inquiry

Can you do CMD-z, or go back in the Undo list to get the regions back? If so will it always then recur if you try to do that same drag action again?

First do you have your MIDI notes at full velocity? (In the Piano Roll, select the Velocity tool and drag up on the notes until red). Note that for some complexly-programmed instruments, this may change the sound of the notes in addition to making them louder. Then on the EXS front panel you can adjust the overall volume -- see p. 408 of the Instruments and Effects manual. If you want to get into detailed EXS editing, you can adjust the volume of individual samples in the EXS Editor window. Nothing particularly bad about using the Gain plug-in to boost volume though if that works for you.

I've never heard of this -- what exactly causes it? Dragging multiple regions (audio, softsynth)? Dragging the end(s) of region(s) to/over the beginnings of other regions? If audio, does it matter whether the regions are contiguous in the same audio file, separated regions of the same audio file, separate audio files?

There are a few things that might be going on here. Sometimes the Piano Roll display decides to jump up vertically after you pencil in a note, so you may be pencilling in new notes in the wrong place. This would produce very obvious (probably higher) notes. If the changes are the "tone" not note, it's probably a synth that changes its sound on purpose automatically over time, or that you have accidentally entered automation data (in the Piano Roll, or main Arrange tracks) that is changing parameters on the synth. Read Chapter 10, Chapter 16 and Chapter 26 in the main Logic User Manual, and read the section for the particular plug-in synth you are using in the Logic Instruments and Effects manual. Then open the synth plug-in you are using and play around with its controls.

They may be 8bit or 32bit which Logic can't read, or just have some unusual header data. In any of those cases you'll need to open them and resave them in another app first. If you have Logic Studio see if one will open in Soundtrack Pro. If so, you can set up STPro to batch process them (see STPro manual).

What is producing the drum sound? EXS, UB, external hardware synth?

That shouldn't be happening at all. Try saving a copy of the project, restarting your computer, and seeing if the regions have reappeared. Also look in the Bin to see if the regions of the audio file still exist there. (Though may be hard to figure out if you have a lot of regions for that audio file.) If you can reproduce this happening consistently by doing something (dragging 4 regions at once?) then it should get reported as a bug.

Just to clarify, the things in the main Arrange panel are "Tracks" the things in the Mixer are "Channel Strips". You can (vertically) resize Tracks in all sorts of ways. You can't (horizontally or vertically) resize Channel Strips at all.

Everyone complains about this -- hopefully Santa's got the elves at work on it for L9...

If you want to be diligent, report the problem to Apple at: http://www.apple.com/feedback/logicpro.html It's best if you can try to recreate it first. Let them know whether it always or only sometimes happens.

13 milliseconds? That's 573 samples @ 44.1kHz. Do you mean 13 samples?

I don't know about your particular situation, but this sort of thing would be very typical for Logic. I think the key commands might be saved by default as part of your main Logic preferences, so if you have backed up a copy of: USER/Library/Preferences/com.apple.logic.pro.plist Replacing that may give you back your key commands. You should of course back up your entire OSX user folder regularly -- Time Machine will do it for you. Also you can "export" your set of key commands from the key commands window (in the Options dropdown menu). Good to do that and back up the copy in case you need to restore just the key commands and not all the app preferences.

Yes, definitely need a "high precision mode/legacy mode" switch (in Extended Parameters section).

It depends on the audio file in question. Many sample files in the Logic library have sloppy starts, with lots of (nearly) silent samples before the waveform really begins. Some sample files may have a nicely trimmed start, but the nature of the drum sound (a longer initial "thump") means that sloping off the start will be unnoticeable (or virtually so).

With a tightly-trimmed 909 kick, the 32-sample UB attack (silence+slope) is producing not only a detectable difference in "punch", but the whole tone of the kick itself is very noticeably altered (psycho-acoustic phenomenon it seems).