Add new or change music filters

[DrByte]

Yes, you're not explaining it well.

You're assuming the music system will "just work" for whatever unexplained use you intend to apply it to. CAN YOU PLEASE BE MUCH MORE SPECIFIC?

The music filters re-use some internal things, such as (but not limited to) repurposing the 'manufacturer' for 'artists' ... and simply repurposing is very different than adding additional custom fields for very custom data that you wish to filter by.

WHAT do you want to filter?
WHAT extra data will you need to collect in order to filter it?
WHAT business problem will all of this specifically solve?
WHAT exact pieces of the "music filter" are the things you want to mimic? There are numerous things in the music stuff. Is it the sidebox dropdowns that you want? Is it the display of certain info on the product-info page that you want? Is it certain controls on the admin back-end that you want? Is it certain search-isolation things that you want, and which ones?
etc
etc
etc

Explain your end goal, and maybe we can help you better. You're jumping into presuming a certain technical implementation before first explaining the problem that you want to solve.

[AlteredVision]

I have an automotive website that sells all kinds of parts for your vehicle. Using categories is fine but I want something a little better and more of an industry standard. What I need to have is a way to filter results with keywords, like manufactures does. I want to group a bunch of items into 1 group but also have them in another group all done inside the item itself. This way I can have the manufacture as the main categorize making it easy to put all their items on sale and update them and also giving the customer a way to find the product through several variables. I have several manufactures and the parts fit into different categories.

I want it setup just like the music product type where I can have one item go into several filters.

My filters need to be:
Manufactures
Suspension
Drive-train
Performance
Interior
Exterior

[DrByte]

I recall someone posting about a purchasable addon that is catered to the auto parts industry. I'm guessing that it takes into account all the things you're mentioning. Maybe it's worth exploring rather than reinventing it all. Might be some free plugins already available too.

To write it yourself, much like the book product-type, you will need to add various extra custom fields to the database, add those fields to all relevant forms in the front-end and the admin, add validation logic to make sure submitted data is accurate, add extra search fields and build the logic to accommodate those fields during search requests, perhaps add pulldown menus for filtering, etc.
Existing product-type plugins will help you see which files are involved with most things related to custom product-types ... which is basically what you're talking about.

You said you want to expand the existing manufacturer keyword filter ... but if I'm following your wording correctly, I think you're making an assumption about "keywords" that doesn't accurately match to "manufacturers". Manufacturers are stored as a list of numbers with corresponding names, and if someone wants to filter by a manufacturer, they pick from a list of names which then sets the filter id to the number associated with that manufacturer, thus returning only the entries for that manufacturer. No keywords at all. The music filters work the very same way: a bunch of predefined values associated with names, and those values/numbers are stored in a table related to the product, so that lookups can be done based on the selected numbers.