From the website:
Our library of sound samples has been specially recorded by members of the Philharmonia, and is free to use.
It includes all standard orchestral instruments, as well as guitar, mandolin, banjo, and a vast array of different percussion instruments.
https://philharmonia.co.uk/resources/sound-samples/
The sound samples can be used in spi.
If somebody can give a tutorial on how to convert these sound samples to synth so that usage is easier in spi.
Like use_syth :violin
a quick answer, afaik it’s not possible to use with use_synth :violin as natives synths are coming from “supercollider world” But you can use this samples with the sample instruction.
Here’s a list of thousands of free samples that may be of use to Sonic Pi users:
We have a sticky thread of samples and other resources… I just cant find it right now… (the latest
bunch of meds just kicked in, and I’m sort of… .confused)… someone knows where it is…
Please add these…
Eli…
Yes, that’s what @Eli was talking about 
@bcgreen24 - the above is a freely editable wiki post that anyone is allowed to add to - great idea to add your find there
Goodbye Ethan
Many thanks for your support, Sir.
‘Respec’.
Eli…