The miniDSP Flex is
a stereo
input, four-channel output
compact high-resolution audio processor.
It features stereo analog inputs, two digital inputs (SPDIF and optical),
USB audio, Bluetooth streaming with LDAC™ and aptX™ HD codecs and automatic
Bluetooth input selection, and an OLED front panel with physical volume
control.
The miniDSP Flex can be upgraded to run stereo (two-channel) Dirac Live® room
correction. This requires an additional purchase for the Dirac Live
license. You can either purchase the miniDSP Flex with Dirac Live already
activated, or purchase the Dirac Live upgrade at a later time from within
the Device Console. Refer to the instructions here:
The miniDSP Flex has a wide range of applications in home and
professional audio. This section illustrates a few of them.
Figure 1 shows the miniDSP Flex used as a
digital preamp with subwoofer integration. The Flex provides accurate
and flexible integration between the subwoofers and the main speakers as
well as comprehensive EQ and tuning options. This is a very
cost-effective way to build a complete audio system that includes all
the benefits of modern DSP technology.
Add the optional Dirac Live
software upgrade for world-class room correction.
Figure 1. miniDSP Flex as preamp with subwoofer integration
Figure 2 illustrates a similar use of the
miniDSP Flex as a digital preamp, but the output channels have instead been
configured to act as crossover for a pair of active 2-way speakers.
Amplification can be via a multichannel power amplifier as shown, or a
pair of stereo amplifiers.
Figure 2. miniDSP Flex as preamp and active crossover
In Figure 3, the miniDSP Flex has been
used as an accessory in a home theater system, to manage multiple
subwoofers. Driven from the A/V receiver's subwoofer output, the miniDSP Flex
can be used to independently adjust gain, delay and parametric EQ
of each subwoofer for optimum multi-sub performance.
If you purchased your Flex directly from miniDSP, your software will be
available from the User
Downloads section of the miniDSP
website when your order ships. To access the download, you will need to
be logged into the website with the account you created when purchasing.
If you purchased your Flex from a miniDSP dealer, you will receive a
coupon together with the product. Redeem this coupon at this page:
The User Downloads link is visible from
the drop-down menu at the top right of the website:
Navigate to the miniDSP Device Console section and select the download according to your platform:
Windows, macOS with Intel CPU, or macOS with Apple ARM CPU.
Double-click on the downloaded miniDSP Device Console-x.y.z.dmg image file to open it.
(The version number x.y.z embedded in the file name will change over time.)
Drag the miniDSP Device Console application icon to your Applications folder.
To run the miniDSP Device Console, locate it in the Applications folder
and double-click on it. To make it easier to run in future,
right-click on its dock icon and select Options -> Keep in Dock.
Info
The macOS version of miniDSP Device Console is installed for all users on the computer.
Double-click on the downloaded
MiniDSP Device Console Setup x.y.z.exe installer to run it. (The version number x.y.z embedded in
the file name will change over time.)
Install the miniDSP UAC2 USB Audio driver:
Start miniDSP Device Console.
Navigate to the Settings screen and select Install USB Audio Driver:
Device Console will confirm that you want to install the driver.
Click on the PROCEED button.
Note: we recommend that you accept the default installation location.
The first time you run the
miniDSP Device Console, you may see a
Windows Firewall warning such as the one below. Ensure that "Private
networks..." is checked and "Public networks..." is not checked. Then
click on "Allow access." This warning dialog may appear more than once.
Info
The most recent miniDSP processors require the UAC2 driver to be at least version 5.40. If you have
difficulty with the UAC2 driver or control panel, use Check USB Audio Driver to
make sure that you have the latest version.
Info
The Windows installation of miniDSP Device Console is for a single user. If it needs to be run in more than one account
on your PC, it will need to be installed for each account.
The miniDSP Device Console ("DC") is the new configuration and control
software for miniDSP audio processors. It replaces the earlier "plugin" control
software. In contrast to the earlier software, Device Console provides:
A single software program to control all miniDSP processors
Over-the-air (OTA) self-updates
Detection and installation of firmware upgrades for your processor
Purchase and activation of Dirac Live upgrades (where applicable)
If you have not used Device Console with your Flex before,
you will need to perform a one-time migration procedure. See Migrating to DC.
To connect
to a device for editing and control, click on its name. DC will update to display the
device-specific sidebar on the left and the signal processing control interface in the main area on the right.
The signal processing area is divided into sections for the input channels and output channels.
There is a control strip for each channel. The output channel strips also contain the
signal routing matrix.
If this is the first time you have used Device Console with your
miniDSP Flex, Device Console will check for an existing preset
that was created with the older MiniDSP-2x4-HD "plugin" user interface.
If found, Device Console will automatically import it. This is done on a preset-by-preset basis.
When you are done, click DISCONNECT.
Tip
Once you have switched to miniDSP Device Console, don't use the older MiniDSP-2x4-HD
"plugin" user interface to connect
to the miniDSP Flex any more.
The Template Devices screen displays the complete list of devices supported by Device Console.
This can be used to explore features of a processor that you do not have, or to edit your processor
settings when you are not able to connect to it.
To edit a template device, click on it.
A template device "mirrors" the real device, so that you can edit your settings
while not connected. That is, while you are editing the real device, the
current preset is copied to the corresponding template device whenever you change presets
and when you disconnect. You can then edit those
settings in the template device.
Tip
While editing a template device, the level meters will display a "dummy" signal.
To turn off the level meters while editing a template device, click the Mute button in the left sidebar.
When you are done editing in the template device, click FINISH.
When you connect to your real device again, Device Console detects that you have edited
the template and asks you if you want to use the settings from the edited template.
Or, you can discard the changes you made in the template and revert to the
settings that your device had the last time you were connected to it. This is done on a
preset-by-preset basis:
Info
You will see a similar dialog if you edit the settings of your device using a
different computer or the older "plugin" user interface (the latter is not recommended
once you have migrated to the miniDSP Device Console).
Info
If you have more than one
device of the same type, only one of them can be edited using the
template device.
If you have more than one device of the same type or
need to edit your devices from more than one computer, you will need to
manage your presets by exporting them to and importing them from files.
See Importing and Exporting.
These settings are for Device Console itself (and not any connected
processor).
The Modes selection sets the DC to display with a light theme, a dark theme, or with the same theme
as your operating system (Windows or macOS). If you choose the System option, you may need to quit
Device Console and restart it for the change to take effect.
The Install USB Audio Driver feature installs the latest version of the miniDSP UAC2 audio driver.
It appears on Windows only.
See Installation for more information.
The Create Program Snapshot feature is used to help miniDSP support diagnose issues you may
be having with your unit. See
Obtaining Support.
To select the input source, drop down the selector menu and select the desired input:
Info
The input source can also be selected
from the front panel or with a remote control.
The
set of inputs that can be selected can be set up by clicking on the CUSTOMIZE SELECTION button. Any input
source can be enabled or disabled here. This is a convenience feature so that unused inputs do not have to
be cycled through when using the front panel or remote control. Use this menu to deselect unused inputs:
To import a preset from a file, click the IMPORT button, then navigate to a saved preset file and click
Open. The preset will be loaded from the file. If Device Console is currently
connected to the miniDSP Flex, the preset will also be sent to the Flex.
To export a preset to a file, click the EXPORT button. Navigate to the desired location in the file system,
change the file name if desired, and click Save.
Info
It is not possible to load a preset from the Flex back to the Device Console.
We strongly recommend always exporting your presets to files when they are complete, to ensure that
you don't lose them in future.
Tip
To copy all settings from one preset to another, export the first preset to a file, select the
second present, and then import the file that you just saved.
miniDSP Device Console will check for firmware updates when a device is connected, and notify you if
one is available. To manually update the firmware, click the Refresh DSP Firmware
and Refresh XMOS Firmware button.
Tip
You do not need to use these buttons in normal operation. They are there in case your
Flex has
issues and/or miniDSP Support instructs you to refresh the firmware.
Click on BUY UPGRADE. A browser window will open on stripe.com. Enter your payment
details and click Pay. You will be redirected to an acknowledgement screen, and
also receive a receipt by email.
Info
After you press the Buy Upgrade button, miniDSP Device Console will wait for an acknowledgement
from the payment system.
If you decide not to proceed with the upgrade, click the back-arrow button near the top left
of the purchase screen. Here is an example:
If you just close the payment window, Device Console will wait 30 minutes for the acknowledgement; in that case, quit and restart the Device Console application.
After payment completes, return to the miniDSP Device Console window. You will see acknowledgement of successful payment:
Click OK to return to the upgrade screen:
Click on RETRIEVE KEY ONLINE to retrieve the activation key. Then click ACTIVATE to activate the upgrade on your Flex.
Tip
Retrieving the activation key online requires an active Internet connection. If you have a device
that needs to be activated while offline, save the activation key file that was attached to the purchase acknowledgement email onto a USB stick. On the device to be activated, click LOAD FROM FILE and select the file from the USB stick.
After activating, the Flex will restart. When it comes back online, it will appear in the Device Console list of devices as a Flex (DL).
The miniDSP Flex presets will not be converted to the Flex (DL).
When reconnecting, you can choose to either restore all presets to their default values
or to use existing Flex (DL) presets.
Click on "Idle Timeout" to set the idle timeout to a value between 3 and 120 seconds. After this period of time, the
front panel will turn off. It will turn on again on any user interaction.
The front panel and rotary encoder provide access to the key features of the
miniDSP Flex. These can also be accessed with a remote control.
To change the volume, rotate the encoder. The volume changes in
0.5 dB steps. Minimum volume is -127.5 dB and maximum volume is 0.0
dB.
To select a preset, press the encoder knob once, then
rotate until the desired preset number is displayed. Either press
the encoder again or wait for a second. The display will show "Pls
wait..." while the new preset is being loaded, and then return
to normal.
To select an input source, press the encoder knob twice, then rotate
the encoder until the desired input source is displayed. Either press
encoder knob or wait for a second and the display will
return to normal with the new input selected.
To mute output, press and hold the
encoder knob. When the display changes to show "Mute?," release the
knob. To unmute, repeat this procedure.
To put the Flex into standby, press and hold the encoder
knob. When the display changes to show "Standby?," release the knob.
To take it out of standby, press the encoder knob.
Tip
All these operations can also be performed with the remote control.
DC power. The supplied 12 VDC
power supply includes a set of interchangeable power pins for USA,
UK, Europe and Australia. Fit the correct pins for your country.
Connect the DC plug to the 12 VDC power socket.
Ground lug. This can be connected to an external electrical
ground if it is necessary to ground the chassis of the Flex. This
need is uncommon, and most of the time it can be left unconnected.
USB port for control and audio streaming. Connect to an
available USB port on your computer. This port can also be connected
to a network streamer with USB output for audio playback.
Bluetooth antenna. Screw on the supplied Bluetooth antenna here.
Optical digital input. Connect a digital source using a TOSLINK
optical cable. Sample rates from 32 up to 216 kHz are supported.
Coax digital input. Connect a digital source using an RCA cable.
Sample rates from 32 up to 216 kHz are supported.
Reset button. For use in specific circumstances only.
See the Trouble-shooting and Support section.
Analog inputs. Connect an analog source here using RCA cables.
Typically, the left channel is connected to input 1 and the right
channel is connected to input 2. The maximum input voltage is 2.0
Vrms.
Analog outputs. Connect equipment such as a power amplifier and
subwoofer using RCA cables. Typically, output 1 is the left channel
and output 2 is the right channel. See Section 6.4 for a variety of
other connections. The maximum output voltage is 2.0 Vrms.
Balanced analog inputs. Connect an analog source here. The input
jacks are balanced TRS (1/4" tip-ring-sleeve) connectors, so XLR to
TRS adapter cables can be used to connect to equipment with XLR
outputs. Typically, the left channel is connected to input 1 and the
right channel is connected to input 2. The maximum input voltage is
4.0 Vrms.
Balanced analog outputs. Connect equipment such as a power
amplifier, active speakers and subwoofer here. The output jacks are
balanced TRS (1/4" tip-ring-sleeve) connectors, so TRS to XLR
adapter cables can be used to connect to equipment with XLR inputs.
Typically, output 1 is the left channel and 2 is the right channel.
See Section 6.4 for a variety of other connections. The maximum
output voltage is 4.0 Vrms.
Analog inputs. Connect an analog source here using RCA cables.
Typically, the left channel is connected to input 1 and the right
channel is connected to input 2. The maximum input voltage is 2.0
Vrms.
Digital outputs. Connect to a DAC, a home theater receiver, or
active speakers with digital input. Each digital connection carries
two output channels -- output channels 1 and 2, or output channels 3
and 4. The TOSLINK and SPDIF outputs for each pair of channels carry
the same signal and are both active at the same time. The sample
rate on the digital outputs is 96 kHz (miniDSP Flex (without Dirac Live)).
The miniDSP Flex has a range of input sources and output connections.
This section provides an overview of the basics so you can
quickly get started with playing audio.
The diagram below illustrates a basic connection of a stereo amplifier and a
pair of speakers to the miniDSP Flex. Since the default settings
of the Flex route the input channels to
output channels 1 and 2 with no crossovers active, you can make this connection
for initial testing and listening.
Connecting a stereo amplifier and speakers to the miniDSP Flex
Of course, more complex connections are possible using the additional outputs. In that case, the
internal processing will need to be set up using the miniDSP Device Console.
Refer to the Signal Flow and DSP Reference sections for details.
Warning
Ensure all equipment is powered off when making audio connections.
Warning
Before playing audio for the first time, turn the volume down using the front panel encoder.
Increase it gradually after audio playback starts.
The miniDSP Flex includes the
LDAC™ and aptX™ HD Bluetooth
codecs for high-fidelity Bluetooth™ audio.
Info
LDAC is an audio coding technology developed by Sony that enables the
transmission of High-Resolution (Hi-Res) Audio content, even over a
Bluetooth connection. Unlike other Bluetooth compatible coding
technologies such as SBC, it operates without any down-conversion of the
Hi-Res Audio content[^3], and allows approximately three times more
data[^4] than those other technologies to be transmitted over a
Bluetooth wireless network with unprecedented sound quality, by means of
efficient coding and optimized packetization.
LDAC is supported on recent Android devices. If your device does not
support LDAC, you can still pair it with the miniDSP Flex, but Bluetooth audio
will use a lower bitrate codec.
aptX™ HD is designed to deliver high definition (HD) audio over
Bluetooth, to help you get the very most from your music.
Pairing your mobile device with the miniDSP Flex is essentially the same
as pairing it with other Bluetooth audio devices such as headphones or
your car.
To put the miniDSP Flex into pairing mode:
Press the encoder button on the miniDSP Flex twice and rotate it until the
display shows "Bluetooth."
Press and hold the encoder and the display will change to
"BTPairing." The miniDSP Flex is now in pairing mode.
Open the Bluetooth Settings on your mobile device to
pair with the miniDSP Flex. The exact appearance will vary depending on your
specific device, but this series of screenshots illustrates a
typical sequence:
If your device supports LDAC, enable it by using the
gear icon:
When Bluetooth audio is selected as the source, the usual front panel
display will display the source (lower right corner) as one of:
BT(C)
The miniDSP Flex is paired over Bluetooth.
BT(NC)
No Bluetooth device is paired.
BT(P)
The miniDSP Flex is in pairing mode.
Once paired, the miniDSP Flex will receive and play the audio stream from the
paired device. If the Bluetooth input is not selected when you start
audio playback, the miniDSP Flex will automatically switch to the Bluetooth
input source when audio is Bluetooth detected.
The miniDSP Flex accepts stereo PCM audio at sample rates of 44.1, 48,
88.2, 96, 176.4, and 192 kHz over USB. The same USB connector is used
for playing USB Audio as well as for configuration.
To play USB Audio from a computer, use the
supplied cable to connect the USB 2.0 (Type B) port of the miniDSP Flex
to a free USB port on your computer.
Alternatively, connect a network streamer to the USB port. For an
example using the Raspberry Pi, see this application note on our
website:
The miniDSP Flex is USB Audio compliant, so no drivers need to be installed to play audio on macOS.
Open Audio MIDI Setup (in Applications->Utilities) and
click on its name in the list on the left-hand side.
To set the miniDSP Flex as the default audio output device, right-click
and select "Use this device for sound output":
Note that individual audio playback apps may allow the miniDSP Flex to
be selected for audio output independently of the system default. They
may also control sample rate automatically.
The miniDSP Flex sends its four output
channels to the computer over USB. Click on the Input button in
Audio MIDI Setup to see them. These can be used to monitor or record the
output channels of the miniDSP Flex:
To set the miniDSP Flex as the default
audio output device, open the Settings app and navigate to the
System -> Sound page. Select the Flex with the radio button:
To change the bit depth and sample rate,
click on the rightward angle symbol >. Click the selector next to Format to pop up the sample
rate menu. Sample rates
up to 192 kHz can be selected:
The miniDSP Flex sends its four output channels to
the computer over USB. These can be used to monitor or record the output
channels after DSP processing:
To avoid Windows resampling the outputs from the Flex, set the sample rate
here to the DSP's internal sample rate: 96 kHz.
If your audio application supports ASIO®
audio drivers, we recommend selecting the miniDSP ASIO Driver in its
settings. This typically allows the application to automatically change
sample rate. For example, in JRiver Media Center:
The current settings of the miniDSP Flex can be viewed by opening the
miniDSP UAC2 Control Panel from the Windows Start menu (under the
miniDSP Ltd folder). This control panel allows you to view current
settings. In addition, it can be used to set buffer size, although we
recommend that you leave this setting at the default. If you are having
an issue with inadequate output volume over USB playback, check the
Volume tab.
To see the installed version of the UAC2 driver, use the About tab:
The infrared remote control provided with the miniDSP Flex controls all
key runtime functions.
Standby
Put the miniDSP Flex into standby and take it out again.
Mute
Mute and unmute audio output.
Volume
Reduce or increase the volume. Each
press changes the volume by 0.5 dB. Holding down a button will
accelerate volume change to 3 dB steps.
Media control
Have no effect
with the Flex.
Dirac Live
Has no effect with the Flex.
Source selection
Cycle through the available input sources in order: TOSLINK, SPDIF (coax), USB, Bluetooth, Analog.
Preset (1 through 4)
Switch to the selected preset. It will take a few seconds for the
preset selection to complete while the processor loads the new filters from
its flash memory into the DSP.
The miniDSP Flex can be used with a Logitech®️ Harmony®️ remote. The
same functions as the stock remote are programmed into the Harmony
database. In addition, you can set up buttons for direct input source
selection (instead of cycling through input sources).
The procedure is as described in the application note linked below,
except that you should select "minidsp flex" as the device instead of
"shd".
With the addition of a miniDSP
Wi-DG Wi-Fi to USB
bridge, the miniDSP Flex can be remote-controlled from a phone or tablet
running Android or iOS (iPhone/iPad).
Note that currently the miniDSP Control App cannot be used over the
Bluetooth connection. It will work only if a Wi-DG is connected to the
USB port of the miniDSP Flex.
Warning
If the USB port is being used for iOS/Android app control via the Wi-DG,
it cannot be used for USB Audio streaming.
The diagram below is a simplified representation of the signal flow
through the miniDSP Flex (without Dirac Live):
Signal flow of the miniDSP Flex (without Dirac Live)
The audio signal flows from left to right in the above diagram:
One of the five stereo input sources is selected by the user. Volume
control is applied before any further processing.
The selected stereo input signal is passed through the input channel
processing blocks: level metering, input gain, and parametric EQ.
The processed input channels are fed into a
2-in 4-out routing
matrix that routes/mixes the two processed input channels to the
four output channels.
Each output channel runs a comprehensive set of DSP functions:
parametric EQ, crossovers, FIR filtering, level metering, delay, output gain and compressor.
The combination of the routing matrix and the crossover blocks on the
output channels is what gives the miniDSP Flex the ability to be used in many
different system configurations.
Each input channel has a customizable label displayed at the top of the
channel strip. To change
the label, click on it, type a new label (up to 12 characters), and
press the Enter key.
Displays the current signal level in real time, after volume control and channel gain have been applied. (For example, if the
actual input signal level is -10 dB, the volume setting is -20 dB and the channel gain is 0 dB, the meter will show -30 dB.)
Info
The Flex must be connected and online
to display signal levels.
The gain of each input channel can be set to a value between ‑72 dB and
+12 dB. (0 dB, the default, is unity gain or no change in level.)
To set the gain, click on the Gain value of that channel.
The gain can
be entered by moving the slider or it can be entered numerically. The up and down arrows
can be used to change
the gain in 0.1 dB increments.
Click on this button to open the parametric EQ settings window for that input
channel. There are ten parametric EQ filters on each input channel.
See Parametric EQ.
Each input channel can be sent, or routed, to any number of output channels.
This is accomplished with the routing buttons at the top of the
output channel strips:
In addition to routing, the miniDSP Flex supports mixing, where
input channels can be mixed at different levels to a single output channel. The complete
set of routing controls along the top of the output channel strips is therefore also called
the "matrix mixer."
To mix both input channels to an output, select both of them:
By default, each input channel is mixed at "full strength" – that is, without any attenuation, as
indicated by the "0 dB" label. To mix at different levels, click on the level button and either use the slider
or enter the desired value directly. The gain of the signal being mixed can be
set to a value between -72 and +12 dB.
In this example, both channels are mixed at half level (-6 dB):
This section illustrates a few examples of signal routing. The input and output channels have been
renamed by typing in the labels at the top of the channel strips. We recommend you do the same to
help avoid errors.
The diagram below shows the connections for a stereo pair of speakers plus a single
subwoofer. This is the simplest type of active system, so is a good introduction to the
advanced features of the miniDSP Flex. It is also known as a "2.1" system.
The stereo amplifier is connected to outputs 1 and 2, and the subwoofer is
connected to output 3. In the diagram, it's a powered subwoofer. (Never connect
an output of the Flex directly to a subwoofer driver or speaker.)
Typical connections for subwoofer integration with the miniDSP Flex
The routing for this system is:
The left and right inputs are sent to outputs 1 and 2. Both inputs are summed and sent to output 3.
Outputs 1 and 2 will usually have a high pass crossover filter to remove the sub frequencies, and output
3 will have a low pass crossover filter.
The diagram below shows the connections for a two-way active
speaker. Amplification can be either a multichannel amplifier, or a pair of stereo amplifiers.
Typical connections for a two-way active speaker using the miniDSP Flex
The routing for this system is:
The left input is routed to outputs 1 and 3, and the right input is routed to outputs 2 and 4.
Each output channel will need a low pass filter for the woofers or a high pass filter for the
tweeter.
Click on this button to open the parametric EQ settings window for that output
channel. There are 10 parametric EQ filters on each input channel.
See Parametric EQ.
A delay of up to 80 ms
can be applied to each output channel. To set the
delay, click on the delay button for a channel. The delay value can
be entered by moving the slider or it can be entered numerically. The up and down arrows can be used to change
the delay in 0.01 ms increments.
The gain of each output channel can be set to a value between ‑72 dB and
+12 dB. (0 dB, the default, is unity gain or no change in level.)
To set the gain, click on the Gain value of that channel.
The gain can
be entered by moving the slider or it can be entered numerically. The up and down arrows
can be used to change
the gain in 0.1 dB increments.
Parametric equalization (PEQ)
is a flexible type of
equalization filter.
It can be used to correct for errors in loudspeaker
output, to compensate for acoustic room effects, and to tailor the
overall system response for best sound.
Click on the PEQ button to open
the parametric equalizer settings window:
The miniDSP Flex has
10 parametric EQ filters on each input and output channel.
The graph displays the response of each filter in a light color and the
combined response of all
enabled filters as a heavy line. For example, the
curve shown above has a low-shelf boost at 100 Hz, a dip at 500 Hz, and a
high-shelf cut at 5000 Hz.
Change the frequency and gain of each filter by clicking and dragging on the drag-points
(colored circles) on the graph. The full set of parameters can be edited as described below.
Hovering the mouse over any curve brings up an overlay showing the
frequency and the gain at that frequency.
The parametric EQ filters can be set in either basic mode or advanced mode. Basic mode allows
each filter to be specified simply by providing four parameters, while advanced mode requires
the use of a separate design program.
For PEAK filters, this is the center frequency of
the peak or dip. For HIGH_SHELF and LOW_SHELF filters, this is
the frequency at which the gain is half of the set value.
For ALL_PASS
filters, this is the center frequency of the phase shift.
For PEAK filters, this is the gain in dB at the
center frequency. For HIGH_SHELF and LOW_SHELF filters, this is
the gain in dB reached at high or low frequencies respectively. A filter
has no effect if its gain is set to 0 dB. Gain can be adjusted in
increments of 0.1 dB up to +/- 16 dB.
This item is not present for the ALL_PASS
filter type.
Q controls the "sharpness" of the filter. For
PEAK filters, lower Q gives a broader peak or dip, while higher Q gives a
narrower peak or dip. For HIGH_SHELF and LOW_SHELF filters, Q
controls how quickly the filter transitions from no gain to maximum gain.
For
ALL_PASS filters, higher Q gives a steeper phase transition.
Except for filter type, parameters can be edited by:
Clicking and dragging on a slider. Once the focus is on a slider,
you can also change the value with the left and right arrow keys on the keyboard.
Clicking in the value field and typing a new value. Once the focus is in a value field,
you can also change the value with the up and down arrow keys on the keyboard.
Move the mouse cursor over the parameter and use the mouse scroll wheel or equivalent gesture on a trackpad.
The Tab key will move focus between fields; Shift-Tab will move in the opposite direction.
To jump quickly between the parametric EQ window of different channels, enable the
Menu switch at the top right. Jump to a different channel by clicking on the
row of buttons:
Each
channel can be linked to one other channel. When a channel is linked to
another, the PEQ settings of that channel are mirrored to the other.
Typically, corresponding channels on the left and right are linked: for
example, left and right tweeter and left and right woofer.
To link a
channel, enable the
Menu switch at the top right. Click on the channel that you want to link the current channel to.
After confirming, an indicator appears to show the new link:
Info
A channel can be linked to only one other channel. That is, you cannot link three or more channels.
To reset all parametric EQ bands of the current channel to the default settings, enable the
Menu switch at the top right and click the RESET TO DEFAULT button:
Warning
This operation is not reversible, so be sure you mean to reset all bands! Save your settings
to a file first if you need to keep any.
Advanced mode enables custom biquad programming for
almost infinite flexibility in filter implementation.
In this mode, each individual filter
to be specified by its biquad coefficients. The coefficients must be generated by a design program
such as Room EQ
Wizard (REW). The design program must be set
for a 96 kHz sample rate.
Each parametric EQ filter can be individually switched to advanced mode. Paste in the
coefficients in the format shown and click on the PROCESS AND APPLY button for them to take effect.
Click the RESET button to set the coefficients back to their default values.
Info
Switching between basic and advanced mode does not convert between Frequency/Gain/Q and biquad
parameters.
The basic parameters and advanced biquad coefficients for each filter are
stored independently and the selected set is used for processing.
To load the file, select the Menu switch at the top right and click the LOAD BIQUADS FILE button.
The filters are set to advanced mode starting at EQ1.
If the loaded file contains fewer than 10 biquads, then only that number of
EQ filters will be set to Advanced mode. For example, if loading a file with six biquads, EQ1 to EQ6 will be set to
Advanced mode, and EQ7 to EQ10 will not be changed. This can be used to good effect in cases
where manually-set parametric EQ (in Basic mode) is required in addition to parametric EQ developed
with a design program.
If the loaded file contains more than 10 biquads, then only the first
10 will be loaded.
The community-developed biquad calculation spreadsheet allows many
filter types to be calculated, including notch filters, Linkwitz
transforms, and filters with arbitrary Q-factor. Access this spreadsheet
here (requires Microsoft Excel):
Room EQ Wizard is a free acoustic measurement and analysis tool,
available for Windows, Mac and Linux platforms. It includes the ability
to automatically generate a bank of parametric EQ biquads based on a
measurement. These coefficients can be saved to a file from REW and
loaded using the Device Console. Room EQ Wizard can
be downloaded from:
Crossovers "split" the frequency band to send to different drivers. In a
two-way loudspeaker, for example, a low pass filter is used to remove high
frequencies from the signal sent to the woofer, and a high pass filter
is used to remove low frequencies from the signal sent to the tweeter.
When integrating a subwoofer, high pass filters are used on the speakers
and a low pass filter on the subwoofer.
Crossover filters can also be
used to limit low frequency content delivered to a speaker or subwoofer,
to help protect it from over-excursion.
Unlike conventional analog crossovers, the flexibility of DSP allows a
completely arbitrary mix of different filter slopes and types. Filters
can be set at any frequency or disabled completely. This allows maximum
flexibility in matching your crossover to the acoustic characteristics
of the loudspeaker drivers.
Each output channel has independent high
pass and low pass crossover filters. Click on the CROSSOVER button to
open the crossover settings window:
The current channel is displayed in orange, with the others displayed in
grey. Hovering the mouse over the curve brings up an overlay showing the
frequency and the attenuation at that frequency.
The crossovers on each output channel can be set in either basic mode or advanced mode. Basic mode allows
each crossover filter to be specified simply by providing two parameters, while advanced mode requires
the use of a separate design program.
In basic mode, there are two crossover filters on each output channel: high pass
(removes low frequencies) and low pass (removes high frequencies). In basic mode, these two
filters are completely independent and each has its own settings.
Sets the nominal cutoff frequency of the crossover. In actual fact, the
crossover has a more or less gradual transition from "full on" to "full
off," as determined by the filter slope.
Selects the type and slope of the filter. The steeper the slope, the
more quickly frequencies above or below the cutoff frequency are
attenuated. There are three types of filter:
Butterworth (BW)
Available in 6, 12, 18, 24, 30, 36, 42, and 48 dB/octave, Butterworth
crossover filters are 3 dB down at the cutoff frequency.
Linkwitz-Riley (LR)
Available in 12, 24, and 48 dB/octave, Linkwitz-Riley crossover
filters are 6 dB down at the cutoff frequency.
Bessel
Available in 12 dB/octave only, a Bessel filter gives a more gradual
roll-off through the crossover region.
Except for filter type, parameters can be edited by:
Clicking and dragging on a slider. Once the focus is in a value field,
you can also change the value with the left and right arrow keys on the keyboard, or by
using the mouse scroll wheel or equivalent gesture on a trackpad.
Clicking in the value field and typing a new value. Once the focus is in a value field,
you can also change the value with the up and down arrow keys on the keyboard, or by
using the mouse scroll wheel or equivalent gesture on a trackpad.
If the focus is on the Enable button, it can be toggled with the Space key.
Move the mouse cursor over the parameter and use the mouse scroll wheel or equivalent gesture on a trackpad.
The Tab key will move focus between fields; Shift-Tab will move in the opposite direction.
To jump quickly between the crossover window of different channels, enable the
Menu switch at the top right. Jump to a different channel by clicking on the
row of buttons:
Each
channel can be linked to one other channel. When a channel is linked to
another, the crossover settings of that channel are mirrored to the other.
Typically, the corresponding
drivers on the left and right channels are linked: left and right
tweeter, left and right woofer, and so on.
To link a
channel, enable the
Menu switch at the top right. Click on the channel that you want to link the current channel to.
After confirming, an indicator appears to show the new link:
Info
A channel can be linked to only one other channel. That is, you cannot link three or more channels.
By default, the crossover graph shows the crossovers of all four output channels.
The current channel is displayed in orange and the others in black.
If you wish to view only a subset of channels, use the switches to the right of the graph to select
channels to hide. In this example,
channel 2 is the current channel. Channels 1 to 3 are visible, while channels 4 to 8 are hidden:
The crossover settings of channels 1, 2 and 3 can be changed by using the channel selection buttons at the top of the window
to jump between them. As long as you stay on these channels, the set of hidden channels stays the same.
However, if you switch to a hidden channel, that channel then becomes visible. (For example, if you switch
to channel 6, then channels 1, 2, 3 and 6 will be visible.)
The crossover block on each output channel has eight biquads. In Basic mode, four are allocated
to the high pass filter and four to the low pass filter. In Advanced mode, however, the eight biquads
are all specified by their coefficients, in the following format:
These biquads can be used for almost
infinite flexibility (within the limits of eight biquads). For example, you could use two biquads
for a fourth-order high pass filter, and the remaining six for parametric EQ.
Paste the coefficients into the text box, then click on the
PROCESS AND APPLY button for them to take effect.
Info
Switching between basic and advanced mode does not convert between Frequency/Filter type and biquad
parameters.
The basic parameters and advanced biquad coefficients for each filter are
stored independently and the selected set is used for processing.
The community-developed biquad calculation spreadsheet allows many
filter types to be calculated, including notch filters, Linkwitz
transforms, and filters with arbitrary Q-factor. Access this spreadsheet
here (requires Microsoft Excel):
Room EQ Wizard is a free acoustic measurement and analysis tool,
available for Windows, Mac and Linux platforms. It includes the ability
to automatically generate a bank of parametric EQ biquads based on a
measurement. These coefficients can be saved to a file from REW and
loaded using the Device Console. Room EQ Wizard can
be downloaded from:
FIR filtering is a powerful and advanced feature . It allows construction of complex arbitrary
equalization and crossover filters with independent control of amplitude
and phase.
FIR ("finite impulse response") filtering differs from the IIR
("infinite impulse response") filters used in the PEQ and crossover
blocks. Technically speaking, IIR filters are recursive, meaning that
each output value is partially calculated from earlier output values as
well as from input values. While an IIR filter requires only a fairly
small of values to be specified, an FIR filter is specified by a large
array of numbers.
FIR filtering allows very complex filters to
be constructed, with the aid of suitable design software. These filters
can correct for amplitude only ("linear phase filters"), phase only,
or a combination or both.
These numbers are conventionally referred
to as "taps." The miniDSP Flex can compute a total of 4096 taps.
Taps are allocated to each block according to the number of loaded taps.
The miniDSP Flex can compute a total of 4096 taps. These
can be distributed as you wish across the
four output channels,
with the limitation that each channel must have 6 or more taps
and can have no more than 2048 taps.
The decision on how many taps to
allocate to each channel is up to you and should be determined after
working with an FIR filter design program.
To load coefficients, click Browse, navigate to the file containing the filter
coefficients, and open it. The first few coefficients will be displayed and the buttons
will change:
The displayed graph will also change to reflect the response of the loaded file.
To jump quickly between the FIR filter window of different channels, enable the
Menu switch at the top right. Jump to a different
channel by clicking on the channel buttons:
The filter coefficients must be created with the aid of filter design
software. miniDSP does not provide any such software, instead referring
you to the many software packages available for this purpose (both
freeware and commercial). Please see the FIR filter
tools
page on our website. The design program must be set
for a 96 kHz sample rate.
If, after selecting a filter file or
setting coefficients, the frequency response graph does not change as
expected, make sure that the Enable FIR switch is turned on.
Tip
If you zero all* filter taps, make sure
that you also disable the the filter, otherwise there will be no audio
through that channel.
The compressor reduces the gain of an output channel when the audio
signal reaches the level specified by the Threshold parameter. The
gain of the channel will be progressively reduced as the signal
increases above the threshold, according to the Ratio parameter.
This can be used to limit the power delivered to speakers and thus
reduce the risk of damage from overdriving.
This
screenshot shows an example Compressor setting:
(Note that the compressor algorithm is bypassed by default, so click on
the Bypass button to see the curve as shown here.)
In this example, the threshold is set to −20 dB, so the compressor will
activate when the signal on that channel reaches −20 dB (relative to
full output). The ratio is set to 2, so if the input signal level to the
compressor then increases by 10 dB, the output level will increase by
only 5 dB. If the input signal level to the compressor is at full scale
(0 dB), then the output level will be limited to −10 dB.
Two additional parameters control the action of the compressor: the
attack time and the release time. These two parameters govern how
quickly the compressor activates when the signal level exceeds the
threshold, and how quickly it deactivates when the signal level reduces.
The optimum settings may need to be tuned by ear. For more information,
see the Wikipedia article Dynamic range
compression.
The compressor block is disabled by default. To enable it, click on the Enable Compressor
switch. The graph will change from a dashed grey line (disabled) to a solid colored line (enabled).
Clicking and dragging on a slider. Once the focus is on a slider,
you can also change the value with the left and right arrow keys on the keyboard.
Clicking in the value field and typing a new value. Once the focus is in a value field,
you can also change the value with the up and down arrow keys on the keyboard.
Move the mouse cursor over the parameter and use the mouse scroll wheel or equivalent gesture on a trackpad.
The Tab key will move focus between fields; Shift-Tab will move in the opposite direction.
To jump quickly between the compressor window of different channels, enable the
Menu switch at the top right. Jump to a different channel by clicking on the
row of buttons:
If you have used the older "plugin" software with your miniDSP Flex, you will need to
perform a one-time migration procedure to use it with miniDSP Device Console.
Follow the procedure described below. Please be sure to perform all
steps in order.
Tip
If you are having trouble using your device with Device Console, we recommend
that you start
again from step 1 and make sure that every step is done in order.
1. Check that you have the latest version of Device Console¶
Start miniDSP Device Console. Go to the Settings page and click on CHECK NOW:
If a newer version of Device Console is available, you will see a popup offering to
download and update to the latest version. Click YES.
In the Settings page of Device Console, click on Install USB Audio Driver:
Device Console will confirm that you want to install the driver.
Click on the PROCEED button.
Info
You may already have the latest version of the driver installed. However, we recommend that you always
reinstall when migrating to DC, to ensure that this is the case.
Connect your Flex to your computer and power it on.
It will appear on the Discover Devices page
of Device Console. Click on it.
If the Flex needs a DSP Firmware update, this window will appear:
If this message appears, click on Update Now. (If it does not appear, you do not need a
firmware upgrade and can jump straight to the next step.)
After the firmware update completes, the Flex will restart.
Tip
In some cases, the Flex will not restart properly. If you experience odd symptoms, such as Device Console not returning to the Discover Devices page, the
Flex not appearing on the Discover Devices page, or the DSP Firmware update screen appearing again,
power cycle the Flex and restart Device Console.
Locate your Flex on the Discover Devices page. Click on
it. You will see a message like this:
(If you do not see this message, you do not need to upgrade the firmware and you can skip ahead to the next step.)
Click on the Download button to download the Migration pack containing all necessary files.
Alternatively, you can download it at any time by clicking on this link:
After downloading, if your browser did not automatically unzip the downloaded file, unzip it manually
by double-clicking on it (macOS) or right-click on it and select "Extract All" (Windows).
The firmware in your Flex must be upgraded for it to work properly
with Device Console. This is a one-time operation that must be performed with the
firmware upgrade utility contained in the Migration Pack.
Check that the Flex is connected to your computer via USB
and that it is powered on.
Start the firmware upgrade program.
For Windows, navigate to:
XMOS Firmware ⟩ Firmware_Upgrade_Tools ⟩ Windows ⟩ miniDSPUAC2Dfu
Double-click on the miniDSPUAC2Dfu.exe program to run it.
For macOS, navigate to:
XMOS Firmware ⟩ Firmware_Upgrade_Tools ⟩ Mac
Double-click on the miniDSP USB DFU.app program to run it.
The firmware update utility will start:
Click on Browse and select the firmware file from the XMOS_Firmware folder of the migration pack. It will have a name like "miniDSP_Flex_XMOS_v1.59_up.bin." (The version number embedded in the file name may change.)
Warning
Do not proceed if you cannot locate the correct firmware file. The name of the firmware file must begin with "miniDSP_Flex_XMOS" or you could damage your Flex.
Click on the Start button.
You will see a progress bar as the upgrade proceeds.
Warning
DO NOT DISCONNECT THE USB CABLE OR POWER FROM THE Flex WHILE FIRMWARE UPGRADE IS IN PROGRESS. DOING SO MAY “BRICK” YOUR Flex.
Once the firmware upgrade completes, you will see a message that the upgrade completed successfully.
Click on Exit.
Now that your Flex firmware has been updated to a version that is compatible with
Device Console, future firmware upgrades can be done directly from within Device Console.
Presets that were previously loaded into the Flex using the miniDSP 2x4 plugin will
automatically be imported into Device Console.
If no existing presets are found, you will be prompted to initialize the presets to defaults when you
connect to the Flex. In that case, click on Initialize to default settings.
If you get no sound while playing music, double-check the following
items. Depending on the specific processor, you may be able to do this
with the aid of the level meters in the miniDSP Device Console.
Check which input source you have selected.
Check the connection and cabling between the source(s) and the
processor.
Check the master volume setting.
Check that the processor is not muted.
Check your Routing and make sure that you are routing inputs through
to outputs.
If your processor has crossovers, check your crossover settings. (In
particular, some processors have a default high pass filter set at 1
kHz on some channels as a safety measure for 2-way active speakers.
If using these channels for subwoofers, the high pass filters must
be bypassed.)
Check that output cabling is connected to the correct connectors on
the rear panel and to the correct inputs on downstream equipment
(e.g. amplifiers).
Check that downstream equipment (e.g. amplifiers) is not muted,
turned down, or turned off.
If the soundstage width is very narrow, check that you have not summed
left and right input channels and routed the sum to left and right
speakers. This will result in a mono signal and hence a narrow
soundstage.
If the soundstage is "weird", check the routing and crossover settings
and make sure that left and right are consistent. If you are
implementing an active speaker, double-check all connections on the rear
panel.
a. The firmware versions obtained from the Display Versions button in miniDSP Device Console.
b. A clear explanation of the symptoms you are seeing.
c. A description of troubleshooting performed and your results.
d. (Recommended) For quickest resolution of your issue, include the current program snapshot.
This can be obtained from the Device Console Settings screen.
