General
A mandolin orchestra is almost exclusively composed of plucked string instruments like mandolins and guitars - only the double bass is a stranger as a bowed string instrument. Plucked string instruments are played with a plectrum or with the fingers. The double bass is played both with the fingers (pizzicato) and a bow (arco).
Mandolin
In most mandolin orchestra of this day and age, you'll find only Neapolitan and Roman mandolins (and relatives from the same instrument family). In the BMO these are instruments from such famous builders as Luigi Embergher (Italy), Reinhold Seiffert (Germany) and Alex Vervaet (Belgium).
 |
 |
 |
Embergher
|
Seiffert
|
Vervaet
|
| mandocello - mandola - mandoline |
mandoline - mandola - mandoline |
mandolines |
All instruments of the mandolin family have "courses", they have more than one string per pitch. The Neapolitan and Roman mandolin are tuned in quints. The strings are plucked with a plectrum, a small sort of "pen" that can be manufactured from various materials (tortoise shell, plastic).
The most common types of Roman and Neapolitan mandolin:
Mandolin:
tuning: g – d’ – a’ – e’’ (same as the violin)
role in the orchestra: soprano- and alto instrument
Mandola:
tuning: G – d – a – e’ (1 octave lower than the mandolin)
role in the orchestra: tenor instrument
Note: Some instruments that are part of the same family are now rare - almost a curiosum, except for the occasional part for the mandolcello:
Piccolo mandolin:
tuning: g’ – d’’ – a’’ – e’’’ (1 octave higher than the mandolin)
Alto mandolin:
tuning : c – g – d’ – a’ (1 quint lower than the mandolin)
Mandolcello:
tuning: C – G – d – a (1 quint lower than the mandola)
Mandola-basso:
tuning: G’ – D – A – e (1 octave lower than the mandola)
Mandolone:
tuning: C’ – G’ – D – A (1 octave lower than the mandolcello) or G’ – D – A – e (same as mandola-basso).
Guitars
The guitars in a mandolin orchestra are all of the classical, acoustic variety:
tuning: E – A – d – g – b – e’ (quarts, except g – b = third)
role in the orchestra: often bass instrument (accompaniment with bass voice and chords), sometimes also melodic parts
Double bass
The only bowed string instrument in a mandolin orchestra and because of that a bit of a stranger, is the double bass:
tuning: E’ – A’ – D’ – G (quarts– 1 octave lower than the lowest four strings of the guitar)
role in the orchestra: the bass instrument
used techniques: pizzicato and arco - with the fingers as well as with the bow.