Yes, `` is just "a smell". It is in fact neutral, but without `` in front of it, I usually perceive it as a bad one (as I also do with "smell" in English). Like if you say, "What a smell!" in English, I think most people would take this to mean a bad smell rather than a good one.
Also, to say "smells" or "producing a smell", the form is **** .
> * → A smell is coming from the kitchen.
> * → An aroma/good smell is coming from the kitchen.
>
Note that you will often hear `` even though it's kind of redundant.