Wet / dry automation in EQ?

If you send to a bus, you are creating two signals - so yeah, it will be louder. The key to doing it this way would be to make the send pre-fader, and then bring the fader up while bringing the send down... crossfading them, if you will.

You could also find a Space Designer preset that sounds lofi-ish, there are plenty if you explore the warped category. Again, you would have to crossfade the wet/dry.

Or, you could set up a MatchEQ. You can drag in your own curve into the graphic area - some experimention will be required to get your curves right. Watch the little help tags. Start by clicking and dragging, do not let go of the button, hold shift to change the Q, let go of shift to move freq/gain. Once you let go of the mouse button that curve is what it is - you can only add new curves. You can always reset the curve.

Now when you have your lofi sound how you want it, you can automate the "apply amount" from 100% (or however much) to zero.

Edit to add: you could set up your lofi EQ how you like it, and bounce several seconds of that, then drag that file into the match eq.

I had a similar challenge as the original poster to do this kind of fx in Logic Pro 9 last year.

If interested check out the link on this page, the track in question is Track 12 - Devil In Your Head.

I managed to achieve the effect I believe you are after by using a tweaked Space Designer setting and some extreme EQ that was then bounced down to a stereo file, I then faded the original clean version from underneath the effected version using automation. I also layered some other lofi sounds too for extra ambience. Overall it seemed like the easiest way although there was a lot of trial and error involved. Good luck.

Which version of Logic Pro are you using?

Also, have you thought about putting the EQ itself on a Bus and then automatting the Bus level itself?