Several things at work here. This should answer most of the issues raised here...
[PERFORMANCE CONTROL] is connected to the four rows of eight buttons by a dotted line that runs down the left side of the grid of buttons. This left side indicates that the first row of eight is
Part Select 1-8... Reading the number on the left side of the slash.
The second row of eight are “Part Mute” or Solo according to the two button on the far right of that row
The third row of eight are
Motion Sequence Select 1-8
The fourth row of eight are
Arp Select 1-8
[PART CONTROL] is connected to the four rows of eight buttons by a dotted line that runs down the right side of the grid of buttons.
The right side indicates that the first two rows of eight are
PartSelect 1-16... Reading the number on the right side of the slash.
The third row of eight is
Motion Sequence On/Off 1-8
The fourth row of eight is
Arp On/Off 1-8
If you are playing with
KBD CTRL Performances (which always occupy 1-8),
Performance Control is as advertised, it allows you to control, select Parts, and perform the current Performance. You have access to the eight possible Parts, you can Mute/Solo any of them, you can select a Motion Seq and select an Arp.
When
Part Control is most used, typically, you are working with an external DAW, where you likely will be using the 16 Part multi-timbral capability of MONTAGE; being able to directly select from all 16 Parts, you are able to Mute any of the 16 Parts and are able to Solo any of the 16 Parts. - you can selectively turn On and Off MS or Arps.
Now, when Category Searching... there are three kinds of Search for programmed sounds from Performance Home.
1) to select an entirely new Performance: “Performance Category Search” — two ways to get to this Search: press the dedicated button or tap the name to view a pop-in menu.
2) to select a new (“+”) Performance to “merge” with current Performance: “Performance Merge” — Touch a “+” in a Part slot
3) to select a new Part to
replace an existing Part - press a Part Select button, then use [SHIFT] + [CATEGORY SEARCH]: “Part x Category Search”
Pressing a Part Select button, then pressing [SHIFT] + [CATEGORY SEARCH] is
exactly the same as touching the Part Name; Touching that Part Name box which *selects* a Part, and it opens the pop-in menu to “Category Search”.
Example, say you’re building a Multi-timbral setup for use with a DAW, you would start by using “Performance Category Search” > Touch “Init” > Touch “Multi/GM”. This places an instrument in each of the 16 Parts. You would
replace the selected default Part with one you select. Part by Part substitute your selection.
When using this Part
replacement type Search, the last selected item’s Main/Sub Category remain, and the Part you last selected is highlighted in search grid. Say you are looking for a bass sound... once you set Main = Bass, and Sub = Electric, when ever you return to this Part, it will assume you are going to search for new Electric Bass, so that when press [SHIFT] + [CATEGORY SEARCH] it returns to Electric Bass in the search grid.
I notice that when I press the 'PERFORMANCE HOME' button, the 'CATEGORY SEARCH' button goes out and the 'PERFORMANCE CONTROL' button illuminates automatically.
The normal default is for the [PERFORMANCE CONTROL] button to light, when you initially recall a Performance. This is because it is the most useful for most Performances, but this is
programmer’s choice. For example, recall any of the Tone Wheel organ (B3) sounds where a flashing [PART CONTROL] is the default — it flashes to denote the Faders are now Element/Operator level instead of Part Volumes. This is a programming choice. It means the Faders can be used as pseudo-drawbars.
Press [SHIFT] + [PERFORMANCE (HOME)] to view the “Overview” screen. The top right side let’s you select whether “Performance Control”, “Part Control”, or “Element/Operator” is the active setting for the Performance. Why you set it a certain way can vary depending on what you use the Performance for...
If you are using a Performance as a 16 PART multi-timbral setup, you may opt to store the Performance with the [PART CONTROL] button lit, giving you access to all 16 Parts.
If you are using a Performance where you require individual Element Level control (as with B3 type sounds) you may opt for the "Element/Operator" option.
Normally there is only one of each Single Part Piano in the 'Preset' Category. There are 39 of them. But when I call up 'Category Search' from the 'Performance Home' screen by tapping on the Part title I want to change - it changes first to the 'User' Bank and I select the 'Preset' Bank, then the 'Single' Attribute, then 'Name' and 'Piano' to arrive back at the Preset Single Part Piano screen correctly - but there are 43 of them, not 39. This is because 4 of them are repeated - Concert Grand Piano, CP2007, Honkytonk, and Rock Brite Piano - those 4 appear twice each.
Next, repeat entries: You are using “Part x Category Search” - means you are replacing an existing Part. The discrepancy between the 39 Acoustic Pianos you see when searching “Performance Category Search” and the 43 you see when doing a “Part Category Search” comes down to the first time they are listed you are seeing just the Preset Single Performances. The second time it includes the “GM Bank” entries 001 “Concert Grand Piano”, 002 “Rock Brite Piano”, 003 “CP2007”, and 004 “Honkytonk”.... which are available as both.
GM (General MIDI) 128 Normal instruments — is 16 Categories with 8 sounds in each category: In the "Piano Category" the first four GM sounds are based on the Acoustic piano (one for classical/jazz, one for rock--the Brite piano is fashioned after a Yamaha C7 - arguably the most recorded piano in pop/rock music history due to its ubiquitous presence in top studios), one was clearly a Yamaha "CP" (so unique it made the GM set), and the Honkytonk, well, you have to have one, the next two are E.Pianos (one is a Rhodes, the other is a Yamaha DX EP), followed by the Harpsichord and the Clavinet.
These sounds are available as Single Part Performances
and are included in the pseudo-GM Bank. You will see they are actually in the instrument twice... once as Single Part Performances with an MSB/LSB locator:
MSB 64/LSB 14/PC 023 _ Concert Grand Piano
MSB 64/LSB 14/PC 024 _ Rock Brite Piano
MSB 64/LSB 14/PC 025 _ CP2007
MSB 64/LSB 14/PC 026 _ Honkytonk
And the other listing is from the GM BANK:
MSB 0/LSB 0/PC 001 _ Concert Grand Piano
MSB 0/LSB 0/PC 002 _ Rock Brite Piano
MSB 0/LSB 0/PC 003 _ CP2007
MSB 0/LSB 0/PC 004 _ Honkytonk
That is what you’re seeing when you “Part Category Search”. This allows you to recall it as whole Performance (all Parts change together) or as a Part on any MIDI Channel (only the specified Part is changed).
Say you wanted to send a MSB/LSB/PC to switch from “Seattle Sections” to the “Concert Grand Piano” you’d want to use 64/14/023
If however, you wanted to change just the sound in Part 13 to switch to “Concert Grand Piano” you’d want to use 0/0/001.
The pseudo-GM set that Yamaha fashions for the synths is NOT a separate GM chip, like most manufacturers do (they pop in a GM sound set which can fit on the head of a pin — and sounds different from the rest of their Synthesizer). Yamaha fore goes the Official GM logo, we break the rules and just fashion it out of sounds that are made from the same engine as all other sounds... with all the frills... Dual Inserts, 3-band and 2-band EQs, pre/post the Inserts, etc.,etc., etc. so the MSB/LSB/PC line up to the normal list of 128.
Hope that helps clarify the mysteries.