Pinnacle Systems Mbox 3 Technology Guide
Third-Generation Mbox
Technology Guide
Table of Contents
Design Philosophy Behind the Third-Generation Mbox Family .....................................................3
The Elements of a Great Audio Interface ......................................................................................3
Converters .................................................................................................................................3
Preamps .....................................................................................................................................3
Clocking .....................................................................................................................................3
Emissions Compliance ...............................................................................................................3
The Keys to the Mbox Sound ........................................................................................................4
Listening Tests ...........................................................................................................................4
Premium Components and Efcient Layout ...............................................................................4
World-Class Clocking and Jitter-Elimination Technology ...........................................................4
Industrial and Electrical Design ..................................................................................................4
Power .........................................................................................................................................4
Hardware Build ..........................................................................................................................4
Expertise ....................................................................................................................................5
Signal Path, Internal Layout, and Routing .....................................................................................6
Mbox Pro Signal Path ................................................................................................................7
Mbox Signal Path .......................................................................................................................7
Mbox Mini Signal Path ...............................................................................................................7
Additional Resources.....................................................................................................................8
Appendix........................................................................................................................................9
Mbox Family Specication Comparison .....................................................................................9
Mbox Pro Input Frequency Response .................................................................................... 10
Mbox Pro Output Frequency Response .................................................................................. 10
Mbox Pro Input THD ................................................................................................................11
Mbox Pro Output THD .............................................................................................................11
Mbox Input Frequency Response ........................................................................................... 12
Mbox Output Frequency Response ........................................................................................ 12
Mbox Input THD ...................................................................................................................... 13
Mbox Output THD ................................................................................................................... 13
Mbox Mini Input Frequency Response ................................................................................... 14
Mbox Mini Output Frequency Response ................................................................................. 14
Mbox Mini Input THD .............................................................................................................. 15
Mbox Mini Output THD ........................................................................................................... 15
Design Philosophy Behind the Third-Generation Mbox Family
In designing the new Avid® Mbox® family of audio interfaces, our industry-leading engineering team set out
to create best-in-class products that would surpass their previous efforts in this category—as well as those
of other manufacturers. To meet this goal, we leveraged technology from our top-of-the-line Pro Tools|HD
recording systems, and also drew from our extensive experience developing mobile recording solutions.
In addition, we conducted numerous customer surveys and interviews, and incorporated a broad array of
user requests into the new Mbox series—from higher audio quality and enhanced integration with Pro Tools®
software, to a rock-solid new chassis and ergonomic front-panel design. Finally, we carefully optimized each
member of the Mbox family for its specic function—from serious desktop production to mobile eld work.
The Elements of a Great Audio Interface
It’s important to understand the reasons why some interfaces sound better than others, even when recording
at equal sample rates and bit depths. Much of the answer lies in the quality of the components.
Converters
Even if the performers, instruments, rooms, and microphones are excellent, a recording can suffer if the
interface uses poor-quality converters to convert between the analog and digital domains. Low-quality
converters create noise and distortion, which degrade the quality of the recording. Excellent converters
deliver pure, powerful sound, even when the nal playback medium is only 16 bits.
Preamps
It’s important to use preamps that deliver high gain without introducing unwanted noise and hiss from
their internal circuitry. This provides clean, natural-sounding audio regardless of how much gain is
required. The signal-to-noise ratio* (expressed in negative values) is an important gauge of the quality
of an interface’s converters and preamps; lower (more negative) numbers indicate better performance.
Clocking
Audio interfaces must clock their converters at regular intervals in order to capture sound accurately.
A poorly designed clock can breed jitter, causing the interface to sample audio irregularly. The irregularity
results in audio distortion. An excellent clock has minimal jitter, ensuring that the digital audio converters
stay rigidly time-locked and minimize related distortion.
Emissions Compliance
An excellent audio interface will be designed and manufactured to ensure that electronic emissions
comply with the emission limits set by national and international standards agencies. It will also comply
with the requirements to continue to properly operate with specied levels of emissions from nearby
electrical and electronic equipment.
It’s not enough to just use premium-quality components—it’s absolutely critical to arrange and connect them
with the utmost precision and expertise. This requires a deep level of experience and specialized training.
*Beware when comparing signal-to-noise specs from different manufacturers. Some companies only measure the noise
introduced by the preamps and ignore the complete signal path; others state the theoretical specs of the converters and not
the actual measured specs. This results in a signal-to-noise ratio that is misleading. Avid publishes only “real-world” specs,
so users will know how the interface will truly perform before making a purchase.
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The Keys to the Mbox Sound
Listening Tests
Before commencing work, our design team engaged in a series of listening tests. We sampled Avid
interfaces as well as products from other manufacturers, then worked to develop the clearest, most
transparent-sounding interfaces possible. With each subsequent revision of the electronics, our team
reconvened for another set of exhaustive listening tests to ensure exceptional performance.
Premium Components and Efcient Layout
Our engineers started by selecting the best possible components. They sourced the nest D-A and A-D
converters, as well as crystal-clear preamps for pure, pristine sound from start to nish. Then they worked
to ensure the shortest possible path between components, resulting in superior audio quality. (See signal
path diagrams in “Signal Path, Internal Layout, and Routing” section.)
World-Class Clocking and Jitter-Elimination Technology
The Mbox Pro interface features critically acclaimed JetPLL technology to provide extremely stable
synchronization and eliminate jitter that can degrade audio quality. The Mbox and Mbox Mini interfaces
also feature high-quality clocks to provide accurate, low-jitter audio sampling and exceptionally low
resulting distortion.
Industrial and Electrical Design
Our engineering team worked hand in hand with our industrial designers to pair an aesthetically pleasing
and ergonomic exterior with optimized internal electronics and connections. We carefully considered the
position of every element. For example, we placed the preamp jacks on the same side of the interface as
the gain pots and controls in order to ensure the shortest possible internal path—rather than routing them
amongst other components that could introduce noise and interference. We ne-tuned every detail, down
to the routing of every copper trace on the printed circuit boards. We spent months balancing the external
design with the internal, in order to deliver an intuitive user experience as well as pristine sound.
Power
Since the Mbox Pro interface is intended for project studio use, it features an extremely efcient,
low-noise power supply. In contrast, the Mbox and Mbox Mini each feature state-of-the-art bus power
architecture in order to deliver high performance during mobile use, as well as in the studio.
Our engineering team paid exceptional attention to detail when considering the power requirements
for each Mbox interface. All microphones draw different levels of power, so we started by sampling a
wide variety of popular mics to understand the range of power needs. Then we designed the interfaces
to provide adequate phantom power for all possible mics, with a slight bit of headroom. We carefully
selected every single power-drawing component in the interfaces, continually minding the overall power
budget. Then we pored over the schematics to analyze hot spots, and cut back wherever possible to
ensure power efciency—without ever compromising performance.
Hardware Build
In direct response to customer feedback, the third-generation Mbox interfaces are housed in
professional-grade, rugged, metal chassis designed to withstand the rigors of heavy-duty mobile and
studio use. All structural components are made of metal; a solid metal extrusion encases a secondary
inner metal chassis, which ensures the precise alignment of all internal components. In addition, the
metal enclosure—along with proper circuit design, ltering, and layout—provides immunity to emissions
from nearby electronics equipment, keeping the sound quality pristine. A molded plastic faceplate and
soft-touch knobs enhance the aesthetic and tactile appeal.
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Expertise
Our engineering team relied on their personal experience as musicians and audiophiles to ensure that
the Mbox interfaces would yield pleasing, musical results in even the most demanding circumstances.
For example, if pushed to the point of distortion when capturing heavy vocals, the distortion sounds
musical rather than harsh. These audible performance characteristics further separate Mbox from
products by other manufacturers.
Like our engineering team, our testing department is full of working musicians, audio engineers, and
audiophiles. These power-users rigorously tested the interfaces to make sure that they would perform
optimally in a vast array of real-word scenarios—with a wide variety of computers, operating systems,
microphones, and other gear. After standing up to their discerning ears and uncompromising scrutiny,
we knew the Mbox interfaces would meet the sonic expectations of even the most demanding users.
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