Hi,
ReplayGaining converted SACD files with foobar2000 seems to result in songs that are played with noticeable less volume than other files.
Therefore I'd like to create an action that adds 5dB to the calculated ReplayGain tag.
I tried several options with 'format value' and 'replace value', but could not get mp3tag to actually add 5dB to the RPG value.
Grateful for hints..
See the help on arithmetic functions: https://docs.mp3tag.de/scripting/#arithmetic-functions
You use them in format strings.
Just a footnote: isn't the sole purpose of SACDs to deliver a higher definition and better dynamics (up to 120db) so that applying replay gain to level it all out is as though you added a soup cube to Paul Bocuse's consomme?
Ooops - so easy, thank you! 
Re Footnote: The .dsf files had been converted first to FLAC (after which they already had less volume, probably due to wrong settings in the foobar2000 SACD decoder plug in) and then to .mp3 (on which I want to apply the replay gain adaptation).
Thx again
Just another footnote: ReplayGaining shouldn't interfere with the dynamic so much, just shift it (upwards in my case). But converting to lossy format does indeed take away a lot of definition & dynamic.
EDIT: Added P.S.
A quick question to someone who apparently knows something about it: can you add ReplayGain to FLAC- and if yes, if you convert it to WAV, will the WAV also be boosted?
I doubt that you find a field/chunk for the replaygain information in a wav file.
AFAIK the following pieces of information are supported:
Chunks in a .wav file
Type Main Sub Purpose of chunk
RIFF WAVE fmt is typically 16 bytes long and contains the basic info about samplerate, number of channels etc. This chunk is required.
RIFF WAVE data The audio data itself. In order to be able to read this, you must have the data from the "fmt" chunk. This chunk is required.
RIFF WAVE cue A cue chunk specifies one or more sample offsets which are often used to mark noteworthy sections of audio.
LIST adtl labl An entry in an array containing an a label or name which is associated with the cue points from the "cue " tag in order to provide names for the markers.
LIST INFO INAM The name of the file (or "project").
LIST INFO ISBJ The subject.
LIST INFO IART The artist who created this.
LIST INFO ICMT A text comment.
LIST INFO IKEY The keywords for the project or file.
LIST INFO ISFT The software used to create the file.
LIST INFO IENG The engineer.
LIST INFO ITCH The technician.
LIST INFO ICRD The creation date.
LIST INFO GENR Genre of content.
LIST INFO ICOP The copyright information.
RIFF WAVE bext Broadcast extension chunk.
I assume for WAV files there is only the destructive way to go how to apply ReplayGaining, and this is by physical change the data stream.
DD.20170119.1012.CET