When using LAME DLL with EAC, in the Compression Options/Waveform/Sample
Format pull down menu, what's the difference between "Preset CBR 192 kBit/s"
and "192 kBit/s 44100 Hz Stereo."

The Preset CBR settings are very weird - if you select a low setting - "Preset CBR 96 kBit/s" or a high setting - "Preset CBR 256 kBit/s" the mp3 is always encoded as 32 kBit/s???

Also why would you switch between "Use VBR quality" and "Use VBR average bitrate?"

It seems that the VBR quality number ONLY affects the "Minimum VBR" settings - it has no effect any of the Presets or the CBR (obviously) settings. I still don't know what the "Use average bitrate" button affects.

"VBR average bitrate" would be the ABR implentation. Regular VBR is generally recommended here but if you really need to keep the bitrate to a particular level you could go with ABR over CBR. LAME Recommended Settings

Those entries named with "preset" mean that they use the --alt-preset ( or now --preset ) commandline.
Concretely, it means they are --preset (fast) medium/standard/extreme/insane , --preset x or --preset cbr x ( being x a bitrate ).

The others do not use the --preset commandline so they don't use the internal benefits that the switch (generally) gives.

Note that using the "preset" ones is the recommended option.

However, since 3.94 presets are ALWAYS used in Lame.

But what's with the Preset CBR settings - now matter which one you use, 128 kbit/s or 256 kbit/s, the mp3 comes out 32 kbit/s???

One of the reasons the executable version is preferred to the DLL is EAC's disorganized interface to it. Switch to the EXE, set it up as outlined in Wiki for smooth encoding.

As for the DLL, if you must experiment, get the latest recommended version of (LAME 3.97b2 and unzip the DLL contained within to your EAC directory. You must be using the wrong DLL if you get 32 kbps files no matter what CBR preset you select in that dropdown box. Did you check those files with EncSpot or Mr. QuestionMan to determine their bitrate/encoding settings?

The difference between "Preset CBR 192 kBit/s" and "192 kBit/s 44100 Hz Stereo" is that the former maps to --preset cbr 192 (nspsytune), the latter to an oldschool gpsycho mode where you control parameters from the LAME DLL tab (under Compression settings). Besides the potential for producing encodes inferior to those done with a --preset, the second case has a serious drawback: no LAME Tag is written.
HTH

This is what it says in the EAC Wave Format Pulldown menu:

LAME MPEG Layer-3 Encoder v3.97 DLL v1.32

So I must have the correct version...

I tested three mp3s:

1. 192kbps 44100 Hz Stereo
2. Preset CBR 192 kbps
3. Preset Standard

MrQuestionMan showed this:

1. 192 kbps MPEG 1 Layer III LAME 3.97
2. 32 kbps MPEG 1 Layer III FhG
3. 133 kbps MPEG 1 Layer III LAME 3.97bv2 Preset Standard

What's with the FhG?

I tested LameDrop with CBR 192 and got this:

192 kbps MPEG 1 Layer III LAME 3.97b cbr192

So maybe the DLL is just quirky with EAC and doesn't allow the Preset CBRs to worl properly?

It is not the DLL, it is EAC's fault. I tested and could not reproduce this. Then it occured to me that the version I was using was v0.95b1. I downloaded the latest version (0.95b3), and it does exhibit the behavior you described. So I guess this is a bug particular to the latest version of EAC.