Audio-3587 is still in Beta

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    INDEX


        1 .... INTRODUCTION

            1.1 .... Compatability

            1.2 .... Further Reading

            1.3 .... "User" and "Advanced" Modes

            1.4 .... Thanks


        2 INSTALLATION

            2.1 .... (not relevant during beta phase)


        3 THE MAIN SCREEN

            3.1 .... General Keys

            3.2 .... Digital Distortion

            3.3 .... Volume
 
            3.4 .... Automatic Volume Correction (AVC)
 
            3.5 .... Speaker Balance
 
            3.6 .... Stereo Seperation

            3.7 .... Treble

            3.8 .... Loudness

            3.9 .... Bass

            3.10 ...  Micronas Dynamic Bass (MDB) - A.K.A. "Bass Boost"


        4 .... ADVANCED STEREO SEPERATION

            4.1 .... Screen Icons & Layout

            4.2 .... Controls

            4.3 .... Speech

            4.4 .... How Does it Work?

            4.5 .... 3 Speaker Mono

            4.6 .... Keys


        5 .... ADVANCED MICRONAS DYNAMIC BASS (MDB) SETTINGS

            5.1 .... Brief Explanation

            5.2 .... Screen Layout

            5.3 .... Speech

            5.4 .... Controls

            5.5 .... Keys


        6 .... PROGRAMMERS NOTES



-------------------------------------------------------------------------------



1 - INTRODUCTION
""""""""""""""""



1.1 - Compatability
"""""""""""""""""""

This new advanced set of audio features is only avialable on MP3 players which
utilise the MAS-3587F audio DAC.  This includes the following units:

  # Archos Jukebox Recorder
  # Archos Jukebox Recorder F.M.
  # Archos Jukebox Recorder Version 2



1.2 - Further Reading
"""""""""""""""""""""

Full(er) details on the Micronas MAS 3587F device can be found at:
http://www.micronas.com/products/documentation/consumer/mas3587f/index.php
...especially the document:
http://www.micronas.com/products/documentation/consumer/mas3587f
/downloads/mas3587f_2pd.pdf
"MAS 3587F - MPEG Layer 3 - Audio Encoder/Decoder - MICRONAS"



1.3 - "User" and "Advanced" Modes
"""""""""""""""""""""""""""""""""

In this document I will refer to "User Mode" and "Advanced Mode".  During
development Advanced mode was commonly referred to as "Geek" mode.

"User Mode" options are the basic daily settings that most people will use on a
regular or infrequent basis.

"Advanced Mode" options are generally options which will be used by the
audiophile, purist and Knob Twiddlers amongst us.  If you like me, are the kind
of person who enjoys optimal sound quality, you will have great fun playing
with these advanced settings to optimise your own setup.


The Main audio controls are designed to fit on a single screen.  And there are
two further Advanced Mode screens for fine-tuning the "Stereo Seperation"
(a.k.a. "Channel Configuration") and the "Micronas Dynamic Bass" (a.k.a. "Bass
Boost").



1.4 - Thanks
""""""""""""

Even from it's first Beta Release Audio-3587 has been heralded as:
    # Some of the most innovative work to come along in a LONG time.
and
    # The "next big thing" after flashing and voice fonts.

I thank John A and Fred M for those kind words; and indeed all those who have
already, and may as yet, thank me for this offering.  It is kind words like
these and the feeling of having made a positive difference that makes it all
worth while.

So without further ado, it is my great pleasure to present AUDIO-3587...



2 - INSTALLATION
""""""""""""""""

*-* Please note that at the time of writing Audio-3587 is in Beta release.
*-* For installation during Beta phase, please refer to the latest
*-* release notes for the download and installation procedure.
*-* Available at http://homepage.ntlworld.com/cyborgsystems

*-* The following instructions will not become valid until final release.


Venture to http://homepage.ntlworld.com/cyborgsystems and navigate to the
Enhanced Rockbox page.

Identify your Jukebox as either "V1", "V2" or "FM" ...If you are unsure there
is a little table with pictures lower down the page under the heading
"Supported MP3 Players" which will help.

Download the correct file for your machine.

...more to come when these files actually exist...



3 - THE MAIN SCREEN
"""""""""""""""""""

When you start Audio-3587 you will always be presented first with the Main
Features screen.  This screen is presented as a list.  Each item on this list
has an identifying icon on the left of the screen with it's current settings on
the rest of the line to the right.



3.1 - General Keys
""""""""""""""""""

UP      Move the highlight-bar (cursor) up one line.
        If the cursor is on the top line, it will 'wrap' to the bottom line.

DOWN    Move the highlight-bar (cursor) down one line.
        If the cursor is on the bottom line, it will 'wrap' to the top line.

ON+UP   Move the control which is currently highlighted up one line.
        This setting will be remembered for future use.

ON+DOWN Move the control which is currently highlighted down one line.
        This setting will be remembered for future use.

LEFT    Lower the level of the current control by one unit.
        See individual controls for more detail.

RIGHT   Raise the level of the current control by one unit.
        See individual controls for more detail.

F3      Reset the current selected option to it's system default.

F2      Reset all options to their system defaults.
        F2 will ask for a yes/no confirmation to help avoid accidents.

F1      Save settings and exit.

OFF     Save settings and exit. (also)

ON+F1   Show help.  This will display the title of each icon along side it, and
        along side "Volume" is displayed the Audio-3587 version number.

ON+F2   Save settings to disk.
        You may save any number of settings files for each environment you
        wish to use Audio-3587.
        I have "Walkman Headphones", "Home Hifi" and "Desktop Speakers"
        It is just as simple to have "Abba", "AC/DC" and "Classical Music"

ON+F3   Toggle the backlight on and off
        The backlight will return to it's system setting when you exit the
        Audio-3587 Main screen.

All other controls are described in detail for each setting below:



3.2 - Digital Distortion
""""""""""""""""""""""""

Because both Rockbox and Audio-3587 allow you greater access to the audio
controls there is a risk of creating what is called "Digital Distortion" or
"Digital Clipping".

In reality it is something that is unlikely to effect you, and if it does you
would need to be quite the purist to notice it.  However, comments have been
made by purists so...

Audio-3587 will warn if there is a risk of digital distortion.  The way it does
this is to flash the 'cone' (triangle) portion of the Speaker Icons.

The speakers which flash will be those which have values that can be changed to
ease the problem, or remove it completely.

The important thing to know is: If at any time the Digital Gain is greater than
0dB, there is a risk of Digital Distortion.

The risk is calculated like this:

Volume:  Volume_dB + Loudness_dB + max(Treble_dB,Bass_dB)  >  0dB
Treble:  Volume_dB + Loudness_dB + Treble_dB               >  0dB
Volume:  Volume_dB + Loudness_dB + max(Treble_dB,Bass_dB)  >  0dB
Bass:    Volume_dB + Loudness_dB + Bass_dB                 >  0dB

["max(a,b)" means the larger of the two numbers 'a' and 'b']


3.3 - Volume
""""""""""""

+-+  /|  ^      LEFT   -1dB   ON+LEFT  MUTE
|%| / | / \ /   RIGHT  +1dB
|%|"  |    V
|%|_  |  ^      PLAY   Toggle Advanced/User Mode
|%| \ | / \ / 
+-+  \|    V    F3      -18dB


User Mode Options:      MUTE,    1%  ... 88%  (LINE OUT) ...  100%
Advanced Mode Options:  MUTE, -114dB ...  0dB (LINE OUT) ... +12dB

When Line Level is selected the Audio-3587 display will show the words "LINE
LEVEL" on the volume bar.  This happens in both User Mode or Advanced Mode.

NOTE: The percentage (%) scale is NOT a true linear scale.  For values 1 ... 27
a step size of 2dB is used.  For values above 27 a step size of 1dB is used.
This allows for more user-readable scale, while maintaining greater control and
accuracy at higher volumes.

NOTE: The volume scaling algorithm used by Audio-3587 when in user/percentage
mode is DIFFERENT to that used by Rockbox version 2.2 and earlier.  With this
earlier firmware, "line level output" was achieved at approximately 92%.  With
Audio-3587, "line level output" is achieved at precisely 88%.



3.4 - Automatic Volume Correction (AVC)
"""""""""""""""""""""""""""""""""""""""
      
+-+  /|         LEFT   Shorter Delay
|%| / | ____    RIGHT  Longer Delay
|%|"  |
|%|_  | ____
|%| \ |      
+-+  \|         F3     OFF


Valid options:  OFF, 20mS, 2S, 4S, 8S   ['S' is Seconds]


AVC will attempt to maintain an equal volume output.  This should help to
correct the difference in volume between different tracks or different sections
of classical music.

The volume will be analysed periodically and appropriate adjustments made.

The user controls how long the chip waits between adjustments.
  # 20mS (milliSeconds) is useful for spoken word and in-car applications.
  # 4S (Seconds) is recommended for most other applications.

AVC works by "normalising" to -9dB all signals in the range -18dB ..to.. 0dB.
[See mas3587f_2pd.pdf, page 10]



3.5 - Speaker Balance
"""""""""""""""""""""

|\  +--+  /|    LEFT   Right Quieter   ON+LEFT   MUTE Right
| \ |%%| / |    RIGHT  Left Quieter    ON+RIGHT  MUTE Left
|  "|%%|"  |
|  _|%%|_  |    PLAY   Toggle Advanced/User Mode
| / |%%| \ |
|/  +--+  \|    F3     Centre Sound


User Mode Options:      Left 1% ... 100%, -CENTRE-, Right 1% ... 100%

Advanced Mode Options:        NORM      :      MUTE
                              NORM      : -1dB ... -127dB
                                     -CENTRE-
                        -127dB ... -1dB :      NORM
                              MUTE      :      NORM


NOTE: The percentage (%) scale is NOT a true linear scale.  Values in the range
1 ... 20 represent 1dB steps from -1dB ... -20dB.  For values greater than 20 a
linear scale is used to achieve a value in the range -21dB ... -127dB(Right) or
-128dB(Left).    This allows for more user-readable scale, while maintaining
greater control and accuracy when making fine adjustments to the stereo
position.



3.6 - Stereo Seperation
"""""""""""""""""""""""

|\  I  I  /|    LEFT   Previous Option     ON+LEFT   Mono
| \ I  I / |    RIGHT  Next Option         ON+RIGHT  Karaoke
|  "I  I"  |
|  _I  I_  |    PLAY   Advanced/Custom Settings
| / I  I \ |
|/  I  I  \|    F3     Stereo


Valid options:  MONO, MONO-LEFT, MONO-RIGHT, MONO-LOUD, MONO-3-SPKR,
                CUSTOM, STEREO, STEREO-NARROW, STEREO-WIDE,
                KARAOKE (a.k.a "Extreme Wide")


MONO            All sound is equally represented in each speaker.

MONO-LEFT       Left channel is heard equally in both speakers.

MONO-RIGHT      Right channel is heard equally in both speakers.

MONO-LOUD       Both channels are sent to both speakers simultaneously.

MONO-3-SPKR     All sound is equally represented in each speaker,
                but the right channel is inverted.
                For details on how to connect the third speaker, see the
                section "3 Speaker Mono" under "Advanced Stereo Seperation"

CUSTOM          User configuration selected.

STEREO          Left channel is sent entirely to the left speaker and the
                Right channel is sent enturely to the left speaker.

STEREO-NARROW   The left speaker is 75% left channel and 25% right channel
                The right speaker is 75% right channel and 25% left channel

                The upshot is an increase in volume for sounds that are
                balanced in the centre.

STEREO-WIDE     The left speaker is 100% of the left channel with
                50% of the right channel removed
                The right speaker is 100% of the right channel with
                50% of the left channel removed

                The upshot is a decrease in volume for sounds that are
                balanced in the centre.

KARAOKE         The left speaker is 100% of the left channel with
                100% of the right channel removed
                The right speaker is 100% of the right channel with
                100% of the left channel removed

                The upshot is a that all sounds which are balanced in the
                centre are completely removed.  And because vocals are nearly
                always in the absolute centre of a recording it is normally the
                vocals which disappear.

NOTE: Pressing PLAY on Stereo Seperation will take you to the Advanced/Custom
Settings page. This seperate page is discussed in detail below.



3.7 - Treble
""""""""""""

+-+  /|   ^     LEFT   -1dB     ON+LEFT   -1/8dB (0.125)
|%| / |  / \    RIGHT  +1dB     ON+RIGHT  +1/8dB (0.125)
|%|"  | /   \
|%|_  |
|%| \ |
+-+  \|         F3     0dB


Valid options:  -12dB ... +12dB  (in steps of 1/8th dB)


Each step of 1dB is precise.  The 1/8th steps are approximate.
[See mas3587f_2pd.pdf, page 9]



3.8 - Loudness
""""""""""""""

+-+  /|  /"\    LEFT   -1dB     ON+LEFT   -1/4dB (0.25)
|%| / | /   \   RIGHT  +1dB     ON+RIGHT  +1/4dB (0.25)
|%|"  |
|%|_  |         PLAY   Toggle Centre Frequency
|%| \ | \   /
+-+  \|  \_/    F3     0dB


Valid options:  0dB  ... +12dB  (in steps of 1/4 dB)
                1KHz ...   2Khz


Each step of 1dB is precise.  The 1/4 steps are approximate.

Loudness effectively increases both the Treble and Bass while leaving the
centre frequencies comparatively untouched.  There is a choice of TWO centre
frequencies, 1KHz and 2Khz.
[See mas3587f_2pd.pdf, page 10]



3.9 - Bass
""""""""""

+-+  /|         LEFT   -1dB     ON+LEFT   -1/8dB (0.125)
|%| / |         RIGHT  +1dB     ON+RIGHT  +1/8dB (0.125)
|%|"  |
|%|_  | \   /
|%| \ |  \ /
+-+  \|   V     F3     0dB


Valid options:  -12dB ... +12dB  (in steps of 1/8th dB)


Each step of 1dB is precise.  The 1/8th steps are approximate.
[See mas3587f_2pd.pdf, page 9]



3.10 - Micronas Dynamic Bass (MDB) - A.K.A. "Bass Boost"
""""""""""""""""""""""""""""""""""""""""""""""""""""""""

+-+  /|         LEFT   -5%      ON+LEFT   -10Hz
|%| / |         RIGHT  +5%      ON+RIGHT  +10Hz
|%|"  |
|%|_  |         PLAY   Advanced/Custom Settings
|%| \ | ^m^m^
+-+  \| #####   F3     50% @ 90Hz (Harm=50:50, Shape=140Hz)


Valid options:  OFF,  5%  ...  100%   (in steps of 5%)
                     20Hz ...  300Hz  (in steps of 10Hz)


The STRength of the MDB is defined on a linear scale over 0db ... +127dB in 21
steps.  That is, each step of 5% is equivalent to approximately 6dB.

The Centre Frequency should be set as close as possible to the cut-off
frequency of the speakers or headphones being used.  For most relatively cheap
headphones this will be about 90Hz.  For good quality HiFi speakers, the
cut-off frequency is likely to be about 50Hz.

The previous paragraph is paraphrased from the official datasheet.  Although to
me, and others like me, it seems more likely that the Centre Frequency should
be set BELOW the cut-off frequency of the speakers or headphones being used, so
as to boost the INaudible bass frequencies, without boosting the low end bass
frequencies that are already audible.

Probably the easiest way to find the "right" frequency for your
headphones/speakers/ears is to turn the gain up full (100%); then change the
centre frequency until you can hear "good quality" bass; finally turn the gain
down until the "good quality" bass is also at a "sensible volume".

You may define "right", "good quality" and "sensible volume" in any way that
makes you feel most happy.

Audiphiles may like to note that, in User Mode, the MDB Shape (discussed
further under Advanced/Custom Settings) is set to 1.5*Centre_Frequency, but is
limited to within the range of 50Hz ... 300Hz in 10Hz steps.  MDB HARMonics are
left untouched, unless an F2/F3 Reset is requested, then the HARMonics will be
reset to the default of 50:50 Fundamentals:Harmonics.

Pressing PLAY on MDB will take you to an Advanced/Custom Settings page. This
page is discussed in detail below.



4 - ADVANCED STEREO SEPERATION
""""""""""""""""""""""""""""""



4.1 - Screen Icons & Layout
"""""""""""""""""""""""""""

++
||       __
||      /  \        This icon represents the
||      /  \        LEFT stereo channel
||          \  /    of the source material
||          \  /
|+----+      ""
+-----+


+----\
|+---\\  __
||   || /  \        This icon represents the
||   // /  \        RIGHT stereo channel
|+==//      \  /    of the source material
||  \\      \  /
||   \\      ""
++   ++


        |\   +--+
 /\     | \_ |%%|
/  \  / |   \|%%|   This icon represents the
    \/  |    |%%|   LEFT speaker or headphone
 /\     |    |%%|   output
/  \  / |   /|%%|
    \/  | /" |%%|
        |/   +--+


+--+   /|
|%%| _/ |  /\
|%%|/   | /  \  /   This icon represents the
|%%|    |     \/    RIGHT speaker or headphone
|%%|    |  /\       output
|%%|\   | /  \  /
|%%| "\ |     \/
+--+   \|


  _-_
 / | \
/  |  \             This icon respresnts the
(--+--)             fact that the source waveform
\  |  /             is to be used UN-INVERTED
 \ | /
  "-"


  _-_
 /   \
/     \             This icon respresnts the
(-----)             fact that the source waveform
\     /             is to be used INVERTED
 \   /
  "-"



To assist with quick recognition of left and right icons, both 'Left' icons
appear on the left of the screen, and both 'Right' icons on the right of the
screen.



4.2 - Controls
""""""""""""""

Each Source (L~ and R~) may feed any combination of Left and/or Right outputs
(=>| and |<=).

En route to the speaker, the waveform may be optionally Inverted (-) or left
UnInverted (+).

The waveform cannot be amplified beyond it's original magnitude, so the
amplification range peaks at precisely 100% of the original waveform.

When the range is displayed in decimal, the amplification if the waveform is in
the range:
-1.000 ... 0.000 ... 1.000 and is accurate to three decimal places.

When the range is displayed in hexadecimal the range is confined by a 20-bit
2's compliment number and therefore offers the range:
-80000h ... 00000h ... 7FFFFFh

Although the hexadecimal representation allows for greater accuracy for
settings, it is normally not necessary to be accurate to beyond the 1/10th of a
percent which is easily available with the more readable decimal
representation.



4.3 - Speech
""""""""""""

When speech is enabled for menus in the main Rockbox code, the following are
true of the audio references to the screen layout.

The box at the Top of the screen which carries the signal from the Right
Channel to the Left Speaker is called "R to L".

In a similar vain the box on the Left is "L to L", Right is "R to R" and Down
is "L to R"

The inversion is denoted by the prefix "plus" or "minus" before the number
(minus being inverted.)

The number is always read in full whether in decimal or hex mode.



4.4 - How Does it Work?
"""""""""""""""""""""""

This is NOT the place for a discussion on wave theory, but at it's core, the
following basic overview should suffice:

If a given moment in the wave were represented by the number "10", then the
inverse of that moment would be "-10" ...if you add both of these together you
will end up with "0" ...silence!

If you add the "+LEFT" channel to the "-RIGHT" channel, anything that appears
in both channels will be removed ...by example "Karaoke" mode does precicesly
this.  As most vocals are recorded in the centre of the sound and the
instruments are recorded to the left or right in the stereo positioning, the
upshot is that the vocals are removed and the instruments remain in-tact.  Of
course, the closer an instrument is to the centre of the stereo positioning,
the more it will be faded out.

An interesting example of Karaoke mode failing is a track by "Godley & Creme"
called "An Englishman in New York" where the vocals remain and most of the
music is lost!


The screen may be considered as four controls:
Source-Left   +/-  *Amplification  ->  Destination-Left   (L->L)
Source-Left   +/-  *Amplification  ->  Destination-Right  (L->R)
Source-Right  +/-  *Amplification  ->  Destination-Left   (R->L)
Source-Right  +/-  *Amplification  ->  Destination-Right  (R->R)

..where + implies an UNinverted wave and - implies an INVERTED wave.

For reasons I don't understand it seems popular to use INVERTED signals as the
norm and an UNINVERTED signal as the exception.



4.5 - 3 Speaker Mono
""""""""""""""""""""

3 Speaker Mono requires is a method by which you may add a third speaker to
your setup.  This will affect a overall increase in perceived volume.

From the perspective of the waveform, each channel is composed 50:50 of both
Left and Right waveforms.  The output to the Right speaker is inverted.  (The
choice of Left or Right here is arbitrary.)

Electrically you need to add a third speaker somewhere...

We will first consider the wiring for two speakers under normal circumstances:
The Left speaker is wired between Left-Out and Ground
The Right speaker is wired between Right-Out and Ground

The 3rd speaker is wired between Left-Out and Right-Out

You may also find some other very interesting audio effects by editing the
Advanced Stereo Seperation settings while the third speaker is connected.



4.6 - Keys
""""""""""

The following is a list of all keys and their effect.

At any time:    F1       Toggle HEX/DEC mode
                F2       Rotate through presets
                F3       Invert currently highlighted source waveform
                PLAY     Toggle edit mode

Edit mode OFF:  LEFT     Select Left->Left
                RIGHT    Select Right->Right
                UP       Select Right->Left
                DOWN     Select Left->Right
                ON       Save current settings as "Custom" and exit
                OFF      Reject current settings and exit

Edit mode ON:   LEFT     Move left one digit
                RIGHT    Move right one digit
                UP       Increment current digit
                DOWN     Decrement current digit
                ON+UP    Set to maximum
                ON+DOWN  Set to zero
                OFF      Exit edit mode



5 - ADVANCED MICRONAS DYNAMIC BASS (MDB) SETTINGS
"""""""""""""""""""""""""""""""""""""""""""""""""



5.1 - Brief Explanation
"""""""""""""""""""""""

The method used by Micronas to boost the bass signal utilises a phenomena
called The Missing Fundamental which is based on the principle that if the
relative harmonics can be heard by the human ear, the brain will infer the
missing fundamental.

Now in English...

Every sound is made up of lots (and lots) of little sine waves.  Each of those
"fundamental" sine waves causes lots of little intference patterns in other
areas of the audio spectrum called "harmonics".

Think about throwing a stone in a duck pond.  Where the stone hits the water is
the "fundamental" point of impact.  All the ripples are "harmonic
interference."

The clever thing is the speed at which the brain can immediately tell where the
fundamental should be by only seeing/hearing the harmonics.

The upshot is that your cheap walkman headphones - that CLAIM to respond to
frequencies down to 20Hz (yeah right, for 15, I don't think so) - can be made
to sound more "bassy" if the Audio Chip adds some extra harmonics to make your
brain imagine the missing bass fundamentals.

All very clever stuff, probably loads about it on the web if you search hard
enough.



5.2 - Screen Layout
"""""""""""""""""""

+----------------------------------------------+
|          [FUND:HARM]                         |
|      dB       |                              |
|       |                                      |
|       |                                      |
| [STR]_|     ______                           |
|       |    /      -_                         |
|       |   /         -_                       |
|       |  /            \                      |
|       | /              \                     |
|       |/                \_________________   |
|       |                                      |
|      -+-----------------------------------Hz |
|  .__  |       |       |                      |
|  |            [FC]    |                      |
|  |_S                  [SHAPE]                |
+----------------------------------------------+



5.3 - Speech
""""""""""""

The screen shows a graph which reflects the various MDB settings.

You will always start at Strength when you enter this screen.

The overall Sstrength of the effect is described as "MDB Volume".

The Centre Frequency of the effect is described as "MDB Frequency".

The balance of Fundamentals versus Harmonics is described as "MDB Balance".

The low-pass Shape or Corner frequency is described as "MDB Loudness".



5.4 - Controls
""""""""""""""

The advanced MDB effect is controlled by four parameters.


## [FUND:HARM] - Fundamentals -vs- Harmonics

   Valid Options:     7F:00 ...  3F:40  ... 00:7F
                    100%:0%     50%:50%     0%:100%

   The left parameter is the amount of gain applied to the fundamental
   frequencies, and the right parameter is the amount of gain applied to the
   harmonic frequencies.

   Remeber the fundamentals do already exist, it is just that your headphones
   are not recreating them properly.

   NOTE: For reasons of accuracy, these values are only displayed in hex.

   NOTE: The value stated for 50:50 is taken from the MAS-3587F datasheet.


## [FC] - Centre Frequency

   Valid Options:   20Hz ... 300Hz  (in steps of 10Hz)

   The centre frequency specifies the audio range for which the effect will be
   most prominent.


## [STR] - Strength

   Valid Options:   0dB ... 127dB  (in steps of 1dB)

   The overall amount of Bass Boost that will be added to the original signal


## [SHAPE] - Shape or "Corner Frequency" of the Bass curve

   Valid Options:   50Hz ... 300Hz  (in steps of 10Hz)

   This controls a second phase of bass processing which is a Low Pass Filter.

   Originally this was more accurately represented with grey-scale shading on
   the graph, but sadly that had to be removed due to memory restrictions.



5.5 - Keys
""""""""""

PLAY            Select next parameter.

UP or RIGHT     Increase current parameter by 1 step.

DOWN or LEFT    Decrease current parameter by 1 step.

F2              Reset to Micronas suggested setting.
                STR = 64;  FC = 90;  SHAPE = 140;  FUND_HARM = 3F:40

F3              Reset current parameter only to Micronas suggested default.

F1 or OFF       Save settings and return to Main screen.


The FC, SHAPE and FUND:HARM parameters cannot be changed when MDB is switched
off.  At this point, the only key which will effect the graph are UP and RIGHT.



6 - PROGRAMMERS NOTES
"""""""""""""""""""""

Programmers may like to be aware of the following compile-time switches in
Audio-3587.c

DEFAULT_VOLUME_IS_LINE_LEVEL
    TRUE:  The Volume will reset to 0dB when F2 or F3 is used to control it.
    FALSE: The Volume will reset to -18dB when F2 or F3 is used to control it.

USE_ICONS
    TRUE:  Icons are used to represent the parameters on the Main screen.
    FALSE: Text labels are used to represent the parameters on the Main screen.

SPEAK_AMERICAN
    TRUE:  Uses "CENTER" and "SPATIALIZER"
    FALSE: Uses "CENTRE" and "SPATIALISER"

SAY_DEEBEE
    TRUE:  The speech synth says "D.B."
    FALSE: The speech synth says "Decibels"

The main source is a little over 5,000 lines of code + supporting libraries.
Due to memory restrictions any further additions are likely to present you with
major RAM trouble ...although there is always room for code optimisation, it is
likely to come with a time overhead.

Feedback is always welcomed.

cs_bluechip (@at) webtribe (.dot) net