How to record a good guitar sound
First you need to prepare three things
1. One can buy a Mercedes-Benz microphone
2. A digital audio recorder with a few megabit ranges
3. An ear that can hear the best position of the mike
I think that a microphone over a few thousand yuan already has a fairly good quality (it is recommended that you buy two to do stereo recording) A 16-bit digital audio recorder can record great results, if you use it correctly, and once you know what you are doing, the best position is no longer so important
[Indoor Soundtrack]
One thing that is extremely important for good recording is called the "indoor soundtrack", which will greatly render the original timbre of your guitar, because the sound emitted by the guitar will be reflected by all the objects in the room, walls, floors and ceilings
When we're in an empty room, it's easy to perceive this phenomenon, it sounds empty and echoing, and once we've put a carpet on the floor, hung curtains, and placed furniture indoors, it doesn't seem to exist
This is not the case, even in the living room full of carpets, curtains, furniture and upholstery, the sound is still reflected in a lot
Every chamber reflects the sound, so the sound is changed when you play the piano. You can do an experiment yourself, take a harness so you can stand and play the guitar, now go outside the house, somewhere in the garden, as far away from any wall as possible, play your guitar and listen carefully, what do you hear?
First you'll notice that the volume seems to be a little smaller, because there's no sound reflected by walls or furniture, the only sound you hear is coming straight from your guitar to your ear, and now listening more closely, you might agree that your guitar sounds awesome, the tone is average and pure, much better than you used to hear
If you're not standing right now, get up, walk back into the house and keep playing the guitar, and as soon as you get inside, you'll notice the original sound in the room, as if you had turned on the effects
We get the following revelation: Acoustic guitars sound best in outdoor open spaces, and once you're inside the house, what you hear is not the original timbre of your guitar, but the timbre distorted by all the reflected sounds in the room.
Unfortunately, there's a 99% chance that this sound is much worse than your guitar's natural, unreflective sound, and you probably never knew it because you're used to the sound you're always playing in the room, and your brain is smart enough to compensate for your distorted acoustic impression and make you accept it naturally, however once you start recording, it gets worse, and I'll explain why in the next paragraph
[Improved indoor soundtrack]
In order to reduce the reflection effect of sound waves when recording, professional recording studios are usually stuffed with a variety of sound absorbing cotton and diffraction plates, in order to prevent the sound waves from oscillating back and forth in the room (the role of sound absorbing cotton).
If there is still oscillation, also scatter the sound waves to every corner (the role of the diffraction plate), you can immediately detect this phenomenon. Because it sounds "dead" in the studio, it's good, because then there won't be extra echoes in the tones you record, and once these echoes are recorded you can't get rid of them, but it's easy to add them afterwards with an electronic echo device.
However, these absorbing cotton pads and diffraction plates work well for high-frequency tones, but not for low-frequency tones. In fact, when you're recording a guitar, most of the sound-absorbing cotton still reflects many of the sounds made by the 6th, 5th, or even 4th strings.
At the same time, the diffraction board will not diffuse these tones, these reflection effects are not as easy to detect as the 'chat echo in an empty room', in fact, what you hear is mainly those higher frequency tones, as for the guitar emitting lower frequencies, almost unavoidable reflections, which will lead to uneven bass response, bass stress and the overall quality of guitar recordings
Fortunately, there are two remedies to avoid the above problems:
1. Go and record your guitar in an open space. Make sure there's no wind, no rain, no cows, or other noisy animals (including insects that might stop at your microphone), and then ask a big guy at air traffic command to arrange that no plane will fly over your head within a recording radius of about 40 kilometers.
All nearby roads are blocked, and then anyone near you (assuming a kilometer away from you) is asked to stand as a wooden man and not move until you finish recording
2. Record in a large building (at least 20x20 meters larger, the bigger the better, and the ceiling should be about the same height.) Most cathedrals are probably OK, but all the walls and floors have to be carpeted and then stuffed with a big, soft thing to cram the doorway, which reduces the echo.
It's great to be like a big opera house, all you have to do is wrap him up and give yourself plenty of time to record.
In the two methods just mentioned, you won't be bothered by the reflective echo of the recording, and then you can have a good recording very simply. However, these two solutions don't seem to work in reality for some reason, so you might want to keep reading.
[Standing Wave]
I've mentioned the bass-heavy phenomenon of guitar recordings, which is a well-known problem for passers-by. If you've ever recorded a guitar at home, you know exactly how it sounds, and certain bass are particularly noticeable and seem to resonate with your entire sound system.
If you try to remove these bass with a timbre control or equalizer, you'll at most get a thin, no-solid sound.
If you really want to know the details of these ins and outs, you should ask a physicist or consult the relevant professional information. I'll explain only the most basic principles here, because any other part is beyond the scope of this article, but I'll use some animations from that site to explain
The first thing you need to know is that sound waves (or any wave) will add up, which is easy to understand, two guitars are louder than one, and in the animation below you can see how it happens, two waves one large and one small, one to the left and one to the right, when the two meet they superimpose each other to produce a larger wave
Now look at the small black dot on the right, and you can imagine that it is a small cork floating on the surface of a pool, and the small cork moves up and down much more than when there is only one wave. This is the result of the addition of two waves. (Here I would like to add a little bit about this physical phenomenon called centralized interference.)
But now look at the little dot on the left, which is only slightly next to it, and although it is under the influence of the addition of the same two waves, it is stationary.
This is the interference effect of waves, the above example, called standing waves. Several waves can be synthesized into standing waves, and unlike normal traveling waves, the amplitude of standing waves varies greatly at different locations.
The immovable dot (or the immovable cork) can be explained this way that one wave pushes it up and the other pulls down by the same amplitude, because both waves have the same wave type and speed of movement, so the effect of cancellation lasts forever, while the other cork, because of its different positions, makes the two waves always work against each other, and when one wave pushes up, the other wave does the same, and when one wave pulls down, the other wave does the same.
[Standing wave in the studio]
Now the cork in the pond behaves the same as your Macri's gold leaf. In the studio, the two waves are caused by the sound waves from your guitar and the reflected waves from all the walls, floors, and ceilings.
In other words: in all rooms, including the recording studio, there will be sonic interference. When sonic interference occurs, the volume varies greatly depending on where you are. To put it another way: if you play a tone with a guitar, the volume recorded will change depending on the position of your microphone.
But that's not too bad, all you have to do is put Mike in a good volume position, right? Unfortunately, this is not the case. Because the audio is different in different wavelengths, the interference of each frequency is also different, so the volume is not only determined by the microphone position, but also related to the frequency recorded!
The overall effect is related to many factors (room size, interior items, sound absorption properties, etc.) so complex that it is almost impossible to predict.
The generation of standing waves in the room means that many different audios cancel or amplify each other in completely unpredictable ways. Basically, this is saying that when you record your guitar indoors with a microphone, it will sound like you're going through a multi-segment equalizer.
We usually refer to the result of this sound effect as the "indoor sound effect".
Now you can understand why people who own recording studios always spend a lot of money on sound-absorbing boards. This reduces the reflection of sound waves and thus the problem of sound waves interfering with each other.
However, as mentioned earlier, even with excellent sound absorption equipment, the fundamental frequency sound emitted by the guitar bass empty string E, A and even D strings is still easy to reflect. That is to say, especially the bass strings are prone to cause relatively large problems. Regardless of how the microphone is installed, certain frequencies are amplified (like the black dot on the right in the figure) and some are reduced (the black dot on the left).
As soon as you move your microphone or guitar a little, there will be different corresponding frequencies that are amplified or reduced, and this is completely unpredictable. Now you can understand why often your in-room guitar recordings often have annoying bass, which means that you are in a position where a particular bass rate plus its reflected tone results in an overall volume amplification.
If you change the position of your microphone, the same thing happens, just on different tones. This doesn't help, because moving the microphone doesn't solve the problem. This kind of sonic coherence occurs throughout the room.
In theory, EQ (equalizer) can solve this problem, but the problem is that you need to have a highly skilled sound engineer, and then EQ has many segments (I would say at least 64 segments). Not only that, but the distortion produced by different frequencies is so complex that we can't fix it with our ears.
And then even worse, the adjustment of the equalizer will change over time, as you may move your guitar causing the form of the sound waves to interact with each other will change.
[What can we do?]
The sound situation of any indoor space can be improved by some appropriate sound treatment. In fact, many people will tell you that the room can be adjusted to a near-perfect state.
However, as long as you don't know what true perfection is for you, it's hard to find an efficient solution. But from another point of view, a good indoor space can also add a lot to your recordings. Unfortunately, most of the houses we stayed in were not ideal in terms of interior space.
When I recorded my first album, I had exactly the same problem as above. No matter what my sound engineer does, I don't like the sound that comes out. It took me a lot of time to figure out what the real problem was, and that's why I decided to write this article.
That way you can save that time practicing. My solution is very thorough, like some kind of "total approach". It's basically about removing the sound effect from the studio (or any room). First of all, I choose a very clear basis for "perfect sound".
In my case, the sound I recorded on my guitar in open space, I then performed a numerical simulation of the acousticity of the studio (fortunately I had a strong physics background) to find out where the interference problem was minimal. In retrospect, this step wasn't absolutely necessary, but I think it helped a little bit anyway, and then I used a portable, battery-powered digital recorder to record each song in an open space, which sounded really great, but unfortunately was ruined by birdsong, wind, flies parked on microphones, and a plane or two.
Other than that, the sound is simply amazing! In the studio, we cut out the disturbed fragments and use the remaining parts to generate a recorded spectrum, as follows:
And when we also made the studio spectrum for the same song, the difference between the two was immediately apparent, and then, for the difference between the two spectrums, we used a 64-track digital equalizer to adjust the spectrum of the studio to make it close to the spectrum obtained in the open space, so we got a lot of progress!
Finally, I went a step further: I made a computer program and some electronic devices to change the studio spectrum to a waveform of the outdoor spectrum (or any reference spectrum) while recording, as if it were an automated pre-recording method.
The advantage of this method is that for later enhancement or attenuation of specific frequencies sometimes produces additional noise or strange sounds, so strong equalization is sometimes needed, while the disadvantage is that each piece must be recorded twice, once outdoors and once in the studio! And I can't change guitars or strings in between.
The studio configuration looks something like this:
Peel a little, it should be this
So record with any microphone, even with standing waves, bass-heavy, and other nasty things. A computer connected to a programmable equalizer can change the spectrum of a recording into something like an outdoor recording, even before the music reaches the digital recorder! The result of this recording sounds very natural and balanced.
Finally we mastered the recording, added a little echo effect with a high-end device (Lecixon 960L-S), and performed equalization, in fact this step was added to the simulation of the indoor acoustic sound (echo effect and frequency filtering), you can hear the results from the following demonstration file.
All in all: my approach is to use high technology to eliminate the studio acoustics as much as possible, the high-frequency reflections are eliminated by the sound-absorbing panel in the studio, and the remaining low-frequency effects (soundwave interference) are eliminated by the computer-controlled EQ, which basically recreates the sound of my guitar outdoors, which is my personal "natural sound", and then adds a little echo and a little bit of voice control in the process of mastering, in fact this step simulates the acoustics of the excellent recording environment.
[So what can you do?]
The methods described above are high-tech and may not be feasible for everyone, but here are a few tips, based on the same principles as above, which may greatly improve your guitar recording.
Six tips for recording acoustic guitars
1. Find some boards with sound-absorbing cotton pads, about a meter square or larger, and place them behind your recording position, which will absorb a lot of the sound that is reflected in the room or recording room and interferes with the sound emitted by the guitar (no need to cover the whole room with boards).
Two sound-absorbing cotton boards are attached to the multitasking board, drill a few holes in the side of the board, and tie them up with a line so that they can stand in a V-shape, and you can easily fold up and store it, placing the screen behind your recording position.
2. Use the most space you can find to record, maybe you can enter the lobby of a factory on the weekend, or a friend's large storage room, the larger the room where you record, the less problems with sonic interference.
It's great to have a home recording studio to practice, but it's best to consider having a portable device that includes two microphones, a portable digital recorder, and one or two sound-absorbing panels that you can use whenever you can borrow a large space.
3. If you want to record stereo sound, lean the heads of the microphones together so that any sound interference problems are the same for both channels, so that it can be easily removed with an equalizer afterwards.
4. Point the microphone in different directions to create a beautiful stereo sound, one microphone pointing to the twelfth grid and the other to the panel under the bridge, this configuration I think is best, keep the guitar close to the microphone, keeping a distance of about 30-40 cm.
5. Never point the microphone at the sound hole, which will only produce very low frequency tones, not mid-high notes.
6. Use recording software plus a spectrum analyzer so you can see your recording spectrum, then identify those bass-heavy frequencies and use intelligence to remove them, rather than trying mistakes or luck.