AGILE AV dsp amp User manual

User Manual
AV dsp amp

User manual version 1 AV dsp amp
Table of contents
Product description ...................................................... 3
Type remarks ........................................................... 3
Key features ........................................................... 3
Applications ........................................................... 4
Connections ............................................................ 5
System information .......................................................
Description ............................................................
Hardware Architecture .................................................. 8
Digital audio input ..................................................... 8
Audio performance data .................................................. 8
Remote control ......................................................... 8
Product overview ......................................................... 9
Hardware part .......................................................... 9
Software installation ................................................. 11
Control panel ......................................................... 11
Filter design ......................................................... 12
Graph Area ............................................................ 13
Filter Definition Area ................................................. 14
Settings window ....................................................... 14
Work flow ............................................................. 15
Measurement ......................................................... 15
Designing filters .................................................... 1
Download .............................................................. 18
Firmware update ......................................................... 18
Examples ............................................................... 19
Example 1: 2-channel stereo setup ....................................... 19
Example 2: Stereo setup with active subwoofer ........................... 21
Technical data .......................................................... 22
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User manual version 1 AV dsp amp
Product description
Type remarks
Firmware version 1.3 (October 2009)
Key features
•Compact design
•Personal Computer controlled
•Two UcD100 power amplifiers
•Pop-free start and stop control
•Stereo analogue input
•Subwoofer output
•Fully user customised filtering
•Button panel controlled
•Remote controlled
•Link communication master / slave (only with two modules)
•Low signal to noise (-100dB)
Optional features, by adding a digital audio board.
•SPDIF stereo audio input
•Input sample rates up to 192kHz
•Link communication trough SPDIF link cable (one cable for audio and
link)
•USB audio input
•Low signal to noise (-104dB)
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-The first time the AV dsp amp is used all biquads are zero, so there are no filters
installed. onnecting any speakers and audio input at this point may cause some
damage to them.
-Take notice on what changes you make, changing a 2channel modules to stereo
setup can damage your speakers because both channels may be full range!
-After updating the firmware please be sure to also download the latest version of
the manual from our website

User manual version 1 AV dsp amp
Applications
With one module the following applications can be set up, further explained in
the “Hardware part chapter :”
•Stereo passive filtered system
•Briged mode for single subwoofer (max 140Watt into 4 Ohms)
•Mono/mid 2-way setup (tweeter + sub)
When two modules are used the following applications can be set up, also
explained in “Hardware part :”
•2-way active filtered stereo system
•2 channel system with active subwoofer
•2 channel system, both modules in bridge mode for more power
All setups are both possible with analogue and optional with the digital audio
inputs SPDIF and USB.
Note that all setups have the ability to use an extra channel by connecting a
active subwoofer to the subout. By this you will have the opportunity to build a
3-way system.
onnections
Figure 1
Overview of the connections on the front of the AV dsp amp.
Function
1Amplifier output, for slave speaker in stereo setup
4Analogue input left channel
5Analogue input right channel
6Subwoofer output
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User manual version 1 AV dsp amp
7IR in (3,5mm); max 4,5V
8a USB control input
9Master trigger output, slave trigger input
Right channel trough
11 ~230 volt input
Digital version only:
2SPDIF audio input
3SPDIF audio output
Audio trough for slave module
8b USB audio input
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User manual version 1 AV dsp amp
System information
Figure 2
Description
The AV dsp amp is a class D amp for use in powered speaker systems. As an active“ ”
speaker controller, a AV dsp amp can form the basis of a powerful active two-way
monitor. In stereo mode one AV dsp amp will power an active master / passive
slave pair. Finally, the module may also be used as a one-way 140W amplifier.
All signal processing, including volume control, is done using the on-board
DSP (digital signal processor).
Figure 1 shows the block diagram of the amplifier. When two modules are used,
the second unit slaves to the first unit (master) through a link cable. The link
cable (a stereo mini jack cable) carries both the right audio channel and
control data. This way, both units respond to the master’s control panel.
A PC controls the AV dsp amp through the USB port. This connection is used to
upload the configuration and filter settings. An optional board permits use of
the USB link for audio as well as an SPDIF link. In digital mode, master/slave
linking is done through the SPDIF in/out connections instead of the mini jack
cable.
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User manual version 1 AV dsp amp
Hardware Architecture
The standard version of the AV dsp amp has a stereo analogue audio input. This
analogue signal is converted to digital, processed by the DSP and then
converted back to analogue. A microcontroller controls the DSP, reads the
control panel and communicates with the PC and/or another AV dsp amp that may be
attached.
Digital audio input
The optional digital input board plugs into the main PCB and carries two RCA
connectors, SPDIF in and SPDIF through. Incoming SPDIF is linked through
directly to the output and sent to the DSP through an asynchronous sample rate
converter (ASRC) for jitter removal. The USB part adds a hub and an audio device
which in turn also transmits audio over the ASRC to the DSP. The ASRC chip scans
its input for whichever signal is active. In a stereo setup and in digital mode
the SPDIF through cable doubles as a master/slave link, obviating the need for
the mini jack cable. The mini jack cable remains functional though and does not
have to be removed.
Audio performance data
MBW=20kHz, unless otherwise noted. All filters set to unity. Noise levels
unweighted.
Item Symbo
l
Mi
n
Typ Max Unit Notes
Input level Vin 2.2 V
Input impedance 10k Ohm Analogue cinch
inputs
Output level LS1 100 W Into 4 Ohms
LS2 100 W Into 4 Ohms
Signal/Noise SNR 100 dB ADC
104 dB DAC
Total harmonic
distortion+Noise
THD+N TBD
Analogue sampling rate Fs 48 kHz
Delay per channel 0 0 340,
3
cm Set in software,
not for subout
channel
0 0 1000 us
Supported digital
sampling rates
Fs 32, 44.1, 48,
88.2, 96, 192
kHz All input rates
converted to 48kHz
Gain 20 dB volume at 0dB
Remote control
The master unit is fitted with small control panel which is placed on the front
of AV dsp amp. Volume and standby/on is controlled by the pushbuttons and by a
infrared remote control. When 2 AV dsp amp modules are used only one control
panel is needed, because the trigger communication between master and slave.
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Stereo
audio in Right speaker
Left speaker
P amp V1.0
Led
Volume
Down
Volume Up
Ir Reciever
On/Off
ontrol
Panel
Figure 3
User manual version 1 AV dsp amp
Product overview
Before you can use the AV dsp amp in your particular setup, you first have to set
the right settings. This is done by pc software, called DSP filter design.
Please do not connect any spea ers to your system yet!
When you want to set up a system with the AV dsp amp you apparently know what you
want. So with this information you can setup your system as follows:
Hardware part
Stereo setup: Connect the module to your pc by a USB cable and select on witch
side of the room your master module will be, the speaker with the
AV dsp amp. When your master is the left channel the slave will
become the right channel. When you want to set the master as
right channel with analogue input you will have to change the
input cinches, left in the right cinch and right in the left.
This is because only the right channel is linked trough, so if
you want the left channel to be linked trough you just switch
left and right. For digital sources the left and right channel
are linked.
Bridged
setup: Connect the module to your pc by a USB cable and select
where the master module is placed, master module is left or
right audio or functions as a subwoofer. When you use 2 AV dsp
amp for a stereo bridged setup you will also have to initialise
the second (slave) module, see example in the last chapter of
this document.
In bridged mode the jumper (see figure 2) must be placed and the
speaker must be connected between J4 speaker+ and J2 speaker+.
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User manual version 1 AV dsp amp
In all other setups the jumper is not placed!
When you want to set the master as right channel with analogue
input you will have to change the input cinches, left in the
right cinch and right in the left. This is because only the right
channel is linked trough, so if you want the left channel to be
linked trough you just switch left and right. For digital
sources the left and right channel are linked.
2 Channel: Connect the module to your pc by a USB cable and select what kind
of 2 channel you want to setup. When you want to set the master as
right channel with analogue input you will have to change the
input cinches, left in the right cinch and right in the left.
This is because only the right channel is linked trough, so if
you want the left channel to be linked trough you just switch
left and right. For digital sources the left and right channel
are linked. An example is given in the last chapter of this
document.
On all setups there is also the ability to use the Line out sub. This can source
an active subwoofer module.
When 2 modules are used these two can be linked by a trigger cable. This cable
holds device data and also carries a audio channel on analogue source. If the
digital board is installed then the SPDIF link cable can be used to communicate
between the 2 modules. This cable is placed from master SPDIF out to slave SPDIF
in cinch. The trigger cable is no longer needed in this setup. On USB audio
input on the master the SPDIF output is also used for linking master to slave.
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P amp V1.0
Led
Volume
Down
Volume Up
Ir Reciever
On/Off
Stereo
audio in
ontrol
Panel
trigger +
right ch
LF HF LF HF
Figure 4

User manual version 1 AV dsp amp
Software installation
System requirements:
•Pentium class or higher
•64MB RAM
•USB1.0 or higher
Tested on Windows 2000, XP, Vista, Windows
All files are compressed in the setup.zip file. This zip file contains 2 DLL
files for communication and a .EXE file, which represents the DSP filter
design program.
1. Unzip the setup.zip file on your hard disk
2. Open the DSP filter design.EXE by double clicking the file“ ”
ontrol panel
Now the program is ready for use.
You see the following window,
called the control panel.
Figure 5
When the program is running connect your AV dsp amp to your
pc by the USB cable. Windows will automatically detect and
install the AV dsp amp and the USB audio device. When the
installation is done the connected window will appear and
the connection light will turn green. You can also manually
make a connection by the connect button, on the bottom“ ”
right of the control panel.
Now you can adapt the settings of the AV dsp amp real time through USB. On the
left of the control panel you see the Force input and active input groups. This
shows you the settings of the audio inputs of the AV dsp amp, and lets you
control these inputs (only when digital audio board is added).
Audio can be provided in 3 ways, analogue, SPDIF and USB audio. The selection of
any of these inputs can be automatic, auto detect . This means that when any of“ ”
the inputs is presented there will be switched to this channel automatically.
This is done by setting the analogue input as the standard source. During
analogue in the other two inputs are scanned for any valid signal. The first
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Figure 6

User manual version 1 AV dsp amp
channel that contains any valid audio is selected and becomes the new input
source. But if you put in the USB cable but you want to use the analogue input
you can force the analogue input to be used. This can be done for all inputs, the
options Analogue, SPDIF and USB Audio.
When the module selects one of the inputs this is shown by the active input
lights.
Under the Setup select part the system setup can be selected. There can be
chosen between:
2-channel Stereo Bridged
Master on the left Master on the left Master on the left
Master on the right* Master on the right* Master on the right*
Mid/Sub, L+R Sub, L+R
Side, L-R
* Only on digital audio board, for analogue version cinches has to be changed
like described in ‘Hardware part’.
The output signal of the subout channel van be controlled in the Subout“
control panel. Normally this will be set to L+R to use one subwoofer, but if you”
want to use a subwoofer on both sides you can set the subout to only use left or
right input signal.
The last thing that can be controlled in this window is volume. This can be done
by setting the scrollbar to a desired position or by typing the value in the
volume field , this value is send when pressed enter .“ ”
All of the configurations made here will be redirected from master to slave,
when presented. So there is no need to connect the slave module to the pc.
The slave module is always the opposite of the master, so master left will set
the slave to right. This is done automatically because the module knows whether
it is master or slave.
Only when the module is switched off by remote all settings, like volume and
setup, are stored in memory.
Filter design
When you want to make some filters
for your module they can be
designed in the Filter design .“ ”
Under view there can be switched
between the control panel and the
filter design window.
The following pages will give you a
widespread instruction of the
possibilities of the program.
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Figure 7

User manual version 1 AV dsp amp
Figure 8
Graph Area
The magnitude tab shows the imported driver responses, filters, individual
biquads, individual filtered driver responses and the sum.
olour Function
Blue, thin Measured woofer response
Green, thin Measured midrange response
Red. thin Measured tweeter response
Blue, thick Filtered woofer response
Green, thick Filtered midrange response
Red, thick Filtered tweeter response
Light blue,
thick
Response of filter, selected channel only
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User manual version 1 AV dsp amp
Orange, thick Response of selected biquad
Black, thick Sum response
Having all of these on at the same time quickly produces an intractable mess so
these graphs can be separately enabled or disabled in the filter definition
area.
The impulse or step tabs show the time domain response of the imported drivers
and the sum response, and are used to demarcate the anechoic portion.
Filter Definition Area
The three channel tabs, labelled Tweeter, Woofer and Subwoofer are
functionally identical. The top left frame is used to import response files.
The select button opens a file. The show checkbox turns display of the“ ” “ ”
measured graph on or off. The Common Settings box controls global gain (for
each channel), delay, and the visibility of plots.
The amplified channels have up to 12 biquads, selected using the Biquad“
Section radio buttons in the middle. The Subwoofer lineout has only 6 biquads”
sections, for only simple filter settings. To the right is a settings area
specific to the type of function selected. Unused biquads are set to unity.
The selected biquad is edited by selecting a function and setting relevant
parameters.
The delay has a maximum value of 1000us for channel 1 and 2. The subwoofer
channel does not include any delay. Distance is calculated by
soundspeed/delay=distance, maximum distance is therefore
340,29meters/0,001secondes=34,029cm. Note that the minimum step-size is
0, 08cm cause the sample rate of 48000.
Settings window
The settings window is under File > Settings Measurement sampling rate sets…
the sample rate used in the imported response files (typically 48kHz).
Processor sampling rate is that of the DSP hardware. Note that this setting
does not control the sampling rate of the hardware. Rather, it informs the
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User manual version 1 AV dsp amp
filter design application of what that sampling rate is. In short, leave this
at 48kHz.
The select button opens a file dialogue box witch is not used in this
application.
Work flow
Measurement
Measuring using the DSP unit set to “flat”
Perform impulse response measurements for each driver separately. Save the
entire impulse record truncation can be done later on the filter design–
program.
Measuring using an external amplifier
A separate amplifier may also be used for measuring the drivers, provided the
amplifier’s output impedance is as low as the DSP unit’s.
Importing response data
Select the tab for the channel you want to import and click select . The filter“ ”
designer expects the impulse response measurement as a text file with one
sample per line.
There is no restriction on the absolute gain of the impulse response data. The
only thing that matters is that the absolute gain be the same for all three
measurements. The filter designer computes a gain offset based on all loaded
responses to centre them collectively on the vertical scale.
Truncating response data
Switch to the impulse or step response graph.
Figure 9
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User manual version 1 AV dsp amp
The first echo is apparent at 5ms. Zoom in until you see only the anechoic
portion of the impulse response. Dragging the mouse, left-button down, from
left to right marks a zoom area. Dragging from right to left zooms out. Dragging
with the right button down pans the plot left and right.
Figure 10
Click truncate . Anything currently outside the display is drawn in grey and“ ”
not processed. You will notice that in the frequency graph a portion of the low-
frequency response is also drawn in grey. This is to remind the user that
insufficient information is available to make *any* correction below this
frequency. A way of obtaining quasi anechoic low-frequency measurements is
making close-up measurements. Working with such measurements requires a good
deal of interpretation but it is doable.
Important: Avoid making any corrections for which no anechoic data is
available. If reflections are included, they are guaranteed to dominate the
measurement at low frequencies, and you will end up making corrections for
circumstances that are highly specific to the room in which the measurement was
made. Power-response data can only be made in a proper echo chamber or
preferably, by collating a large number of anechoic off-axis measurements. A
reverberant measurement in a normal live room just won’t do.
The steps of loading and truncating data can be repeated at any time. This can
be particularly practical when combining close-up and far-field measurements
during the filter design phase. The window in Figure 10 shows the result of
this. The small knot of corrections made around 0Hz is based on close-up data
first loaded separately. The LF section of the test mule is quite smooth apart
from one internal standing wave.
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User manual version 1 AV dsp amp
Designing filters
Biquad
function
Parameters Use
Unity - Section is not used
LPF1 Cut-off frequency (always
-3dB)
First order lowpass
LPF2 Cut-off frequency
(asymptotically)
Q
Second order lowpass. A Q of
0. 1 corresponds to
butterworth. 0.5 corresponds
to LR2. Two identical
sections with a Q of 0. 1 form
an LR4 filter.
HPF1 Cut-off frequency (always
-3dB)
First order highpass
HPF2 Cut-off frequency
(asymptotically)
Q
Second order highpass. A Q of
0. 1 corresponds to
butterworth. 0.5 corresponds
to LR2. Two identical
sections with a Q of 0. 1 form
an LR4 filter.
Shelf1 Centre Frequency (halfway
point)
Gain
Direction
First order shelf. Useful for
baffle-step correction
Shelf2
Centre Frequency (halfway
point)
Gain
Q
Direction
Second order shelf. Useful
for correcting internal
cabinet resonances and for
the midband peak/dip combo of
most midwoofer speakers.
Asymmetric
Shelf
Pole frequency and Q
Zero frequency and Q
Equalising the bottom end of
closed-box woofers with large
magnets
Boost/Cut Centre frequency
Q
gain
Dip/peak filter. For peaks, Q
is defined by the poles. For
dips, Q is defined by the
zeros. Thus the same filter
with opposite gains will
cancel.
The first step is equalising the magnitude responses of the drivers flat over
their entire useable frequency range.
The weapons of choice are shelving filters, and boost/cut sections. A sharp
peak followed by an equally sharp dip can be corrected using a second-order
shelving filter with a high Q.
Exercise care when deciding what to correct. When correcting for diffraction
errors, do not exceed a Q of 3 lest the cure be worse than the ailment. Errors
that are caused inside the driver, or internal cabinet resonances that emanate
through the same diaphragm, may be corrected ruthlessly provided the–
measurement has sufficient resolution to pin them down.
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User manual version 1 AV dsp amp
As a rule of thumb, sharp dips are diffraction artefacts while sharp peaks are
caused by the drivers themselves. Exceptions are room resonances (if the
response is not correctly truncated) and diffractions on repetitive patterns.
The second step is designing the actual crossover filters. All the usual
strategies work. Delaying higher frequency drivers with respect to lower-
frequency ones is a powerful alternative to using asymmetric slopes and yields
substantially improved coherence through the crossover region.
Download
Under download the user can press load DSP to download its designed filters to“ ”
the AV dsp amp.
Firmware update
Every module has the ability to update its firmware, when provides a new
firmware version. The firmware version of the module is shown in the statusbar
of the filter design window and under About.
The firmware can be easily updated by USB, the same for master and slave module.
Under option download you can find Firmware update . When this option is“ ” “ ”
selected the user can select the new firmware file. This is a complete hex file
provided by , no adapts can and may be made by the user!
After the file is selected the update begins.
DO NOT DISCONNECT THE MODULE AT THIS PIONT!
When the progress bar is filled the update is completed. On a CRC error the
update is automatically restarted, after three errors the update is aborted.
Figure 11 shows a completed firmware update.
After restarting the module the new firmware is running.
Note that the new firmware does not have any filters installed, so the filters must be reloaded with the
correct values.
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User manual version 1 AV dsp amp
Figure 11
Examples
Example 1: 2-channel stereo setup
This example will guide you through setting up you 2-channel stereo system with
the AV dsp amp, picture of this kind of setup is given in Figure 4. The master
module is always the one with the control panel connected.
First you got your 2 modules with no cables or speakers connected!.
Master
1. Plug- in the power connector and switch the module to ON
2. Power up the module by the control panel or remote
3. Start the pc program, filter design
4. Plug-in the USB cable (assumed that you’ve already installed the
software as described in chapter “Software installation )”
5. Wait for automatic connection, a popup is displayed as in Figure 6. If
connection is not automatic the press the connect button. If there is“ ”
no response there is a problem with the USB connection or your operating
system that can not detect the USB device
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User manual version 1 AV dsp amp
6. Set the system to the desired setup, for this example 2-channel –where
the master represents the Left speaker
Figure 12
. When needed set the desired input, for now just leave it Auto detect.
Note that in auto detect the USB source is selected when the module is
connected to the pc
8. Switch to the Filter design Window under view, or press ctrl+f
9. Fill in your biquads with the desired filters, in this preliminary
software the high channel is channel 1 and the low channel is channel 2
10. Download the filters to you module under Download, or press ctrl+F9
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User manual version 1 AV dsp amp
11. When download is completed you can power down the module
12. Start with the SLAVE module
Slave
1. Start the pc program, filter design. Or go back to the control panel
(ctrl+c) if the program is still running
2. Plug- in the power connector and switch the module to ON
3. Plug-in the USB cable (assumed that you’ve already installed the
software as described in chapter “Software installation )”
4. Wait for automatic connection, now the program detects a slave module,
this is shown in a popup. If connection is not automatic the press the
connect button. If there is no response there is a problem with the USB“ ”
connection
5. Switch to the Filter design Window under view, or press ctrl+f
6. Fill in your biquads with the desired filters or use the same filters as
the master module. In this preliminary software the high channel is
channel 1 and the low channel is channel 2
. Download the filters to you module under Download, or press ctrl+F9
8. When download is completed you can power down the module and disconnect
the USB cable
9. Master and Slave are now set up as a 2 channel stereo system
Final setup
When both modules are installed it is time to complete your setup.
- First connect your speakers as explained in chapter Product overview
- Connect the trigger cable (mini jack) or SPDIF cable between both
modules, depending on the used audio source
- Power up master and slave module
- Turn on the master by control panel or remote
- Lower you source volume, prevent loud start-up volume
- Connect your source to the AV dsp amp
Ready!
Now the system is fully setup and can be controlled by the control panel, remote
control or by connecting the module to your pc. From now on you can update your
filters at any time, just repeat the Master and Slave steps.
* If your slave module is not turned on by the master try to power down the
slave, turn the master off, wait 5 seconds, power up slave and turn the master
back on
•When there is something that does not work try to repeat the
installation
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