I have a whole box of tapes to record and convert to mp3. I'm planning on running the tape deck through a dj mixer then into audacity. Once I have the levels right going into audacity and after it is recorded, what other processing should I or shouldn't use? I'm thinking no compression, maybe eq, but I can eq on the mixer. Maybe normalize? Or just make sure the levels are good and just leave it.

That sounds like a solid approach to converting your tapes to digital files.
What is the end use for this stuff, are you going to sample it or are you archiving it?

I would just normalize it and leave it. I would also make sure that the level leaving the tape deck is optimal and isn't causing any distortion.

I'm going to be converting the tapes for a friend of mine. I'm kinda excited about it because, there is a lot of 80's and 90's hip hop. But , also there is a bunch of tapes he recorded off radio stations. I know there are a lot of old dj clue, kid capri, and funk flex mix tapes from the radio in there,(when they were playing stuff like illmatic, enta da stage, etc). There is also a bunch of single tapes , you know were they would release one track on it then have the instrumental, acapella, and maybe like a dub version. So, I'm sure there are going to be a ton of stuff to sample, especially off the radio recorded tapes. I'm not so worried about the levels coming out of the decks. I just want to keep them sounding like the tapes and try not to process them to much.

Normalize, EQ, done.

Only use compression for taste. Otherwise, leave it alone.

I've got an assload of tapes I need to record myself...

Also, try to play back the tapes through a dolby recommended for the recording. HXPro dolby playback would be best for all circumstances, though.

I agree with the eq, but the normalization I'm to to sure. I say that because, I was thinking of running the input of the channel on the mixer from the tape a little in the red. Then just watch the levels in audacity, if things get out of control I can just turn down the volume with the master volume on the mixer. So I guess the next question would be, is it better to keep the levels little low or try and keep the levels as close as possible 0 db? I think if low then use normalization. If louder then no normalization.

Got some junk in your trunk, eh? How many tapes does it take to be considered an ass load?

Well, in this case, assload is approximately 250. But this is only in tape-scale. In, for instance, record-scale, 250 may not be an assload and 1000 would. It's always a mystery until you find that point where you know for sure...that you have...AN ASS LOAD.

I have about a printer paper box full of tapes to convert, and I think my friend has at least another 2 more printer paper boxes full he wants to convert also.

Ha ha! In a movie called blue juice they're talking about 'fuck off big' waves, they define a fuck off as about ten full ons! Gotta love an accurate measurement system!