AAA U U DDDD IIIII OOO 3333 55555 888 77777 A A U U D D I O O 3 5 8 8 7 AAAAA U U D D I O O 333 5555 888 7 A A U U D D I O O 3 5 8 8 7 A A UUU DDDD IIIII OOO ===== 3333 5555 888 7 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 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" The audio controls are designed to fit on a single screen ...although consideration has been given in the source code to support: fonts; languages; menu "pointer" (instead of higlight bar); and alternate layouts for the "advanced" or "custom" screens. The main "user" function screen is presented as a list. Each item has an identifying icon on the left of the screen with it's current settings on the rest of the line to the right. Generally: # UP and DOWN are used navigate from one item to the next. # ON+UP and ON+DOWN are used to change the order of the controls # LEFT and RIGHT will modify the value by one unit. # F3 will reset the current selected option to a system default. # F2 will ask whether to issue a complete audio reset. # F1 and OFF will exit the Audio_3587 Settings Menu. # Other controls are item specific and can be found below. Volume """""" +-+ /| ^ LEFT -1dB ON+LEFT MUTE |%| / | / \ / RIGHT +1dB |%|" | V |%|_ | ^ PLAY Toggle Advanced/User Mode |%| \ | / \ / +-+ \| V F3 0dB User Mode Options: MUTE, 1% ... 88% (LINE OUT) ... 100% Advanced Mode Options: MUTE, -114dB ... 0dB (LINE OUT) ... +12dB NOTE: The percentage (%) scale is NOT a true linear scale. For values 1 ... 69 a linear scale is used to achieve a value in the range -114dB ... -19dB. Values above 69 represent 1dB steps from -18dB ... +12dB. 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 in user/percentage mode is DIFFERENT to that used by Rockbox version 2.1 and earlier. With this earlier firmware, "line level output" was achieved at approximately 91%. With AUDIO_3587, "line level output" is achieved at precisely 88%. NOTE: If the volume is raised ABOVE 0db, it is possible (even likely) that Digital Distortion will occur on loud recordings. A warning system for this is planned, but not yet implemented. Archos avoids this problem in their firmware by restricting the user to values <= 0dB Automatic Volume Correction (AVC) """"""""""""""""""""""""""""""""" +-+ /| LEFT Shorter Delay |%| / | ____ RIGHT Longer Delay |%|" | |%|_ | ____ |%| \ | +-+ \| F3 OFF Valid options: OFF, 20mS, 2S, 4S, 8S 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. # 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] 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. 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-LOUD, MONO-LEFT, MONO-RIGHT, MONO, CUSTOM, STEREO, STEREO-NARROW, STEREO-WIDE, KARAOKE (Extreme Wide) Pressing PLAY on Stereo Seperation will take you to the Advanced/Custom Settings page. Ths page is discussed in detail below. 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] 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] 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] Micronas Dynamic Bass (MDB) """"""""""""""""""""""""""" +-+ /| LEFT -5% ON+LEFT -10Hz |%| / | RIGHT +5% ON+RIGHT +10Hz |%|" | |%|_ | PLAY Advanced/Custom Settings |%| \ | ^m^m^ +-+ \| ##### F3 50% @ 90Hz (Harm=50:50) 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. It may be noted that, in User/Basic 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. MDB HARMonics are left untouched, unless an F3 (reset) is requested, then the HARMonics will be reset to the default of 100:0 Fundamentals:Harmonics. Pressing PLAY on MDB will take you to an Advanced/Custom Settings page. Ths page is discussed in detail below. Advanced Stereo Seperation """""""""""""""""""""""""" ++ || __ || / \ 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 both of left and right, both 'Left' icons appear on the left of the screen, and both 'Right' icons on the right of the screen. Each Source may feed any combination of Left and/or Right outputs. En route to the speaker, the waveform may be optionally inverted. 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 available with the more readable decimal representation. 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. 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. 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 Accept 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 Advanced MDB Settings """"""""""""""""""""" Centre Frequency Strength Shape/Corner Frequency Fundamentals:Harmonics