The Direct Connection
Thanks in part to the popularity of Podcasting and of consumer-friendly recording applications, a number of manufacturers have added USB microphones to their product lines. This class of products brings the allegedly esoteric concept of the “digital mic” (which is really just an analog mic with a built-in A/D converter) into the realm of the personal studio.
The plug-and-play convenience of a USB mic makes it desirable for someone who wants a good-sounding, cost-effective transducer for Web-bound programs or demo use but doesn't know anything about studio technology. Such simplicity is also good for recordists and multimedia creators who want to forgo preamps, mixers, and outboard digital interfaces in mobile applications yet want a higher level of fidelity and features than an inexpensive, consumer mic offers.
Although the USB mic's list price may be comparable to that of an XLR version, the street price is often more aggressive. That's because manufacturers are aiming for the prosumer market. Prosumers are hobbyists and nonspecialists who buy inexpensive and easy-to-use products that include some pro-level features. A company can tap into this growth area by simply repurposing the technology from its regular line into a product with mass appeal. However, the question for those of us who think seriously about audio quality remains, do USB mics sacrifice sound and useful features for convenience?
In this article, I will cover six USB mics that are intended for personal-studio use, are available on their own (rather than being available only as part of a Podcasting package), and are priced between $90 and $350. At the 2007 Winter NAMM show, I saw several additional models, some of which will be available by the time you read this (see the sidebar “USB Mics on the Horizon”).
Getting on the Bus
FIG. 1: The USB A connector (on the left) goes to the computer host, while the USB B connector attaches to the mic.
The USB (Universal Serial Bus) protocol is used worldwide for data transfer between peripheral devices and computers. The original 1.0 specification, which offered a transfer speed of 1.5 Mb per second, was later superseded by 1.1 (12 Mbps) and finally by 2.0 (480 Mbps). You can hot-swap USB devices, and the appropriate drivers will load and unload dynamically.
Like other USB devices, these mics have a square-shaped USB B port. This means you can use a standard cable with a USB B connector on one end and the flat USB A connector, which always goes to the host, on the other (see Fig. 1). As a result, replacing a lost or malfunctioning USB mic cable is relatively easy — an important point if you're traveling.
Internally, the USB connector uses four pins: two for data, one for ground, and one providing +5 VDC of power. It's good to keep this last spec in mind because the amount of power a microphone receives is critical to how it sounds. And because many of the products in this roundup are based on mics that require phantom power, how a manufacturer steps up the voltage and implements power conditioning, buffering, and noise filtering — USB power is notoriously dirty — will have a major impact on a mic's overall sound. Unfortunately for the consumer, manufacturers keep this information proprietary, as well as any details about the built-in A/D converter, which plays an equally important role sonically.
The Main Players
The mics in this roundup are marketed as being convenient to use and having a level of sound quality that is enough above that of consumer-grade mics to warrant the extra cost. Besides sound quality and ease of use, however, I was also interested in the differences between the sizes and shapes of the mics. Portability is a big asset if you're planning to work while on the road (as some of the EM editors do).
FIG. 2: The Blue Microphones Snowball offers omni and cardioid polar patterns, as well as a cardioid setting with a –10 dB pad.
Blue Microphones Snowball
With an attractive Mac-centric look, the Snowball contains a pair of electret condenser capsules and offers two polar patterns, each with a slightly different sonic signature (see Fig. 2). Although the Snowball's cardioid capsule is similar to that of Blue's 8-Ball, it uses a different amplification circuit in order to add presence, according to the manufacturer. Blue also says that the omni capsule is unique to this mic.
Besides the USB connector, the back of the mic includes a 3-position switch to select a cardioid pattern, a cardioid pattern with a -10 dB pad, or an omnidirectional pattern. A red LED on the front glows when the mic is fully powered.
On the bottom of the Snowball is a swivelmount that, when attached to the stand, allows you to position the mic roughly 45 degrees forward or backward. That's handy if you want to avoid recording plosives by facing the mic up or down, and out of the direction of the mouth. The Snowball comes with a telescoping tripod table stand (6.75 inches at full height) and a USB cable.
The published frequency response graph shows the omni pattern with a flat response up to about 5 kHz, with a 6 dB rise at around 10 to 11 kHz, then a drop to 0 dB again around 18 kHz. The cardioid pattern bumps up 5 dB around 1 kHz, drops down, then goes up 4 dB at 10 kHz before dropping off at 18 kHz.
FIG. 3: The MXL USB.006 has a built-in attenuation switch with –5 and –10 dB settings.
Blue intended the Snowball to be simple and easy to use, and it is. Like most of the other USB mics, the Snowball's A/D converter has a 16-bit, 44.1 kHz resolution. However, the Snowball doesn't give you the option of selecting a lower bit depth or sampling rate. A company spokesman noted that although there are newer USB chips offering a greater bit depth, it wouldn't be of interest to the typical Snowball user: anyone wanting a higher resolution would use a regular mic with a dedicated converter.
However, Blue offers a pair of downloadable firmware applets — high gain and low gain — that give you control over the Snowball's output level. With the Snowball plugged in, simply launch one of the applets and it will download the data to the mic's converter chip in about five seconds. Once downloaded, unplug the mic from your computer and then reattach it to hear the new gain level. Prior to March 1, 2007, the Snowball shipped with the lower gain setting, but by the time you read this, the mic will be shipping with the higher gain setting.
Marshall Electronics MXL USB.006
The MXL USB.006 is a side-address cardioid condenser with the same 0.79-inch diaphragm used in the MXL 990 condenser (see Fig. 3). The mic includes a 3-position switch to control the amount of gain before the A/D converter: Hi (no pad), Medium (-5 dB pad), and Lo (-10 dB pad). You'll notice a gentle thump as you switch between levels.
The microphone's frequency response is 20 Hz to 20 kHz. Although the manual includes no other specs, it does offer instructions on using the mic in a Windows and Mac environment, including GarageBand in particular. A red LED illuminates from behind the grille when the mic receives power.
The MXL USB.006 comes with a nontelescoping tripod stand, a USB cable, a lightweight plastic mic clip, a thin foam windscreen, and a vinyl case that includes a separate compartment for the mic. The clip is attached by unscrewing the ring at the base of the mic, setting the mic into the clip, and then reattaching the base ring. Overall, the MXL USB.006 doesn't feel as solid as the other mics in the roundup, although its lighter weight can be a plus if portability is an issue. In a desktop situation, the clip and tripod held the mic securely.
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The Australian-made Røde Podcaster feels solid and is much heavier than the other mics in the roundup (see Fig. 4). Designed specifically for voice-over work rather than music recording, this neodymium-based dynamic mic has a 1.1-inch diaphragm with a cardioid pattern. It was designed for maximum off-axis rejection so that room tone and noise from shuffling papers wouldn't be prominent in the signal.
FIG. 4: Røde''s Podcaster is a dynamic mic with a built-in headphone output and overall level control for latency-free monitoring.
The Podcaster comes with a USB cable, a rugged mic clip that screws onto the locking collar at the base of the mic, and, when you register the mic online, a conditional ten-year warranty from the date of purchase. The mic clip gives you 180 degrees of positioning, which I found especially useful with an end-address mic.
On the side of the Podcaster are a stereo headphone minijack and a headphone volume control that lets you set the level of the combined signals of the mic and digital recording software. (You'll have to set the balance of the input and playback tracks within your audio application.) The onboard headphone output is designed to give you latency-free monitoring as you record. Considering that the mic is designed for use by nonspecialists, many of whom may not know about technical issues such as latency and buffer sizes, the onboard headphone jack is a very useful feature. On the opposite side of the mic is a status LED that indicates when the mic is receiving power.
The Podcaster is nearly 8.5 inches long and reminds me of that old broadcasting standard, the Electro-Voice RE20, in appearance. The published frequency response is 40 Hz to 14 kHz, with an 8 dB presence boost around 9 to 10 kHz. The response chart in the manual shows a 16 dB drop at the lowest extreme and about a 10 dB drop after about 12 kHz.
The capsule is not internally shockmounted and the mic is susceptible to handling noise. You'll want to use Røde's PSM-1 spider-style shockmount ($49) if floor- or tableborne rumble is an issue.
The manual is very useful and provides tips on using the mic with a Mac and PC, getting the best results when recording, and installing and using the Podcaster software for Windows users (available from www.rodepodcaster.com). The application, which boosts the level before the A/D converter to improve the signal-to-noise ratio, offers a volume control, a level meter, and a mute button.
FIG. 5: The Samson CO1U has a fixed supercardioid polar pattern.
Samson offers USB versions of two of its mics. Many of the specs of the USB and non-USB versions are similar, although the SPL is several dB lower and the self-noise is slightly higher in the USB mics.
Like the original CO1, the CO1U is a side-address mic with an electret condenser element, a 0.75-inch internally shockmounted diaphragm, and a supercardioid polar pattern (see Fig. 5). This type of pattern is useful for spoken-word applications, where you want a high degree of rejection of off-axis sound.
The frequency response is 50 Hz to 18 kHz. The included chart shows the low end dropping at 150 Hz to about -7 dB at 50 Hz. The upper end has a 2 dB presence boost at about 3 kHz and a 4 dB rise at 11 kHz, before dropping to -6 dB at 18 kHz.
When purchased as single units, the Samson USB mics come with a lightweight plastic mic clip, a USB cable, a tabletop tripod stand, Cakewalk Sonar LE, and a vinyl bag that is big enough for the mic only. However, the CO1U I received was part of the CO1U Recording Pak ($249.99). Along with the microphone, clip, USB cable, and Cakewalk Sonar LE, the package includes a weighted tabletop stand, a spider-style shockmount, and a locking aluminum flight case.
The CO1U feels solid and substantial in your hand, and the included base and clip hold the mic securely. As with the MXL USB.006, you attach the CO1U to the mic clip by unscrewing the base, setting the mic into the clip, and then reattaching the base.
Although its USB mics work fine on their own, Samson offers a freeware applet called SoftPre (Mac/Win) that gives you greater control over the gain within the mic's internal A/D chip. With a range of -62 to +48 dB in 1 dB increments for the CO1U and Q1U (and a range of -13 to +24 dB for the CO3U), the applet offers input metering with a clip indicator, a switch for inverting phase, and a low-cut filter (-12 dB per octave), which is continuously variable from 21 to 200 Hz.
FIG. 6: The Samson CO3U is a condenser mic with three patterns (omni, supercardioid, and figure-8), a –10 dB pad, and a low-cut switch.
Based on the CO3 design, the CO3U (see Fig. 6) has two 0.75-inch diaphragms. According to the published frequency response chart, it yields an overall flatter response than the CO1U, but with an 8 dB presence boost at 7 kHz. The CO3U lets you choose one of three polar patterns from a switch on the back: omni, supercardioid, and figure-8. On the front of the mic is a switchable -10 dB pad and a low-cut filter (-6 dB at 180 Hz).
The CO3U feels solid like the CO1U and comes with the same set of accessories. The CO3U is also available in a Recording Pak configuration ($344.99).
The Q1U is a dynamic end-address microphone that resembles a handheld vocal mic (see Fig. 7) but is not resistant to handling noise. It features a 1-inch element with a Mylar diaphragm. Like the other Samson mics, it comes with a mic clip, a USB cable, a tabletop tripod stand, Cakewalk Sonar LE, and a vinyl bag for the mic. It has a wide, supercardioid pattern, though the response chart shows that there is less off-axis rejection in higher frequencies.
The published frequency response is 50 Hz to 16 kHz. The chart shows a gentle rolloff beginning at 200 Hz and dropping -10 dB to 50 Hz. The presence boost starts at 1.5 kHz and reaches +5 dB at 5 kHz, rolling off to 0 at 10 kHz and dropping to -8 dB at 16 kHz from there. Like the previous two mics, the Q1U feels hefty and solid.
FIG. 7: The Samson Q1U is a dynamic USB mic with a 1-inch element.
I began the roundup by setting up each mic on my desktop and, one at a time, plugging them into the USB port on the back of my Mac G4 tower (running Mac OS X 10.3.9), my Mac G4 laptop (running OS X 10.4.8), and a Dell laptop running Windows XP. I wanted to know if the mics were truly hassle-free to set up, and to see if there were any obvious differences between them. All of the mics were immediately recognized by the computers and passed audio to my recording applications. From then on, I used my Mac laptop for the recording tests.
Initially I didn't use any additional software to bump up the signal. With the Mac, I increased the gain to maximum in the System Preferences→Sound panel whenever possible to test each mic's output limits. In the Input section of the System Preferences→Sound panel, I received an input volume control for the Snowball, Podcaster, and each of the Samson mics. With the MXL USB.006, however, a message reading “the selected device has no input controls” replaced the horizontal volume control. Perhaps that is because the MXL USB.006 has a level control on the mic that attenuates the gain to the internal A/D chip.
Surprisingly, the three Samson mics were significantly louder than the other mics when simply plugged into the computers. To get distortion-free recordings on the Mac, I brought the level down slightly using the System Preferences→Sound panel. In addition, I downloaded and installed Samson's SoftPre to get more control over the volume level and to use the highpass filter. Samson offers only a Universal Binary version for OS X, but I was assured it would work with a G4.
However, whenever I launched SoftPre, the overall level of the mics was reduced, forcing me to boost the signal when recording by about 20 to 30 dB on the CO1U and Q1U, and 10 dB on the CO3U. In addition, the mics didn't always behave properly, even when SoftPre wasn't launched.
According to a Samson spokesman, SoftPre installs a kernel extension, which in my case was conflicting with other software extensions on my laptop. He added that “a very small number of users that install SoftPre have encountered system conflicts. When this occurs, we recommend uninstalling SoftPre and using the mic without the application.” With Samson's help, I did the uninstall, though it required a few more steps than I had anticipated. (The steps to do an uninstall for Windows XP users are already online, and the OS X instructions should be online by the time you read this.)
Despite my troubles with SoftPre, Senior Editor Mike Levine had no issues when using it with his Samson CO1U and Mac G5. If you purchase a Samson mic, I suggest that you use it without SoftPre for a period of time and download SoftPre only if you really need features such as low cut or a phase switch.
Stop Your Whining
There is quite a bit of online discussion and marketing hype about the self-noise in a USB mic, which is often described as a high-pitched whine. In fact, a representative from Marshall Electronics told me that the company has worked hard to eliminate this annoying artifact from its USB mics using proprietary electronics.
However, the MXL USB.006 was the only mic in the roundup to have a noticeable high-pitched noise artifact (a B-natural, in fact). The noise was very quiet and was perceptible mostly at the beginning and end of the recordings.
The Samson mics, on the other hand, had a bit of hiss that was evident on exposed or low-level sources, with the Q1U generating the highest level. The self-noise of the Snowball and Podcaster were negligible.
Because USB mics are primarily designed for Podcasting and songwriting uses, the majority of my testing was with voice and acoustic guitar at 16 bits, 44.1 kHz. However, I also subjected the mics to the shaker test to see how they would respond to a high-frequency source. And although the performance of the dynamic microphones would differ greatly from that of the condensers, all of the mics received the same treatment in this roundup.
In my spoken-word tests, I stayed about four inches from the mics. Overall, intelligibility and clarity were not a problem with any of the mics. The Snowball's cardioid pattern emphasized the upper frequencies of the voice, with minimal chest tone, even up close. The omni pattern was slightly brighter, and as I got closer, it emphasized sibilance too much.
The MXL USB.006 added more of the lower tones I expected when speaking close to a cardioid condenser. Although it picked up less sibilance than the Snowball, the MXL USB.006 emphasized lip smacks slightly.
The CO1U didn't have the sibilance problems and retained a nice balance of vocal tone. There was more self-noise evident in the track, but it wasn't high enough to render the track useless. The CO3U had a rounder, tighter sound, with the directional patterns yielding more satisfying lows as I moved closer to the mic.
The Q1U also sounded good with spoken material, although the noise floor was more noticeable. Sibilances were downplayed, but when they got through, they sounded a bit crunchy.
On voice, the Podcaster delivered as promised, excluding environmental noise and room reflection nicely, while giving a robust vocal sound (even with a thin voice like mine) that is free of annoying sibilance. To get the most out of it, I had to get right up on it when speaking.
To record a Taylor 110 acoustic guitar, I placed each mic a distance of 12 inches from the instrument, pointing where the neck attaches to the body. This guitar sounds particularly bright, and it is always interesting to see how much of that brightness a mic picks up.
The two Snowball patterns yielded bright, jangly, and somewhat bass-lean tracks, with a perceptible hole in the lower mids. Of the two patterns, the omni version was a little peakier and not as satisfying on its own as the cardioid version.
By contrast, the MXL USB.006 track emphasized the guitar's upper mids, making the instrument sound a bit throatier but very pleasant. Compared with the other condensers, it seemed to compress the guitar a little.
The CO1U sounded somewhat similar to the MXL USB.006 but wasn't as dark. It offered a bit more of the welcome jangly high end.
Of the condensers, the CO3U captured the nicest overall tone in cardioid and figure-8 modes, and I took advantage of the proximity effect to get a beefier sound along with a +10 dB gain boost using SoftPre. In contrast, the mic's omni pattern was a little thinner sounding, although that could help the guitar fit nicely into a crowded mix.
The two dynamic mics yielded a nice punchy sound, with the Q1U being a little meatier than the Podcaster. The greater directionality of the Q1U sensed the subtle movement of the guitar as I played it and resulted in a bit of phasing.
Shakin' All Over
For the shaker, I recorded at distances of 2 and 4 feet from each microphone but moved closer when required. I even played behind the mics to see how much rear rejection or pickup each one had.
At 4 feet, the shaker was more than the Snowball's omni pattern could handle in high-gain mode. So I installed the low-gain applet, which reduced the level dramatically, allowing me to get a nice signal level and tone from the front. Playing to the side and behind the mic, the timbre shifted and the output level was reduced, however. When I used the CO3U in omni mode, the rear and side results weren't as dramatically different than the sound from directly in front of the mic.
The Snowball and CO3U in cardioid mode, the MXL USB.006, and the CO1U captured quite a bit of room tone at 4 feet but yielded good results right away. At 2 feet, the shaker timbres were more defined yet still pleasant. Also at a distance of 2 feet, the Podcaster and Q1U gave me the clear and direct sound I was looking for.
Give Me Convenience or …
Overall, I was surprised at the sound quality of the six USB mics, and at how much my preconceptions changed after spending time with them. They are, indeed, easy to use, and I grew to enjoy the luxury of needing only a mic and a USB cable whenever I felt the urge to record an idea while it was still fresh.
I would characterize the Blue Snowball as having the brightest reproduction of the bunch. It has excellent clarity, and its dual capsules, two polar patterns, and pad setting are a plus. The rear coloration in omni mode was a minor annoyance. The Snowball is spherical and intentionally the size of a softball, which is something you should take into consideration if you plan to travel with it.
The Marshall Electronics MXL USB.006, on the other hand, had a darker quality that was very pleasing on voice and guitar. The two pad settings are a good selling point, although I didn't use them. The self-noise was the biggest issue for me with this mic.
The heavy-duty Røde Podcaster excels at what it was designed for: voice-overs. But it performed admirably with instruments and singing, and I found the direct headphone output and level control to be very useful. It's also the most expensive mic in the roundup, and because of its size and weight, it wouldn't be my first choice for traveling. But for studio use, it feels like it will last a long time.
Each of the Samson microphones has its own sonic personality, and I happen to like the sound of the CO3U the best. Having three patterns, as well as low-cut and pad switches, also works in the mic's favor. The CO1U and Q1U, however, have a lower price point working for them. My only gripe is that these three have a higher noise floor than the other mics.
One thing worth noting is that despite the popularity of the USB format today, it won't be around forever. Unlike a tube mic from the '50s or '60s, a transducer with a built-in A/D converter (whether it is 16- or 24-bit, or 44.1 or 48 kHz resolution) is not futureproof and is going to have a relatively short life span. When it comes time to upgrade your studio and/or computer, you're stuck with the resolution of the A/D chip, not to mention the USB interface. (If you have a SCSI peripheral collecting dust in your studio, you know how quickly computer products drop support for data protocols.)
On the other hand, you can always mate a better preamp and converter to a standard mic. Consequently, if you're looking at a USB mic as a long-term investment, a product such as the USB2200a (see the sidebar “sE Electronics USB2200a”) will leave you with a traditional microphone long after USB ports are no longer supported by computers and their operating systems.
In the meantime, if you simply want an inexpensive microphone for a few years of Podcasting or songwriting that lets you leave your preamps, interfaces, and XLR cables behind, then any of these USB mics will be a worthwhile investment.
Gino Robair is a senior editor at EM.
Go to the next page for sidebars and USB mic comaprison chart
USB MICS ON THE HORIZON
Apex Electronics (www.apexelectronics.com) will be shipping the Apex181 ($99) by the time you read this. The side-address mic includes a 0.79-inch internally shockmounted diaphragm with a cardioid pattern.
FIG. A: The Samson G-Track can also be used as a 2-channel interface.
Avant Electronics (www.avantelectronics.com) will offer the Avantone CU-2 ($199), a true condenser with a cardioid pattern and a 1.37-inch diaphragm, a switchable -10 dB pad, and an 80 Hz rolloff switch. The mic comes with a shockmount and a wooden case.
The Blue Microphones Snowflake is a single-capsule design that uses the same cardioid electret element and converter chip as the Snowball. Although the Snowflake doesn't include a pad switch, it is smaller than the Snowball and has a built-in stand that lets the mic rest on a desktop or attach conveniently over your laptop monitor.
Marshall Electronics is expanding its USB mic offerings with the MXL USB.007 stereo microphone ($219.95) and the USB.008 large-diaphragm condenser ($199.95). The USB.007 uses a stacked pair of the same 0.79-inch capsules used in the 990 and USB.006, but permanently positioned in an x-y pattern. The USB.008 has a 1-inch capsule found in many of the MXL mics. Both mics include a selectable attenuation switch. The company has also announced the USB Mic Mate ($99), an XLR-to-USB converter that lets you plug any microphone directly into your USB port.
The Samson G-Track ($199) has the same capsule as the CO1U but adds a 2-channel interface into the mic body (see Fig. A). Features include a stereo instrument/line input on minijacks with a gain control, a stereo headphone output with a level control, and an onboard gain control for the mic. You can send two channels of external audio through it, or send one external channel with the mic signal. The package includes audio and USB cables, a small tripod mic stand, a mic clip, and a copy of Cakewalk Sonar LE.
sE Electronics recently unveiled the USB1000 ($249), a small-diaphragm condenser. Like the USB2200a, the USB1000 includes voltage conditioning circuitry that is linked to the Mac/PC output switch.
SE ELECTRONICS USB2200A
Sharing features of the 2200a, the USB2200a ($499) has a 1-inch diaphragm, a cardioid polar pattern, and discrete FET electronics (see Fig. B). However, the USB2200a is unique in the context of this roundup because it includes an XLR output, which can be used simultaneously with the USB output. The mic can be powered from the USB bus or with +48V phantom power. Consequently, the USB2200a is a mic you can use in professional situations as well as for Podcasts and other informal uses.
It's worth noting that you can simultaneously record from both outputs at once. The mic includes a mini stereo headphone jack and a balance control to set the level between the mic signal and audio from your recording software.
FIG. B: The sE Electronics USB2200a includes an XLR output as well as headphone monitoring with a mix control.
The USB2200a also includes a 100 Hz rolloff switch, a -10 dB pad switch, and a Mac/PC switch. According to the manufacturer, the switch changes the mic's impedance to accommodate the differences in “sensitivity” of the USB bus between the two computer platforms, noting that the Mac's USB bus needs to see 15 dB more gain. However, I was unable to verify this because a production version of the mic was unavailable during my research, nor was I able to get a comment from Apple about this difference.
The USB2200a includes a separate circuit board that provides power conditioning, buffering, and noise filtering to deal with the problems inherent in power coming from the USB bus. Unlike the other mics in this roundup, the USB2200a accepts a mini-B connector on its side.
The published frequency response of the USB2200a is mostly flat, although down 1 dB from 40 to 300 Hz. From 500 Hz, it's flat at 0 to 2.5 kHz, where it begins its 3 dB rise to about 11 kHz. At 20 kHz, the response is roughly -1 dB. sE Electronics also says that although the converter chip has a 16-bit resolution, it can lock to sampling rates of 88.2 and 96 kHz.
USB MICROPHONE FEATURES COMPARED
||40 Hz-18 kHz
||20 Hz-20 kHz
||44.1 and 48 kHz
||-5 and -10 dB
||40 Hz-14 kHz
||50 Hz-18 kHz
||omni, supercardioid, figure-8
||50 Hz-18 kHz
||50 Hz-16 kHz