USB Microphone Guide
Everything you need to know about choosing and using a USB microphone for voice recording and communication.
Introduction
There are many ways of getting a microphone signal into a computer for communication and/or recording, but the USB microphone is the simplest, offering a good balance of quality, price, and ease of use, and additionally offers consistency of sound across a range of systems and locations. Here we look at USB microphones as a one-stop solution to your computer audio needs.
Educators and students can use voice recordings and live audio in a wealth of different contexts, including podcasting, screencasting and online learning environments. However, many users find it difficult or confusing to choose and configure audio peripherals, particularly microphones, to get good sound. A well chosen USB mic, combined with an awareness of a few basic principles which will be outlined in this document, can provide you with all you need to master what is sometimes considered the 'black art' of getting a good vocal sound.
Key Facts
- The microphone connects to the computer USB port
- Consistent sound across different systems
- Plug&Play installation
- Many USB mics have a headphone jack for monitoring
- Many USB mics are optimised for voice
Definition
A USB microphone by definition connects directly to a USB (Universal Serial Bus) port on your computer. Almost all desktop and laptop computers from the last ten years have at least one USB port. In practical terms this single device allows you to talk into the microphone, and route the signal through your computer with the minimum of intermediary steps, ready for anything from online chat and tele-conferencing to recording podcasts or screencasts.
The microphone pick-up element of a USB microphone (the bit which picks up the actual soundwaves from the air) is no different per se from any other type of microphone. What differentiates it from a standard mic is that the pick-up signal is amplified internally, and then directly passed to another internal circuit to convert its electrical output signal into digital data. This digitised signal is then transmitted by a USB cable, and converted into standard PCM digital audio by the microphone's driver software. This may sound complicated, but as it is all done automatically inside the USB microphone, the process is largely invisible to the user.
Benefits
The USB microphone handles all of its own digital conversion, and presents the computer with digital audio information in a standard format, and thus combines a microphone with a microphone preamplifier, and at least some of the functionality of a computer soundcard, all integrated into a single device and housed in a familiar microphone body. USB microphones can therefore be used regardless of a computer's other audio capabilities - even if there is no soundcard present at all!
Some USB microphones have other audio features and connectors in addition to this bare minimum, and can fulfil a wide range of audio tasks beyond simple microphone functionality, while still enabling basic 'no frills' microphone input when that is all that is required.
USB microphones are not able to match 'separates' systems - including microphone, audio interface, and potentially other outboard processors (dedicated microphone pre-amplifiers, equalisers, compressors, etc) - for sound quality, as their individual components are generally cheaper, and in a fixed configuration. However, what they lack in absolute fidelity and flexibility - needed for critical recording tasks - they gain in integration and ease of use, making them ideal for day-to-day use, and for the less technical user. Internal settings are optimised by the manufacturer, and then fixed in this configuration.
In many cases settings are chosen with a particular use in mind, and many are optimised for voice recording. If your intended use is compatible with this preset factory set-up, a USB microphone can save you a lot of the time and knowledge needed for correct set-up, and will simplify the recording workflow.
While there is a quality ‘ceiling' beyond which a USB microphone will not take you, it also presents very few opportunities to go wrong.
USB microphones
There are many good USB microphones available, and more being developed all the time, so these are just a few representative examples. JISC Digital Media do not endorse any product or manufacturer, and no endorsement should be inferred. We include a 'like-for-like' audio comparison later in this document.
Samson Go Mic
A miniature condenser microphone hardly bigger than a matchbox, the Go Mic offers directional and omni-directional patterns, an ingenious built-in stand swivel mount/clip and a headphone output. It uses a small diaphragm condenser capsule, which gives a wide and even frequency response, with excellent sensitivity and clarity.
For louder sources, you can select a directional pattern with a -10dB pad, which lowers the sensitivity by half. When plugged in the Go Mic is instantly available, with Plug&Play driverless operation for Mac and PC. A compact and versatile microphone.
- Type: Dual small diaphragm condenser
- Pattern(s): Cardioid uni-directional, cardioid uni-directional -10dB, omnidirectional
- AD Converter: 44.1kHz/16-bit
- Frequency response: 20Hz-18kHz
- Output(s): mini USB, 3.5mm stereo mini jack headphone output
- Accessories: cable, carrying case, integrated clip count, Cakewalk LE software
- Guide price: £30
Rode Podcaster
As the name would imply, the Rode Podcaster was designed with podcast production very much in mind, and it is a solid and well-built directional dynamic microphone, with response tailored to close-up vocal work. Dynamic capsules are less sensitive to quieter sounds, so pick up less background noise in louder environments, and the Podcaster gives a crisp, dry vocal character, with a slightly curtailed frequency response. While it does not give the frequncy range or flat response of a condenser microphone, it is quite forgiving of different vocal styles and more difficult environments
The Podcaster has a headphone output with direct monitoring mix control, allowing latency-free monitoring while recording without needing to route through software, as well as the facility to listen to computer audio output.
- Type: Dynamic
- Pattern(s): Cardioid uni-directional
- AD Converter: 48kHz/18-bit
- Frequency response: 40Hz-14kHz
- Output(s): USB, 3.5mm stereo mini jack headphone output
- Accessories: cable [optional stand mount, shockmount, tabletop stand]
- Guide price: £135
Logitech ClearChat Pro USB
A headset microphone (i.e. combined with heaphones), the Clearchat Pro USB offers Plug&Play simplicity and basic but functional sound quality for non-critical audio tasks (e.g. chat, informal screencasting etc). Very simple to set up and use.
- Type: Headset
- Pattern(s):
- AD Converter:
- Frequency response: 100Hz - 10kHz
- Output(s): USB, built-in headphones
- Guide price: £39
Blue Yeti
The Yeti by Blue Microphones is a large and full-featured USB microphone, standing 12" tall including its integrated (though removable) stand. Incorporating three separate condenser capsules it offers three different pick-up patterns, including the less common bi-directional or 'figure of 8' pattern, which can work particularly well for interviews, as well as standard cardioid and omni responses.
The Yeti also offers a stereo mode, making it, along with the Alesis AM3, one of only two USB stereo mics we know of. Also unusual is the ‘Gain' control on the back, which allows you to alter the amount by which the microphone signal is amplified before digitisation. This makes it more similar in use to a separate microphone and soundcard combination, and is a very welcome feature. Of course too much internal gain can easily lead to distortion, so this needs to be handled with care, but it makes level matching for a wide range of sources far more accurate.
There is also a headphone output on the base of the mic with a corresponding level control knob on the front, which offers zero latency monitoring - though microphone audio still has to be enabled and routed via the computer's audio control panel - and it has a handy mute switch to mute microphone signal.
- Type: Multi-pattern Condenser
- Pattern(s): Cardioid (unidirectional), Omnidirectional, Bi-directional (figure of 8), X-Y Stereo
- AD Converter: 48kHz/16-bit
- Frequency response: 20Hz - 20kHz
- Output(s): Headphone output with level control
- Additional features: Custom stand included, internal gain control
- Guide price: £100
Blue Snowball
The Blue Microphones Snowball is also widely used for podcasting. Its features are basic, offering input only, with no headphone output for monitoring, meaning you will need another audio device or soundcard to enable you to listen to your results. The condenser capsule offers directional cardioid pickup with switching for both full level, and -10 decibels to accomodate louder sources, as well as an omnidirectional pattern.
The Snowball has an eyecatching design, and good build quality, and it comes bundled with a nice desktop tripod stand, but its features do look limited when compared to some other designs.
- Type: Multi-pattern Condenser
- Pattern(s): Cardioid (unidirectional), Cardioid -10dB, Omnidirectional
- AD Converter: 44.1kHz/16-bit
- Frequency response: 40Hz - 18kHz
- Output(s): none
- Additional features: Custom stand included
- Guide price: £80
Audio comparison
This is a test recording and side-by-side comparison of all of the microphones listed above. All were recorded in a single session, in exactly the same position and using exactly the same software:
All audio examples recorded at highest quality offered by the device, and with absolutely no signal processing or data compression. Relative playback levels were adjusted for each recording to give similar subjective volume.
Choosing a USB microphone
If you are serious about getting a good vocal sound from a USB microphone it is essential that you choose one which is suitable for your voice and environment, as well as being compatible with your system(s). Most USB microphones are compatible with all the most common operating systems, but getting a sense of their audio performance can be more difficult from reviews and specifications alone, and even audio examples can be misleading if not recorded under identical conditions.
By far the best way to choose a microphone is to try it for yourself, and if you have the opportunity then call or visit a reseller and ask for a demonstration. If you have a laptop, take it with you and ask if you can plug the mic(s) in and see (and hear) them in action. If you plan on a thorough demo/test before you buy, then it may be best to aim for a quieter time of day.
Form factors
USB microphones come in a variety of physical forms: table-top 'stem' microphones, stand-mounted mics of many shapes and sizes, or combined with headphones into USB headsets. Each of these can produce usable results, though be aware that there can still be a wide range of audio quality, as demonstrated by the audio comparison above.
Pick-up patterns
Most USB microphones are directional, meaning that they pick up sound most strongly in a single direction or 'axis', with sources becoming quieter the further 'off-axis' they become, and quietest when behind the microphone. Some are omnidirectional (pick up in all directions equally), and a few offer pattern switching, sometimes in combination with a ‘pad' setting which makes the mic less sensitive and therefore able to record louder (or closer) sources.
Uni-directional, or ‘cardioid' response is generally most suitable for a single speaker, and omnidirectional are good for groups and interviews, though they often pick up more background noises too. Some microphones offer more unusual patterns (e.g. figure of 8) or stereo, offering more versatility.
Detailed information about microphone pick-up patterns is available from our Microphone Guide.
Conversion quality
As explained above, a USB microphone will include circuitry for Analogue to Digital (AD) signal conversion. This works in the same way as a computer soundcard or audio interface converts its inputs into digital audio, and has the same specifications regarding resolution and quality.
Many also include matching Digital to Analogue (DA) converters, to allow monitoring of the signal and listening back to recordings on headphones.
44.1kHz sampling rate and 16-bit bit depth are the resolution of standard CD audio, and your USB microphone should offer this resolution or better, as most do.
Audio outputs
Many USB microphones have a built-in headphone output. While audio input is of course a microphone's primary purpose, a key part of getting good results from it is being able to hear clearly the sound that it is picking up after, and sometimes during recording. Without an audio output on the mic, you will need a second audio device or soundcard to plug headphones into for listening. A single device filling both roles is cheaper, simpler, and again offers consistency across multiple systems.
A USB microphone which includes an audio output (usually in the form of a headphone jack) will guarantee you two things:
- You will be able to monitor results at the same quality that they were recorded
- The output will offer sufficiently low latency* to allow real-time monitoring
*A note on latency: Basic soundcards will often introduce a significant delay (latency) between input and output, leading to a very off-putting ‘echo' when listening to yourself speaking into the microphone. A latency of more than about 20ms can make monitoring audio whilst speaking difficult, and higher latency figures can make it almost impossible. USB microphones which offer audio outputs usually have low latency.
Perhaps counter-intuitively, using higher sample rates will give lower latency
Getting the best from the mic
As noted above, the fact that a microphone comes in an integrated USB package does not mean that it is different in use from any other microphone, and the same guidelines apply:
For voice-over recording try to use the mic at fairly close range (10-30cm) in a quiet, non-reverberant space (see our advice on Setting Up An Audio Workspace for some pointers in getting the right conditions and ‘vibe'). For interviews, again try to get speakers as close to mics as is realistically possible without making them self-conscious. Condenser microphones or voice-optimised dynamics tend to give best results.
Try to relax and use your normal voice and style.
Use a pop shield or move the mic out of the 'line of fire' to avoid 'popping' from plosive consonants. For a demonstration see our Microphone Technique screencast - use of the popshield is covered at 11 minutes in.
Listening
There are two distinct stages at which you will want to listen to, or ‘monitor' the sound coming from your USB microphone, and they have different requirements.
While recording - While the mic is in use, you or someone else may wish to monitor the signal to improve microphone technique, to monitor levels, or for ‘confidence monitoring' of the signal being recorded. For this you need headphones, and either a USB microphone with a direct or low latency headphone monitor output, or a similarly equipped soundcard. Consult our Headphone Guide for advice on choosing headphones. The best types for this task are closed-back or ear canal designs, as they give best isolation and are therefore least likely to be picked up by the microphone.
Monitoring during recording is, however, optional, and some people - especially those with less experience of recording their voice - can find it off-putting to hear their own voice while speaking. Experienced voice artists and sound engineers, however, will always monitor the microphone signal while recording or broadcasting, and it is useful to be comfortable with doing this even if it initially feels awkward, as it will improve the way you use the microphone (in the long run!).
After recording - You will need to listen back to recordings made from the microphone, either on headphones or speakers. Any audio output from the computer can be used for this, though obviously we would advise using the best quality monitor output available.
Direct monitoring
To simplify routing and avoid latency altogether, some USB microphones have a ‘direct monitoring' facility, whereby microphone audio can be mixed with playback from the computer without being routed through the computer at all. This makes setting up monitor mixes for voice artists relatively simple, as the microphone monitor level can be controlled with a simple control on the microphone itself.
Be sure not to enable both direct and software monitoring simultaneously though, as the tiny delay between the two will make for a very odd, ‘hollow' sound when mixed together. If your Monitored signal sounds strange, try switching off software monitoring in the relevant Control Panel.
Installation
Most latest generation USB mics are Plug&Play, and automatically install their own drivers, or use pre-configured or generic ones offered by the most common operating systems, but you should still check compatibility with your system.
Most current USB mics require no intervention during installation, which begins automatically on connection.
Set-up
Whilst USB microphones simplify connection and configuration of the input chain, needing no external power supplies, no input gain settings, and only a single connection cable, there are still a couple of settings which may need initial attention.
Depending on what operating system and which audio applications you are using, and the features of your particular device, you may need to select your USB microphone as the system audio input and/or output. You also need to optimise the recording level for your voice:
Windows XP
- Start > Control Panel > Sounds and Audio Devices >
Select your input and output devices
- Start > Control Panel > Sounds and Audio Devices > Volume
Click ‘Volume' buttons to show mixer pane, adjust recording and playback levels, and to enable monitoring of various sources through headphones/speakers
- Start > Control Panel > Sounds and Audio Devices > Volume > Options > Properties
Choose which devices will appear on the Record/Playback mixer panes. Microphone is often not displayed by default, and additionally is frequently muted by default, to avoid potential feedback (but also thereby disabling monitoring).
Windows 7
- Start > Control Panel > Sound > Recording
Use the 'Set Default' button to select your chosen device for sound recording input.
Open the ‘Properties' pane and adjust the input level slider until you have a healthy level, but which does not overload the meter:
Mac OSX
- Applications > Audio MIDI Setup >
Select the device and use the menu pictured to assign it as system input/output device. Set input level with the Input Volume slider shown.
Note: Some applications have a microphone input level control/level meter amongst their options. This will generally be directly linked to the corresponding system-wide input level control set in the Audio Control Panel/Preferences, as detailed above. Any adjustment of either this or the system level control will therefore be reflected in the other.
Using multiple USB microphones
A question frequently asked is whether you can use two or more USB microphones simultaneously to capture stereo or multichannel audio, record different speakers, multiple interviewees etc. The answer is very much dependent on your computer.
Apple Macs running OSX 10.2 or later have the facility to create Aggregate Devices (sets of input and output options) which will allow applications to address multiple devices - including USB microphones - using a single aggregate driver. Though a slightly technical set-up procedure is required, once configured the microphones (and other devices) will appear as separate sources within Garage Band, Logic, or any other application with a selectable audio driver on your Mac.
For Windows PCs an extension called ASIO offers similar facilities. ASIO is owned by Steinberg, and therefore only available on products licensed to use ASIO drivers, which unfortunately most USB mics are not. Non-ASIO multi-channel recording with USB mics on Windows is theoretically possible, but in practice very tricky to set up, due to complex clocking issues and driver cross-compatibility. At present, multichannel recording on Windows using multiple USB microphones is not a realistic option.
Check out our blog post from a while ago about some experiments using multiple USB microphones.
For any Multi-USB scenario you will of course need sufficient USB ports available to plug in and power your mics.
Conclusion
USB microphones provide the simplest way for the user with limited time, experience, technical know-how or budget to get good quality audio routed onto their computer. While not perhaps flexible enough for the demanding user, they can offer excellent performance with the minimum of fuss in set-up and configuration, and score highly for consistency of results and ease of use.
They also come in many different incarnations suitable for a wide range of potential uses, and their self-contained nature can make them an excellent choice, particularly when recording voice for podcasting, screencasting, etc.
