Be careful with posting wrong or inaccurate information.
Effects are settings which are applied to a track.
Effects aren't downloadable by themselves, but you can download them along with a patch.
The word "effect" is, first of all, a very generic term that is used in many different ways. When you narrow it down to GarageBand, then there is a specific component, the so-called "Audio Effects Plugin" This is a like a little add-on application (a so-called Plugin) that is loaded onto a Track. You can manage that in the Inspector of the Smart Controls Window.
By adding a specific Audio FX Plugin to a Track you apply an "effect" to that audio signal on that Track. For example, a Delay Plugin to add a delay effect, a Reverb Plugin to add a reverb, or an EQ Plugin, to change the frequency response, etc.
So you apply (load) an Audio Effects Plugin to a Track and based on its settings it has a specific effect on the audio signal. The various onscreen controls in the Smart Controls Window lets you further adjust the parameters of those loaded Plugins.
Audio Effects Plugins are freely available on the internet (free and paid-for), can be downloaded and installed on your system so you can use them on your Tracks.
Patches are synthesized instruments, and yes, you are able to download them.
A so-called "Patch", the way it is used in GarageBand, is not a "Synthesized Instrument" (I don't know where you get that idea).
- A Patch is just a setting file with the .patch file extension.
- There are Factory Patches and User Patches (stored on your drive in two locations) and they are displayed in the Library Browser inside GarageBand.
- A Patch contains the settings of a specific Track, what type of Instrument Plugin, Audio Effects Plugins, configuration, any routing to other Tracks (hidden in GarageBand).
- A Patch does not contain any audio files or plugins itself, just information which plugins to load and how to adjust it.
- When you click on a Patch in the Library Browser all those settings stored with that Patch are loaded onto the currently selected Track.
- Different types of Tracks (MIDI, Audio, Drummer) have different types of Patches. You see that when selecting a different type of Track in the Tracks Area and the Library Browser displays different Patches.
Hope that helps
Edgar Rothermich - LogicProGEM.com
(Author of the "Graphically Enhanced Manuals")
'I may receive some form of compensation, financial or otherwise, from my recommendation or link.'