High-quality audio preamps, compression and A/D conversion in a portable unit
Page 1 of 1
The Apogee Mini•Me (MSRP $1,495) is a sweet little 24-bit/96K portable box that combines three valuable audio functions: preamplification, compression/limiting, and Analog-to-Digital (A/D) conversion. It’s compatible with both Macs and PCs and connects directly to them via USB – with no hassles. You get instant recognition and connectivity, the way things are supposed to work.
Measuring 10” long by 5” wide and 1” tall, the Mini•Me is designed for mobile recording (it can operate from either the included 12V power supply or on battery power ranging from 6V to 16V). Just hook it to a USB-equipped laptop loaded with your favorite audio recording app, and you’re ready to capture a high-quality stereo audio signal. If you don't have USB, AES/EBU and S/PDIF digital outputs are also included. The output options include 16-, 20- or 24-bit audio at 44.1, 48, 88.2 or 96 kHz. The USB output is limited to 44.1/48kHz, while the AES/EBU (XLR) and S/PDIF (RCA/coaxial) digital outputs can handle everything up to 96 kHz. Apogee also makes a version without USB for $1,295 (MSRP).[an error occurred while processing this directive]With all it includes, the Mini•Me is a downright bargain. Its high-quality preamps, compressor/limiter and A/D converters are ready for any professional situation, on the road or in the studio. There's 48v phantom power for microphones and a headphone jack for monitoring. And because its outputs are clocked by a high-stability reference crystal oscillator, the Mini•Me can even serve as a master clock.
Apogee Electronics (www.apogeedigital.com) has somehow packed all this functionality into a compact unit that doesn't feel cramped or awkward. The knobs are accessible, and the LED input meters are easy to read. In a clever bit of ergonomic design, the two analog input jacks serve double duty as XLR and TRS inputs.
|Front View: The Mini-Me comes in a handsome extruded metal case with purple knobs. LED meters and input volume controls are at left, compression and sample rate settings are in the center, and phantom power button is at near right.|
|Rear View: Input jacks at right double for XLR or TRS plugs. USB and headphone monitor jacks are in the middle, while AES and S/PDIF digital outputs are at left.|
The compressor/limiter is equipped with two proprietary Apogee processes, Soft Limit and Push-IT. Soft Limit is an analog process that prevents digital overs by rounding out peaks in the incoming signal, beginning on peaks at about –4dBFs and smoothing them out up to 0dBFs. Push-IT is a gain control circuit consisting of a compressor and limiter that are integrated with Soft Limit. Push-IT gives you extra boost when you need it or slams on brick-wall limiting when the signal rises above a certain decibel level .
Between the two, you can adjust an incoming signal for maximum saturation without distortion. The graph below shows the various compression and limiting curves generated by the combination of Soft Limit and Push-IT.
|3 (curve starts at –14 on the left axis) This shows the response curve of SLC setting Compression 3. Top switch in far right “SLC” position, bottom switch far right in curve “3” position.|
off (curve runs from the origin, bottom left, to +0/-0) Circuit bypassed. Top switch in far left “off” position.
SL (curve runs from the origin to +2/-0) This shows the response curve of Soft Limit only. Top switch in center “SL” position. The bottom switch position is not relevant.
2 (curve starts at -25.5 on the left axis) This shows the response curve of SLC setting Compression 2. Top switch in far right “SLC” position, bottom switch in middle curve “2” position.
1 (curve starts at the origin and exits right at about -1.5 dBFS) This shows the response curve of Soft Limit/Limit 1 circuit. Top switch in far right “SLC” position, bottom switch in far left curve “1” position.
This is a well-built professional product that sounds terrific. In fact, although it’s designed for mobile applications, it’s fully suitable for studio use. I used the USB output with equally good results recording to both a Mac G4 running OS X 10.2.6 (with BIAS Deck 3.5.2 as the host application) and a Windows 2000 machine (running SONAR 2.2). I also hooked the Mini-Me up to the AES and S/PDIF inputs of a Mackie d8b digital mixing console and recorded an acoustic guitar. All three inputs (USB, AES and SPDIF) produced sparkling clear recordings from the mic preamps, using the compressor and A/D conversion.
I wouldn’t hesitate to use the preamps for anything. They’re clean and open, with some character if you push them. I tried the Mini•Me with acoustic guitar, electric bass, synths and voice. The preamp can deliver a robust sound for keyboards and direct bass, and the compressor is particularly useful for dialing in more oomph from these instruments. Through both an Audio-Technica 4050/CM5 mic and a Studio Projects C1, acoustic guitar and voice were clear with great definition. I tried recording two channels at once using both mic inputs, and the Mini•Me delivered the same good quality to both channels.
|The Mini•Me in its optional carrying case (MSRP $49.95).|
And the A/D conversion is first-rate – I hooked a CD player into the Mini-Me’s analog inputs and then routed the AES digital output into the Mackie d8b’s digital inputs. There was an audible improvement in the high-end frequencies, compared to the sound of the CD player going straight to the mixer.
The Mini•Me has another handy conversion trick, too: If you get the sample rates mismatched between the Mini•Me and your computer, the unit will convert sample rates automatically. Or, if you select, for example, 24-bits on the unit and 16-bits on the computer, the Mini•Me will automatically apply UV22HR conversion encoding (more on this below) to the signal sent to the USB port (at 44.1/48 kHz only).
While the Mini•Me is a new product, the technology behind it didn’t just fall from the sky. Apogee has a legacy of high-quality professional audio devices, most of them full-size rackmountable units. In fact, the Mini•Me represents a sort of return to Apogee’s roots: The company’s first products were portable reference units such as the AD 1000, which also featured a two-channel mic preamp. But key aspects of the technology Apogee uses in its current top-of-the-line products have trickled down to the Mini•Me, too. The mic preamps are designed by the same team that produced Apogee’s well-regarded Trak 2 preamp. And the compressor/limiter is built on the company’s Soft Limit process for maximizing digital signals without overloading, with the addition of the Push-IT circuit.
|The UV22HR Encoding Process |
Excerpted from the Mini•Me Manual
|If you are producing recording for 16-bit CD – or 20-bits for many DVD-Video projects – then you need a method of reducing the high resolution 24-bit output of a modern conversion system to 16 or 20 bits. Apogee UV22HR Encoding – the latest and most powerful development of Apogee’s original UV22 process – is an entirely different approach to word-length reduction. UV22HR does its job without sonic compromise, and without adding a sound of its own, preserving the sound stage and tonal balance of the original high-resolution source. The effects are even audible on original 16-bit recordings. |
UV22HR Encoding adds an inaudible, algorithmically-generated concentration of energy around 22 kHz. Technically, it’s known as “Sub-Nyquist-band dither”. Much as the bias on an analog tape recorder smooths out magnetic tape recording non-linearities, UV22HR silently captures resolution beyond 20 bits on a standard, 16-bit CD. In addition, this inaudible carrier smooths the rough edges of even the most inexpensive CD player or external converter. UV22HR makes your recordings sound better on all listening systems.
The truly unique statistical properties of UV22HR guarantee a constant white noise floor, very similar in character to analog tape noise, no matter what the input source. If you listen to a UV22HR encoded recording, you can hear a stable, accurate sound stage and faithful tonal balance more than 24dB into the noise – just as you do on analog tape.
Yet the UV22HR’s low audible noise floor sits at the theoretical limit for a 16-bit or 20-bit system. Nothing is lost – but a great deal is gained. In listening test after listening test, engineers and reviewers alike choose UV22 over all other systems. Many thousands of CD titles have already been mastered using Apogee UV22 and UV22HR processors. Apogee’s process is today in use in the vast majority of US mastering houses, and it is estimated that as many as 80% of the hit records mastered in the United States today utilize the system.
Another great inclusion in the Mini•Me for those who have to convert down from 24-bit to 20 or 16 bits is Apogee’s proprietary UV22 encoding process. This performs bit reductions that retain most of the sonic characteristics of the high bit-rate signal.The Mini•Me has an upgraded version called UV22HR (see sidebar).
In fact, given the Mini•Me’s range of features, a professional sound card isn’t even required for outstanding digital audio recordings. With a signal path going right from the analog source into the Mini•Me’s converters, and then to the computer via USB, the signal quality is at least comparable to, and probably better than, what you’d get through most sound cards. And of course, you can mix multiple audio tracks in your software application, so a mixer isn’t required, either.
This is important to mobile recordists, but it’s also an economical way for a home studio to get professional-sounding results. Going direct from the Mini•Me to the computer without a mixer, you can only record two tracks at a time. Even if you had a mixer, the Mini•Me has only two channels anyway. But if you’re multitracking, as opposed to recording a number of separate tracks live, the two-channel limit doesn’t matter. And what you’d save on a good sound card and a mixer is about the cost of the Mini•Me.
If you’re looking for a professional dual-platform audio interface for mobile recordings, the Mini•Me fits the bill perfectly. It’s great for independent filmmakers (it’ll ouput digital black) or radio interviewers in the field, or even, as Mercenary Audio’s Fletcher points out, Deadheads wanting to make concert bootlegs (the band permits this). But it’s also a great option for project studio owners who need high-quality mic preamps and A/D conversion. In addition, the Mini•Me’s UV22HR makes it an ideal final step between a computer sound card (or outboard mixer) and a mastering device. This device is a clear winner, and merits serious consideration from audio professionals, field recordists and project studios alike.
|USB Hookup |
The Mini•Me's USB connection works right out of the box with Mac OS X 10.2.3 and higher – no drivers or set-up to contend with at all. The Mac’s new Core Audio framework under OS X automatically recognizes the Mini•Me’s USB connection, and then names it as an input source in both its own interface and in the menus of OS X-compatible audio programs.
The image at left shows what OS X's CoreAudio Window looks like in BIAS Deck 3.5.2 after the Mini•Me has been connected via USB.
The Mini•Me is compatible with Macintosh OS 9.x through 10.x (version 10.2.3 recommended for USB hookups). USB functionality under OS 9X can be set up through Apple’s Sound Manager or via the Mini•Me's custom USB Audio ASIO driver.
For PCs, the Mini•Me has a special downloadable ASIO driver written by Apogee, which the manual urges you to use because the native Windows drivers “do not play back properly.” With SONAR 2.2’s new ASIO functionality and the Mini•Me ASIO drivers, the performance was flawless.
If you’re hooking the Mini-Me up to a computer that has a sound card, you do have to manually switch from the sound card drivers to the Mini-Me’s drivers in your audio application. The example at right is from Cakewalk's SONAR 2.2, where the existing M-Audio Delta drivers were deselected, and Apogee MiniMe drivers were then selected.
The Mini•Me is compatible with Windows 98SE, ME, 2000 and XP (Mini•Me custom ASIO drivers are recommended for USB hookups).
[an error occurred while processing this directive]