Pump Up The Volume With USB

Microsoft's 2003 introduction of the Media Center Edition of Windows XP helped propel a growing synergy between PCs and entertainment systems that continues unchecked to this day. One unsung player in this ongoing convergence of computing and entertainment is the humble USB connection.

The USB link enables the connection of not just on PC gear, but also various types of home-entertainment equipment. These include audio-video receivers, DVD players--including high-definition versions such as Blu-ray and HD-DVD--and even cable and satellite set-top boxes.

Making sense of this sizable collection of gear becomes easier if you approach the USB connection in either of two ways:

• USB as the pathway to audio coming out of a PC. This can involve various kinds of signal processing or delivery, typically in the form of inline sound cards and signal processing.

• USB as a mechanism for attaching audio devices into entertainment systems. As a way to add more inputs alongside existing audio and video capabilities.

In this recipe, I will survey both these areas. I will emphasize the ways system builders can use this information to serve their customers and expand their business.

USB AS THE PATHWAY FOR AUDIO

USB turns out to be a surprisingly good method for enabling PC audio. Even the relatively old USB 1.1 standard, which tops out at 12 megabits per second (Mbps), is good enough to handle conventional stereo audio and some compressed forms of multi-channel surround sound. (Note: Don't confuse Mbps with MBps; the latter stands for megabytes per second.)

USB 2.0, of course, is even faster--and more powerful. With a raw data rate of 480 Mbps, it is 40 times faster than USB 1.1. That means USB 2.0 offers more than enough speed to accommodate high-definition video and various 5.1 or 7.1 multi-channel surround-sound schemes.

Today's high-definition DVD formats, including HD-DVD and Blu-ray, place the biggest demands on data-transfer rates. HD-DVD rates top out at 36.55 Mbps, with 29.4 Mbps allocated for video and the rest for audio. Blu-ray tops out at 54.0 Mbps, with 40.0 Mbps for video, the rest for audio.

USB SOUND CARD ADD-ONS OR REPLACEMENTS

Several sound technologies will work with USB on PCs. These include inline sound-card replacements, USB-attached external sound-processing devices, USB audio amplifiers, controllers, and speaker systems.

For these types of products, you simply insert a new or additional sound card into the PC via a USB port. Here, you will find two types of products: USB inline sound cards, and external sound-card devices.

The distinction comes primarily in terms of size and price. The inline devices are about the same size as a USB Flash drive; the external sound card devices are usually at least as big as a pack of cards, and sometimes as big as a hardback book. Looking at price, the inline devices typically cost $20 to $40 each, while external devices run from $50 all the way to $250.

At the low end of this spectrum, USB inline devices can plug into a USB port on one end, then offer various types of audio outputs on the other end. Depending on the system, these outputs may be optical or coaxial digital audio connectors, stereo mini-jacks, standard sound card outputs, and even 5.1 analog audio outputs.

For example, Turtle Beach retails for $40 and includes an equalizer, software digital outputs for home-theater connections, and a mini-headphone jack. Sans audio or headphone cables, the unit looks pretty much like a USB Flash drive:

To view other examples of low-end devices, browse USBgear.com.

At the high end of the inline sound spectrum are numerous external sound-processing devices that attach to a PC through USB. These support a complete range of audio outputs, including digital optical and coaxial outputs, and multi-channel analog outputs (5.1 is common, but some units even offer 7.1 support). They can also support headphone outputs, microphone inputs, and analog stereo outputs.

Probably the best-known vendors in this category is Creative Labs. The company offers the Sound Blaster Live! 24-bit External device. It also offers the Audigy2 NX.

Another supplier, Hercules, offers the href="http://www.hercules.com/showpage.php?swcty=UK&p=84&b=1&f=1">Muse Pocket. Here's a look at the Hercules external sound card; note the audio connections all around, and the huge volume control on top:

For system builders, upgrades to existing systems—or extensions to notebook systems—will most likely provide the best opportunities to sell such gear. Also, fully understanding how to use sound-equalization and sound-capture utilities can create new business opportunities. For example, the Sound Blaster Live! 24 can capture audio from both tape cassettes and vinyl records, then digitize this content into MP3 format. For aging baby boomers with their aging music collections, that could be one attractive service.