new world of sounds - High-quality digital audio AY - dream or reality.
NEW IN THE WORLD OF SOUNDS AY - 2
(C) MONSTER / SAGE GROUP
High-quality digital sound
on ordinary AY -
- Dream or reality?
Continue our discussion of quadrupeds Moscow spektrumista
Oldman'a titled "UltraSound4x3 metod for AY chips".
After careful examination of the theoretical and practical
results by Dmitry Grigoryev revealed the real reasons low
efficiency of the method.
The first and most fatal - simultaneity O ports
AY sample sampling, which is an insurmountable challenge. In
Finally, we hear while playing is not only synthesized by the
three channels of higher quality signal, but each channel
separately, which is nothing but noise! And as I have mentioned
in the previous issue of the newspaper, I was able to reduce
the time between records in the AY data ports, but
unfortunately the noise level was unchanged.
Second, and most harmless in this method poser - Medium
sound channel in the AY (I've got it "B", some "C" because of
the different connection schemes) is reproduced at 30% quieter
than the extreme channels. (In my card from Cervus Elaphus
Company (Moskow) from AY, such as most common in the years of
prosperity Speccy, Channels smiksovany that way.)
Noise is inevitable in the method and the third reason. When
listening digitizing the stereo equipment extreme sound
channels "A" and "C" sound separately, and obtain an output
signal, which is the sum three channels, not really!
The result of all my arguments, as well as learning more buggy
Dennis Sotchenko method (which except for the digitization of
high frequency, we hear the whistle with an amplitude directly
proportional to change in accordance with the deviation from
the real values of the sample) is the new method is very high
quality playback of digital audio, entitled:
Middle Channel Correction (MCC) (C) 1998 Monster / Sage Group
Main advantages and features of MCC:
- An almost complete absence of noise and distortion
compared to
synthesis of single-channel linear 8bit'nogo sound.
- Complete absence of high-frequency whistle.
- Synthesis of 99 shades of digitization of the 256
possible.
A general description of the MCC method:
- A basis the standard formula preorazovaniya 8bit'no
second signal in 4bit'ny.
LET AY = (LN (V +1) / LN 2) * 2-1: IF AY <0 THEN LET AY =
0
AY (0 .. 15); V (0 .. 255)
In my opinion the most correct. In this regard, I fully
solidarity with Oldman'om.
- In the channels "A" and "C" (extreme), or only in "A" or
only in the "C", reproduced in the transformed higher at
piped formula (corrected) 8bit'naya digitization
ka. On average, channel "B" is reproduced Adjustment
signal, reducing the deviation of output from the original
tional, pre-a calculated for each gradation 8bit '
Nogo signal.
Wash easily and can not be, and higher-quality playback for
4bit'nogo muses. coprocessor. True, there are several minor
restrictions in the MCC. Correction signal must be played only
on the average channel AY (for the minimum noise level), so any
software that uses this method should ask the user which
channel is in his Speccy medium (such as order: ABC or ACB?)
Average channel should be smiksovan with the extreme in this
regard: A and C = 100% B = 72% (again, for a minimum level of
noise). Otherwise, you can score on these restrictions, or, if
still not broke, re-calculate the table transformation for a
specific scheme mixing channels.
For comments and questions related to
theory MCC method, write to the newspaper (address on last
page).
This method is completely frivaren, but preferably in a
software product that uses this method, we mentioned his name
(MCC) and its author (Monster / Sage Group).
At lamer this request does not apply.
MCC are looking for all the sources in Fido, and on pages I-Net.
To demonstrate the capabilities METHOD
KEEP THE "SPACE" at boot time NEWSPAPERS
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Authors in this issue:
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___
MONSTER / / SAGE GROUP - all codes, some text
MMCM ___ / / SAGE GROUP - music, logo
MARKET SOFT \ \ / / SAGE GROUP - intro gfx, correction
UnBEL! EVER \ \ / / EXTREME - all texts, main idea
\ \ /
\ __ \ / RuleZ Forever!!!
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Contact addresses:
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Post: 443074 A / H 9966 Muchkaevu Maxim Alekseevich (UnBEL!
EVER) Phone: (8462) 941-595 Sergei (MMCM)
Telegraph: speed_co@yahoo.com
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new world of sounds - High-quality digital audio AY - dream or reality.
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