I know this may sound barbaric but if you can get a supply of strong alcohol such as vodka (I leave you to imagine the options here) you can make very nice cordial by crushing (use a liquidiser) the fruit and mixing the pulp with the alcohol. After a couple of hours use a filter or strainer to remove the remains of the fruit and you get a very nice drink. I use 200grams of clean fruit with a litre of alcohol (or half a pound of fruit to a quart of alcohol).
If you prefer a clear drink, use a coffee filter to remove all the solids. This might take half an hour or so but it is cheap and reliable.
Don't leave the pulp in the mixture too long or the drink gets a woody taste.
This system works well with black/red currants. Blackberries produce a very pretty pink drink but there is little taste.
It's worth experimenting with different fruits and berries but start with strong alcohol and dilute to taste after mixing as the fruit will already reduce the alcohol content and you might get some strange by-products if there is any secondary fermentation.