In recent years a flood of unique-sounding, low-cost ribbon mics has hit the market. These budget ribbons are often paired with low-cost recoding interfaces—sometimes with noisy results.

What if there was a simple analog device that would strip the noise out of your ribbon mic recordings? This is precisely the situation the Cloud Microphones [http://www.cloudmicrophones.com] Cloudlifter ($289 street; $329 MSRP) was designed to address.

The Cloudlifter adds 20 dB or more of gain to the output of a mic (more on this in a moment), so that your mic preamp doesn’t have to do as much boosting. With less noise added to the signal, the “signal-to-noise” ratio tilts significantly in your favor. Here’s why.

Mic Preamp 101
The analog signals generated by microphones are tiny, delicate little things measured in millivolts (thousandths of a volt). Before the signal from a mic can be used it must be boosted in level many times over. This task falls to the microphone preamplifier.

The mic preamp “adds gain,” which simply means a small AC signal enters a circuit and a higher voltage copy of that signal comes out the other side. The amount of gain can be measured in decibels (dB) and a typical mic preamp might provide variable gain up to 60 dB.

Not all mic preamps are created equal. While all circuits add some noise to the signal, some mic preamps use more expensive components or clever circuit design to keep the signal as clean as possible. Others are designed to be more cost-effective, providing more channels for the same price.

And all microphones aren’t the same. Among the three types of microphone capsules—condenser, dynamic, and ribbon—you’ll find a wide range of output levels. Condensers have the highest output voltage, followed by dynamics, while the faintest signals are typically generated by ribbon mics.

Stick a low-output mic in front of a loud sound, such as a guitar amplifier or a cowbell, and even a budget mic preamp will give you a suitable signal to work with. But when working with quieter sources— acoustic stringed instruments, delicate vocals, ambient room sound—the undesired noise added by the mic preamp can get distractingly loud. The best situation would be for the preamp to receive a hotter output signal from the mic. That’s where the Cloudlifter comes in.

No Pain. Lots of Gain.
Housed in a sturdy metal box, the Cloudlifter is about as simple an audio device as you’re likely to find. Four XLR connectors: two inputs, two outputs. No knobs. No switches. Not even an LED. The Cloudlifter gets patched between the output of your mic and the input of your preamp. You can use it with a single mic, or two different mics at the same time.

Although it has no plug or power switch, the Cloudlifter requires power to operate. Your computer’s audio interface, mic preamp, or mixing board must be able to provide phantom power to the Cloudlifter for it to work.

Note that it does not pass phantom power to your microphone. That means it’s safe to use with passive ribbon microphones. However, you won’t be able to use the Cloudlifter with pro-level condenser mics, because they do require phantom power. (But, typically, these have a high enough output level that they don’t really need the extra gain boost.)

The circuitry within the Cloudlifter is simple but effective. Rather than using integrated circuit op-amps, the Cloudlifter is a discrete, 4-transistor design, built onto a small circuit board. The two channels are completely independent, so you need to send phantom power to both channels if you are using two mics.

Let’s Get Testy.
When paired with a budget mic-preamp or computer audio interface, the Cloudlifter can make a clear and substantial difference. First, I recorded a tambourine at a distance of about nine feet, using a stock Beyerdynamic M260 ribbon mic patched into my M-Audio Firewire 410 audio interface. The Firewire 410 has fairly noisy pre-amps and you can hear the background hiss clearly between the tambourine hits (hear Web Clip 1).

Patching the Cloudlifter between the M260 and the Firewire 410 greatly reduced the amount of background hiss, as you can hear in this example (hear Web Clip 2). I took care to adjust the mic-preamp gain to get similar, if not identical, record levels with and without the Cloudlifter in-line. These examples are presented as recorded, without EQ or dynamics processing.

Next, I did some close-miked acoustic-guitar tracks using a Cascade FatHead II ribbon mic plugged directly into the M-Audio Firewire 410. Especially when strumming gently, you can hear the background noise on the track without the Cloudlifter (hear Web Clip 3). Patching the Cloudlifter between the FatHead II and the Firewire 410 once again noticeably improved the noise floor (hear Web Clip 4).

I had similar success with a Shure SM57 dynamic mic. During sections of soft strumming, the self-noise of the Firewire 410 mic preamps is audible (hear Web Clip 5). And again, using the Cloudlifter makes it less noisy (hear Web Clip 6).

Bear in mind that with louder sound sources, the improvement is less dramatic. Here is the same guitar and mic position, but with louder strumming. Even without the Cloudlifter, the noise floor isn’t that bad (hear Web Clip 7). Still, the Cloudlifter does make it better (hear Web Clip 8).

Finally, I placed the M260 so that it is touching the grille cloth, dead-center in front of a guitar amp. The amp’s master volume was not loud enough to compete with a live drum kit, but plenty loud to drive the Firewire 410 without having to crank its mic preamp gain up all the way (hear Web Clip 9). In this case, there’s a subtle tonality difference with the Cloudlifter in the signal path, but the noise floor isn’t an issue either way (hear Web Clip 10).

The manufacturer notes that the Cloudlifter’s 20 dB gain rating is variable, “depending on the mic and preamp using. This has to do with impedance.” The amount of boost “ranges from 20 to 25 db. For example, an SM57 plugged into a Digi002 yields about 24.5 db of gain.” 

The manufacturer claims the Cloudlifter provides an additional benefit of impedance matching. The input impedance of the device is 3,000 ohms, which they say is a better match for passive ribbon mics than the input impedance found on many mic preamps.

M-Audio doesn’t publish the input impedance of the Firewire 410, so I can’t say if the tonal differences I heard are strictly related to this point. However, I do hear subtle differences in addition to the obvious change in background noise. It’s rather difficult to create a fair test for this sort of listening because differences in mic placement relative to the source, as well as variations in performance, can create differences in sound equal or greater than what I’m hearing. But I will go on record as saying I found the Cloudlifter produced a subtly fuller, more pleasing sound to the recorded tracks. Listen to the audio examples on this page and form your own opinion.

Favorable Forecast
The primary benefit of using the Cloudlifter is a likely improvement in the noise floor of your recording. In addition, by blocking phantom power, the Cloudlifter lets you use a phantom-intolerant ribbon mic and a condenser at the same time, if your preamp has a global phantom-power on/off switch. Simply connect your ribbon mic to the Cloudlifter and then plug it into one channel of your mic preamp, while plugging the condenser directly into another preamp input. Turn on your global phantom-power switch and you’ve got two different mics ready to go.

To determine whether the Cloudlifter is right for you, take this simple quiz:

• Do you use passive ribbon and dynamic mics?
• Is your mic preamplifier cheap and noisy?
• Are you recording quiet, acoustic sound sources, distant ambiences, and/or room sounds?

If you can answer yes to all three questions, the Cloudlifter will make an audible improvement in your recordings. You may also benefit from using it with a quality preamp that doesn’t have the right impedance or enough gain to handle a passive ribbon mic.

For tracking loud sounds, the improvement will likely be minimal. But for recording quiet sources, the Cloudlifter is a winner.

Pros: Significantly improves performance of noisy mic preamplifiers when using passive ribbon and dynamic mics. Sturdy construction. Easy to use.
Cons: A little spendy if you only expect to use a single channel.

Rudy Trubitt is an audio producer and performer. Find him at http://Listn.to/RudyTrubitt.