Third-Generation Mbox Technology Guide

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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 Efficient 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 Specification 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 specific function—from serious desktop production to mobile field 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 final 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 specified 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. 3

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 Efficient Layout Our engineers started by selecting the best possible components. They sourced the finest D-A and A-D converters, as well as crystal-clear preamps for pure, pristine sound from start to finish. 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 fine-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 efficient, 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 efficiency—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, filtering, 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. 4

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. 5

Signal Path, Internal Layout, and Routing In addition to selecting premium components and creating the shortest possible signal path between them, our engineers worked to optimize each model’s signal chain for its intended use, as detailed below. Mbox Pro Signal Path The Mbox Pro audio interface features 8 x 8 simultaneous channels of I/O. There are four microphone inputs with 48V phantom power (two XLR/DI combo, two XLR), plus four 1/4” TRS line inputs. The DSP and software‑based mixer lie at the heart of the Mbox Pro interface, facilitating a huge variety of routing options. The mixer also provides access to a variety of hardware-based low-latency effects. 6

Microphone Input The signal goes from the XLR input into a premium-quality preamp with a pad, which provides over 74 dB of gain range (including the 20 dB pad). From there, the signal goes to a high-pass filter, which is controlled by software via a high-quality relay. Then the signal passes to an insert jack on the back of the interface, so the user can send to external devices, and the return will come in through the same insert. Line Input The Mbox Pro interface is specifically optimized for desktop recording scenarios, where a user is likely to leave the line inputs plugged in at all times. A Front/Rear switch enables the user to choose between the preamp signals or line inputs on the back of the interface. The signal from the line input does not pass through the preamp; instead it connects directly to the converter, ensuring that the sound is not colored in any way. The line input features a 4/-10 switch so a user can switch between professional- and consumer-level signals. Then, users have the option of passing the signal to the soft-clip limiter, which features the same technology as our top-of-the-line Pro Tools HD 192 I/O audio interface, enabling users to track extremely hot signals without overloading the inputs and clipping. Finally, the signal feeds directly to the premium-quality A/D converter, which delivers world‑class performance. Instrument Input The instrument input follows the same path as the microphone input, and thereby benefits from the same wide gain range and control via the gain knob. The instrument input is optimized to cover a wide range of signal strengths and output levels (passive and active guitars, etc.). The dynamic range and distortion specs are dramatically improved compared to the previous generation. Mbox Signal Path 7

The Mbox interface provides 4 x 4 simultaneous channels of I/O—two XLR mic/line combo inputs with 48V phantom power, and two 1/4” DI inputs on the front panel for easy access. The Mbox signal path is designed to offer optimum flexibility for mobile scenarios and field use. The line inputs pass through the preamps, so users can plug in a variety of sources and just tweak the gain as needed. The high-quality preamp does not color the signal, and the placement of the mic and line inputs on the same circuit ensures that no additional noise is introduced. As a result, the Mbox delivers clear, pristine sound. The mixer also provides access to a variety of hardware-based low-latency effects. Mbox Mini Signal Path With 2 x 2 simultaneous channels of I/O, the Mbox Mini interface is designed to be a high-quality, personal, portable interface. It’s built for simplicity, and optimized to deliver clean, clear performance. Its twin preamps accept a combination of mic, instrument, and line inputs, and provide exceptional quality like those found on the Mbox Pro and Mbox interfaces. Additional Resources From the powerhouse Mbox Pro to the ultra-compact Mbox Mini, the new family of Mbox interfaces delivers unparalleled sound quality and flexibility for today’s recording enthusiasts. For more information about each model, visit www.avid.com/MboxFamily. 8

Appendix As with all Avid product specifications, the published Mbox specs reflect actual performance measurements. Mbox Family Specification Comparison Mbox Pro Mbox Mbox Mini /-0.1 dB 112 dB -112 dB -100 dB -120 dB 14 dBu / 6 dBV (switched) 10 k (20 k) /-0.1 dB 110 dB -110 dB -100 dB -120 dB /-0.1 dB 106 dB -106 dB -94 dB -116 dB 4.2 dBu 0 dBu 10 k (20 k) 10 k (20 k) Min Gain, No Pad /-0.1 dB 110 dB -110 dB -100 dB -128 dB -120 dB 0.5 dBu 20.5 dBu 1.8 k (3.6 k) 54 dB (74 dB with Pad) -20 dB Min Gain, No Pad /-0.1 dB 110 dB -110 dB -100 dB -128 dB -120 dB 4.2 dBu 24.2 dBu 2.2 k (4.4 k) 54 dB (74 dB with Pad) -20 dB Min Gain, No Pad /-0.1 dB 106 dB -106 dB -94 dB -128 dB -116 dB 0 dBu 20 dBu 2.2 k (4.4 k) 54 dB (74 dB with Pad) -20 dB Min Gain, No Pad /-0.1 dB 109 dB -109 dB -98 dB -120 dB 16 dBV 1 Mohm 54 dB (74 dB with Pad) -20 dB Min Gain, No Pad /-0.1 dB 109 dB -109 dB -98 dB -120 dB 16 dBV 1 Mohm 54 dB (74 dB with Pad) -20 dB Min Gain, No Pad /-0.1 dB 105 dB -105 dB -94 dB -110 dB 16 dBV 1 Mohm 54 dB (74 dB with Pad) -20 dB Aux Inputs (Unbalanced) Freq Response, 20 Hz - 20 kHz Dynamic Range (A-wt) SNR (A-wt) THD N, 1 k, -1 dBFS Crosstalk at 1 k Maximum Input Level Input Impedance /-0.1 dB 105 dB -105 dB -98 dB -120 dB 2 dBV 10 k n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a Line Outputs (Balanced) Freq Response, 20 Hz - 20 kHz Dynamic Range (A-wt) SNR (A-wt) THD N, 1 k, -1 dBFS Crosstalk at 1 k Maximum Output Level Max Level /-0.1 dB 109 dB -109 dB -102 dB -120 dB 14 dBu Max Level /-0.1 dB 109 dB -109 dB -102 dB -110 dB 10.2 dBu Max Level /-0.1 dB 109 dB -109 dB -93 dB -110 dB 10.2 dBu Headphone Outputs Freq Response, 20 Hz - 20 kHz Power into Ohms Max Level, 32 R /-0.2 dB 60 mW into 32 R Max Level, 32 R /-1.0 dB 20 mW into 32 R Max Level, 32 R /-0.2 dB 20 mW into 32 R Line Inputs (Balanced) Freq Response, 20 Hz - 20 kHz Dynamic Range (A-wt) SNR (A-wt) THD N, 1 k, -1 dBFS Crosstalk at 1 k Maximum Input Level Input Impedance Mic Inputs (Balanced) Freq Response, 20 Hz - 20 kHz Dynamic Range (A-wt) SNR (A-wt) THD N, 1 k, -1 dBFS EIN Unwtd, 54 dB gain, 150 R Crosstalk at 1 k Max Input Level (No Pad) Max Input Level (With Pad) Input Impedance Gain Range Pad in dB Inst Inputs (Unbalanced) Freq Response, 20 Hz - 20 kHz Dynamic Range (A-wt) SNR (A-wt) THD N, 1 k , -1 dBFS Crosstalk at 1 k Max Input Level Input Impedance Gain Range Pad in dB 9

1 2 Red Solid 3 DSP Anlr.Level B Left Line Outputs, -10dBu @1kHz Output Freq Resp.at27 Frequency Response and Total Harmonic Distortion (THD) Mbox Pro Input Frequency Response AVID Mbox Pro 1 0.8 0.6 0.4 0.2 d B r 0 1 -0.2 -0.4 -0.6 -0.8 -1 20 20k 50 100 200 500 1k 2k 5k 10k 20k 1k 2k 5k 10k 20k Hz Sweep Trace Color Line Style Thick Data Axis 1 1 1 2 Blue Red Solid Solid 3 3 DSP Anlr.Level A DSP Anlr.Level B Left Left Mbox Pro Output Frequency Response AVID Comment Mbox Pro Mic Inputs, Min Gain Input Freq Resp.at27 -9 -9.2 -9.4 -9.6 -9.8 d B u -10 -10.2 -10.4 -10.6 -10.8 20k -11 20 50 100 200 500 Hz Sweep Trace Color Line Style Thick Data Axis 1 1 1 2 Blue Red Solid Solid 3 3 DSP Anlr.Level A DSP Anlr.Level B Left Left Line Outputs, -10dBu @1kHz Comment 10 Output Freq Resp.at27

1 2 Red Solid 3 Fft.Ch.2 Ampl Left 1 THD (-1dBFS signal) FFT, Line Outputs L Output THD FFT.at27 Mbox Pro Input THD AVID AVID Mbox Pro 0 1 -10 0.8 -20 -30 0.6 -40 0.4 -50 -60 0.2 -70 d B F S -80 d B r -90 1 0 -0.2 -100 -110 -0.4 -120 -0.6 -130 -140 -0.8 -150 -160 20 50 100 200 500 1k 2k 5k 10k -1 20 20k Hz Sweep Trace Color Line Style Thick Data Axis 1 1 1 2 Blue Red Solid Solid 3 3 Fft.Ch.1 Ampl Fft.Ch.2 Ampl Left Left Mbox Pro Output THD AVID Comment S 1 1 AVID Mbox Pro THD (-1dBFS signal) FFT, Mic Inputs, Min Gain M THD FFT.at27 -9 10 0 -9.2 -10 -9.4 -20 -30 -9.6 -40 -9.8 -50 d B u -60 d B u -70 -80 -10 -10.2 -90 -10.4 -100 -110 -10.6 -120 -10.8 -130 -140 20 50 100 200 500 1k 2k 5k 10k 20k -11 20 Hz Sweep Trace Color Line Style Thick Data Axis 1 1 1 2 Blue Red Solid Solid 3 3 Fft.Ch.1 Ampl Fft.Ch.2 Ampl Left Left THD (-1dBFS signal) FFT, Line Outputs Comment S 1 1 11 Output THD FFT.at27 L

1 2 Red Solid 3 Fft.Ch.2 Ampl 1 Left L THD (-1dBFS signal) FFT, Line Outputs Output THD FFT.at27 Mbox Input Frequency Response AVID Mbox AVID 0 1 -10 0.8 -20 -30 0.6 -40 0.4 -50 -60 0.2 d B r d B F S 0 1 -0.2 -70 -80 -90 -100 -110 -0.4 -120 -0.6 -130 -140 -0.8 -150 -1 20 50 100 200 500 1k 2k 5k 10k 20k -160 20 Hz Sweep Trace Color Line Style Thick Data Axis 1 1 1 2 Blue Red Solid Solid 3 3 DSP Anlr.Level A DSP Anlr.Level B Left Left Mbox Output Frequency Response AVID Comment S 1 1 Mbox Mic Inputs, Min Gain T Input Freq Resp.at27 -9 -9.2 -9.4 -9.6 -9.8 d B u -10 -10.2 -10.4 -10.6 -10.8 20k -11 20 50 100 200 500 1k Hz Sweep Trace Color Line Style Thick Data Axis 1 1 1 2 Blue Red Solid Solid 3 3 DSP Anlr.Level A DSP Anlr.Level B Left Left Line Outputs, -10dBu @1kHz Comment 12 Output Freq Resp.at27 2k 5k 10k 20k

1 2 Red Solid 3 DSP Anlr.Level B Left Line Outputs, -10dBu @1kHz Output Freq Resp.at27 Mbox Input THD AVID Mbox 0 -10 -20 -30 -40 -50 -60 -70 d B F S -80 -90 -100 -110 -120 -130 -140 -150 -160 20 20k 50 100 200 500 1k 2k 5k 10k 20k Hz Sweep Trace Color Line Style Thick Data Axis 1 1 1 2 Blue Red Solid Solid 3 3 Fft.Ch.1 Ampl Fft.Ch.2 Ampl Left Left Mbox Output THD AVID Comment AVID Mbox THD (-1dBFS signal) FFT, Mic Inputs, Min Gain THD FFT.at27 -9 10 0 -9.2 -10 -9.4 -20 -30 -9.6 -40 -9.8 -50 d B u -60 d B u -70 -80 -10 -10.2 -90 -10.4 -100 -110 -10.6 -120 -10.8 -130 -140 20 50 100 200 500 1k Hz Sweep Trace Color Line Style Thick Data Axis 1 1 1 2 Blue Red Solid Solid 3 3 Fft.Ch.1 Ampl Fft.Ch.2 Ampl Left Left THD (-1dBFS signal) FFT, Line Outputs Comment 13 Output THD FFT.at27 2k 5k 10k 20k -11 2

1 2 Red Solid 3 Fft.Ch.2 Ampl Left 1 THD (-1dBFS signal) FFT, Line Outputs L Output THD FFT.at27 Mbox Mini Input Frequency Response AVID Mbox Mini AVID 1 0 -10 0.8 -20 -30 0.6 -40 0.4 -50 -60 0.2 d B r d B F S 0 1 -0.2 -70 -80 -90 -100 -110 -0.4 -120 -0.6 -130 -140 -0.8 -150 -1 20 50 100 200 500 1k 2k 5k 10k 20k -160 20 Hz Sweep Trace Color Line Style Thick Data Axis 1 1 1 2 Blue Red Solid Solid 3 3 DSP Anlr.Level A DSP Anlr.Level B Left Left Mbox Mini Output Frequency Response AVID Comment S 1 1 Mbox Mini Line Inputs, Min Gain T Input Freq Resp.at27 -9 -9.2 -9.4 -9.6 -9.8 d B u -10 -10.2 -10.4 -10.6 -10.8 20k -11 20 50 100 200 500 1k Hz Sweep Trace Color Line Style Thick Data Axis 1 1 1 2 Blue Red Solid Solid 3 3 DSP Anlr.Level A DSP Anlr.Level B Left Left Line Outputs, -10dBu @1kHz Comment 14 Output Freq Resp.at27 2k 5k 10k 20k

1 2 Red Solid 3 DSP Anlr.Level B Left Line Outputs, -10dBu @1kHz Output Freq Resp.at27 Mbox Mini Input THD AVID Mbox Mini 0 -10 -20 -30 -40 -50 -60 -70 d B F S -80 -90 -100 -110 -120 -130 -140 -150 -160 20 20k 50 100 200 500 1k 2k 5k 10k 20k Hz Sweep Trace Color Line Style Thick Data Axis 1 1 1 2 Blue Red Solid Solid 3 3 Fft.Ch.1 Ampl Fft.Ch.2 Ampl Left Left Mbox Mini Output THD AVID Comment AVID Mbox Mini THD (-1dBFS signal) FFT, Line Inputs, Min Gain THD FFT.at27 -9 10 0 -9.2 -10 -9.4 -20 -30 -9.6 -40 -9.8 -50 d B u -60 d B u -70 -80 -10 -10.2 -90 -10.4 -100 -110 -10.6 -120 -10.8 -130 -140 20 50 100 200 500 1k 2k 5k 10k 20k -11 20 Hz Sweep Trace Color Line Style Thick Data Axis Comment 2011 Avid Technology, Inc. Product features, specifications, system requirements, 1 All rights 1 reserved. Blue Solid 3 Fft.Ch.1 Ampl Left and availability are subject to change without notice. Avid, the Avid logo, Mbox, Pro Tools, and Pro Tools HD are trademarks or registered trademarks of Avid Technology, Inc. or its subsidiaries in the United States and/or other countries. All other trademarks contained herein are the property of their respective owners. 1 2 Red Solid THD (-1dBFS signal) FFT, Line Outputs 3 Fft.Ch.2 Ampl Left 15 Output THD FFT.at27 S 1 1

Mbox Pro Signal Path The Mbox Pro audio interface features 8 x 8 simultaneous channels of I/O. There are four microphone inputs with 48V phantom power (two XLR/DI combo, two XLR), plus four 1/4" TRS line inputs. The DSP and software-based mixer lie at the heart of the Mbox Pro interface, facilitating a huge variety of routing options.

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