One of the guiding principles for the part books I'm building is that they take into account that not everyone can be there all the time, either at rehearsals or performances. The idea is to create parts that suit the various instruments, but are generic enough that players can successfully jump around from playing lead to being accompaniment.
This past Sunday was the first time we've had just two treble instruments, trumpet and soprano sax, along with the two Eb tubas and percussion - and neither of our alto or tenor voices, the clarinet and trombone.
I played horn on two numbers, which are four voice suites I've been working on. One strings together a Renaissance dance, a troubadour part song, and Lillibulero (Purcell/Beggar's Opera). The other strings together that famous Jeremiah Clarke Trumpet tune with one by Purcell. With the horn on the tenor line they worked well (when I played the right notes).
On everything else I played the new acoustic steel string guitar with the on board mic run through a small keyboard amp. It had much the same effect of the C'ville horns coming to play with the Orange concert band. It gave a middle to the sound that the tubas could plug into from below and the sax and trumpet from above.
At our next little performance I'm thinking of putting mics in the bell of the tubas, so that like me on the guitar, they can work not so hard and yet get a better sound. At the last C'ville Municipal Band concert I was struck by how their three Bb tubas laid down this wonderful bass throughout all the numbers. They sort of created a primal river of sound that everyone else could float and swim along in.
I have an aversion to using amplification in our performances, because over the years, walking into events where there's amplification I've come to view amps as lethal weapons and to think that professional musicians using them are deaf (or that they're way more self involved than is healthy). Judicious use, though, can create a better ensemble mix than not using amplification (or sound reinforcement, which is a probably a better term).
The way I set the level for the guitar was to turn it up just enough so that what was coming out of the amp was about as loud as the guitar itself. I hardly noticed the amp was there, but for the other players it kept my sound steady whether I was facing them or facing out to the audience. This lets me move around as I always did doing music therapy sessions back in San Antonio. I can sing strongly enough to not need a mic in small scale performances like this one, and I much prefer it, as having the mic control where I am feels very constraining.
The deep lesson of what's been learned here has to do with balance. On all sorts of musical issues there's the forest/trees dynamic. Because of my focus on creating part books, that's what I was hearing. The way the guitar brought everything together made me realize I hadn't been hearing the forest. The part books are going to work best if there's a guitar, or rhythm keyboard, or an omnichord or autoharp to give that middle to the sound. You can get by without, but having one of them will make things much easier.
Another thing I was more reminded of than learned, was that rhythm guitar is my strong suit when it comes to music making. The new guitar is a joy to play, and the amplification makes it a whole new experience for me, and I had listened to a Michael Hedges CD here recently which led me to try some new textures. But mainly, I don't have to think about how I'm going to strum. There's a direct connection between the feeling I want and the strum just happening. Except for a few keyboard pieces I've been playing for decades, along with some Dylan songs I've been singing for 40 years, everything else I do musically requires a lot more "left brain" or conscious mental involvement. With rhythm guitar it's all intuition, feeling and sensation with very little thinking.