I may have to try a specific test later, because I thought this was working, and I use it sometimes. Can't do it now though.
Okay, I did a few quick (well, not so quick in the end) tests and the answer is pretty straight forward. I think you have seen what will happen already Altsouza.
Assumptions:
1. Transferring audio files to a Handheld device or a HDD folder for use on a Handheld device.
2. The Handheld device doesn't use any of the Volume Leveling tags to control volume. So the R128 and RG Volume Leveling tags are ignored.
3. You want to normalize all the tracks, which means that the volume levels in the tracks must be changed as tags aren't honoured, which means that the files have to be converted on the fly when writing to the Handheld device or HDD folder.
I always believed, because I had read it in the forum at some time, that any DSP effects defined in the Handheld sync process were applied to the tracks as they were transfered over to the handheld device. What I hadn't twigged to was that you had to force a conversion to happen to ensure the DSP effects were applied. If there is no other reason to convert the audio tracks, then having DSP effects defined doesn't seem to be enough to trigger a conversion of the audio file and apply the volume adjustment defined in the "Volume Level (R128)" tag.
However, if you specifiy the Handheld Option "Conversion>Audio>Mode" as "Specified Output Format", then a conversion will take place every time, and the DSP effects will be applied to the audio file.
To test I edited the "Volume Level (R128)" tag to several values, synced a couple of files to the Handheld, then played the original and synced/converted file in Windows Media Player independently on MC. My understanding is that Windows Media Player doesn't support either EBU R128 or Replay Gain, so it should play the audio file volume as it is from the audio file.
At -50 LU (Loudness Units) the converted tracks were silent in Windows Media Player. I played them in MC as well, just to see how they went, and MC skipped over the whole tracks because I had "Do not play silence" set in my Options.
At -20 LU the converted tracks were very quiet, noticably quieter than the original tracks. MC played then quietly as well.
When I checked the tags in the converted tracks I noticed that the "Volume Level (R128)" tag had been deleted in each. So MC (more correctly our smart developers) is smart enough to apply the Volume Leveling DSP to the audio files, and then clear the "Volume Level (R128)" tag so that if a player can use that tag, the effect doesn't get applied twice.
The attached image shows the important elements of what I tested. Note that I did not turn on Adaptive Volume as that tends to hide the effect of Volume Leveling by a large amount, or at least should try to. I had to assume that if the Volume Leveling DSP is applied to the audio file, then any other DSP would also be aplied.
So Volume Leveling is being applied to Handheld Synchronisation, as long as a file conversion is required or forced. I have to assume that the rules around Volume Leveling over a Playlist are respected during a Handheld sync, since the Handheld sync uses Playlists to select files.
Does that make sense Altsouza? Will this do what you want for your Tom Tom player? Try it and see.