Music has always been an important part of worship. And, since the time of Moses, instrumental music as well as vocal music has appeared in great variety. The tambourine, drums, the lyre, cymbals, lute, harp and trumpet were some of the instruments of the Old Testament. Vocal music appears to have been sung by individuals, small groups and the entire congregation. It was even done antiphonally.
Music was performed as an offering of praise and as a lament. It was used for teaching. It was used as preparation for worship, as in the songs of assent (though one could make a case that this was actually worship rather than preparation for worship).
Over the centuries, the music of worship changed. As new instruments were invented, they were used in worship. Different forms of music came and went. Music without accompaniment, as in Gregorian chant, was the only kind acceptable to some people for a time. Even today, there are groups that don't allow instrumental music in the church (though they are hard pressed to prove a Biblical justification for it). There was a time when music performed in a major key was considered immoral. That was followed by a time when the great majority of church music was played in major keys. Then there was the pipe organ... for a long time, the most popular church instrument, now, possibly supplanted by the guitar. Some songs were sung to the tunes of bar songs, and some religious music became popular in the secular world for a time, as did Amazing Grace, in the 1970's.
Vocal worship music varies from a single line melody to eight part antiphonal performances, from soloists to mass choirs, from melancholy to frantic, from a lullaby to an oratorio. If there is any word that best expresses what church music is and has been, it is probably "varied" or maybe "diverse".
Some of us have studied the techniques of using music most effectively in worship. Various "tricks" can be used to accomplish different ends. For example, loud percussion instruments can drive excitement and may literally, raise blood pressure. Loud accented trumpets, particularly in the upper registers would do the same, especially if supported with a solid base of sound from low brass. A soft, lyrical solo flute, played in a legato style would enhance a contemplative or relaxed attitude. Long tones in a minor key, particularly in a lower register might foster a sober, even sad, atmosphere. The words, if they are to carry a message, must be understandable. If not understandable, they become nothing more than instrumental texture. If certain words or syllables are more important, we can use pitch and dynamics to emphasize some and de-emphasize others. We can increase the time we perform a note, syllable, or word to make it more important, and we slip quickly over words that are assumed or are not so important. An important word or thought is better emphasized at the beginning or end of a phrase, and usually, where the music finds natural emphasis, as on the first or third beat of a 4/4 measure or the first beat of a 3/4 measure. An increasing tempo builds excitement, and a slowing tempo may allow or encourage the participant or listener to relax.
Any number of these techniques can be used, but to the average listener, they are transparent. The listener is only aware that the music was good or bad, or exciting or depressing. One has only to listen to a professional movie to begin to understand the power of these musical techniques.
If we want more people to participate, we have to make the music and words performable on their level. This means that words, melodies and rhythms must be intuitive and fit naturally with the way that people normally communicate. As much as we like to hear complicated sounds and rhythms, most of us are not capable of performing them, and therefore do not participate if we can't do so in a way that we feel we are successful. As an example, we always get more congregational participation when we do familiar songs than when we do unfamiliar ones. We also get more participation if people can anticipate where in the rhythm each word must be sung. That's one of the reasons that traditional church music has long been performed in what might be considered "predictable" styles... major or minor keys with elementary intervals and harmonies, and rhythms where the words flow in much the same manner as when spoken in normal conversation or poetry. That's why even uneducated people often sing very nice harmonies in the traditional hymns or popular music, but few people sing anything but the melody in the more contemporary styles of music.
One aspect of corporate worship is that we try to use or allow to be used, those gifts and talents with which God has endowed each person. Traditional harmonies and ranges, Soprano, Alto, Tenor and Bass, allow almost everyone to sing in a range that works for them. Over time, even people who have never studied music learned to make their own harmonies and counter melodies for the songs they love to sing so that they could perform them in a way that they felt was acceptable. Many "uncomfortable" singers are uncomfortable because the songs they would sing are out of their singing range, and therefore difficult to sing. Much of the contemporary music has no line suitable for low voiced singers.
Traditional music is a bridge between people. If I were to entertain in a nursing home, I would find wide-spread appreciation for the popular songs of the thirties, forties and early fifties. Everyone has many of those songs in their memory, somewhere. Likewise, the traditional songs of the faith, Amazing Grace, A Mighty Fortress is Our God, What a Friend and others, are always a unifying force when Christians of diverse backgrounds come together. Many children of today's churches are not learning those songs, and while an argument can be made that today's contemporary offerings are the unifying songs of the future, we have effectively thrown out a huge library, a
powerful unifying force that already exists. It's as if we decided that we will no longer use existing libraries of
books, and only use internet information... effectively denying any value of those books. We have, in fact, already done that by eliminating hymn books and showing only the words to the songs on our overheads. Many people learned to read music simply by seeing it in the hymn book as we sang the hymns. Even if they didn't know it, they learned to understand the relationship between the positions of the black dots and the direction of the melody.