Hi Martin,
I think that you have a Tyros4 and if so, the following applies.
Voices with the file extension '.UVN' (or '.UVD' for drum voices) are expansion voices which must be installed in your keyboard before you can use them. A '.UVI' file is not a voice, but a 'library' file which can be used to load multiple voices automatically. It is just a simple text file containing a list of UVN or UVD files, where to find them, and which 'slot' in the Custom Voice Table to load them into.
UVN and UVD voice files are of two types.
One type only uses existing wave samples which are already built in to your keyboard's wave ROM.
The other type contains new wave samples which must be loaded into the expansion memory module. This is done automatically as part of installing the voices.
Unfortunately Yamaha use the same file extension for both types! However you can usually tell which type they are (and hence whether they need expansion memory or not) if you look at their file sizes on a computer.
Voices without new samples will be very small (typically a few KB) and can be used without expansion memory.
Voices containing new wave samples will usually be much larger (typically starting at a few hundred KB and going up to hundreds of MB). To use this type you must have expansion memory fitted.
Both types must be installed into the Custom Voice table on the preset drive of your T4 before you can use them.
This is done either individually using the 'Individual Load' option on the screen that opens when you press the 'VOICE CREATOR' panel button (in the group just to the right of the display), or if you have a UVI library file that includes the voices that you want to load, you can use the 'Library Load' option (you can open it in a text editor to see which voices it includes and where it will install each one).
Each position or 'slot' in the Custom Voice table has an address permanently assigned to it which acts as the voice ID. These IDs range from 063-000-001 to 063-000-128 for the 128 max. 'normal' voices, and 062-000-001 to 062-000-020 for the 20 max. drum voices.
When voices are loaded into the Custom Voice table, they are associated with the address (voice ID) assigned to the 'slot' that they are in. When you select one of these voices, you are actually selecting the 'slot', and the voice that sounds will be whatever is actually installed in that slot at that time!
This means that you can use custom voices in styles, MIDIs and Multi Pads, but bear in mind that if you change the voice that is installed in a particular slot in the future, it will be the voice in the slot at that time that sounds!
Note that Yamaha Premium Voice Packs are installed using a different method, and are automatically loaded into a different part of the table. They do not use up any of the 128 normal voice or 20 drum voice slots.
Information about loading, managing, and even creating custom voices is contained in the 'Tyros4 Reference Manual', which is not the same as the 'Owner's Manual'! You can download it if necessary from the following link...
https://uk.yamaha.com/files/download/other_assets/4/314654/tyros4_en_rm_a1.pdf Regards
Ian
