Today I want to show you how to record acoustic guitar on your smartphone. You might already have some experience in this area, but, for most musicians, the phone merely serves as a folder of loose musical sketches, to be worked on and re-recorded on higher-end equipment. But did you know that your smartphone is capable of producing professional-quality audio?
To get started recording on your mobile phone, first check available settings for improving recording quality (sample rate, bit depth, and control input gain). If not using an external microphone, make sure the internal microphone is pointing directly at the 12th fret of the guitar between 10 – 15 inches from the source. Ensure your phone is not sitting on a hard, non-absorptive surface to avoid mechanical vibrations and record in a room that doesn’t have a lot of hard reflective surfaces. Lastly, be sure to put your phone in airplane mode, ensure the battery is well charged, and you have enough available space.
Why your smart phone is perhaps your greatest songwriting tool
There’s actually a lot you can do to improve the quality of the audio you record, including:
- Adjusting your phone’s audio settings for higher quality recordings
- Using an interface
- Recording with an external microphone, or using a dedicated smart phone microphone
- Applying basic sound treatment and mic placement techniques to clean up your recordings
- Using dedicated apps, designed for musicians, rather than just using a dictation app.
When it first dawned on me that my phone could record audio I immediately saw the potential.
Before mobile phones were even a thing, if inspiration struck and I was away from home, the best I could do was try to remember the idea until I got home and had a chance to record. Perhaps your memory is better than mine, but the only way I managed to do this was to continue to hum the idea in my head, often for hours at a time.
Sometimes this method worked, more often than not it didn’t.
I suspect it was also pretty obvious to the people around me, that despite my best efforts, I was distracted, incapable of ‘good conversation’, and best left to my own devices. Other times, like a game of Chinese whispers, I’m sure I ended up recording something that was probably nothing like my original idea.
Nowadays, it’s standard fare for my phone to hold 20+ different melody lines or song ideas I’ve hummed into the microphone that I’ve wanted to retain until I could generate the idea further.
That’s why I consider my smart phone to be the greatest songwriting tool I have at my disposal.
But, can your phone be used for more than just recording an idea? how good can a smart phone recording really sound?
The first place to start is your phone’s audio settings.
Checking your audio settings
Sample rate/bit depth
Regardless of how you go about things, the analog signal being recorded has to be converted to a digital signal, using the phone’s analog to digital converters (A/D converters, also referred to as ADC’s).
The accuracy of this process is governed by the sample rate and bit depth set for A/D converters located in the smart phone’s input jack, charging jack, or BlueTooth chip, depending on which is used.
Sample rate refers to the number of samples (digital snapshots of the analog signal) taken per second, measured in hertz, a term used to describe a unit of frequency. For example, 44.1kHz indicates the sample rate is 44,100 samples per second or 44,100hz.
The other half of the equation is bit depth, which refers to the number of bits (units of digital information) taken each sample e.g. 24-bit (high definition – DVD quality audio) contains more digital information than 16-bit (CD-quality audio).
What is bit rate?
Bit rate refers to the amount of data processed per second of audio, described in SI-prefixes e.g. kb/s (kilobits per second), Mbps (megabits per second).
The higher the sample rate the higher the frequencies capable of being recorded. Most modern smart phones operate at 48 kHz/24-bit (sample rate/bit depth) or higher. There are also smart phone friendly third-party interfaces that include their own converters and allow for higher sample rates e.g. 96kHz and beyond.
The human ear, however, for the most part only detects frequencies in the range of approx. 20hz to 20kHz, which begs the question:
Why record at a higher sample rate if the human ear can’t detect the difference?
Waveforms include both a peak (highest point) and a trough (lowest point). The waveform, as a result, must be sampled twice to produce an accurate digital representation of the original analog signal (Nyquist sampling theory). In simple terms, this means you require at least twice the sample rate, of your highest frequency.
Recording at a higher sample rate than 44.1kHz, in theory, shouldn’t make any noticeable difference to the audio file produced. But, many argue that higher sample rates e.g. 96kHz produce higher quality audio.
With this in mind, the question really should be, do the frequencies we cannot hear have an influence on the frequencies we can hear? There’s a good argument to be made that they do, and with phones and other digital devices capable of storing much higher volumes of data inexpensively, the larger file sizes associated with higher sample rates are less of a problem than they once were.
Adjusting your audio settings
Under the settings of many voice capture or dedicated recording apps, the user can select either ‘compressed‘ or ‘lossless‘ quality for the exported file, which is essentially a measure of the amount of digital information included in the file.
A compressed or ‘lossy’ file is, as the name implies, compressed resulting in data being discarded e.g. the frequency range is narrowed, resulting in a more convenient file size to allow for faster downloads and easier sharing of files.
Some apps, including the voice record pro app, allow you to select VBR (variable bit rate). This increases the detail of an exported MP3 file by allowing variable compression. In other words, it allows for a higher bit rate for different sections of the audio file as needed.
What are Codecs?
Audio codecs are software applications used to reduce file size and bandwidth requirements by essentially compressing and decompressing audio files using a coder and decoder. The coder compresses the file, resulting in a smaller file size, the decoder decompresses the file upon playback.
A lossless file is decompressed or decoded back to its original size. A lossy file is decoded to a smaller file size, this means some information is discarded, resulting in a lower quality audio file. Wav files are not encoded, hence they are often referred to as uncompressed.
Different bit-rate settings can also be selected which allows even more control over the audio file, for example, if exporting to .mp3 (a popular codec) lower bit rates can be selected which alters the quality of the file and file size. A list of the most commonly used codecs can be viewed here.
Many audio recording apps also include an option to adjust gain settings or include some form of gain control. People often get gain and volume confused. Gain specifically refers to the input level, and shouldn’t be confused with volume which refers to the output level. Gain control jump is an automated method of controlling gain, taking into account changing input levels.
You might consider adjusting your gain settings if you notice audible distortion or clipping on your recordings.
Many dedicated audio recording apps also include direct monitoring settings (this may also be labeled ‘headphone monitoring’). When switched on, and if wearing headphones, this allows the person wearing the headphones to hear the audio signal before it is processed by the application, this reduces the potential for latency. You can read more about latency here.
Apps such as the Dolby On app apply Dolby’s noise reduction technology along with compression with the intention of enhancing the quality of recorded audio even further. Under the accessibility settings on iPhone, noise cancellation can also be selected.
It’s beyond the scope of this article to list the settings for all audio apps on either iPhone or Android, but regardless of the platform or app you are using, check the available settings within the operating system and the settings within the app you are using.
There are often settings available that allow you to improve audio quality, however, there is a cost involved, in the form of much larger file sizes.
A .wav file (pronounced WAVE) is often ten times larger than a standard .mp3 (a lossy format) and uses more of the available storage capacity of your device. However, if you deem this a suitable trade-off and want your audio files to include as much digital information, and therefore detail as possible, choose ‘lossless’ audio or .wav over .mp3.
Also keep in mind if you import 16-bit audio files into your DAW and then export at 24-bit, you are essentially adding 8 bits of data containing no additional information. This won’t improve audio quality but will result in a larger file.
Editing/Playback – Listen back on headphones
When listening back to anything you record on your smart phone, use your headphones to assess audio quality. The speakers inside your phone are tiny, and generally speaking, won’t handle the excessive volume, particularly low-end frequencies as well as larger, heavier speakers.
Adjusting your EQ
You may also be tempted to adjust your EQ settings on your phone, however, this will only influence how your recordings sound when played back on your smart phone. Keep in mind, especially if you share your music to social media and platforms such as soundcloud.com that most people won’t be listening to your music using the same settings.
Analog to digital audio conversion is a complex topic, and we’ve really only scratched the surface with the information above, however applying some of these changes to your settings can make a significant difference to the quality of the audio you record. With that now addressed, let’s move on to how you plan on capturing your audio e.g. using direct line recording or a microphone.
Direct line, Internal Microphone or Dedicated Microphone?
When recording acoustic guitar, you generally have three options.
- Direct input e.g. using the pickup on your acoustic guitar (if you have one)
- Using the internal microphone on your phone
- Using an external microphone.
Direct input recording
While it may prevent unwanted external noise, direct input recording isn’t the preferred option for acoustic guitar. Being an acoustic instrument, recording in this way doesn’t allow the natural ambiance of the room to be captured on the recording.
How pickups affect tone depends on the pickups themselves e.g. under-saddle piezo pickups tend to sound thin, excessively bright, and unnatural. This is because they don’t project the sound of the guitar holistically e.g. taking into account the shape of the body, the materials used to build the guitar (tonewoods), and build quality.
A blended pickup system, however, which usually features an internal microphone, along with a magnetic or contact pickup will often sound more natural. If you are interested in learning more about acoustic guitar pickups you can read more here.
So, while direct line recording is not typically used in the confines of a studio, it does have its benefits for recording with a smart phone as an alternative to the internal microphone. Internal smart phone microphones are not terribly complimentary when it comes to capturing the sound of the room you are recording in, and tend to pick up a lot of unwanted noise.
If recording using direct input, interfaces such as IK Multimedia’s iRig can be a good option. I’ve used iRig many times (mostly for recording electric guitars) and have mostly been happy with the result.
Alternatively, if you don’t have a pickup installed on your acoustic guitar, a better option is the iRig Acoustic, which includes a contact pickup that is mounted to your guitar.
Using a portable audio interface
While the two examples above are technically audio interfaces, devices of this nature are mostly referred to as ‘guitar interfaces’ due to the 1/4″ input jack designated for recording electric guitar, or semi-acoustic guitars.
Dedicated, portable audio interfaces such as the iRig Pro IO and iRig Pro Duo include combination 1/4″ and XLR input jacks, 48v phantom power which allows the use of a condenser microphone without an external power source, midi capability, and higher sample rates e.g. 96kHz. Other options include the Presonus Audiobox, and Tascam iXZ interface, although this doesn’t include an XLR jack.
While the products listed above represent good portable options for smart phone recording, if you already own an audio interface, it’s likely you can also connect this to your smart phone using a USB/OTG cable or adapter.
Using A dedicated microphone
If your guitar doesn’t have a pickup, you don’t have an interface, and prefer not to record with the internal mic it’s also possible to record using a microphone.
This can be done in a few different ways:
- Using a Bluetooth microphone
- Connecting a standard microphone using a TRSS cable or adapter
- Via the headphone jack
- Via the charging port
- Using a dedicated smart phone microphone.
The main advantage to using a blue tooth microphone is convenience and mic placement. The microphone obviously doesn’t need to be connected to the phone, and most will remain in a range anywhere up to 150 feet or more.
The downside, in many cases, is sound quality.
Bluetooth microphones can be a little hit and miss, especially in the lower price ranges. Dropouts can also occur, making them less reliable.
It is encouraging, however, to see renowned brands such as Sennheiser entering the Bluetooth smart phone mic market with the ‘memory mic’, a dedicated Bluetooth smart phone microphone. One advantage of the memory mic is that it continues to record even if you happen to be out of range of the phone as it has the ability to sync with the phone when you are back in range.
Using a standard microphone with a TRRS cable or adapter
You can also connect a standard microphone to your phone using an XLR to 1/4″ cable or adapter, and TRRS (tip, ring, ring, sleeve) cable. If you are using an iPhone (later than the iPhone 7) you will also need a lightning adapter, and if you require playback monitoring e.g. if you plan on multitrack recording and want to hear yourself while recording, you will also require a headphone splitter (refer to the image below).
For those unaware, a TRRS cable (pictured on the right) includes three separate points of contact (separated by the black rings in the image above) while the standard TRS cable has only two. While you might have already guessed that two of the points of contact are for the left and right channels for stereo, the third point of contact is for the microphone.
There are a bunch of different cable options including XLR to TRRS and 1/4 inch to TRRS. Be sure to check the compatibility with your device, many people run problems connecting external microphones to smart phones.
Regardless of your preferred option (internal microphone or dedicated microphone) aspects such as your phone’s audio settings and the apps you record with won’t change, however, you may prefer to experiment with gain control and mic placement.
Dedicated external smart phone microphones
If you are serious about recording audio using your smart phone, my recommendation is to get yourself a dedicated smart phone headphone jack or charging port microphone. It’s a far more convenient option if not direct input recording and many of the better options are smaller than a standard size microphone making them as portable as the phone they are plugged into.
Rode developed this version of the VideoMic after Apple removed the headphone jack on the iPhone 7. If you are using an Android phone, the Rode VideoMic Me is essentially the same device, minus the lightning connector.
The VideoMic allows for 24-bit recording, and 44.1 or 48 kHz sample rates. Using a directional mic (the Rode Video Mic Me-L features a cardioid polar pattern) reduces unwanted external noise and allows for constant direct monitoring through the 3.5mm headphone jack.
Mic Placement and Using the Internal Mic
Whether you are using the internal microphone or an external microphone, mic placement e.g. the direction and angle of the microphone and proximity to the source e.g. your acoustic guitar can drastically alter how your recorded audio sounds.
While you might be tempted to position the phone as close to the guitar as possible, internal smart phone microphones tend to overload quite easily, depending on the phone you are using. In my experience, the ideal placement tends to be 10 – 15 inches from the guitar, pointed directly at the 12th fret of the guitar.
This is open to interpretation, however, and can depend on the sound you are going for. For example, the closer the source is to the microphone the more intimate and in some cases ‘warmer’ the recording might sound, moving the mic a little further away brings more of the ambiance of the room into the equation, creating a more spacious but sometimes less defined recording.
10 – 15 inches may not be an ideal distance for all smart phones but it makes a good starting point. In any case, especially if you plan on sharing your music online, test different mic placements, whether using your phone’s microphone, or an external mic and listen back (use headphones, not your device’s speakers) and decide which option is best going to suit you.
The angle of the microphone can also accentuate certain frequencies more than others, which may or may not suit the mood you are trying to create.
If you notice the incoming signal is too hot e.g. there is audible distortion check your gain settings (if possible) and back them of a little if excessively high, or move further away from the mic.
Lastly, don’t be tempted to aim the mic directly at the sound hole of your acoustic guitar. The sound hole is where much of the internal resonance of the guitar body is released which can result in a ‘boomy’ sound due to the excessive low-end frequencies.
Don’t record too far from the source
While recording too close to the mic can cause problems, It’s also important that you don’t record a weak signal e.g. the mic is too far away from the guitar or you will need to increase the volume for playback which also happens to increase the volume of any unwanted noise captured in the original recording. Ideally, record as close to the source as possible without clipping (waveform distortion) while taking all other aspects into consideration.
Should you use more than one internal microphone and record in stereo?
Most smart phones have at least two internal microphones. My iPhone for example has 4 internal microphones. These are located at the bottom and top of the phone and serve different purposes including assisting with noise cancelation. The phone is also capable of detecting the source of the sound being recorded and switching on the closest microphone.
Up until iOS10, you didn’t have a lot of control over the mic or mic’s being used for iPhone, but it is now possible to select stereo in native apps such as the camera app. Some third-party apps allow more control over the microphone being used.
On some Android devices, you can record using internal microphones on the top and bottom of the phone simultaneously however, this isn’t useful for recording acoustic guitar as the microphones can’t be aimed directly at the guitar.
Don’t place your phone on a hard, reflective surface
The last thing to keep in mind with regard to mic placement is the surface the phone is placed upon.
If your phone or external microphone is in contact with a hard non-absorptive surface, there is the possibility of mechanical vibrations being picked up on your recording. This is why mic stands and speaker stands are important when recording in a home studio.
Sound, or acoustic treatment is a complex topic, worthy of an article of its own.
Acoustically treating a room requires an understanding of the physics of sound, and reducing reflection points using dampening and diffusion techniques. Sound waves reflect from hard, reflective surfaces, and accentuate some frequencies over others, making your recordings sound unnatural.
For example, when you strum your guitar the sound waves emanate from the guitar in all directions. This means, the microphone picks up some direct sound but also detects sound waves reflecting from your walls fractionally after the direct sound waves are detected.
This is why studios and rehearsal spaces utilize acoustic panels, or bass traps as they absorb or diffuse sound waves before they are picked up by the microphone.
Nobody wants to go to that kind of trouble for recording acoustic guitar on a smart phone, and the good news is when recording on a portable device you’re not bound to a desk, or a particular room. Your studio fits in your pocket, meaning you could potentially use any room in your home and quickly set up to record. If you can, pick a room with a high ceiling, that isn’t too square and has plenty of furniture or clothing e.g. a walk-in robe. Let your ears be the judge after that.
If you don’t have a good-sounding room to record in, an inexpensive option that can help cut down on sound reflections is a portable vocal booth.
I use one of these fairly often and they can help, especially when recording vocals. They’re not a perfect solution to a poor sounding room, however, they can help.
It’s also important once you have selected the room you will be recording in, to consider where you will be performing within the room itself. Avoid being in close proximity to walls, and for the most part, try to center yourself in the room so there is an even distribution of sound reflection within the room.
Now that you have taken care of your phone’s settings, mic choice, and placement and selected the best room to record in, the last piece of the puzzle to consider is your choice of app.
If you haven’t looked into available recording apps before e.g. you were just using a native voice memo app, you might be surprised to see the number of apps available for both IOS and Android.
Below is my shortlist of audio recording apps or fully-fledged DAW’s I’ve used personally and am happy to recommend.
|Single Track Recording Apps||Multitrack Recording Apps|
|Dolby On – App Store | Google Play||Garageband – App Store|
|Recorder Plus – App Store||FL Studio – App Store | Google Play|
|Voice Record Pro – App Store | Google Play||Music Studio – App Store | Google Play|
|TW Recorder – App Store||Cubasis – App Store|
|n-Track – App Store | Google Play|
Best app for single track recordings
The Dolby On app includes features such as compression, a visual countdown, direct line monitoring, and Dolby’s own noise reduction technology, providing a noticeable increase in audio quality over many other apps I have used.
The app is simple to use, features an intuitive feature and toolset, does a good job of organizing your files, and provides a lot of control over the finished product.
Best Multi-Track Recording App
I could have easily gone for Garageband, but considering it’s only available for iPhone the winner is FL Studio.
As someone who has used FL Studio (formerly Fruity Loops) on and off on PC for over 12 years, I’m impressed by the transition to mobile app and consider FL Studio a powerful multi-track DAW, and loop creator. It’s especially handy for building drum tracks.
It’s highly intuitive, well supported, has a large community behind it producing a lot of helpful content, including Youtube video tutorials. If you are on iPhone, give Garageband a try, it’s free and comes installed on IOS devices. But if on Android, or you aren’t a fan of Garage Band, FL studio is highly recommended.
Summing Things Up
While much of the information above could be applied to a number of instruments in a general sense, the acoustic guitar, being a portable instrument that doesn’t require a power source is ideally matched to the convenience of smart phone recording.
All things considered, with your acoustic guitar in hand and a smart phone (with an audio app installed) and microphone in your pocket you have all you need to get started recording high-quality audio, regardless of whether you are in an acoustically treated room or playing by a fire while camping.
One of the real benefits of modern audio technology has been the lowering of the bar to entry, meaning just about anyone can record music and share it with the world. Considering that means a lot of undiscovered talent now have the opportunity to have their music heard, this can only be considered a huge benefit for all.