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Behind the scenes of the new Fast Track C-series interfaces (Part 6)

Only published comments... Nov 08 2011, 12:00 AM by Leo Der Stepanians

Fast Track C400 and C600 are the best sounding M-Audio branded interfaces. The premium preamps and converters will capture your music with incredible clarity.


For my final Fast Track C-Series blog entry, I wanted to really focus on something that all audio professionals hold sacred: high sound quality.


Here at Avid, building products is an “iterative” process. That means each new interface we launch has the engineering know-how and design expertise of every interface that has come before it. Fortunately, Avid and M-Audio have been building interfaces longer than almost anyone else in the industry and, when it comes to designing such products, we have one of the most seasoned teams of engineers in the world. For the Fast Track C-Series products, the team worked very hard and poured all of their considerable knowledge and expertise into a tough goal: to make the best sounding M-Audio branded interface, ever. This was not an easy goal, but I was fortunate enough to have my friend Chris (one of the key electrical engineers behind the 3rd generation Mbox) heading up the engineering effort.


The 3rd generation Mbox interfaces had been garnering lots of praise from customers and the press, so Chris and I devised the following strategy: Start with a 3rd generation Mbox, remove non-essential features, and do as little as possible to bring the costs down while maintaining the highest possible sound quality. As an example, we did away with the (rather expensive) extruded aluminum housing and metal sub-frame and replaced it with a (very tough) plastic housing. This brought down cost significantly without negatively impacting signal quality. We also removed other components like the “soft limit” circuitry and replaced the more expensive Mbox “push-pull” knobs (which combined gain and pad into one control) with a regular gain knob plus a separate button to engage the pad. Steps like this allowed us to bring down costs while maintaining high audio quality.


Another step we took to maximize sound quality included using digitally controlled speaker select switches, phantom power buttons, and master volume control knob. If you’ve used a Fast Track C400 or C600, you may have noticed that the speaker select and phantom power buttons are not analog-style “toggle” switches (the kind you see on old analog mixers) but rather digital “momentary” switches. From an electrical engineering perspective, it would actually have been easier for us to use analog switches to control these features, but that would mean routing sensitive analog signals all over the circuit boards on the inside of the product. This would result in unnecessarily long analog signal paths and degraded audio quality. Furthermore, these analog switches sometimes get “crackly” over the years due to physical wear and tear. To avoid all of this, we devised a system where the speaker select, phantom power, and the master volume controls actually send “control” data straight to the D/A converters and power supply telling those components what to do. This keeps analog signal paths very short, maintains very high audio quality, and the switches don’t degrade over years of use.


Here is a Fast Track C600 and a very early block diagram I drew up. Thanks to the insight and hard work of the engineering team, we actually scrapped this (primitive) original design and went with a more ambitious design that had better, more powerful features.


A few industry insiders who have seen these products have asked me about what specific components we use for things like preamps and converters. I hesitate to get into discussions about specific components because it’s important to look at an interface as an audio system (i.e., as a whole product, from input to output) rather than a collection of individual components. For example, it is possible to use an expensive high-end preamplifier (or AD/DA converter) in a product but still have it sound bad if the power supply, circuit board layout, or surrounding components are not designed with great care. On the other hand, it’s possible to take a more reasonably priced preamp or AD/DA converter, put it into a product with a very well designed power supply, board layout, and surrounding components and ultimately end up with a better sounding product. I’ve personally seen two products with the same key components that sound vastly different from each other! If you don’t believe me, tell me: How many tube-based guitar amps have you seen that use exactly the same tubes and/or drivers but sound vastly different from each other?


I’ll admit, it’s easy to market an interface as having “ABC-brand” preamp and “XYZ-brand” converter, but this simply doesn’t give you any idea of how good a product sounds. It’s for this reason that we take the high road and not get into long, drawn out, discussions about individual components that don’t give you any useful information about the actual sound quality (even though we do use some very good components).


Ultimately, my advice is: don’t believe the hype… trust your own ears! And don’t take my word for it either—I’m certainly not an impartial judge! If you’re in the market for an interface, go to your favorite dealer and audition a Fast Track C400 or C600 against other similarly priced products. Better yet, ask your dealer if you can try a C-Series interface and a competing product in your own home studio for a few days. Some dealers are OK with this arrangement as long as you promise to buy one of the interfaces that you take home. I’m confident the C-Series interfaces will do very well against anything that is available in the marketplace today!


Oh, and if you try two products (like a Fast Track C400/C600 and a more expensive competitor) and don’t hear a difference, don’t pressure yourself into buying a product because of a fancy brand name or flashy marketing. Pick the product with the best feature set that includes everything you need (or might want as your studio grows) and just focus on creating great work! How’s that for honest advice?


Anyway, I hope you’ve enjoyed reading my blog as much as I’ve enjoyed writing (and photographing) it! If you’re in the market for an interface, I hope you’ll give the C-Series an audition and if you already own a C-Series interface, I hope you’re already creating all kinds of amazing work with it!


Take care,



By the way, if you haven’t already, please check out the new Fast Track C-Series overview video below and C-Series product pages for further details about these products.



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About Leo Der Stepanians

As a Senior Product Manager at Avid, I’m responsible for designing and managing M-Audio branded interfaces including the Fast Track and ProFire lines. I’m a composer at heart and I’m proud to say that I began my career many years ago at the very bottom: as an runner at various studios around Southern California! Later on, I was later hired as a Technical Writer (I’ve written documentation for Alesis, Numark, Akai, M-Audio and Avid) before finally becoming a product manager.

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