Updated: Jun 30, 2020
Ok, there's gazillion excellent videos and pages on the subject, but this question appears quite often in lots of places so I thought I'd make a quick post to handle it as quickly as possible.
I cannot take any credit for the technique: I simply have learned it from others. But I can guarantee it works, as I've used it myself in uncountable location recordings.
As a note, the technique works for most guitars recording as well, for exactly the same reasons I discuss at the end of the post.
I assume you know how to record a vocal take (in terms of having an interface, cabling, microphone, headphones etc) - so I focus only on how to record a great sounding vocal take. Can I get a truly great vocal take at home?
Assuming you are a truly great singer: yes.
Is it expensive or difficult?
Ok, how do I do it?
Use a cardioid microphone. No phone mic - they are usually omni.
Take (or buy) a heavy duvet. Yes, your bedroom one is just fine.
Position your recording microphone, filter etc on its stand, as you always do.
Mount the other mic stand so that it's at its maximum height and the boom arm is set up to make a T shape. Place it behind the microphone/singer combo. Not in front. Behind. Basically the duvet is right behind you. About 50 cm/20 inches will do - so you (or the singer) can fit in. Place it so that there's some space between the duvet and the wall. Again, about 50 cm/20 inches will do. And ah, don't record vocals in a tiled room. :)
Monitor with headphones, and move the setup in the room while monitoring, until you like the sound you're getting in your headphones. It's a good time as any to learn that the microphone position is as important than the microphone itself, if not more. Pretty much all modern mics are proficient at what they do these days - decent at least. Even that cheapo condenser mic you got because you couldn't afford anything else (yes, I'm looking at you, Behringer). Even that 58 dynamic knockoff that you got because you can't afford even the Behringer. Yeah they will be noisy and hyped and the frequency response will be all over the place but you can still use them for recording. Sadly, the same can't be said of many of the people using them - but then that's why this blog exists. :)
If you really want to go overboard (or you only have a tiled room!) you can use two duvets on the sides as well (you will need two additional mic stands).
What is the most important factor in taking a great vocal take?
The music, and the singer.
99% of a vocal recording is about music, performance and recording room, not gear. In that order. Of that 99%, music and performance are 90%. And they are on you!
Now you can head off and try it out - that's all you need to know. But if you're interested in the gory details, here's the last question and answer..
But it doesn't look pro! How can it be so simple?
Yes, it does not look pro.
It's not good Instagram material (maybe TikTok). If you could use a permanent studio-like installation obviously it would at least as effective and much easier on the eyes.
But let's face it: if you could have a permanent studio-like installation, you wouldn't be reading this.
So, yes, the duvet doesn't look pro. But in audio how things look matters nothing.
Nobody listens to a record with their eyes.
The duvet transforms 2 square meters of your room into an acoustically pleasant space, with few reflections and a little bit of diffused reverberation. And these 2 square meters are exactly where you happen to place your mic.
In other words, it gives you results more or less equivalent to a professional studio recording because essentially it does the same thing: it creates a good acoustic space.
Only, it's temporary, and only for a small part of the room.
Now, how can it do that?
The reason is that vocal frequencies are mostly midrange and high-mids. These frequencies are fairly directional and short, so it's easy to find where they go and it's not hard to eliminate them by placing absorbent material in their way.
When you sing in an untreated room, the energy from your voice goes forward towards the mic (obviously), then past it, then it bounces back from the wall you are facing. The mic is cardioid, so it won't pick up much of that (only some side reflections).
But the energy will go past you and bounce back from the wall behind you, and then come back into the front of the mic.
This causes comb filtering or flutter echoes - hollowing out the overall timbre and/or creating these super-ugly ringing echoes in the higher frequencies...which are impossible to get rid of, and scream "bad production".
The duvet is simply a very effective temporary mid-range absorber that you place on the path of these reflections. It absorbs both the energy going towards the wall behind you and the energy bouncing back from the wall towards you and the microphone - effectively removing most of the reflections and de-correlating what's left. Sure, there will be some leftover ringing (typically from floor-ceiling reflections) but since the vox frequencies are mostly directional, most of the sound wave energy will travel in the horizontal plane and hit the strategically placed, and amateur-looking duvet. And be absorbed.
As always, a reflection filter will help with the side reflections. It will still color the sound depending on both where it's placed with respect to the mic, and where the microphone/filter combo is placed in the room. Up to you to move things around, listen, and judge what's best.
So that's it! No excuse for a crappy vocal sound anymore.
Unless of course you insist in using your phone...