and what settings are the best for a cell phone’s speaker and how can i set the LAME options as i want to ( bitrate , quality , samplerate etc).
“Chain” … http://manual.audacityteam.org/index.php?title=Apply_Chain
If I were you I’d learn how to use Audacity on single files first before you try write a macro (chain) to process batches of files.
When you export (save) the file “save as type mp3” click on “options” to set the bitrate.
You can resample using the unimaginatively entitled “Resample” which is in the “Tracks” menu,
remember to change the “Project Rate” (bottom left) to the desired sample rate when you save the track.
File > Edit Chains
does not exist in my audacity v126 !
I don’t think 1.2 does chains, 1.3.11 does, you can get it here, free … http://audacityteam.org/
According to Irish et al …
You can have both 1.2 and 1.3 installed on your machine, but you can only use one at a time.
1.3 will open projects saved in 1.2, but 1.2 will not open projects saved in 1.3.
https://forum.audacityteam.org/t/is-the-a-way-to-jump-to-a-lag/13359/2
I’d not be using Audacity for batch converting files.
Yes it can be done, but it’s like banging in nails with a shoe.
Is it possible to set the bitrate when exporting to MP3 in batch mode? I am unable to set any parameters to ExportMP3 in the edit chains dialogue box.
Not directly.
Audacity uses whatever settings were used last. If you need to change the bit-rate, export a short dummy file in the required MP3 format and those settings will be retained by Audacity and used for future MP3 exports.
This would be a good “Feature Request”. I’m sure that it’s been asked for before, but I can’t find any record of it, so maybe I dreamt it 
You could post a feature request on this forum board http://forum.audacityteam.org/viewforum.php?f=20 (start a new topic on that board requesting this feature).
Features requested on that part of the forum are transferred to the Audacity wiki after other users have had chance to add their support and discuss the proposal. The Audacity developers can then look at that page of the wiki and look at ways of implementing the ideas.
If you’d like to see which other features have been requested, this is the wiki page: http://wiki.audacityteam.org/wiki/Feature_Requests
You get no argument from me on that one. I have to say that Audacity has a very rudimentary batch function at best. Without any way to define the parameters one want to use to configure the sound conversion then there is pretty much no use for it in the first place. What Audacity needs is a full blown macro recorder like Office has. That would be the best option.