Having music stored on a computer is a good thing. Gone are the days of sifting through CD books for that elusive disc; no more annoying skipping of that elusive scratched disc once you have found it. It is an Itunes world. We have all our music ready and waiting for us at a touch of a button, complete with album artwork! Computers, on their own, make great music servers, except for one crucial flaw- the sound cards that are built into them are cheap, 50 cent parts. Solution? Simple! Get a high quality external sound card for your computer and by-pass the low quality one that came built in to your computer.
USB DAC is the industry term for a high-end external sound card. USB stands for Universal Serial Bus, and as you probably know, is simply a universal port built into all computers for connecting a host of different devices. DAC stands for Digital to Analog Converter. This is a chip that decodes the digital information (in this case music stored on your computer) into an analog signal that we can hear. DAC’s have been around since the advent of the CD player and people figured out pretty early on that the quality of the DAC used in CD players had a huge impact on the quality of the sound. For years companies have made external DAC devices as substitutes for the CD players’ built-in DAC. The idea here is the same. The only difference is that we are substituting a computer for a CD player and a USB DAC for a traditional outboard DAC.
Okay, so we know why computers are good, and we understand why we need a USB DAC to get the best sound from our computer. Now for the really fun stuff. Why do these things have the potential to sound better than +20k CD players?
There are many different reasons why these devices sound as good as they do but one of the biggest has to do with a computers inherent ability to do a better job of reading CDs than even fancy CD players. When you are ripping a CD to your computer, the computer can take all the time it needs to read and re-read every pitfall on the CD until it gets a one for one copy of your CD on to the computer. This is called error correction. Because CD players, even very expensive players, have to read the information on a CD and spit it out in real time, they wind up having read errors on the information that gets sent to the DAC inside of the CD player.
Another reason this technology work so well is the USB connection. You may be surprised to learn this but USB is a great way to hook up audio devices. It is a specification that has been around for a long time and it is extremely stable. When you compare it to the connection that we use for hooking up standard DACs to CD players, known as SPDIF, you notice that USB has a major advantage. SPDIF uses a one-directional signal that multiplexes both a data and a clock signal onto one wire. This requires the receiving end to correctly separate the signals. This is what leads to the most dreaded word in digital audio- Jitter. Without getting too technical, jitter, as you might have guessed, is a bad thing. The other problem with a uni-directional signal flow is that you get clocking errors because the clocks that are being used on both ends of the signal don’t sync up a 100% of the time. USB on the other hand, is a Bi-directional connection and therefore has no need for clocks: it essentially syncs itself! While there is intrinsic jitter associated with any DAC system, this type of jitter has decreased significantly with a revolutionary USB controller code developed by Wavelength Audio. End result: very low jitter, and no clocking errors, Hooray!
Okay, so USB DACs are good, but what makes Wavelength USB DACs superior to virtually all other USB DACs on the Market?
The code that Wavelength uses for its USB controller is special and has been written completely from scratch, bringing intrinsic jitter to an all time low. All of Wavelength’s USB DACs feature tubed output stages. Every DAC made is built one at a time, by hand, with a lot of love and attention to detail. There is no assembly line, only superior parts are used; each DAC is a labor of love built by people who love music, for people who love music.
What is a tubed output stage you ask? Vacuum tubes were originally used to build amplifiers before the invention of the transistor. Ask any die-hard audio enthusiast why they are obsessed with tubes and you will be bombarded with adjectives like- soothing warmth, emotional, 3-dimentional, alive and moving sound. A lot can be said about tubes, but the best thing to do is drop by your local hi-fi shop and just listen.
So USB DAC’s make a lot of sense for music but what about home theater? The great thing about computers is that they can be DVD players as well. What most people do is buy a dedicated computer like the Mac Mini by Apple Computers and connect the video output to their new LCD television and presto! Not only can you navigate through your music collection by remote control using Apple’s Front Row application… pop in a DVD and you are watching a movie on a first class Stereo Home Theater system.
Stereo Home Theater is a concept that has been around for a long time but not widely advertised to the public. The argument for stereo home theater is simple: if you have 5K to spend on home theater speakers, you are buying 5 speakers each worth around 1K. Put the same money towards 2 speakers, and… well you get the idea. You might not have sound effects whizzing behind you but rear speakers are a pain to wire for most people anyway. In addition, 2 high quality speakers correctly positioned with a USB DAC have the potential to produce a huge 3-dimensional holographic sound stage that will put all but the most extravagant home theater systems to shame. Stereo lives!!! Keep in mind that this concept doesn’t just work for music and movies, you can stream internet radio, Podcasts, YouTube and Google video movies. The possibilities are endless!
As far as general setup goes, Wavelength DACs are truly Plug and Play. PC or Mac, you are up and running in less than 2 minutes. Just tell your computer that you want to use the Wavelength DAC to process your computer audio and you are good to go. There is absolutely no software to install as the software is actually embedded in the DAC hardware and every Wavelength DAC is instantly recognized as soon as it is plugged into your computer. Simply connect your computer to the DAC via a USB cable, and connect the analog outputs of your DAC to your stereo. USB lengths should not be more than about 10FT. If you need a longer length, extend your RCA cables rather than getting a longer USB cable. A decent music collection with CD quality files (No MP3s!!!) should take up about 250gigs of hard drive space. So, if you need to add more storage to your computer just pick up an external hard drive. Prices have dropped significantly, and you can now buy a 500 gig hard drive for under $150. At those prices you can buy 2 and use one to back up your collection. That’s it! For specific setup instructions and information on the best way to rip music to your computer, please see the Macintosh or Windows setup pages.
A typical setup for a USB DAC system is shown above. We
have two Firewire disks for our library (one is for
backup). We use Firewire over USB drives because we don't
want to overload the USB link. So we use Firewire as the
data will come into the computer via the Firewire
controller and leave the computer going USB to the dac. The
output of the DAC is feed to a preamplifier or integrated
amplifier and then to the amp and speakers. There are
several suggestions for full remote control located on the
setup pages for Macintosh and Windows.
Asynchronous USB
Audio-What’s it all about?
Every USB DAC you have ever
heard uses Adaptive Mode USB Audio. This means the computer
controls the audio transfer rate, and the USB device has to
follow along updating the Master Clock (MCLK) every one
millisecond. The USB bus runs at 12MHz, which is unrelated
to the audio sample rate of any digital audio format (i.e.
44.1K requires an MCLK = 11.2896MHz). Therefore Adaptive
Mode USB DACs must derive the critical master audio clock
by use of a complex Frequency Synthesizer. Since the
computer is handling many tasks at once, the timing of the
USB audio transfers has variations. This leads to jitter in
the derived clock, which means you are not getting the
maximum sonic potential available from computer-based
audio.
Now, for the first time ever,
Wavelength Audio has developed Asynchronous Mode USB Audio.
This means the computer is controlled by the USB DAC. No
longer is the tail wagging the dog. Instead, an
ultra-low-jitter audio master clock located in the DAC
controls the audio transfer rate from the computer. Jitter
is reduced by a factor of greater than 100 times! What's
more, this is accomplished using the standard USB drivers
(Windows or MacIntosh) for easy plug-and-play installation.
Now the convenience of computer-based audio is combined
with the lowest possible jitter. This breakthrough
technology from Wavelength Audio delivers the highest level
of sonic performance and a new era in digital audio.
