I messed in Audacity and used EQ to lower the quality sound of the songs, it sounded alright. Anything else I could do?
There are limits to what you can do. It might help to have a mental image of how the acoustic recordings were made, so that you can figure out what kinds of tweaks might help.
First, none of the things that would be taken for granted today were practical. This rules out stereo, overdubs, even basic editing as we now think of it. It was possible to carefully hack and splice by hand, using carefully timed disc-to-disc transfers, but even this procedure wouldn't give satisfactory results until amplifiers were available. So, all the recorded performances were essentially live.
The physical spaces where the recordings were made wouldn't much resemble their current counterparts. The rooms would be as small as could fit the performers, and would be designed to reflect sound rather than absorb it. Kind of like a bathroom
🙂 Natural acoustic energy had to do all the work of cutting the groove, so it was a good thing to let as much as possible reflect back into the horn.
On those old records, the singers sound like they are shouting. This isn't some kind of distortion, they actually
were shouting. [This is why the crooners, mumblers and talkers only gained popularity after the 1920s, this kind of performance simply wasn't practical in a hall or on record before amplifiers.] Not only did they need to sing loud enough to be heard over musicians who were crowded side by side with them, but if they didn't holler the stylus wouldn't wiggle enough to record their voices.
Small spaces again: you aren't going to have that big hall kind of reverb/echo so common in modern recordings.
You may not be able to "fix" these characteristics on a finished track, but maybe some of these tidbits will help you pick out source material that might respond well to "antiquing" treatment.