and indiepop star. These days some consider it the rotting branch of the publishing industry. (Well, magazines…and books…but…OK, there are several rotting branches of the publishing industry.) Some indexers (namely the ones doing good business) insist all is well in their world, others believe their ship has taken on water but is still afloat, and many wail that the profession is hopelessly outmoded has been dying a slow, agonizing death for decades. Regardless of its current state, indexing is a largely anonymous, specialized profession that gets little notice or consideration from the world at large. So, next time you use a book (!) instead of Google to nail a research paper or win a bet over some useless factoid, think of the indexer who toiled to help you out.

Image credits: Chronicle of Higher Education | ShirtWoot!

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Wait...What'd I Just Say?

Posted March 27, 2014 12:00 AM by Hannes

Several months ago, an acquaintance decided to try out a speech recognition software program to cure writer's block. He found it to be quite "intelligent" for a $50 piece of software - the calibration process was copious but effective, and the program supposedly "learns" based on corrected mistakes in order to eliminate future mistakes before they occur. By his account, the program was difficult to adjust to and absolutely mangled European names, but on the whole he was happy with it.

Speech recognition programs fall within the realm of natural language processing (NLP), which combines computer science, linguistics, and artificial intelligence principles with an eye toward reliable interaction between computers and natural human language. Like other AI fields, NLP has made great progress but still leaves a lot to be desired. Language is heavily rule-based but is also capable of great ambiguity, which of course leads to difficulties even in human-to-human communication. Throughout history, lexicographers and great thinkers alike have developed ambiguous example sentences to demonstrate the subtlety and craftiness which makes human language unique and baffling.

Ambiguity often depends on punctuation, as witnessed by recent memes demonstrating the importance of commas using the statements "Let's eat, grandma!" and "Let's eat grandma!" One of the earliest examples of this type of lexical ambiguity dates to 1327. Shortly after the murder of Edward II of England in that year, one of the king's prison officers received a note which read "Edwardum occidere nolite timere bonum est." This statement could mean one of two very different things depending on how it's punctuated. Place a semicolon after nolite and it means "Do not kill Edward; it is good to be afraid of doing this", while a semicolon after timere renders it "Do not be afraid to kill Edward; doing so is good." The meaning of this note has been widely discussed for centuries.

Homonyms - words which share identical spelling and (usually) pronunciation but have different meanings - also contribute significantly to ambiguity. This phrase was crafted by William Rapaport, a professor at the University of Buffalo, in 1972:

"Buffalo buffalo Buffalo buffalo buffalo buffalo Buffalo buffalo."

Through the use of homonyms, Rapaport designed this grammatical sentence to appear nonsensical. The sentence relies on three different forms of the word "buffalo": as a proper noun (the city in New York), a noun (the large ungulates also known as "bison"), and a verb ("to bully"). By interpreting these usages we can translate the sentence as "Buffalo bison [that other] Buffalo bison bully, [themselves] bully Buffalo bison."

The most common thread behind miscommunication is syntactic ambiguity, or the simple fact that identical sentences and words may carry different contextual meanings. A famous example which plays on the words "fly" and "like" is the sentence pair "Time flies like an arrow. Fruit flies like a banana."

Other instances include:

"We saw her duck."

"Flying planes can be dangerous."

"He saw that gas can explode."

Logical statements can be made even more confusing by combining multiple ambiguities. For example, the statement "The old man the boats" appears to be nonsensical because of the common qualified noun "old man." By playing into our immediate assumption that "old" qualifies "man," this sentence leads us to believe that it's gibberish, but by rereading it and considering "old" as a noun and "man" as a verb we find that it's grammatical. This sentence in particular serves as a kind of verbal optical illusion: by blocking out "the boats" we see the noun "old man," but considering the whole sentence we interpret something completely different.

NLP will probably follow the same old AI destiny: it can make inanimate objects appear intelligent, but they still won't understand meaning or context. (Even Siri's legendary snarkiness is just programming, after all.) And, as this post hopefully shows, even human-to-human speech can be impossibly confusing based on misinterpretation of meaning and context. Besides, eschewing ambiguity would also result in the loss of scores of classic jokes; ask Groucho about that one.

Image credits: Information Insights | Speculative Grammarian

8 comments; last comment on 04/02/2014
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Musical Engineers and Scientists: The Russian Five

Posted February 25, 2014 12:00 AM by Hannes
Pathfinder Tags: borodin cui russian music

As the eyes of the world shift from Russia and Sochi following the 2014 Winter Olympics, it might be neat to focus on a sorely neglected topic here in the West: Russian music. Most mentions of Russian composers are buried in music textbooks and stand out due to their unpronounceable names and tales of extreme poverty and alcoholism (sounds a bit like your first frat party, doesn't it?). But the influence of many Russians - including The Five, a circle of late-19th-century musicians who helped define Russian nationalism - is still evident today. This group is particularly interesting in that the backgrounds of all five men contain significant ties to science, mathematics, and engineering.

The Five: Balakirev, Borodin, Cui, Mussorgsky, and Rimsky-Korsakov

Alexander Borodin is a prime example. He attended the Medical-Surgical Academy in St. Petersburg and followed his education with several years of advanced study in chemistry. In 1862, he received a professorship in chemistry at the Academy and spent his days lecturing, conducting research, and as a practicing physician. His research, including nucleophilic displacement and other reactions of aldehydes, was influential. He independently discovered the Aldol reaction in 1872 and is listed as a co-creator. The Soviet Union went so far as to promote the 1939 Hunsdiecker reaction as the "Borodin reaction," claiming their long-deceased denizen did more significant work toward the discovery than the Hunsdieckers did.

Borodin's aldol reaction and bust.

Borodin treated music as more of a serious hobby, but some of his works are still performed today. His Slavic opera Prince Igor and the similarly exotic In the Steppes of Central Asia are regarded as cornerstones of Russian nationalist music. The popular 1953 song "Stranger in Paradise" was adapted from a Borodin melody heard in Prince Igor.

Cesar Cui, another of The Five, was born in present-day Lithuania to French and Russian parents. He attended the Military Engineering-Technical University in St. Petersburg for secondary and advanced studies and devoted his professional life to the study of fortifications after graduating in 1857. Cui became an expert on the subject: he published numerous books and papers on military architecture and served as fortifications adviser to the Imperial family. After a frontline assignment in the Russo-Turkish War, he secured a professorship in 1880 and became a general in 1906. Cui's music is less-performed than that of other members of The Five, and he is best remembered as an influential music critic, producing nearly 800 articles over the course of his lifetime.

Other members of The Five had similar backgrounds, but ultimately attempted music as a profession, with varying degrees of success:

-Modest Mussorgsky attended Cadet School to facilitate a military career but wound up working most of his life as a civil servant in various offices. He's best known for his highly original pieces Pictures at an Exhibition and St. John's Eve on Bald Mountain (usually known as Night on Bald Mountain). Mussorgsky's professional and musical careers were both cut short by severe alcoholism, which ultimately killed him in 1881 at the age of 42. His final portrait painted days before his death, shown here, is often cited as a classic depiction of the ravages of alcoholism.

-Nikolai Rimsky-Korsakov studied mathematics and navigational sciences in St. Petersburg before ultimately joining the Russian navy. He was soon composing full-time, however, and became one of the most important Russian composers in history. His works, including Scheherazade, musical treatises, and "corrected" versions of Mussorgsky's pieces, are frequently encountered today. (The closing number from Disney's Fantasia, in fact, is a hacked up version of Rimsky-Korsakov's edition of Mussorgsky's Bald Mountain.)

-Mily Balakirev, often thought of as the leader of The Five, studied mathematics at university but immediately focused on music upon graduating. He made his (meager) living as a piano and composition teacher and burned out relatively early, breaking with The Five and suffering several nervous breakdowns with periods of acute depression.

It's difficult to determine whether The Five's common roots in math and science were due to their shared musicality or simply the state of Russian education at the time. Interestingly, their works don't show a particularly mathematical flavor as do those of contemporary pieces by Brahms, for example. It's since been proven that there's a concrete link between musicality and performance in math and science, so maybe the music came first?

Image credits: Naxos | John Wiley and Sons | Lafayette College

4 comments; last comment on 02/27/2014
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Redesigning the Acoustic Guitar

Posted January 23, 2014 12:00 AM by cheme_wordsmithy

As a musician, I am foremost a singer. I love to play my vocal chords. Unfortunately, it's not always easy and fun to make music without an instrument behind the singing. Enter the guitar, one of the few instruments that allows the freedom to sing and play at the same time. My first came into my hands about 9 years ago, and I haven't looked back since.

The acoustic guitar is one of the most versatile instruments ever made, as evidenced by the use and evolution of guitar-like instruments through the centuries. It is also (in my opinion) one of the most beautiful sounding and beautifully made. The earliest "guitarish" stringed instruments called tanburs date back to Ancient Egypt, 3500-4000 years ago. Designs changed as time passed and ideas were passed through different cultures; most, like the European lute, were small bodied with less than five strings. It wasn't until the mid 19th century that the modern six string acoustic guitar began to take shape, with Antonion Torres' invention of the classical guitar. The larger body size and modified proportions improved the guitar's volume and tone; over 160 years later, this design remains largely the same.

Dan Bouillez's new guitar design is an attempt to change that. His guitar is shaped and sized like a regular guitar, with one major difference - the soundboard.

The soundboard on a guitar is the top face of wood where most of the sound generation occurs. When a note on a guitar is played, the vibration from the string is channeled through the bridge to the soundboard, which then also vibrates and causes the tone to resonate into the body and project (typically) out the soundhole in the center. Most acoustic guitars have a fixed soundboard attached around its perimeter to the side pieces.

The Bouillez guitar is different. It boasts a "floating" soundboard that is not connected to the guitar sides at all, but instead is connected to the rest of the guitar only at the bridge. The soundboard is pressed against the neck block and tail block inside the body, and is supported by the "downward and tensile force of the strings". In addition, the soundboard uses a goatskin material, and its thickness is 1/10 of that of a normal guitar board. The Bouillez design allows the soundboard more freedom to vibrate, supposedly creating clearer tones, improved response, and better tone.

I applaud Dan Bouillez for engineering a unique alternative to today's all-too-familiar guitar construction. But how does it sound? After listening to this video of Jesse Solomon playing the Bouillez, I think the sound has the slight flavor of a banjo, fast response and clear tones but a bit metallic and mechanical. Music is in the ears of the listener, of course, and to be sure the music would be better with a higher quality recording. But take a listen and tell me what you think.

Sources:

Bouillez Acoustic Guitar - gizmag.com

Bouillez Acoustics

Guitar images from dannycenter.org, introductiontoguitar.com, and gizmag.com

5 comments; last comment on 01/24/2014
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Montefiore Prescribes Eno

Posted May 03, 2013 10:00 AM by Hannes

Brian Eno has worn many hats over the course of his 64-year life: glam rocker, experimental composer, influential producer (for no less than David Bowie, Talking Heads, Devo, U2, and Coldplay), artist, writer, and political activist. As of late, the English musician has brought his unique talents to the completely different arena of healthcare.

The Independent recently reported that Eno had installed two "ambient sound installations" - for the purpose of creating a serene environment for patrons - at the newly-renovated Montefiore Hospital in Hove, East Sussex, England. One of the installations is generative - created to constantly evolve and never repeat using complex algorithms - while the other is a predetermined soundtrack album accompanied by ambient lighting and art. (The image at right shows Eno with one the art installations at Montefiore.) Public music installations are not unfamiliar to Eno: his well-known 1978 album Ambient 1: Music for Airports was devised to calm nervous fliers in airport terminals.

As an electronic music pioneer, Eno was instrumental in the conception and development of both ambient and "discreet" (a term of his own invention) music. Ambient music is defined as that which focuses more on sonic textures than the more traditional cornerstones of rhythm and melody. Most of Eno's ambient music is very slow and sprawling, with gradual musical changes. (Eno himself has confessed that he typically plays and records his ambient pieces at a normal pace, then slows down the tape.) Discreet music is a type of ambient music - based on the eccentric "furniture music" derived by early-20th century French impressionists - designed not to be explicitly heard but to blend in with an environment and its surroundings and be perceived like a piece of furniture. This probably explains why the hospital was so eager to contract with Eno to enhance their "three-dimensional, all-embracing means of treating patients" - the idea is for the patient or visitor to be comforted and soothed without explicit awareness of what is comforting them.

Just as Eno is no stranger to ambient music, the medical profession is well-acquainted with the benefits of music therapy. Decades of research has shown that music improves patients afflicted with mood disorders, schizophrenia, aftereffects of stroke, Alzheimer's, dementia, and heart disease, as well as children with developmental disabilities. If Eno's ambient installations prove successful at Montefiore, I would hope other medical centers follow their lead and proactively work to comfort those likely to be experiencing stress or trauma.

(Image credit: Long Now Foundation)

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