To many people’s ears, an acoustic guitar creates some of the most beautiful, entrancing sounds of any instrument—if they only knew the challenge in recording them. Professional engineers and DIYers, trying to make sure every smidgen of acoustic goodness is encompassed on their tracks, have to consider whether to plug directly in (DI) to a device, use a microphone, or combine the sonic prowess of both.
While DI is a decent option which allows easy recording and effortless modification of the signal, there’s something particularly special about having an acoustic’s natural tones captured via a well-calibrated mic. As a result, many experienced recording practitioners will use a mic and also run DI so they can blend the signals together for optimal sound quality and tone.
Condenser mics in particular are the tools of choice for recording an acoustic guitar. “Condenser” refers to the technical way in which the mic works. It makes use of a capacitor to change acoustic energy into electrical energy.
The benefits of the condenser mic can’t be understated. They are great at picking up sensitive dynamics and delicate distinctions in sound. This is of course very useful in recording acoustic guitars. The characteristics of the condenser mic allow you to record the acoustic’s sound, whilst staying true to the live, natural vibes we all love.
Types of Condenser Mics
Condenser mics are split into two major groups—small and large diaphragm. The diaphragm of a microphone is a thin piece of material inside the microphone which vibrates when struck by sound waves. The size of the diaphragm affects various aspects of how the mic converts sound wave energy to electrical audio signal.
The challenge then becomes, what type of condenser mic do you use? There are benefits to both small and large diaphragm condensers. We’ll get into the differences between the two, as well as highlighting some popular and effective options at different price points.
Small-Diaphragm Condenser Mics
Small-diaphragm condenser microphones are usually thin, elongated, and have the mic capsule at the end of the tube (imagine singing into a pencil). A smaller diaphragm, packed inside a smaller design, causes the mic to have very consistent signal patterns and excellent transient response—meaning it follows the sound waves very accurately. Also, because they have less mass, the diaphragm moves more with less sound energy and thus has a great high-end response. The sound from this type of mic is usually very detailed.
Audio Technica’s wide-ranging experience in this market showcases excellence. For beginning home recorders looking for a dynamic microphone, the PRO37 small-diaphragm condenser is an incredible bargain. It excels in high-SPL applications and its low-mass element lends itself to a superb transient response. The cardioid polar pattern and sleek, tight design, accurately isolates the sound source, while allowing it to be placed anywhere.
Shure is one of the preeminent names in microphones. With wide frequency response and low self-noise, the Shure SM-81 cardioid condenser mic provides high-quality, unidirectional sound capture, perfect for acoustic instruments. This microphone has a frequency response range of 20 Hz to 20 kHz, a flat response curve for accurate reproduction of sound sources, and rugged steel assembly. If you plan on recording somewhat often, this is a great value.
This longstanding brand, which originated in Germany, knows audio equipment as well as anyone. The Telefunken M61 FET omni-directional mic has one M60 amplifier paired with a TK61 omnidirectional polar pattern, so you can capture sound from all around an environment. Its capsule has a 6-micron gold-sputtered membrane measuring 15mm in diameter. It offers a large, open sound, perfect for obtaining the ambience and vibe of your instrument, while breathing life into any recording. At this price point, you can expect incredibly tight, accurate sound capture.
Neumann‘s expertise shines at this level of mic engineering, such that they can offer a microphone that provides maximum performance at a price much lower than previously possible. With a simplistic design and powerful technology, the KM184 was designed for critical recording and live-sound operations. The KM184 can handle sound pressure levels of 138dB before overloading, while simultaneously maintaining a 16dB A-weighted self-noise, perfect for subtleties in the recording. If you’re seeking the best in small-diaphragm mic technology, this is it.
Large-Diaphragm Condenser Mics
Large-diaphragm condenser mics are, of course, larger, with a fatter, rounder body and “side-addressed” mic capsule. That means you direct your mouth and voice towards the side of it, not the top (no more singing into a pencil). The large diaphragm grabs more acoustic energy and creates a higher signal voltage. The advantage of this type of condenser mic is that it avoids extraneous sounds you don’t want in a recording, but maintains a consistent low-frequency response. This can make the recording sound bigger and smoother.
Owned by the electronics behemoth Samsung, the AKG name melds quality and manufacturing efficiency to give you great mics at an even better price. Case in point, this excellent-quality P420 comes at an entry-level price point. With high sensitivity and 155dB maximum SPL, the P420 delivers rounded warmth. With three selectable polar patterns – cardioid, omnidirectional, or figure 8, you have a lot of potential, coupled with great sound quality. Perhaps you like the smooth, pop tone of a large-diaphragm mic and want to begin recording your guitar at home. Here’s the mic for you.
This UK company takes on the art of mic-making like a science experiment—and the results are very satisfying. Take the Aston Spirit for example. It has a real unique style at a moderate price. If you value aesthetics and want great tone all-around, this microphone hits the mark. Each Spirit mic chassis is individually tumbled for hours to create a seriously worn look, and each microphone is separately engraved with its legends, as well as the Aston brand mantra. Utilizing a 1″ gold evaporated capsule, this mic gives you the option to select Omni, Cardioid, or Figure-of-Eight polar pattern. The Spirit also has a built-in pop filter, shock resistant wave-form design, and a degree of off-axis rejection to eliminate unwanted elements. This mic is an excellent option for new DIY in-home recorders and studio professionals alike.
The Australian owned and operated Rode Microphones boasts state-of-the-art precision machining and international reach. Pure, rich, and full, the large-diaphragm K2 mic encapsulates excellent design tech, resulting in gorgeous aural results. The K2 delivers low self-noise at 10 dBA, high max SPL of 162 dBA, and a mega-wide dynamic range of 150 dB. It brings forth tons of detail, beautiful nuance, and picks up a whisper, while accurately managing even the loudest sounds. If you’re ready to record lovely, ringing acoustic strings with unparalleled quality, this mic should be high on your list.
If you own a studio, or just want the absolute best large-diaphragm mic the market has to offer, Neumann‘s your brand and the U87Ai is your mic. Capable of handling sound pressure up to 127 dB, the U87Ai has 3 selectable polar patterns (omnidirectional, cardioid and figure-8) on the front, with a 10 dB attenuation switch and a low-frequency cutoff switch on the back. Placed in front of a loud audio source it will still cleanly capture all the beautiful nuance of the sound without garbling. By now, you must be getting the picture that Neumann is at the top of their game. If you want to be too, here’s your mic.
Let Your Acoustic Sound be Heard
Recording an acoustic guitar can be a challenge, but with the right stuff, you’ll get great sound out of any acoustic. We’re sure one or more of these options will work great for you. But if you want to check out some additional mics, head over to Samash.com and see all we have to offer.