Last modified: Thursday March 17, 2005 8:09
Last modified: Thursday March 17, 2005 8:09
Theory links
CD Player (CDP):
Formats:
DVD FAQ - Very interesting information about DVD, provided by Jim Taylor.
CD vs SACD vs DVD-A - a good article by Niklas Ladberg
Spectral and Dynamics comparison of LP vs digital formats - quite revealing research, performed by Cristine Tham
DSD vs PCM 24/192 - comparison of DSD and PCM streams by Craig Anderson
Digital Audio formats (modern concepts):
THX Ultra 2 (THX Music) by Gene DellaSala (audioholics)
Understanding Home THX - an interesting article in Home Theater Builder Magazine
Dolby Pro-Logic II x new stereo-to-multi-channel format
Logic 7 the best explanation of the format available, only in the beginning in German, PDF file
Surround sound info page different formats explained
Data compression for Home Theater - by Perry Sun
DAC (digital-to-analog converter):
Different types of DAC Architecture Unfortunately no such article exist, especially concerning new types of DACs like Advanced Segment (the modern DACs line of development, best examples are DSD1794, PCM1792), Sign Magnitude (best example is PCM1704), Advanced multi-bit delta-sigma (AK4395) and older types like multi-bit (best examples are PCM63-K, AD1862), multi-bit delta-sigma (best examples CS43122, AD1955, CS4396, CS4397, etc.) and simple delta-sigma DACs. There are some interesting AES articles exist, we still need such an article about comparison of different architectures and their influence to the sound quality. The explanations how Sign-magnitude DACs work can be found in the data-sheet of PCM1702 (PDF file), and about Advanced Segment DACs - in the the data-sheet of PCM1738 DAC (PDF file).
How DACs work quite good explanation by Kuei Yang Wang, one of diyaudio forum members, the performance of different types of DACs had been explained.
Dynamic performance testing of D/A converters - very important application, issued by Burr Brown, PDF file (the difference between multi-bit and delta-sigma DACs).
I/V conversion for current/voltage conversion - can be used OPA (operational amplifier, resistor, transistor or transformer).
Principles of Data acquisition and conversion One of the best sources for understanding of conversions, PDF file.
General Notes on Digital Audio old, but useful information, provided by Jeff Chan
Principles of Digital Audio Analog to Digital conversion process had been explained.
DF (digital filters):
Digital Filters listening comparison very useful information, provided by Jeff Chan
Zero-over sampling concept - Presented by Ruohei Kusunoki
Oversampling and bitstream methods in audio - an interesting concept of Sampo Syreeni
DSP (digital signal processor):
DSP processors precision and dynamic range of fixed point and floating point Digital Signal Processors
24 bit vs. 32 bit the popular article concerning precision of processing in DSPs
Superior Audio Requires Fixed-Point DSP - comparison of 48-bit fixed point and 32-bit floating point processing.
The Scientist and Engineer's Guide to Digital Signal Processing - the great book in PDF format about DSP processing.
(new) Digital Filters explained - by Nika Aldrich (from his book "Digital Audio Explained: For the Audio Engineer.")
(new) Dither in Floating point systems - by Nika Aldrich (from his book "Digital Audio Explained: For the Audio Engineer.")
(new) Digital distortions in CD's and DVD's - by Nika Aldrich (from his book "Digital Audio Explained: For the Audio Engineer.")
Special THANKS to Nika Aldrich for providing of such great sources of information to Alex Hardware's readers.
Operational amplifier (OPA or op amp):
OPA design The Amplifier Institute's information
Designing an Op Amp headphone amplifier - Op Amp higher harmonics
Measurements of THD in OPA627, AD825 Comparison of THD spectrum in the best for tweaking OPAs
OPAs sounding - a good article about the differences
Distortion ripple mark/ operational amplifier compilation - the translation from Japanese
(unfortunately Babelfish had blocked the automatic translation, so here is the link to the source in Japanese)
DIY op amp - the great article by Nelson Pass (PDF file)
Biasing Op Amps into Class A - an interesting article by Warren Young
Electrolytic Capacitors for Audio:
Black Gate - the best ones for analog signal path (though the most expensive). Best series NX, WK.
Black Gate and distortions - part 1
Black gate and distortions - part 2
Oscon the best capacitors for Digital circuits power supplies (removing noise, etc.)
Elna pretty good ones for analog signal path (Silmic high grade is almost the same as BG)
Other producers Rubycon, Nichicon, etc.
Distortions in capacitors - measurements by Hajime@it.cas.uec.ac.jp (translation from Japanese)
(unfortunately Babelfish had blocked the automatic translation, so here is the link to the source in Japanese)
Jitter:
Jitter suppression and clocking by Daniel Weiss
Jitter Theory part 1 - by Julian Dunn, part one (PDF file)
Jitter Theory part 2 - by Julian Dunn, part two (PDF file)
System performance degradation - a very good explanation how jitter can affect the system measurements
Distortions:
Distortions in Power Amplifiers - The Amplifier Institute's information
Distortions in AV cables, measurements - Very good article, provided by Bruno Putzeys, Chief Engineer Class D Audio at Philips Digital Systems Labs
Cascode amps design - by Nelson Pass (PDF file)
Audibility of Phase distortions Very useful information, especially for multi-channel sound.
Slew Rate and T.I.D. (transient intermodulation distortions) - good explanation of important types of distortions.
Triode Amps and Stereophile Trojan Horses - by Linn T.Olson
The real story on single-ended amps - by Harold Cooper
Spectral contamination distortions test signal - by Jon Risch
Slew rates - by Chris Johnson
Clipping in CD recordings - a serious problem in the musical industry, it still exists in 2004
Dither explained - by Nika Aldrich
ExtraBit - the best dithering algorithm by Alexey Lukin, author of RMAA
Acoustic:
Room acoustics very useful information by Siegfried Linkwitz
Phase, time and distortions in loudspeakers an interesting article by Elliott Sound Products
Sound and Vision Speaker reports - graphs and scans by Hachette Filipacchi Media Inc.
The use of subwoofers - very good article, confirming that one good subwoofer is enough in 5.1 system
New Denon 5805 MultEQ - a good explanation how Audyssey MultEQ XT works
(new) A revolutionary Linear Motor concept - by TC sounds, PDF file.
Equipment:
Modern AV processors - an interesting comparison of AV processor's functions.
Home Theater and DVD - by Jim and Becca Prillaman
Digital amplifiers:
D2Audio concept - one of the most advanced digital amplification ideas.
Power Physics concept - One-cycle sound amplifiers by Dr. Mark Smith, PDF file.
Equibit /TI - new Texas Instrument concept for the line of digital amplifiers (zero feedback).
Tripath - one of the most accepted concepts in digital amplification.
MUETA concept one of the modern interesting concepts
OEM - digital amplifiers producers
Audio questions:
The Audio Pages - by Elliott Sound Products
AGAweb Technical FAQ useful information
Publications of Malcolm Hawksford - extremely useful information
Publications of Dr. David Griesinger - multi-channel theory
Julian Dunn's articles - digital audio
Inaudible High-Frequency sounds Affect Brain Activity: Hypersonic effect - a perfect article in the Journal of Neurophysiology
Perceptual Discrimination between Musical Sounds with and without Very High Frequency components - an experiment of NHK Labs
HK white papers - perfect articles concerning audio questions
(new) Acoustical measurements, room acoustics - several very good articles, provided by audioholics