In terms of historical commercial recordings, I've found surprisingly little. One of the easier items to track down in the US is Songs & Dances of the Azores, a collection of various genres originally released on LP in the 1960s and now available on CD and digital download. Much of that release is drawn from the anthology of historic field recordings collected in the 1960s by the composer and ethnomusicologist Artur Santos: a beautifully remastered 4-CD set of music from São Miguel and a 2-CD set from Santa Maria (Santos also recorded on Terceira, and I hope that will eventually get released as well). Both of those are released by a wonderful label run by Emiliano Toste that specializes in traditional music, as well as some contemporary singer-songwriters. A lot of his huge catalog is recordings by modern folk groups – ranchos, tunas, philharmonic bands, choral groups, and other small groups.
There is also a collection of 78 RPM recordings at the Library of Congress, made in 1939 by Sidney Cowell (wife of the early experimental composer and world music advocate Henry Cowell) with immigrant musicians in Oakland, California.
Contemporary performances are easier to find. There are many regional groups (rancho folclórico) throughout Portugal who perform folk songs and dances in colorful traditional costumes that offer a rather idealized and nostalgic version of "peasant life." These exist in the Azores as well, and they can be seen performing at festivals and other public events. The most well-known and professional singing group seems to be Grupo Belaurora, originally from Capelas on the island of São Miguel.
There are also people who perform older songs on their own, similar to artists in the folk revival of the US and UK on the 1960s and 70s. Two good ones I've discovered from the Azores are Carlos Medeiros and Maria Antónia Esteves.
Perhaps the best place to learn about traditional music, and in fact music of all kinds throughout Portugal, is the amazing and wonderful project A Música Portuguesa a Gostar dela Própria, which is documenting on video a vast array of Portuguese music in every region and style, from the most traditional to current popular and even experimental forms. The genius behind this project is Tiago Pereira, who should be acknowledged as a modern national treasure.
Much of the folk music in the Azores, as in all of Portugal (and most of the world), is directly related to social dancing. Probably the most popular of these dances is the chamarrita, which is something like the "national folk dance" of the Azores and is still done throughout the islands.
But the style of traditional music that most intrigued me and seems most relevant to my own musical interests is called cantigas ao desafío ("challenge songs"). These are "song duels or argumentative discussions that range from the exposition of a topic or story, to the logical debate of a question or series of questions, to the joking exchange of personal criticisms. Two singers usually participate, but under certain circumstances there may be more. Each singer in his turn improvises a quatrain or a sextain, responding to the stanza just improvised by his interlocutor, or relating to the general topic under discussion. Singers (cantadores) are sometimes called repentistas because of their ability to respond quickly. In every duel or desafío (challenge)…a strong sense of competition between the singers also prevails. Even in song duels between close friends, the appearance of conflict and competition is maintained to increase audience interest." (Thomas L. Avery, Structure & Strategy in Azorean-Canadian Song Duels)
Versions of this occur in mainland Portugal as well, but it seems to be particularly associated with the Azores and is also performed frequently in North America (there are hundreds of YouTube videos). They are often performed during religious festas, or on special evenings of food and music (called cantoria) sponsored by a Holy Ghost Society to raise funds for an upcoming festa. The singers are usually older men. One notable exception is 18-year-old Maria Clara Costa, from Terceira, who has been singing desafíos since she was 12. Here she is at age 14, already looking completely self-assured against the much older Ramiro Nunes:
Musically, the structure is pretty basic: a repeated minor/major 2-chord progression, usually played on acoustic guitar plus one or two ornamenting instruments such as viola da terra (Azorean 12-string guitar) and/or guitarra portuguesa (typically associated with fado music); other instruments such as violin or bass are also used on occasion. Sometimes the singers have a quick comeback ready, other times they need a few bars to figure out what they'll do, so even though the music is pretty simple and even boring to play, the musicians have to stay on their toes so they can hit the turnaround whenever the singer is ready. With really good singers, one song can go on for an hour or longer, and it's interesting to observe their intense concentration and active listening, something they have in common with all kinds of improvisers. That focus is obvious in this lengthy duel between Maria Clara and Bruno Oliveira; also, notice how the audience starts off noisy but eventually gets sucked into the drama, cheering the singers after particularly witty stanzas:
This next video shows the cantigas happening in a very different context, much less formal and with multiple singers, one of whom is Bruno Oliveira, who was seen in the video above. This looks less like an official contest, and more like a casual singing session on the street during the festa. The guys are drinking beer and wearing street clothes, and the overall tone is a little rougher and rowdier.
So here we have a style of traditional music that is quite minimal (structurally reductive, repetitive, long duration) and improvisational — qualities that show up in much of my own music, though in very different form. Since my piece doesn't use singers, the improvisational influence from the cantigas ao desafío won't come via words. Instead, in one section of the piece I'm asking the wind players to take turns improvising melodic lines inspired by the desafío melodies, and these will be passed around between the musicians, who will each respond to the melody before them, embellishing and transforming the tune in their own ways.
This will be played over a heavily processed recording I made of Rafael Carvalho playing the decorative viola da terra part of the desafío. He is also heard at the end of the piece, playing a ghostly version of Saudade. Rafael is a fantastic young musician who I met in Ponta Delgada on the island of São Miguel. He's interesting because he is firmly rooted in all styles of traditional music, but he's also very adventurous and is really trying to take the instrument somewhere new in his original music, working with other folk, jazz, and classical players. I hope to be selling his CDs at the performance, and I encourage you to check them out. I would love for him to come play in the US someday.
I also really loved the music of the foliões, groups of men who march in the religious processions and sing beautifully austere praise songs, which reminded me a little of the alabados sung by the Penitente Brothers in New Mexico. The instrumentation varies depending on the circumstance (sometimes they use viola da terra and violin), but I particularly liked the groups that accompany themselves with only minimal percussion — drums, cymbals, tambourines. One of the groups I recorded at the Festa do Emigrante in Lajes das Flores is heard at one point in the piece.
The final Azorean musical influence on my project is the marching/philharmonic bands that seem to be in every major town in the islands. They accompany religious processions at the festas, but then they also play more formal concerts of popular and regional songs. While I haven't made an effort to emulate their actual music in this piece, in the recorded soundscape multiple bands are heard clashing (a nod to composer Charles Ives) and warming up (a nod to my buddy Chris DeLaurenti). They also inspired my choice of instrumentation of brass, woodwinds, and percussion. So just think of our group as a tiny, rag-tag marching band.