Setting up USB Audio in Linux
Linux is an excellent platform for bit-perfect playback. With a simple setup, requiring no driver installation, a Linux computer can be turned into an audiophile music player.
Fuse for Loudspeaker Protection
Fuses are often used to protect loudspeakers from overcurrent. Since they are directly in the signal path, their presence may cause uneasy feelings about their audible effects. So how serious is the fuse-induced distortion? Should we be concerned?
Setting up USB Audio in Mac OS X
Setting up USB Audio in Windows 7/Vista
In Windows 7/Vista, the underlying audio architecture has been completely redesigned and requires a different output mode from Windows XP in order to achieve bit-transparency. We recommend setting the media player to the WASAPI exclusive mode, which gives the audio stream the most direct path to the hardware.
Setting up USB Audio in Windows XP
For bit-transparent playback in Windows XP, we recommend using the ASIO (Audio Stream Input/Output) mode. ASIO bypasses the layers of processing hidden beneath the operating system and provides the most direct path to the audio hardware.
Using Anedio D1 DAC with Logitech Squeezebox Touch
The home computer is increasingly becoming the hub of audio playback and storage. With the availability of large-capacity hard drives at affordable prices, the entire CD collection can be ripped and stored on a hard drive, and any song in the collection can be easily accessed through a media player with just a few clicks. The power and convenience of having all the music collection in one place is very appealing. In this rapidly-evolving era of computer audio, we at Anedio are continuing to experiment with various cost-effective solutions for high-performance digital playback.
Multi-Stage Jitter Reduction
Jitter is an undesirable artifact that is unique to digital audio. In the digital domain, music is represented by a discrete series of samples spaced at a regular time interval. To convert these discrete samples into the analog domain, they must be recreated at regular, precisely-spaced time intervals. This is where the timing error, called "jitter," seeps in. The distortion caused by jitter is non-harmonically related to the signal and sounds unnatural, fatiguing, and harsh. Our goal is to diminish this timing error to a level where it can no longer be perceived.
We have intentionally left our jitter specification blank. It's not because jitter is unimportant. On the contrary, we care deeply about jitter because it produces non-harmonic distortion, which is the reason they are perceived as fatiguing, metallic, and harsh. However, to measure it reliably down to the picosecond level (one trillionth of a second) remains exceedingly difficult, and even if it could be done, a single number is inadequate unless its frequency-domain behavior is also understood. So rather than attempting to present a singe definitive number, we limit ourselves to presenting certain characteristics of jitter that seem relevant to auditory perception.
Designing a Low-Noise System
Often an audio component may measure well on a test bench, but when connected to real systems found in typical homes, it may generate much more noise than that reflected in the bench-top measurement. At Anedio, we are acutely aware of this discrepancy, and we strive to design our equipment to perform well in real audio systems.
Why IC Power Amplifiers?
There was a time when the use of ICs (Integrated Circuits) in high-end audio was almost universally regarded as undesirable. The first ICs designed in the 1960's and 70's had poor slew rates and a host of other problems, making them inferior to discrete designs. However, times have changed. Over 40 years of collective design experiences have transformed the scene. We now understand more about various mechanisms of distortion and have the advantage of more advanced fabrication technologies and faster transistors. We at Anedio believe that IC power amplifiers built using National Semiconductor's LM3886/LM4780 offer truly exceptional performance, on a par with or even superior to discrete designs.
Assumptions in Audio Design
High-end audio is both stimulating and perplexing because of the diverse assumptions about the goals of sound reproduction and the process by which one achieves those goals. We at Anedio start with a set of assumptions about how to optimize an audio system for the most faithful reproduction of music. Other designers start from different sets of assumptions. These fundamental assumptions shape the design process and how the whole system is conceived.
Bi-wiring and Bi-Amplification
One of the overlooked issues in designing audio systems is the crossover hidden inside the loudspeaker box. The crossover has the job of splitting the signal into the low and high frequency components (e.g. in a 2-way system). It is deceptively simple, consisting of a handful of passive components. Yet, it has the exceedingly difficult job of carrying high current and high voltage signals -- about 1,000 times higher current and 20 times higher voltage compared to the line-level stage.