The samples that are only playing back in the left channel could be a few things:
- The samples are stereo files but only have audio in the left channel. This is unlikely, but could have occurred in some conversion process - if the original samples were in mono, and were converted by some utility (like a WAV > AIFF utility, or during an automatic conversion of .sf2 files or something) then it's possible. To verify, play the original samples in the Finder by just selecting them and hitting the spacebar, import one directly into an audio track in Logic, etc. Just double-check this.
- There could be a modulation routing in the middle row in the EXS ui that is routing some mod source to the designation "Pan". Just check that in case. Sometimes, when instruments are converted from some outside format to EXS format, these modulation routings can get borked or set to garbage / insane values. Just double-check this.
- Inside the EXS Editor, the individual zones and groups have Pan controls. Each sample and each Group can be panned. Click the Edit button at the upper right of the EXS front panel and see if that's the case. Once inside the Editor, you can click the Zones and Groups buttons at the upper left to toggle between viewing Zones settings and Groups settings.
The other folders that only have .wav/.aiff/.HO/.HDP files:
- The .HO extension is something I've never seen. Google says, "The HO file type is primarily associated with Knowledge Explorer Knowledge Representation Hierarchy Outline." So.... don't know what's up with those.
- The .HDP extension seems to be a photo file type. Google says, "The .hdp file extension is most commonly associated with files containing HD photos. ... It is used for the creation of high-resolution photo images. HDP files are similar to JPG files, but the HDP file format uses a higher rate of compression and the compression format is lossless rather than lossy." So... those might just be photos.
For the .wav and .aiff files, just dropping folders of samples into the Sampler Instruments folder won't do anything except slow down Logic whenever it needs to re-scan that folder, like every time it launches. To get them to be playable from the keyboard, you'll need to create EXS Instruments that map these across the keyboard (inside the Editor window) and set up the front panel controls like filter, ADSR, etc. To do this:
1 - Open the EXS Editor from the "edit" button at the upper right of the EXS front panel.
2 - In the Editor window, select "New" from the Instrument menu. This will create a new EXS Instrument, but it is NOT automatically saved. If you just close this window or quit Logic it will go away forever unless you save it to disc from the Editor using the "Save As" selection in that same Instrument menu.
3 - To get the sample into EXS, select "Load Multiple Samples" from the Zone menu. This will bring up a dialog where you can navigate to your samples folders, and the list at the bottom will show what samples will be imported. Double-click them in the list at the top to add them to this list. When you're ready, click "Done" and they will be imported.
4 - In the dialog that follows you can select how the samples will be mapped to the keyboard. "Auto Map" will attempt to find root key and mapping info embedded in the file's metadata, or extracting that info from the file names. This may or may not work as intended. If it does, fantastic - if not, you'll be doing some editing of the resulting Zones. "Drums" will just put each sample on a single key, set to "One Shot" mode with Loop turned off, and is really best for drums or one-shot fx samples. "Contiguous Zones" will let you specify a mapping scheme by setting the Zone Width and Start Note for the resulting map.
5 - Once the samples are mapped, you can manipulate the settings in the Editor to assign root note, key ranges, velocity ranges, etc. etc. etc. This is where the heavy lifting is done. You can select multiple Zones and then double-click a parameter and type in the value to set that parameter for all selected Zones, and you can mouse-scroll any numerical parameter to edit it. Selecting any number or Zones and dragging them to a Group in the list at the left will assign them to that Group, and dragging them to an empty space in the Groups list at the left will create a new Group and assign them to that Group. This is how you can do things like create Groups that are switched by sustain pedal, mod wheel position, etc. Note that you may or may not see all available parameters in either the Zones or Groups editors - the View menu lets you show/hide each parameter to reduce clutter.
6 - When done editing, you MUST save the Instrument from the editor window or it will go away FOREVER, instantly. So from the Instrument menu select "Save As" and specify where you want that Instrument to be stored (somewhere inside your Sampler Instruments folder or the folders that alias to it). Then the newly created Instrument should be visible in Logic's browser, the EXS pull-down on the front panel, and be ready for use.
Regarding Ultrabeat, it can be a little simpler to use when you just want to drop single-sample drum one-shots, but the UI is so fiddly that I rarely use it - but then again I am an EXS Jedi/Ninja so I just build stuff for EXS. Once you get the hang of the EXS Editor, saving Instruments, and knowing where to put them and how to access them, it's not hard at all.
Good luck!