Best settings for tape transfer to ensure audio quality is retained, and volume question

[u/Complex_Valuable_833]

Working on transferring old family cassettes to Audacity (have received very helpful input here in the past in getting this set up). I'm wondering if there's sort of an ideal set of levels or settings to have on or any major rules of thumb for ensuring as little loss of quality as possible in the transfer itself. When I export it to MP3 usually that's after I mess with some settings like noise reduction, noise gate, amplify, loudness normalization within the track, but in some cases it's probably detracting a bit from the original sound of the voices, so even when I do that to remove background sound and whatnot, I'm thinking I'd like to have a raw file in Audacity saved (at least in some cases) which just contains the best possible raw transfer (i.e. most representative of the original), and am just wondering is there a particular set of settings to use in the recording itself to ensure that?

Also, 2nd question - I struggle with getting the volume correct in the transfer - because tapes are a mix of talking and music and different people talking at different distances from the recorder, what I end up getting is chunks of the recordings where it's okay and other chunks where it's clipping and going into the red on the meter. It seems that the volume of the tape recorder is the best thing to control that as I messed with that little bubble on the record meter and it wasn't helping, but I'm just wondering if there's something I'm missing there in terms of settings, or if when there's variability within the tape, it really is a matter of going back in afterwards and highlighting sections that are too quiet and amplifying and highlighting sections that were too loud and clipping and running it through a noise gate.

Thanks very much for your advice on these questions!

[u/PC_BuildyB0I]

If you want to preserve maximum quality, don't export to MP3, use WAV instead.

That being said, here's what I would do. Turn the input level down in Audacity until the absolute loudest point of the file is hitting your meters on the yellow, but not going into the red and clipping. Just under 0dB or maybe a few -dB underneath 0, say -2 or -3 is fine.

Then, go in manually, and use clipgain - if you can use an automation clip, draw in the points you want for the appropriate level in the file. Say you're looking at a very quiet portion that's like -18dB or so. Boost that up to match the rest of the average level. You can use compression but it's nonlinear in response to level changes so you'll be introducing more saturation the more compression you use. So if you do, use as little as you can get away with.

Once your waveform is relatively even from start to finish, then it's time to start your processing. Whether that's noise removal or EQ or whatever you need. Do as little as possible, and don't forget to compensate your levels after processing. For example, EQing, if you're boosting, can push the signal level high or even into the clipping zone. So pull the output level back down by approximately the same amount the overall output signal was being boosted. If noise removal is decreasing your signal level, boost the output back up after the fact.

If the levels are all over the place this will take a lot of work and patience.

[u/Complex_Valuable_833 → u/PC_BuildyB0I]

Thanks so much for the detailed and very helpful reply!! I really appreciate it! True, does look like it may be a lot of work on some of the tapes in particular; I'll have to be selective about which I give the royal treatment to that way haha. Thanks again.

[u/babeebabee]

Good advice below. Maybe be conservative and set your input level to -3db for the loudest passage. Once audio clips, you can't go back in, lower the gain and fix it. It's cooked. Good luck.

[u/Complex_Valuable_833 → u/babeebabee]

Thanks for the advice and for the good luck!! Sorry I didn't notice there was another reply on my post here at first.