Your files aren't bad and ID3 tagging isn't necessary for any part of the encoding/decoding process however it is the current standard for mp3 metadata [information about tracks, artists, labels, file origin, etc] and it was clear to me that the game required it when I noticed that it was unable to display filenames. All of my custom tracks were listed with strings of invalid characters such as 'uuuuuuuuuuuuuuuuuuuuuu' and I could only play one track under one genre. The game will play at least one track until it encounters the error, then it won't play another custom track therefore you'll have to remove or edit all of the files which are missing the ID3 data.
My sims party happily to their custom house techno everywhere they go with any stereo object, including venue speakers, after editing the ID3 tags.
But what's the difference between venue speakers and others that this is a problem on them and not the rest of the audios ?
There is no difference which is why I'm sure they'll solve the problem by correcting the file data however there is a possibility that there are multiple instances which aren't of the same context, in which case they'll have to wait for a patch. I've tested every build and I've never seen any problem other than null file data causing rejection of files and/or failure of audio controls.
Edit: In response to your question, I believe that they're encountering the error during loading of the lot since the list is randomized and the stream is activated at that time. Once the error is encountered, the object won't read the next file.
Still doesn't make sense to me why they only encounter it on speakers and no where else.
I don't use custom music myself so I'm not going to hunt this down.
The venue speakers are initialized and activated on load so the probability of encountering the error is greater and if you test personal objects with customs, you'll find that if you increment tracks repeatedly it will eventually play at least one track. I haven't experienced any other problem but that obviously doesn't imply that there isn't any other possibility and no one else has responded to my suggestion or other similar suggestions which can be found everywhere if you search for anything related to the inability of "The Sims 4" to play custom music.
