Austin, Texas Two-year-old startup D2Audio Corp. is gambling that the growing popularity of home theater surround-sound "stereos" with five or more output channels will secure slots for its digital amplifier modules.
The impetus is more than demand for audio/video receivers with "the thin, silver, sleek look" to match the newest flat-panel displays, suggested Rick Knox, D2Audio's chief executive officer. And it's more than the need for full-fidelity audio in smaller, lighter, less power-hungry packages.
What drives D2Audio's business, Knox asserted, is time-to-market. By providing compete drop-in modules and thereby eliminating the tuning and tweaking ordinarily associated with digital amps, D2 hopes to do for digital amps what earlier module makers did for switching regulators.
Like many digital amplifier manufacturers, D2-Audio argues that digital pulse shaving provided by Class D amplifiers will dramatically improve power efficiency and will eliminate the need for bulky metal heat sinks. D2 will even use digital signal processors to reduce the battery of filter components normally required at the output.
The modules combine an "adaptive controller" chip and software with such discretes as power FETs and filters. The modules are adapted to the number of channels being driven. A typical eight-channel module sells for about $100.
The main controller includes a DSP core licensed from ParthusCeva Inc. (San Jose, Calif.) that is compatible with the Motorola DSP instruction set. The DSP and D2Audio's software give customers "the capability to integrate some of their own secret sauce" into their systems, the company said.
The business model of shipping a standalone digital amplifier chip to a customer with a reference design was "a broken model," said Glenn Burchers, vice president of marketing at D2. "Audio quality issues aside for a moment, digital, or Class D, amplifiers are not easy to design. Getting good sound quality from a digital amplifier is not trivial.
"And driving 50-watt speakers is not the same challenge as 100-W speakers it takes 10 times the power to double the volume."
Burchers previously worked for a company that supplied digital amplifier ICs but left it up to the customer to come up with the complete amplifier subsystem. That created "enormous support issues" for his former employer, he said, since combining a Class D amplifier chip with high-power transistors and other discretes is an engineering challenge that goes beyond the knowledge base at many audio system companies. Burchers recalled one customer that tried to create a digital amplifier module from Burchers' company's chip but had ended up with a larger, more power-hungry amplifier than if the amp had been based on a linear device.
D2Audio pitches its drop-in modules as relieving the pain of digital amplifier design. The company's business model is in many respects similar to the strategy used years ago by manufacturers of switching regulator modules. Every power supply designer knew at the time that a switching regulator could be orders of mag-
nitude more efficient than a linear regulator but without specialized tuning and tweaking, switchers could be difficult to use. Companies like Na-tional Semiconductor were able to expand the market for switching regulators by integrating the required FETs and filter components into drop-in modules that required no extra tuning.
The drop-in module strategy may allow D2 to go from an early October appearance at the 115th Audio Engineering Society convention in New York to a January announcement of 10 to 12 confirmed customers at the 2004 International Consumer Electronics Show (CES) in Las Vegas. The company's announced customer list includes high-end stereo makers Audio Agile (Wetter, Germany), Jamo (Hrsholm, Denmark), Harman Kardon (Washington), Sonance (San Clemente, Calif.) and Speakercraft (Riverside, Calif.).
CEO Knox expects the "thin, silver, sleek" look to prevail at CES. Many of D2Audio's customers are designing receivers measuring 3.5 inches high less than half the height of systems based on linear amps. Home entertainment systems constitute an estimated 70 percent of D2Audio's market. For the time being, the company plans to stay at the high end of the market, where the amp drives speakers of 50
W or more per channel. That is where the margins are greatest, Knox said.
D2Audio earned $12 million in first-round venture funding from Austin Ventures and Sevin Rosen Funds and recently raised a second round, of $15.5 million, to attack an audio market that Forward Concepts (Tempe, Ariz.) now pegs at $2 billion.
"Digital amplifiers save power, a great amount of power," said Will Strauss, president of Forward Concepts. "And they can be very small, which means that you can cram a high-performance amplifier into a small box, creating new form factors."
Audiophiles debate the merits of digital audio components, but Strauss claims that any distinguishable differences are subtle. "And digital amplifiers are getting better, while linear amps are kind of stuck," he said. "It adds up that the market for digital amps is starting to really take off."
"Digital amplifier design is not a very mature field," said Skip Taylor, D2Audio's chief technology officer (and Knox's college roommate). "One reason we have been able to get on our feet so fast is that the knowledge base is fairly small. We knew most of the people that we were able to recruit to come to work here."
Taylor for 13 years was director of engineering at Peavey Electronics Corp. (Meridian, Miss.), a major producer of keyboards and studio recording gear, before coming to Austin to work at Cirrus Logic Corp. for five years. Roughly 15 former Cirrus engineers now work at D2Audio, joining 35 other staffers, nearly all of whom have experience in digital amplifiers. The company expects to double the size of its staff next year, to 100.
Customer demand is partly behind the fast ramp. D2 has been working with a low-volume contract manufacturer in Corinth, Miss., to test out its module fabrication. Volume manufacturing got under way last month in Mombai, India (formerly called Bombay).
"Our biggest challenge right now is bringing up the volume manufacturing facility in India, transferring the manufacturing and testing techniques learned at the low-volume facility in Corinth," Knox said.