Here are some recordings of Unaccompanied Psalm Singing. This is the old way of singing in the Scottish Presbyterian Churches. Unfortunately it has become very rare and even many congregations which still do it have adopted modern translations of the Psalms. In my church we still use the 1650 Metrical Psalms which were approved by the General Assembly of the Church of Scotland.
We believe the Biblical rule of worship, amongst other things, requires the exclusive singing of the Psalms without musical accompaniment. Nowadays you'll tend to only find this form of worship in the Highlands and Islands of Scotland, but some congregations in the Lowlands still do it. It once was the norm in all Protestant churches.
The first video is an example of Gaelic Psalm Singing. The precentor "puts out the line" which means he songs the line of the Psalm himself and then the line is repeated with the whole congregation joining in. Below that are some English singings (which is the vast majority of Psalm singing now, including my own congregation). English singing is a bit more "polished" sounding than in Gaelic (depending on the congregation!) but still very nice. And of course Biblical.
