SX-7 SX-9 SX-11 SX-12a
SX-20 SX-22 SX-23e SX-26
Digital Audio Adapter
User's Manual
For DOS
and Windows
January 25, 1996
ANTEX ELECTRONICS CORPORATION
1125 W.190TH STREET, SUITE 100
GARDENA, CALIFORNIA 90248
9000-2347-7006
TABLE OF CONTENTS
INTRODUCTION..........................................................................1
ABOUT DIGITAL AUDIO ..............................................................1
MINIMUM HARDWARE RECOMMENDED..................................6
ADAPTER INSTALLATION..........................................................6
JUMPER SETTINGS........................................................6
I/O ADDRESSES AND INTERRUPTS............................7
SX-12a, SX -20..................................................................7
SX-7..................................................................................7
SX-9, SX -11......................................................................9
SX-22, SX -23e, SX-26......................................................11
DRIVER INSTALLATION..............................................................16
DISKS...............................................................................16
WINDOWS DRIVER INSTALLATION..............................17
WINDOWS DRIVER CONFIGURATION.........................17
DOS DRIVER INSTALLATION .........................................19
USING DOS DEMONSTRATION SOFTWARE..........................20
PROBLEMS RUNNING THE DEMO................................25
USING WINDOWS DEMONSTRATION SOFTWARE................26
ANTEX MIXER..............................................................................30
MIXER BUSES.................................................................31
RECORD MODE.............................................................31
PLAY MODE (Feedthrough).............................................31
MIXER DEVICES..............................................................31
UTILIZING DIGITAL AUDIO COMPRESSION UNDER WINDOWS 32
ISO/MPEG -1 BITRATES & FORMAT EXTENSIONS..................34
FIGURES
Figure 1: Analog-to-Digital Conversion........................................3
Figure 2: Digital-to-Analog Conversion........................................5
Figure 3: SX -12a, SX-20 Connector Locations............................8
Figure 4: SX -7 Connector Locations...........................................8
Figure 5: SX -9 and 11 Connector Locations...............................10
Figure 6: SX -22, 23e and 26 Connector Locations.....................13
Figure 7: SX -22, 23e and 26 Balanced Connectors...................14
Figure 8: SX -22, 23e and 26 Digital Connectors........................15
Figure 9: DOS Demo Environment..............................................21
Figure 10: The Antex Demo Window...........................................26
Figure 11: Message Box reporting an unavailable compression
format or an invalid sample rate...........................................27
Figure 12: File Open dialog box...................................................28
Figure 13: Antex Mixer.................................................................30
INTRODUCTION
The Series 2 Digital Audio Adapters are IBM AT compatible add-on
boards which convert high fidelity analog signals to digital data for
storage to, and retrieval from, disk.
The Series 2 adapters sample two channels of audio from 6.25
kHz to 50kHz with 16 bit resolution. They incorporate Sigma Delta
technology with 64 times oversampling, providing superior fidelity
at greater than 90 dB signal-to-noise ratio.
ABOUT DIGITAL AUDIO
In professional circles, digital audio has been with us for over 10
years. With the advent of the compact disk in 1983, digital audio
has become commonplace as a consumer item. Few will argue
that digital audio has afforded an order of magnitude improvement
in overall sound quality and signal-to-noise ratio over the best
analog systems which preceded them. But just what is digital
audio, and where and how is it used?
It is possible to use digital data transmission techniques to
transmit digital audio signals by wire or radio. However, this
practice has not yet become common due to the extremely wide
signal bandwidth required to transmit real-time digital audio
signals. For the present, digital audio techniques seem largely
confined to the recording and playback of music and other audio
signals where, in a few short years, digital audio technology has all
but replaced the previous analog record/playback techniques. In
the present decade we will see digital audio technology replace
analog technology in most signal processing functions in both the
professional and consumer markets. It is also likely, particularly
with the advent of fiber optic cables, that digital audio technology
will be utilized in the transmission of real-time audio signals on a
widespread basis.
But what is digital audio?
1
In essence, digital audio is a technological process whereby an
analog audio signal (produced when sound waves in the air excite
a microphone) is first converted into a continuous stream of
numbers (or digits). Once in digital form, the signal is extremely
immune to degradation caused by system noise or defects in the
storage or transmission medium (unlike previous analog systems).
The digitized audio signal is easily recorded onto a variety of
optical or magnetic media, where it can be stored indefinitely
without loss. The digitized signal is then reconverted to an analog
signal by reversing the digitizing process. In digital audio
record/playback systems, each of these two functions is
performed separately. In digital audio signal processing systems
(where no record/playback function occurs) both analog-to-digital
and digital-to-analog conversion processes occur simultaneously.
A variety of techniques are possible, but the most common
method by which audio signals are processed digitally is known as
linear pulse code modulation, or PCM. Let's take a brief look at
how PCM works.
Converting an analog signal to digital is a two-stage process,
sampling and quantization. This is illustrated in Figure 1. At regular
intervals, a sample-and-hold circuit instantaneously freezes the
audio waveform voltage and holds it steady while the quantizing
circuit selects the binary code which most closely represents the
sampled voltage. Most digital audio is based on a 16-bit PCM
system. This means that the quantizer has 65,536 (216) possible
signal values to choose from, each represented by a unique
sequence of the ones and zeroes which make up the individual
code "bits" of the digital signal.
The number of these bits generated each second is a function of
sampling rate. At a relatively low sampling rate of 8 kHz (suitable
for voice) far fewer code bits are produced each second than, for
example, at the 44.1 kHz sampling rate used for commercial
compact disks. For a two-channel stereo signal at a 44.1 kHz
sampling rate, some 1.4 million bits are generated each second.
That's about five billion bits per hour,which is why you'll need at
least an 800 Megabyte hard disk to record an hour of compact disk
quality music.
2
Figure 1: Analog-to-Digital Conversion
To visualize the analog-to-digital conversion process, refer to
Figure 1. At the top is one cycle of an analog input signal wave.
We've used a simple sine wave to make visualization easier. In
this example, the signal has a peak-to-peak amplitude of 20 units,
measured by the scale on the left. The sampling frequency is
many times higher than the signal being sampled and is shown
along the bottom of Figure 1. Once for each cycle of the sampling
frequency, the sample-and-hold circuit "slices" the input signal,
allowing the quantizing circuit to generate a (digital) number equal
to the closest (of the 65,536 possible discrete values) quantization
value of the input signal at the time the sample is taken. This
repeats for each successive cycle of the sampling frequency and
the quantizer generates a continuous "bit stream" which
represents the quantized signal. The continuous stream of digital
audio information is converted into a digitally modulated signal
using a tech nique known as linear pulse code modulation.
Digital-to-analog conversion (used in playback) is the exact
opposite of the analog-to digital conversion process and is
illustrated in Figure 2.
3
In digital-to-analog conversion, the PCM bitstream is converted at
the sampling frequency to a continuously changing series of
quantization levels which are individual "steps" of discrete voltage
equal to the quantization levels in the analog-to-digital process.
The shape of this continuously changing stream of quantization
levels approximates the shape of the original wave. This is shown
in the top half of Figure 2. This signal is then passed through a lowpass filter, which removes the digital "switching noise." The end
result, shown in the bottom half of Figure 2 is an analog output
signal whose waveshape is a very close approximation of the
original analog input signal. The foregoing is a very brief and, of
necessity, oversimplified explanation of how digital audio works.
For the interested reader, the book Principles of Digital Audio by
Ken C. Pohlmann, copyright 1985 by Howard W. Sams, is highly
recommended.
4
Figure 2: Digital-to-Analog Conversion
5
MINIMUM HARDWARE RECOMMENDED
?16 MHz 386-SX or compatible
?28 mSec average access hard disk
?1:1 Interleave hard disk controller
?Mouse
?VGA display
ADAPTER INSTALLATION
Make sure the main power to your computer is OFF. You will need
a full-size, 16 bit/AT slot. If you are unfamiliar with the internal
design of your computer see its "Guide to Operations" manual for
step by step installation procedures.
Read JUMPER SETTINGS and for information about configuring
the adapter before plugging it into the slot.
JUMPER SETTINGS
These SX series adapters have four hardware jumpers. They are
JP1, JP2, JP3 and JP4, which are used for multiple board
operation. JP1 should be installed for a single board system.
NOTE: On the SX-7, jumper JP2 serves as the adapter selec tion
jumper. Adapter 1 is at the top, with adapter 4 at the bottom.
1
2
PLACE JUMPER HERE IF YOU HAVE ONLY ONE
ADAPTER
3
4
6
I/O ADDRESSES AND INTERRUPTS
The valid I/O addresses for the SX7, SX9, SX11, SX-12a, SX20,
SX22, SX23e and SX26 are:
180h, 22h, 280h, 300h, 320h and 380h
The valid interrupts are:
2, 3, 4, 5, 10, 11 and 12
SX-12a, SX-20
There are 5 external connections located on the front surface of
the audio board's metal bracket (Fig. 3).
Audio Input:
Line: RCA jacks, 2VRMS/+6dBV max (digital clipping),
with an impedance pf 20 k ohms
Audio Output:
Headphone: 1/4" stereo phone jack, 0.5 VRMS into 8
ohms
Line: RCA jacks, 2VRMS/+6dBV max (digital clipping),
with an impedance of 470 ohms and a load
impedance of >10k ohms
SX-7
There are four external connectors located on the SX-7 audio
board's metal mounting bracket. See Figure 4. There is also one
three pin header (JP1) for an optional user-supplied headphone
connection, which would allow for a front panel headphone jack.
7
SX-12a/SX-20
Balanced Analog I /O Connector
678
9
RIGHT LINE IN
LEFT LINE IN
HEADPHONE OUTPUT *
RIGHT LINE OUTPUT
LEFT LINE OUTPUT
* Stereo Headphones
Figure 3: SX-12a, SX-20 Connector Locations
1
LEFT
RIGHT
GND
JP1
SX-7
DB-9 Balanced Out
Headphones
Unbalanced Right
Unbalanced Left
Pin Assignment
1 Gnd
2 nc
3 nc
12345
DB-9
Female
4 Right Out 5 Left Out 6 nc
7 nc
8 Right Out +
9 Left Out +
Figure 4: SX-7 Connector Locations
8
Audio Output:
Line:
Unbalanced - RCA jacks, 2VRMS/+6dBV max (digital
clipping), with an impedance of 470 ohms and a load
impedance of > 10 k ohms
Balanced - Nine pin D connector, -16 dBm maximum, with
an impedance of 47 ohms and a load impedance of 600
ohms
Headphone:
1/4" Stereo Phone Jack, 0.5 VRMS into eight ohms
SX-9, SX-11
There are 5 connectors located on the SX-9/SX -11 audio board's
metal mounting bracket. See Figure 5, 7 & 8. for more information
on the SX -9/SX-11 connectors.
Audio Output:
Line:
Balanced - Nine pin D connector 0 to +26dBu(digital
clipping) - software selectable with 1dBu resolution, with an
impedance of 50 ohms and a load impedance of 600 ohms
Unbalanced - 1/8” stereo mini jack 2VRMS/+6dBV max
(digital clipping), with an impedance of 470 ohms and a
load impedance of 10k ohms
9
Balanced Analog I /O Connector
678
9
for S/PDIF
SP-100 Header
apt-X adapter
????????????????????
????????????????????
Adapter # Jumper Block
Balanced Analog Header
SP-100
DB-9
Female
7 pin Mini DIN Female
7
6
4
5
2
1
SX-9/SX-11
DB-9 Balanced Out
Stereo Mini Headphones
Unbalanced Right
Unbalanced Left
AES/EBU, S/PDIF Digital Out
Pin Assignment
1 Gnd
12345
Pin Assignment
1 Ground
2 nc
3 Out - AES/EBU+ or S/PDIF+
4 nc
5 Out - AES/EBU - or S/PDIF-
3
6 nc
7 AES/SPDIF sense - This line should
be connected to Ground for
AES/EBU operation and left floating
2 nc
3 nc
4 Right Out 5 Left Out 6 nc
7 nc
8 Right Out +
9 Left Out +
Figure 5: SX-9 and 11 Connector Locations
AES/EBU Digital:
7 pin Mini DIN jack. Professional AES/EBU: EIAJ CP-340
Type I / IEC-958 Pro or Consumer S/PDIF: EIAJ CP-340
Type II / IEC-958 Consumer
10
SX-22, SX-23e, SX-26
There are 5 external connectors located on the SX -22 audio
board's metal mounting bracket. There are 7 external connectors
on the SX -23e/SX-26. See Figure 6, 7 & 8 for more information on
the SX -22/SX-23e/SX-26 connectors.
Audio Input:
Line:
SX-22:
Balanced - Nine pin D connector (-10dBu, +4dBu and
+16dBu - software selectable) with an impedance of 20k
ohms.
The SX-22 balanced analog I/O levels are specified in dBu,
where 0 dBu is 0.775 Vrms or 2.19Vpp for a sinewave. If
an I/O is connected as unbalanced then the level is 1/2 the
balanced I/O. The adjustable level is referred to as Trim.
The following Trim settings are available on the SX -22.
VdBu VRMS VPP VRMS-if connected as
unbalanced
-10 0.245 0.693 0.12
+4 1.23 3.47 0.6
+16 4.89 13.8 2.4 -(approx the same as
SX12a/20 unbalanced I/O)
The input and output trims may be adjusted separately, but
both input or both output channels must have the same
setting.
11
SX-23e/SX -26:
Balanced - Nine pin D connector 0 to +26dBu (digital
clipping) - software selectable with 1dBu resolution, with an
impedance of 20k ohms
Unbalanced - 1/8” stereo mini jack 2VRMS/+6dBV max
(digital clipping), with an impedance of 20k ohms and a
load impedance of 10k ohms
AES/EBU Digital (SX -22, SX-23e & SX-26):
7 pin Mini DIN jack. Professional AES/EBU: EIAJ CP-340
Type I / IEC-958 Pro or Consumer S/PDIF: EIAJ CP-340
Type II / IEC-958 Consumer
Audio Output
Line:
SX-22:
Balanced - Nine pin D connector (-10dBu, +4dBu and
+16dBu - software selectable) with an impedance of 20k
ohms.
SX-23e/SX -26:
Balanced - Nine pin D connector 0 to +26dBu(digital
clipping) - software selectable with an impedance of 50
ohms and a load impedance of 600 ohms or greater.
Unbalanced - 1/8” stereo mini jack 2VRMS/+6dBV max
(digital clipping), with an impedance of 470 ohms and a
load impedance of 10k ohms
Headphone (SX -22, SX-23e & SX-26):
1/4" stereo phone jack, 0.5 VRMS into 600 ohms or greater.
12
AES/EBU Digital (SX -22, SX-23e & SX-26):
Headphones
Balanced I/O
Digital AES/EBU I/O
Balanced Analog Header
Balanced I/O
Digital AES/EBU I/O
Balanced Analog Header
Unbalanced In
Unbalanced Out
7 pin Mini DIN jack. Professional AES/EBU: EIAJ CP-340
Type I / IEC-958 Pro or Consumer S/PDIF: EIAJ CP-340
Type II / IEC-958 Consumer
Adapter # Jumper Block
SX-22
SP-100 Header
????????????????????
????????????????????
SP-100
apt-X adapter
Adapter # Jumper Block
SX-23e/SX-26
Digital Header
Digital Header
Figure 6: SX-22, 23e and 26 Connector Locations
Headphones
13
Balanced Analog I /O Connector
12345
Balanced In - XLR male shell, female pins
135791113
15
Balanced Analog Header
DB-9
Female
6789
GND
+ 3
12345
6789
Balanced Out - XLR female shell, male pins
SX22 Balanced I/O to XLR
- 2
- 2
+ 3
1
+ 3
1
+ 3
1
Left
1
Right
- 2
Left
- 2
Right
Pin Assignment
1 Ground
2 Right In 3 Left In4 Right Out 5 Left Out 6 Right In +
7 Left In +
8 Right Out +
9 Left Out +
Unbalanced In - Female RCA
Left
12345
6789
Unbalanced Out - Female RCA
SX22 Unbalanced I/O to RCA
Right
Left
Right
2 4 6 8 10 12 14 16
?
?
?????
?
?????
?
?
?
Figure 7: SX-22, 23e and 26 Balanced Connectors
Pin Assignment Pin Assignment
1 Right In + 2 Ground
3 Right In - 4 Ground
5 Left In + 6 Ground
7 Left In- 8 Ground
9 Right Out + 10 Ground
11 Right Out - 12 Ground
13 Left Out + 14 Ground
15 Left Out - 16 Ground
14
7 pin Mini DIN Female
7
SX22 S/PDIF cable wiring diagram
SX22 AES/EBU cable wiring diagram
XLR Female pins,
AES/EBU Output
6
4
5
3
1
2
Digital I/O header - JP7
???
1
3
5
7
???
2
?
4
6
?
8 (nc)
Pin Assignment
1 Ground
2 In - AES/EBU 3 Out - AES/EBU+ or S/PDIF+
4 In - AES/EBU +
5 Out - AES/EBU - or S/PDIF6 In - S/PDIF+
7 AES/SPDIF sense - This line should be
connected to Ground for AES/EBU
operation and left floating for S/PDIF
7
6
5
4
7 pin Mini DIN Male Plug
Back view of plug
3
2
1
Figure 8: SX-22, 23e and 26 Digital Connectors
S/PDIF In
S/PDIF Out
Female RCA jacks
5
7
6
4
7 pin Mini DIN Male Plug
Back view of plug
3
2
1
XLR Male pins,
Female shell
1
3
GND
2
1
3
AES/EBU In
Male shell
2
15
DRIVER INSTALLATION
DISKS
Disk 1. The "WINDOWS DRIVERS" disk contains Windows
drivers and applications (Note: The DOS 3.2/Windows 2.0
drivers continue to come on a single disk):
? ANTEXWAV.DRV - Windows Wave Driver for SX3,
SX5e, SX7, SX9, SX11, SX12a, SX20, SX22, SX23e,
SX26, SX33, SX33e, Z1, Z1e
? SAPIZ1.DRV - OPL3 FM Synthesizer for Z1 and Z1e
? VAPIZ1.DRV - YM3802 MIDI driver for Z1 and Z1e
? MIDIMAP.CFG - MidiMapper config file with Z1 and Z1e
specific maps
? ANTEXMIX.EXE, MMMIXER.DLL - Antex Mixer Applet
and DLL
? ANTEXDEM.EXE - Antex Demo
? OEMSETUP.INF - Windows definition file for manual
driver installation
? SETUP.EXE and supporting files - Windows driver
installation utility
? README.TXT (optional) - Windows information
16
Disk 2. The "DOS DRIVERS" disk contains DOS drivers and
applications:
? SX25.EXE - DOS V3.3 TSR driver for the SX7, SX9,
SX11 SX-12a, SX20, SX22, SX23e and SX26
? Z1.EXE - DOS V3.3 TSR driver for the Z1, Z1e, SX3,
SX33, SX33e
? SX5E.EXE - DOS V3.3 TSR driver for the SX5e
? ADG.EXE - Digital audio player/recorder
? README.TXT (optional) - Additional information
WINDOWS DRIVER INSTALLATION
1. Insert the DRIVERS disk into your floppy drive (assumed to be
A:)
2. Start Windows
3. In Program Manager, click on File then Run..
4. Enter A:SETUP in the command line box, then press OK.
5. When the driver installation is complete, Windows should
restart automatically. If not, exit then restart Windows manually.
WINDOWS DRIVER CONFIGURATION
To change the adapter type, I/O address and interrupt settings of
the Wi ndows driver:
1. Select Control Panel in the Main group of the Program Manager.
Then select Drivers.
17
2. Select "Antex Audio Driver for Windows" from the list of installed
drivers. Click on Setup.
3. To set adapter type:
"Antex Audio Driver Setup" displays the adapter types assigned
to adapters 1-4. Change the type by using the drop down
menus for each adapter. Information about the number of
devices, I/O address, and interrupt number are displayed to the
right of each adapter.
4. To set the number of devices, I/O address, or interrupt number:
Select Advanced in "Antex Audio Driver Setup". Select an
adapter to reconfigure.
Change the number of devices, I/O address, or interrupt
number by selecting the appropriate buttons. Invalid choices
are displayed in gray.
Test new settings by selecting Test.
NOTE: The driver version number and date displayed in the
middle left of the "Antex Advanced Setup" screen. Refer to this
information when reporting problems to Antex Technical Support.
18
DOS DRIVER INSTALLATION
1. Insert the DRIVERS disk into your floppy drive (assumed to be
A:)
2. Type A:
3. Type INSTALL driveletter:\path to copy all files from the disk to a
subdirectory on your hard disk.
ex. INSTALL C:\ANTEX
REMEMBER: When the Windows driver installation is complete,
Windows should restart automatically. If not, exit then restart
Windows manually, or your changes will not be implemented.
19
USING DOS DEMONSTRATION SOFTWARE
On the enclosed disk is the demonstration software for the SX-7,
SX-9, SX-11, SX-12a, SX-20, SX-22, SX-23e and SX-26 boards.
Filenames are as follows:
Driver Program
SX25.EXE
DOS Demonstration Program
ADG.EXE
To run the Demonstration Softwa re:
1. Load the disk files into their own directory on your hard disk
using the DOS copy command (all files must be in the same
directory).
2. Install your mouse driver
3. Install the driver by running SX25.EXE
4. Run the demo ADG.EXE A=(I/O Address) I=(Interrupt)
ex. C>ADG A=280 I=2 (This is the default setting.)
5. At this point there should be a short pause as the board
initializes, then the demo environment should appear(Fig. 9).
Note: The left button of your mouse is to execute a command, the
right is to escape. You may also use the highlighted letter of the
command to access it directly from the keyboard.
20
Figure 9: DOS Demo Environment
KEY COMMANDS:
Q-Quit
Quits the demo program and returns to DOS.
C-Channels
Allows choice of channel configuration.
MONO-Single channel record/play.
STEREO-Dual channel record/play.
T-Format
The format for encoding or decoding audio data:
PCM16 - 16 Bit Pulse Code Modulation,
uncompressed.
PCM8 - 8 Bit Pulse Code Modulation,
uncompressed.
PCMU8 - 8 Bit Pulse Code Modulation,
uncompressed. This format is compatible with
Microsoft 8 Bit WAV format.
21
ADPCM1 - Series 1 compatible Adaptive Differential
Pulse Code Modulation compression.
ADPCME - Enhanced Adaptive Differential Pulse
Code Modulation compression, DVI compatible.
CDIB - Compact Disk Interactive level B
compression, CD-ROM XA compatible.
CDIC - Compact Disk Interactive level C
compression, CD-ROM XA compatible.
DOLBY - Dolby AC-2 Compression.
MPEG - ISO/MPEG -1, Layer I/II. Refer to
"ISO/MPEG-1 BITRATES & FORMAT
EXTENSIONS " for more information.
A-law - CCITT G.711 compression (European).
Available on the SX -9, SX-11, SX-23e and SX-26.
?-law - CCITT G.711 compression (North
American). Available on the SX -9, SX-11, SX-23e
and SX -26.
F-File
Audio file name to record or play.
I-FileFormat
The file format for recording/playback. Choices are:
apt-X - apt-X Compression. Available on SP-100
equipped adapters only, i.e. SX -11, SX-26.
ATX - The Antex default audio file format.
WAV - The Microsoft audio file format.
22
A-SampleRate
Allows you to change the sample rate. Enter the desired
rate in Hz.(ex 44.1 kHz=44100 Hz)
Rec Vol dB
Left: < >
Right: < >
To adjust the recording volume, click the mouse over the <
or > symbol on the screen. < lowers the volume from 0 to 30 dB in one dB increments. > raises the volume from -30
to 0 dB in one dB increments.
Play Vol dB
Left: < >
Right: < >
HEADERLESS - Raw digital audio data without
header information.
To adjust the playback volume, click the mouse over the <
or > symbol on the s creen. < lowers the volume from 0 to 30 dB in one dB increments. > raises the volume from -30
to 0 dB in one dB increments. Note: 0 dB = full volume.
Record/Play Level dB
Bargraph displaying the volume of each channel.
S-Stop
Stops record or playback.
23
S-Start
Starts playing or recording. You must select SetPlay or
Monitor (Set Record) prior to executing this command.
D-Append
Allows you to append new recorded material onto the end
of an existing file.
P - Play
Play a file.
R - Record
Record a file.
M - Mo nitor
Monitor the record channel (equivalent to Set Record
command).
E - SetPlay
Queues a file for playing. Press Start to begin playing
Center of Screen - Mixer
Controls the connections between source and destination
lines. To change a connection, click and hold on the
source channel button of the connection you wish to
redirect. Drag the pointer to the new destination channel
button and release the mouse button (you will see a line as
you move across the mixer screen).
Bottom Right of Screen
Displays driver status and errors.
24
PROBLEMS RUNNING THE DEMO
Symptom: The screen appears to be frozen.
Solutions:
1. Verify that the driver is loaded.
2. Make sure you type the correct I/O and interrupt
locations on the command line of ADG.
3. Make sure to use the HEX value for the I/O.
4. Make sure syntax of ADG line is correct.
5. Make sure the I/O and interrupt of the adapter are
not conflicting with other system hardware.
25
USING WINDOWS DEMONSTRATION SOFTWARE
Figure 10: The Antex Demo Window.
The Antex Demo program allows basic recording and playback of
.WAV files in any of the compression formats available on the
Antex Audio board you have installed in your system.
Sample Rate
This list box selects specific sample rates for recording,
and displays the sample rate of the file that is currently
playing. Not all sample rates are available for each
compression format. If a sample rate is invalid for a
specific compression format, the program will display a
message box similar to Figure 11.
26
Figure 11: Message Box reporting an unavailable
compression format or an invalid sample rate.
Compression:
This list box selects specific compression formats for
recording, and displays the compressed format of the file
currently playing. Each Audio Adapter has specific
compression formats that it supports. If the compression
format selected cannot be used on the Audio Adapter that
you have, a message box similar to Figure 11 will appear.
To select the compression ratio of an MPEG file, double
click on MPEG in the Compression list. A drop-down
menu displays the bitrates available for the current sample
rate.
Channels:
These buttons select mono or stereo recording, and
displays the current files number of channels.
VU Meters:
The VU meters show the relative signal of the current file
that is being recorded or played.
Wave Device:
If your computer has more than one Antex Audio board, this
drop down list box will allow selection of the specific board
to be used for recording and playback.
27
File:
This button allows for selection of a specific file to be used
for recording or playback. Once this button has been
pressed the dialog box in Figure 12 will appear.
Play/Stop:
Once a file has been selected, pressing the play button will
start the playback. During playback, this button changes to
"Stop". If a file has not been selected the "Open" dialog box
appears and allows selection of a specific file to playback.
Record/Stop:
Once a file has been selected, pressing the record button
will start the recording. During recording, this button
changes to "Stop". If a file has not been selected the "Save
As" dialog box appears and allows selection of a specific
file to record into.
Figure 12: File Open dialog box.
Volume:
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These controls allow changing the volume of the playback
only.
Customer support is available from Antex @ 1-800-338-4231.
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ANTEX MIXER
The ANTEX Mixer allows you to control the volume of the inputs
Figure 13: Antex Mixer
and outputs on the ANTEX digital audio cards. The Mixer is also
the way you route audio sources to either the record bus, for
recording to hard disk, or to the play bus, which diverts signals to
the line outputs.
Features of the Antex Mixer include:
SLIDE CONTROLS for adjusting input or output volume levels on
all active components and the master volume control. With your
mouse, drag the slide control bar up to increase the volume level,
and drag the slide control bar down to reduce the volume level.
BUTTONS that toggle for recording or playing on the individual
devices available. Clicking on the REC/PLAY button lets you
select the destination for each input device.
SOUND LEVEL METERS to show input or output levels when
recording or playing in digital audio or Wave audio.
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MIXER BUSES
Each mixer input may be routed to either the record or play bus by
toggling the bus button directly above each pair of input sliders.
RECORD MODE
The record bus is a composite mix of all audio inputs with their
REC buttons pressed. This mix is routed to the A/D converter and
digitized for recording to hard disk. You can then minimize the
ANTEX Mixer and use the Antex Demo, Microsoft Sound Recorder,
etc. to record.
Note: You will not hear any audio until the recording has started.
For instance, pressing the REC button in the Antex Demo.
PLAY MODE (Feedthrough)
The play bus is a composite mix of all audio inputs with their PLAY
buttons pressed. This mix is routed to the output jacks.
Note: You must toggle the button to REC if you want to record
audio to the hard disk.
MIXER DEVICES
LINE IN jack.
WA VE Digital audio playback.
Note: This device is playback only, so its Mixer mode
is always PLAY.
REC IN Record volume control. This slider is a master volume
control for all inputs assigned to the record bus.
MASTER Play volume control. This slider is a master volume
control for all inputs assigned to the play bus.
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UTILIZING DIGITAL AUDIO COMPRESSION UNDER
WINDOWS
At this point in time Microsoft is in the early stages of supporting
various compression formats for waveform audio under Windows.
An update to the multimedia standards was released that defines
the methods of passing data about compressed files as well as a
preliminary list of recognized compression formats. However, due
to the fact that Antex is the only manufacturer to offer multiple
compression formats today, there has been a lack of motivation for
software developers to create applications that take advantage of
digital audio compression. As a result, there are currently no
Windows applications that can demonstrate the full capabilities of
Antex digital audio hardware.
We have provided a Windows demo, ANTEXDEM.EXE to allow
you to access the extended compression functionality of the Antex
adapters.
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Audio Adapter Compression Capabilities
The Antex Series 2 and Series 3 product line contains audio
adapters with a range of signal processing capability. The following
table itemizes each product's record and playback functionality
with respect to compression format.
Product OKI
SX-5e P P P P - - - P P - -
SX-7 P P P P - P P - - - SX-9 P P P P - P P P R/P P -
SX-11 P P P P - P P P R/P P P
SX-12a R/P R/P R/P R/P - R/P - - - - -
SX-20 R/P R/P R/P R/P - R/P R/P - - - SX-22 R/P R/P R/P R/P - R/P R/P - - - -
SX-23e R/P R/P R/P R/P - R/P R/P R/P R/P R/P -
SX-26 R/P R/P R/P R/P - R/P R/P R/P R/P R/P R/P
SX-3 R/P R/P R/P R/P R/P R/P - - P* R/P -
Z1e/
SX-33
SX-33e
8-Bit
16-Bit
ADPCM
PCM
R/P R/P R/P R/P R/P R/P - R/P R/P R/P -
PCM
DVI SONY
CDIB&C
CDIB
CDIC
Dolby
MPEG MSADPCM A-Law
AC-2
? -Law
R = record capability
P = play capability
* current DSP software supports play mode only, but record
capability will be added soon
apt-X
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ISO/MPEG-1 BITRATES & FORMAT EXTENSIONS
ISO/MPEG supports several compression rates and encodes flags
that describe the audio data. The flags and other options are
selected by typing MPEG with[extensions] switches in the
Format text box of the DOS demo. (The bitrates in the Windows
demo are selected by double-clicking on MPEG in the
Com pression list to get a bitrate drop-down menu)
MPEG[extensions ]"
where [extensions] is a concatenation (in any order) of:
/L =1 (layer 1) or
=2 (layer 2),
/sr =32000
=44100 or
=48000 (to specify the sample
rate),
/M =st (mode = stereo)
=js (mode = joint-stereo) or
=dc (mode = dual channel) or
=sc (mode = single channel)
/kB =Kbits per second per channel
/E =1 (crc error checking) or
=0 (no crc error checking),
/C =1 (copyright protected) or
=0 (not copyright protected),
/O =1 (original) or
=0 (copy),
/Em =0 (no emphasis) or
=1 (emphasis 50/15ms) or
=2 (reserved)
=3 (CCITT J17)
For example to get a 5.5:1 compression ratio, layer II and joint
stereo in a 44.1kHz file:
1. Select 44100 from the SampleRate menu
2. Click on the text box lableled Format
3. Type MPEG/kb=128/m=js/l=2
MPEG -1 has a range of compression ratios that are user
selectable. The compression ratio selected will depend upon the
audio quality required. The MPEG -1 format specifies the
compression ratio by defining the desired bitrate. The compression
ratio obtained for a given output bitrate therefore changes with
sample rate.
34
In the Antex driver the bitrate is specified on a per-channel basis.
Therefore, requesting 64 kbits/s and stereo will result in a 128
kbits/s compressed MPEG stream. Supported bitrates (per
channel) and compression ratios are as follows:
Layer I
32 Khz 44.1 Khz 48 Khz
Bitrate
(kbits/s)
32 16
64 8.0
96 5.3
Compression
ratio
Bitrate
(kbits/s)
32 22.1
64 11.0
96 7.4
128 5.5
Compression
ratio
Bitrate
(kbits/s)
32 24.0
64 12.0
96 8.0
128 6.0
160 4.8
Compression
ratio
Layer II
32 Khz 44.1 Khz 48 Khz
Bitrate
(kbits/s)
32 16
48 10.7
56 9.1
64 8.0
80 6.4
96 5.3
112 4.6
128 4.0
160 3.2
192 2.7
224* 2.3
256* 2
320* 1.6
384* 1.3
Compression
ratio
Bitrate
(kbits/s)
32 22.1
48 14.7
56 12.6
64 11.0
80 8.8
96 7.4
112 6.3
128 5.5
160 4.4
192 3.7
224* 3.2
256* 2.8
320* 2.2
384* 1.8
Compression
ratio
Bitrate
(kbits/s)
32 24
48 16
56 13.7
64 12.0
80 9.6
96 8.0
112 6.9
128 6.0
160 4.8
192 4.0
224* 3.4
256* 3.0
320* 2.4
384* 2.0
Compression
ratio
* These bitrates are available for mono files only.
Layer II uses a more sophisticated compression algorithm than
Layer I, so it is recommended that Layer II be used wherever
possible.
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