CD has laid back and uninvolving sound

What album were you comparing? Many modern CD's sound worse than high
quality Vinyl. The hyper compression of dynamics in the mastering process
makes many CD's sound harsh in your face and completely lacking subtlety,
nuance and "life".

I have two CD's of Duran Duran Rio. The first one is flat and terrible sounding.
The second one sounds much more like Vinyl. This second one was remastered
from the original master tapes and came out after the first CD. So it is a mixed
bag.

If you want to make an accurate comparison - try Mudcrutch by Tom Petty - the
vinyl comes with a audiophile CD made from the master tapes whilst the regular
CD release is compressed crap, as usual, thanks to the major labels.

Shadorne: that is interesting to have both the audiophile vinyl and CD in one package. I listened to Händels Messiah this afternoon (René Jacobs, Harmonia Mundi CD) and I found the midrange not so fleshed out and overall sound also less warm than vinyl. To me it is not only a matter of "bad" mastering but this type of sound is inherent to CD reproduction. Of course you can warm the sound up with tubes but then you would only change the cosmetics

If you are comparing two different recordings then there are so many variables that I am not sure one can draw a conclusion. Even with allegedly the "same" recording or from the same master tapes - differences will exist unless a special effort is made to ensure the CD is the same as the Vinyl master (as in Mudcrutch).

A fair comparison would be to run your Vinyl through a fairly good quality ADC and DAC from the same manufacturer (say Benchmark) and to see if you could tell the difference in a blind test (is it live Vinyl or is it memorex?). If you cannot then it is safe to assume that a CD made from the digital audio file from the ADC would as good.