A Comprehensive Guide to Gain Staging, Recording, Mixing, and Mastering Levels for Classical Guitarists, Part II

Part II - Mixing & Mastering Levels

Embarking on the musical voyage of recording classical guitar involves numerous steps, each with its own significance. We've previously explored gain staging and setting recording levels - fundamental processes that lay the groundwork for a pristine, high-quality recording. Our focus now turns to two intricate yet essential aspects: setting the mixing and mastering levels correctly.

The mixing phase is where we ensure each microphone used in capturing the performance is balanced and clear, contributing to a rich and harmonious soundstage. Following this, we dive into mastering - the final step that optimizes the recording's levels and tonal balance for various playback systems and streaming platforms.

In Part II of this series, we'll delve deep into the processes of mixing and mastering levels, providing insights to help you polish your classical guitar recordings to their fullest potential.

Mixing Levels

In the mixing stage, we blend and balance the individual elements of our recording. This stage is critical in ensuring the complete richness of the guitar is captured, with no aspect dominating the others. This balancing act becomes especially crucial when recording classical guitar, where we often employ multiple microphones to capture a comprehensive sonic image of the instrument.

Balancing the Multiple Microphones

During my recording sessions, I often employ multiple microphones, each positioned at different locations to capture a broad spectrum of the guitar's tonality. Each microphone contributes a unique facet to the overall sound, and blending these distinctive 'voices' is key to creating a robust and rich recording.

When using the AB Stereo technique, I often process both microphones together, maintaining the natural balance they create. However, it's not uncommon that I might apply additional EQ or other treatments to each microphone separately, if there is a problem that stands out.

M/S Stereo with Neumann TLM 193 & 170, each microphone gets different treatment

For more complex microphone arrays, I apply thorough care to each microphone, treating each channel individually. This might involve applying EQ adjustments or other processing to each track separately, to ensure they blend harmoniously together. For a classical guitar, I aim for a mix level of around -18 dBFS, with peaks no higher than -6 dBFS.

It's crucial to monitor each channel's levels, ensuring that none are too loud or overdriven. This helps prevent potential distortion and maintains the integrity of the recording, leading to a balanced and natural-sounding result.

Using Reference Tracks to Maintain Perspective

Working extensively on my mixes sometimes makes me overly familiar with the material, leading to a potential loss of objectivity. To counter this, I utilize reference tracks. These are, essentially, sonic benchmarks that guide me in crafting the depth, presence, and dynamic contrast of my guitar recordings. My advice is to make a list of your favourite-sounding classical guitar recordings and occasionally compare them to your mix.

While the aim is not to mimic these references, juxtaposing my mix with these standards helps regain perspective and fosters fresh insights. This practice ensures that my recordings can confidently stand alongside commercially produced tracks, adding an invaluable layer of quality control to the mixing process.

Preserving the Dynamics: Taming Peaks Without Sacrificing Expressiveness

Classical guitar draws much of its expressive power from subtle variations in loudness and intensity. To honour this characteristic, I strive to preserve the instrument's natural dynamic range as much as possible in my mixes, generally avoiding the use of compression, which can flatten these dynamics and yield an unnatural sound.

In some cases, however, a track may have rogue peaks that cause distortion. To prevent this, I turn to a limiter, specifically the FabFilter Pro-L2. This limiter tactfully reins in these peaks, maintaining the overall dynamic shape of the performance without introducing the potential adverse effects of compression.

High-quality studio monitors for accurate listening

There are exceptions, of course. If I'm faced with a subpar recording that needs salvaging, or if the classical guitar is part of an ensemble mix, I might cautiously introduce compression to help the guitar find its place among the other instruments. But for solo classical guitar recordings, my preference is always to allow the instrument's natural dynamics breath. The true beauty of the classical guitar, after all, resides in its subtleties and nuances.

Mastering Levels: The Final Adjustments to Your Classical Guitar Recording

Mastering is the last but certainly not the least important stage in music production. It's in this phase that we delicately adjust the overall levels and tonal balance of the mix, making sure it's polished and cohesive for listeners. In classical guitar recordings, mastering's primary goals are to ensure that the recording sounds its best across various playback systems and to prepare it for distribution on streaming platforms. While mastering doesn't drastically transform the recording, it refines it, solidifying its sonic integrity and ensuring it's ready for the world to hear.

Deciphering LUFS for Consistent Perceived Loudness

A significant aspect of mastering is understanding and correctly using LUFS, or Loudness Units relative to Full Scale. Unlike Peak or RMS levels, which measure the absolute values of audio signals, LUFS take into account the human perception of loudness. In other words, they measure loudness as our ears perceive it.

This is based on the fact that human hearing is frequency-dependent. We are more sensitive to some frequencies compared to others, especially in the mid-range. LUFS measurements integrate these psychoacoustic principles, providing a more accurate measure of perceived loudness. This ensures recorded music retains its intended impact, regardless of the playback scenario, providing consistency across different platforms and distribution methods.

Youlean Loudness Meter is an essential tool

A reliable loudness meter is a vital tool for effective mastering. My choice is the Youlean Loudness Meter, a free tool that's become an invaluable asset in my mastering toolkit as it provides accurate LUFS measurements, peak levels, and true peak readings, all crucial for mastering.

The Youlean Loudness Meter also gives us the ability to monitor the loudness over time, providing a clear, visual representation of the dynamic range throughout our recording. This information is crucial when making adjustments during mastering.

Aiming for Optimal Loudness

Mastering is not about winning a loudness war. Instead, it's about achieving a comfortable and consistent listening level that provides an enjoyable experience across various listening scenarios. I typically aim for a loudness level of -14 LUFS. In addition, I ensure that my recordings remain below -1dB True Peak. This practice avoids potential clipping and distortion, preserving the natural dynamics and integrity of the recording.

Striking the Right Tone, One Level at a Time

The journey towards a professional-sounding classical guitar recording is a meticulous one. It calls for a keen eye (and ear) at every stage of the process, from capturing a clean signal, through balancing your recording and mixing levels, to the final act of polishing your track through mastering.

But it not just about mastering the technicalities. It's a delicate dance between the science of sound and the artistry of music. We're not simply chasing perfect readings on a meter. Our true pursuit is to transpose the nuances, emotions, and soul of the performance into a recording that touches the heart of the listener.

Best Type of Microphone for Recording the Classical Guitar

One of the most usual questions I get asked is which microphone is the best for capturing the classical guitar, but as with all deep questions in life, I'm afraid there is no simple answer. Our guitars, nails as well as playing techniques differ vastly. Besides, our rooms have unique properties, and of course, our tastes vary. Another decisive factor is our listening environments, but that's a subject for another day.

I've written on Classical Guitar Tones extensively about the different microphones, brands and models. If you have been here for a while, you've seen me test all sorts of microphones, entry-level to high-end. In this article, I take a step back and present my thoughts on the different types of microphones, their strengths and weaknesses. Plus some words on the different polar patterns.

On being passive 

Ribbon microphones have a relatively simple design with no active circuitry and use a thin metal ribbon suspended in a magnetic field. Most ribbon designs hear sound bi-directionally and produce natural and complex recordings. They have the reputation of being fragile and need careful handling and storage.

Dynamic microphones are similar to ribbons as both capture sound by magnetic induction. In contrast, they are very robust, resistant to moisture, and have low sensitivity. In practice, they offer no real asset in classical guitar recordings as their advantages benefit mainly on-stage use and capturing of loud sources.

For the most part, I don't get along well with ribbon or dynamic microphones, mainly because of their sensitivity or lack of. I often play soft passages or employ silence in my music, and with passive microphones, one has to crank the gain on the preamps to get sufficient levels, resulting in unwanted noise. After all, the classical guitar is a soft and delicate instrument, and no matter which preamps you use, it is impossible to get noiseless classical guitar recordings with passive microphones.  

Ribbon microphones are also quite forgiving to the various mechanical "non-musical" noises, such as nail and fretting sounds. And this is why some people love them, especially on harsher and louder instruments and a less subtle repertoire. But, I find the response of most but the finest ribbon microphones, principally with the thinnest ribbons (some Royer, AEA, and Samar makes come to mind), quite sluggish.

Phantom power required

Nowadays, there are a plethora of active ribbon microphones, purposed for capturing softer sources and being less dependent on the preamp choice. These tend to work better with classical guitar. Yet, even high-end active ribbon microphones are far from being noiseless. I understand that for some people noise is a nonissue, but for me, it is a distracting element. I like deep blacks and hate when the softer parts or rests are being washed away by preamp hiss.

Also, the figure-eight polar pattern found in most ribbons makes them less than ideal for many recording situations. They do work nicely as a side microphone in an M/S stereo array.

Capacitors move the (recording) world

Condenser microphones require a power source to function and generally produce a high-quality audio signal mainly due to the small mass of the capsule. They can capture on tape utmost detail, sometimes even too much of it, and are the most used transducers in recording sessions and concert halls. 

Most of the classic designs have been either tube or transformer equipped condensers, but with the dominance of digital recording, transformerless solid-state condensers have increasingly gained popularity in classical recordings for their additional clarity and lower self-noise.

Size matters

Condenser microphones are categorized by the size of their diaphragm and come in two main types: small-diaphragm, like most Schoeps' and the Neumann KM184, and large-diaphragm, like the Neumann U87 and AKG C414.

So, which one is better for the classical guitar, you may ask? Not so fast. Again, the answer is not straightforward. 

Let's talk first about their differences.

Small diaphragm condensers are usually more accurate, with a faster transient response and superior off-axis response. They are also smaller and lighter, so they are easier to carry, besides being visually unobtrusive. The latter is a decisive factor in why SDCs dominate the concert world.

Paying audiences generally don't enjoy seeing a stage the musicians surrounded by several dozens of microphones and bulky heavy-duty stands to support them. Neumann, Schoeps and DPA provide small-diaphragm condenser systems with every possible polar response and mounting option a classical sound engineer might on location.

Polar patterns say more than you think

The downsides of using SDC's on a classical guitar, especially at home, are only a few but nontrivial. Small-diaphragm condensers are tuned for specific roles. Directional microphones are either purposed for close spots on soloists, used in combination with a stereo array at some distance, or for the main pickup and thus are tuned to compensate for the high-end frequency loss that occurs. The result, when used inappropriately, is either a poor low-end response or hyperrealistic recordings with exaggerated high-end. In other words, they can easily sound thin and harsh.

On the other hand, SDCs with an omnidirectional response (the real microphones), especially those that have been tuned for the free field, offer an optimal response at both ends of the spectrum. Additionally, they provide greater flexibility in positioning owing to the absence of proximity side-effects but become a challenge to use in non-treated rooms that universally suffer from early reflections and standing waves.

Microphones with wide- or sub-cardioid polar characteristics come to close the gap, with a better low-end response than their cardioid cousins, some room rejection, and sometimes less pronounced high-end. Unfortunately, small-diaphragm cardioids with such polar patterns are rare, and except for the bargain Line Audio CM3 / CM4, they are always on the expensive side.

So, where does the good old large-diaphragm condenser fit?

Generally speaking, LDC's suffer from a pronounced proximity effect, transient smoothing and suboptimal off-axis colouration. In addition, they require sturdier stands, are more difficult to position due to their size and weight, and can be quite visually intrusive in videos.

All these intricacies cannot be good, right? Moreover, excellent sounding large-diaphragm condensers suitable for the classical guitar are quite rare and expensive, as most LDC's are targeted for vocal pickup.

Any advantages?

As I wrote above, noise on a recording can be distracting. The smaller the size of the capsule, the greater the self-noise of condensers. Tube and transformer-based microphones are also subject to higher noise levels. Therefore, transformerless large-diaphragm condensers have lower noise to signal ratios, with several Gefell, Austrian Audio, and Neumann models reaching nonexistent self-noise figures.

Likewise, many universal studio LDC's grant additional flexibility, as they bring multiple polar patterns, removing the need to own or carry multiple microphones or capsules on a session. With a modern microphone, like the excellent and most versatile Austrian Audio OC818, you can not only choose on the fly between any possible polar pattern, but you can also do it long after the recording has been completed.

Here is my recording of Debussy’s Prelude VIII. Recorded on location with a pair of Austrian Audio OC818s.

Let's proceed to checkout.

One can make a good recording with any decent microphone, some experimentation and post-production skills to boot. There are no excuses for bad recordings in 2022.

On a budget, neither ribbon nor large-diaphragm condenser microphones of decent quality can be found as cheaper offerings are made either for a vintage vibe or vocalists in mind. Line Audio's small-diaphragm condensers are the undenied kings of the entry-level recording setup.

When searching for a high-end classical guitar recording setup to capture a world-class guitarist with a magnificent guitar in an excellent sounding room, a pair of exceptional and well-positioned omnidirectional or somewhat directional condenser microphones is hard to beat. DPA, Gefell, Austrian Audio and several high-end Neumann condensers come to mind. In such a scenario, the size of the diaphragm is incidental. With less ideal conditions, even high-end SDC's on a solo classical guitar, be it directional or not, can expose flaws and produce unattractive recordings. 

To conclude, in most situations I favour large-diaphragm condenser microphones for their inherent sound qualities and noiseless behaviour. First-class LDCs can produce a luxurious recording and provide a pleasant listening experience. I also like how they look on videos; unapologetic, proud and predominant, almost commanding. With that said, the realism that some of the best SDCs treat the listener when every element is exemplary can be breathtaking.

Perhaps it is more advantageous to bring together small- and large-diaphragm condensers in an elaborate three- or four-microphone array.

6 Common Mistakes When Recording the Classical Guitar at Home

Part I - The room and the microphones

You just bought a couple of microphones and want to start recording your classical guitar at home; share your recordings with your friends, archive your performances, or start your career as a professional guitarist or recordist. Additionally, recording yourself will force you to look straight into your flaws, thus improving you as a player. 

These past few months, I have received quite a few emails and taught several Skype sessions with the focus on recording classical guitars. There are a few mistakes that seem to be common, mistakes that we all do when we first start recording. 

In this article, I discuss some of the flubs of the beginner recordist that have to do mainly with the microphones and the room.

You can also read the 6 Common Mistakes When Recording Classical Guitar at Home, Part II article, where I discuss about utilizing a proper signal chain and achieving satisfactory results in post-processing.

Mistake no.1 - Not spending enough time to study the room

Julian Bream - A Life on the Road (Book, 1982)

Every room is different, and If I had to take something out of the brilliant Julian Bream’s book "A Life on the Road" is how essential is to take the extra time to find the spot of where the guitar sounds the best in the room you are; the position in the room and the angle towards the sides are some of the things to consider. 

Of course, Julian Bream mainly talks about performances, but the same logic applies to the recording aspect as well. The best sounding spot in the room will allow you to play more comfortably, thus you might sculpture a nicer sound of your guitar; and depending on the microphone technique you use, added ambience or the elimination of unwanted reflections will have an enormous impact on the final recording.

Usually, most of us sit where it is convenient and don't think much about positioning the microphones, as long as they are not in the way. Some others, they like symmetry and will position themselves or the microphones in the middle of a square or rectangular room; the worst sounding spot in a room like this, introducing a plethora of problems that are impossible to remove.

So, try a few different positions, angle the guitar towards one of the sidewalls, maybe sit a little closer to the back wall, to give some space and allow the guitar to project properly. Better yet, ask someone else to play the guitar, ask them to try a few different positions and observe how it affects the sound. Use your ears as if they were the microphones.

Mistake no.2 - Placing the microphones too far away from the guitar

Norbert' Kraft’s distant miking with a spaced pair of Neumann microphones

If you have ever watched any Naxos videos, you must have noticed Norbert Kraft's distant and wide miking. Similar techniques can be seen any many famous recordings. Getting influenced by professional recordists can be inspiring, but also equally misleading as the source material is very different. Techniques that can be excellent in a church, large halls, or even a well-treated studio never apply to the smaller room reality of the home recordist.

By following such techniques you might end up placing the microphone(s) closer to the front wall than the guitar. Even when the microphone(s) are close to equal in distance, it is possible to end up with an overly diffused and roomy sound; as a result, the sound of the small room will be forever embedded in your recording. Getting too wide will also be a problem if the room is not wide enough. Also, the guitar is a small instrument and rarely benefits from a very wide pick up. Therefore, try moving the microphones closer to the guitar but not too close. 

Mistake no.3 - Placing the microphones too close to the guitar

Pat Metheny - nylon string recording; don’t try this at home!

After failing with the "church-technique", many of us want to get rid of the small room sound altogether, we have amazing reverb plugins anyway, and start positioning the microphone(s) very close to the guitar, I mean really close. To a similar erroneously path can arrive those with an acoustic guitar background or those who have witnessed some terrible close-miking examples in even famous recordings.

The problem is actually... threefold:

Firstly, by placing the microphones too close, finger and other mechanical noises will creep in, resulting in an annoying and unattractive recording. You may start cutting high frequencies to remove some of those artefacts but sooner or later you'll end up with an immensely dull recording. 

Then, most of us usually start with directional microphones, those exhibit a pronounced low-end frequency response due to the proximity effect. One can balance the unwanted boost with careful EQ-ing, but beginner recordists won't have the skills for that. The low-frequency boost combined with the need to cut high-end information will produce an unbalanced imitation of a classical guitar. 

Furthermore, the classical guitar is a complex instrument; every part of the top projects different frequencies that they all combine at some point to create a cohesive and rich sound. Normally this point is around the length of the soundboard, about 50cm, that should be the limit of how close you can get with the microphone(s): Greater distance is preferable if the room allows, but, never record classical guitar closer than 50cm. 

Remember, classical guitar needs space!

Mistake no.4 - Not experimenting with microphone height, angle and techniques

Placing the microphone(s) at the height of the guitar is a decent place to start, but as microphone height and angle influences so much the overall character of the recording, ignoring other possibilities will frustrate you as you will have to fight with post-processing to get the desired result. It is preferable to spend the extra time and set up the microphone(s) correctly.

Normally, as classical guitarists learn to project their sound slightly upwards, the further away you place the microphone(s), the higher they should be positioned. And, by allowing the microphone(s) to face a bit downwards, so to be on-axis with the guitar, you can achieve a realistic and full-range recording with great definition. This technique will capture what is usually called the "audience perspective".

Spaced AB Pair of Austrian Audio OC818 at 103cm height that point slightly downward

If you notice that the guitar, guitarist or microphones to sound a little sharp, you can angle the microphones slightly off-axis to reach a smoother treble response. 

In the case of spaced pairs, it is not uncommon to point the microphones somewhat outwards so that they are not parallel to each other. But in a small room, and at greater distances, additional room reflections will soak into the recording. Thus, I've found that is more desirable to point the microphones slightly inwards or a little higher to achieve a mildly off-axis response but with less "room" in the recording.

For those who pursue an intimate and fuller sound, with a tame high-end and less room, what is called the "player's perspective"; miking the guitar a little closer and with the microphone(s) lower is a good place to start. Avoid placing any microphone opposite of the soundhole, otherwise, the recording will become boomy. For an even fuller sound, place the microphone(s) lower yet, and point them upwards.

The discussion about miking techniques is a complicated one and deserves its own article(s), but until I write it, these ideas should get you a bit more involved.

Mistake no.5 - Not checking for phase problems in stereo recordings

The 2CAudio Vector plugin includes a phase meter and its free!

The classical guitar should be recorded in stereo. Either a pair of spaced condensers or one of the several other stereo setups will do. Except for the coincident microphone techniques, like M/S Stereo and X/Y, any technique that involves two or more spaced microphones, can potentially become a phase nightmare.

Phasing has a noticeable influence on the sound quality of your recording, as due to cancellations and comb filtering it can potentially leave your recorded guitar sound thin and weak. Be sure to check for phasing problems with a proper plugin (I use the 2CAudio Vector, it has a phase meter, plus some other welcome features and its free), adjust the microphones until you minimize phase - everything higher than 80% on the meter is acceptable. You can still compensate for phasing during mixing, but it’s always better to take care of it beforehand.

Mistake no.6 - Thinking that more expensive microphones or preamps will fix all problems

Shopping for new microphones, interfaces and other toys... I mean tools... is fun; a big chunk of writings on this site is about reviewing and comparing recording equipment. But, at this age, pretty decent recordings can be made with a reasonable budget. So blaming the gear is only an excuse for not willing to go the hard way.

Refrigerator racks with outboard equipment can be fun, but we can do a lot with a couple of decent microphones and an audio interface

I'm not arguing that equipment doesn't matter; it does. It just not going to substitute for bad microphone positioning, an unsuitable room or not refined guitar technique. Contrary, more accurate and detailed microphones will accentuate any of the problems that are present. 

Learning how to use what you've got, experiment with various microphone techniques and positions; take steps to adjust your room for a better sound. And why not, maybe spend some time practising and try to be well-rehearsed before you press the record button. These are some basic actions to take that can drastically improve your recordings in a meaningful way.

Closing thoughts 

Mistakes are part of the learning process; don't be afraid to make them, and don't hesitate to experiment. After all, recording is a journey, and the process of trying things can be a valuable lesson in becoming a more accomplished recordist.

I hope that this article might encourage you to try out different microphone positions, learn and improve your room. Optimistically, the information provided here will guide you to make better recordings.