No, they just remove some of the reflections. Of course, this is assuming that the "quality of the sound" is not hampered by the current unwanted reflections (unlikely).
Remember the old band days, when tuning at a gig was: "give me an E!" - if you had a keyboard player, great, otherwise it was whoever tuned first's pitch!
Just a a couple dB centered around 300-400Hz. Doesn't leave the bass sounding thin, but its only when there are a couple of electric guitars in the mix, and I may scoop those a little too. Depends on the song and the mix.
It all depends - on the song, the bass's tone and what that song calls for.
I DI the bass and use either an Ampeg (for clean bass) or Fender-bassman-type (for rock bass) plug in. I'll scoop some mids out in a guitar-heavy track, and might add an octave pitch shift (up 1 or down 1) in the mix...
As others have said, use condensor mics on the guitars. Try to record the guitar parts first, then track the vocals, unless you want the 'live feel', in which case you are going to get some bleed, making it harder to mix well.
Not sure what you mean by using a 'transformer' or the rest of your comment. Transformers, in the electric world, transform a higher voltage into a lower one.
My guitar (for the DI) was plugged directly into the interface.
I tried using my Taylor 310ce (with Exp 1.3 pickup) DIed, single-miking it at the same time a few times. I mixed a very small amount of the DI into the mix to get some 'crispness', but in general it was too quacky.
Kind of like Bob Seger's Turn the Page. Learning it form the radio back in the early 80s, the A major sounded like A minor. Most people played it that way. Years later, found it was actually A major. I still hear people playing it wrong.
Finally sold my TC Helicon Play Acoustic after a month of ads in the usual places. Sold at $240, bought it for $299 with the first 'stimulus' money in 2020!
Used it for 3-4 live Zoom stream things but decided it wasn't for me, so never touched it again. It did make slick-sounding harmonies -...
Acoustic foam is not the best choice for sound absorption, but can take a little of the 'slapback echo' out of a bad room. It does nothing for the low end (where the 'mud' is).
Unless you have concrete walls, use the 'spike method' - hammer 2" finish nails into the wall, then just impale the...
Since in your original recording you recorded BOTH vocal (with mic) and guitar before, is it possible the mic was still plugged in and recording the metronome sound coming out of the monitors?