I'm trying to determine which of the following is better quality.

Xing (new) joint stereo VBR or
Lame 3.92 stereo 192KB CBR.

EncSpot gives me the green for both of them. The Xing one is 2.5mb smaller than the Lame one.

Your expertise is much appreciated. I'm not asking to encode, I'm asking as I have an album in both
formats and don't know which one is the better one quality wise.

- km

Me personally I would keep lame version because of really bad experiences with xing-ed mp3s (yeah, I know the new xing is supposedly much better than the old).
On the other hand I think you should trust your ears. In the end it is you who will listen to those mp3s. I would suggest using MP3Gain to get both album versions to the same loudness level and then listening with earphones.

LAME 192 kbit sounds very good to my ears, so in this case I wouldn't try to get better.

Xing (new) is hardly new...
LAME is king.
Personally I would prefer a 128kbps LAME to a 320kbps Xing.

Ok now you just sound like you hate Xing for no logical reason. Lame may be better then xing but it is silly to say that lame at 128 sounds better then Xing as 320. You make your whole point useless when you make baseless claims like that.

It'd be good to know the (average) bitrate of the Xing file. Telling the size of one of the files will do also.



Do you know some more details (e.g. what else does EncSpot let you know, what's the frequency cutoff in spectral view ...)

Probably the lame file is better, but IMO the Xing *could* be better if its bitrate is not much lower than 160kbps, the lame file has no (or very high) lowpass and you're not sensitive to pre-echo. (Pre-echo is my "favourite" artifact. All others are annoying to me if they're clearly noticable but pre-echo is not in most cases.)

I'd just listen to the lame files (or some of them) very carefully several times with good headphones. If you hear something that appears wrong (maybe do some artifact training before -> see FAQ) compare to the Xing file ...

Try these on both LAME and Xing:

http://lame.sourceforge.net/download/samples/

I didn't say it sounds better, I just said I'd prefer it.
At least with LAME I'd be more confident that there are no
artifacts...