The thousends of wav files are digitized with SONAR from a lot of tapes and the customer wants to have a collection where the files have nearly the same volume / loudness.
I search a "professional" tool - not a amateuer freeware.
There a lot of amateur tools for MP3, like MP3Gain, but I search the same tool for wavefiles.
I have Wavlab and Adobe Audio, but this DAWs make complex operations to the wavefiles like limiting and compressing. We only want to raise or lower the volume of each file and render the file with the new voulme. No compressing, no limiting.
Normalising to -0,2 dB makes not really sense, because the songs are from 1950 to 1990 and have a very differnet loudness.
The tool should listen to a lot of files and then begin to render the files.
 
I searched the internet, but I find nothing, that is professional. I find Nugen AMB Loudness Module, but 2377 $ is too much.
Has anybody ever done that and found a good tool?

Check out TC Electronics LCn Loudness Correct using the Watch folder feature.
I don't think either TC or Nugen's demos are restricted. I would demo & see if they work for you.

TC Electronic's LCn Loundness Correct's standalone app does this I think
http://www.tcelectronic.com/lcn/
 

Have you tried the options to the algorithms in Adobe Audition (I think that is what you have)? I have CS5.5, so some of the GUI may be different. Under Effects->Match Volume, there are 5 "Match to" options under the settings button in the lower left. "Perceived Loudness" may be the one you are seeking, and I *thought* that it generated a static rise/drop for each file, but not sure now that you imply it does not. The "Limiter" portion is the only option I have in that dialog, which is just to prevent clipping when folks get aggressive with volume increases.

Thank you, this is exact what I'm searching for.
I will make a test with the LCn Loudness Correct. It's only 99$.
And also a test with Adobe Edition Match Volume.
Let's see what is better.

LCn Loudness Correct looks like an interesting tool, but it seems odd they would have gone to all that work and don't support VST plug-in and don't support MP3s.

Technically VSTs have no way of processing an entire file.  Which is why they don't have a VST version of this.  It's why there aren't any normalize VSTs either.  In order to see the whole file (or even a chunk) a VST needs some sort of "capture" mode (or another plugin) to record.  Then it can process the whole thing.  I guess ProTool AAX plugins have some sort of full file mode  (no clue really, not interested in ProTools).
 
The MP3 support is mostly a matter of patent licensing.  It was very costly to get a MP3 license.  Now with the patents having expired that may change.
 

I beleive MLoudnessanalzer by Melda can do this. I beleive you need to set the base LU and then it will normalize them. I beleive it can also batch process them also, so you do have to do them one by one.