Mobridge K2 MOST25 8.1.1 User manual

mObridge
K2 MOST25 8.1.1 Amplifier
Installation and User Guide

Page 1
Welcome 2
Disclaimer 3
Overview 4
Vehicle Compatibility 4
Kit Contents 4
Technical Specifications 5
Hardware Installation 6
System Layout 6
Installation Guide 6
Wiring Harness 6
mObridge DSP GUI 8
Firmware Update 8
Speaker Mapping 10
Wiring channels vs GUI channels mapping 11
Mono Inputs 12
Phone, Nav, PDC and Chime Gain Adjustments 13
Delay 13
Saving Setups & Presets 14

Page 2
Welcome
Dear Buyer,
Congratulations on your purchase of a mObridge K2 MOST25 8.1.1 Amplifier series. mObridge
prides itself on striving to develop and manufacture products to the highest engineering quality
standards and seamlessly integrating these products with factory audiovisual systems.
The mObridge K2 MOST25 8.1.1 Amplifier is one of the most advanced DSP aftermarket
amplifier integration interfaces available for MOST25 based vehicles and come with an easy to
use PC & Mac Graphical Interface for setting up and tuning the K2 MOST25 8.1.1 Amplifier
systems. This can be downloaded free from our www.mobridge.us website.
Features, depending on the K2 MOST25 8.1.1 Amplifier model include channel mapping to 9
amplifier channels and one RCA output channels, 1024 Point Parametric Graphic Equalizer for
each channel, as well as a ‘Master EQ’, Crossover Type and crossover points for each speaker,
crossover slope, individual speaker time alignment, phase adjustment, Q factor (Both left and
right), summing for subwoofers and centre channel upmixing. The user can also use the radio
controls to change preset settings in the K2 MOST25 8.1.1 Amplifier for different tuning profiles.
As with all mObridge products, we have included a USB port for USB upgrades of the software
allowing for new features to be added as they become available. The K2 MOST25 8.1.1
Amplifier series can be updated by simply loading the latest software from our website and
through the use of the DSP user interface.
The K2 MOST25 8.1.1 Amplifier series may also have system function upgrades available for
purchase and download from time to time. These will also be available on our website.
We hope you enjoy your new enhanced listening experience!
Kind regards,
mObridge

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Disclaimer
mObridge makes every effort to try and keep the support and installation documentation up to
date.
We do not reimburse or bear costs arising from installations should installation issues occur.
mObridge can be contacted via email and also via its worldwide distribution network. We
always recommend contacting the local distributor first, and although we endeavour to answer
emails we receive in a timely manner, due to time zone differences we may not be able to
respond immediately.
mObridge always recommends professional installation of these products as they are
technically complex, involving optical fiber across multiple vehicle configurations and software
versions within these vehicles.
In some cases, vehicles may require coding by specialist workshops and diagnostic equipment.
mObridge always recommends allocating a number of hours to any installation, just in case any
issues should arise.

Page 4
Overview
Vehicle Compatibility
The mObridge K2 MOST25 8.1.1 Amplifier series is compatible with specific BMW, Mercedes,
Audi, Porsche, Mini, Jaguar, Landrover, Toyota and Aston Martin vehicles. Please refer to the
website to see the complete compatibility list:
● K2 MOST25 8.1.1 Amplifier
Kit Contents
The mObridge K2 MOST25 8.1.1 Amplifier kit contains the following items:
● K2 MOST25 8.1.1 Amplifier
● Separate power and ground connection for more current capability
● MOST ‘T’ piece harness
● Female 2+0 MOST connector for harness extension
● Male 2+0 shell for harness extension
● K2 amp patch harness
● Mating half connector compatible with Porsche, Audi and Mercedes allowing the installer
to make a specific patch harness into the oem harness.
● Free software download from mObridge DSP PC Application (This is not provided in the
package contents)

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Technical Specifications
Hardware & Software Version
Current Hardware Version v3.0
Current Software Version V0.5.2

Page 6
Input
Digital Input MOST25 optical
Output
Low power channels 6x 175W @ 4ohms
High Power Channels 2x 300W @ 4ohms
Subwoofer channel (full range) 1x 500W @ 4ohms / 1000W @ 2ohms
Power Supply
Hardware Installation
System Layout
K2 MOST25 8.1.1 Amplifier
Installation Guide
Wiring Harness
1. For K2 MOST25 8.1.1 Amplifier installations, the installation process changes depending
on whether the vehicle has an amplifier, and also if it has MOST fiber optic presently
installed
a. For vehicles with a fiber amplifier, the factory amplifier must be removed and the
K2 MOST25 8.1.1 Amplifier unit can be installed in its place. Connect the OEM
fiber previously connected to the amp, directly into the K2 MOST25 8.1.1
Amplifier unit.
b. For vehicles without an OEM amplifier or MOST fiber, use the supplied optic
extension and connect from the fiber port behind the radio to the MOST fiber port
on the K2 MOST25 8.1.1 Amplifier.
c. For vehicles without an OEM amplifier but still equipped with MOST fiber,
disconnect the fiber from the radio and connect it to the supplied ‘T’ piece
harness. Connect one side of the ‘T’ piece harness to the K2 MOST25 8.1.1
Amplifier and then connect the remaining plug back to the radio unit to add the
K2 MOST25 8.1.1 Amplifier to the MOST loop.

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*NOTE: with options (b) and (c), you must reprogram the system to use the external
amplifier for the K2 MOST25 8.1.1 Amplifier to operate properly. Use the mObridge MOST25
OBD programmer to reprogram the system.
2. The Kit comes with a pigtail harness from the amplifier so that the installer can either
wire this directly into the wiring system of the vehicle or we provide a mating half
connector allowing the installer to make a patch harness into the factory system. The
mating half will fit Mercedes, Porsche and Audi vehicles. For BMW we are presently
working on a plug and play solution for this as well as all other cars.
3. It is not critical to match the speaker wiring speaker for speaker to the vehicle as the
mObridge DSP will perform channel mapping. We do recommend wiring the two high
power channels into larger speakers though.
4. The subwoofer channel is labelled on the wiring harness
5. The two higher power channels are labelled separately on the harness for easy
identification.
6. We also provide an extra power wiring harness as this amplifier is quite powerful. This
will allow more current into the amplifier on top of the patch cable power and ground. We
highly recommend using this extra power cable so that the amplifier does not suffer
voltage drops due to inductance in long run exiting vehicle power connections.
Wiring channels vs DSP GUI channels
Vehicle Phone Nav PDC Chimes Voice
BMW Sink 1 Sink 2 Sink 4 Sink 3 Sink 2 (same as
Nav)
Audi Sink 1 Sink 2 NA NA Sink 3
Porsche Sink 1 Sink 2 NA NA Sink 3
Mercedes Sink 1 Sink 2 NA NA Sink 3
Landrover Sink 2 Sink 2 (same as
Tel)
Sink 3 Sink 4 Sink 2 (same as Tel)
Jaguar Sink 2 Sink 2 (same as
Tel)
Sink 3 Sink 4 Sink 2 (same as Tel)

Page 8
mObridge DSP GUI
mObridge DSP is a complete Digital Signal Processor (DSP) graphical user interface (GUI) for
advanced in-vehicle audio tuning on the K2 MOST25 8.1.1 Amplifier unit. It can be used to
harness the full DSP capabilities of your mObridge device, and to perform firmware updates
easily thanks to automated online updates.
mObridge DSP can be downloaded from our website, and is available for Windows and macOS
desktop operating systems.
Some of mObridge DSP’s features include:
● Input/output channel mapping
● 1024-point master and channel parametric equalizer
● Time alignment
● Crossover link emulation
● Phase inversion
● Mono input channel gain and delay adjustment
● Channel muting
● Advanced channel filtering algorithms, including:
○ Butterworth, Bessel, Chebychev, and Linkwitz-Riley filter designs
○ Low-pass, high-pass, and band-pass filters
● Centre channel upmixing
● Automatic online firmware updater
Please note, not all features mentioned above are available to every mObridge device.
For more detailed information regarding mObridge DSP, see the “mObridge DSP
Manual”.
The mObridge DSP tuning interface can be used in both ‘Live’ and ‘Offline’ modes. Offline mode
allows you to configure various settings with your mObridge device disconnected, and then
store them for later fine-tuning in the car if desired.
We recommend that all tuning be done with a ‘Live’ system because this way you can hear all
changes being made in real-time. Graphic EQ, crossover, and time alignment changes can all
be heard as you make the changes when ‘Live’.
You can connect to the K2 MOST25 8.1.1 Amplifier via the provided USB port.
Firmware Update
mObridge DSP can be used to install the latest K2 MOST25 8.1.1 Amplifier firmware. mObridge
DSP can perform firmware updates either using the automatic online updater, or you can
manually download the latest firmware for an offline update here:
● K2 MOST25 8.1.1 Amplifier

Page 9
The mObridge K2 MOST25 8.1.1 Amplifier unit will need to be connected in the car, and
powered up for the unit to be able to be updated. Once it has connected to mObridge DSP, the
user will be presented with the following screen:
Figure XX - K2 MOST25 8.1.1 Amplifier is connected to the DSP GUI
Once the K2 MOST25 8.1.1 Amplifier is connected, simply click on the ‘Connected” button in the
top right-hand corner. This will display the Device tab as seen below.

Page 10
Figure XX - Update Page
If performing an online update, make sure the ‘Check Online for Updates’ option is ticked and
then press the ‘Firmware Update’ button. This will automatically check for the latest software
update for the connected device and begin the upgrade process.
If performing an offline update, make sure the ‘Check Online for Updates’ option is unticked and
then press the ‘Firmware Update’ button. This will open a window where you can select the new
K2 MOST25 8.1.1 Amplifier firmware file to update to and the update procedure will begin.
Once the update has completed, the K2 MOST25 8.1.1 Amplifier unit will restart. Sometimes it
is a good idea to let the car sleep after the firmware upgrade as some MOST systems do not
like ECU’s resetting on the MOST bus.
Speaker Mapping
Once the K2 MOST25 8.1.1 Amplifier unit is connected to the mObridge DSP application, you
will see the below screen.

Page 11
Figure XX - Configuration Page
The Configuration tab will allow you to configure the channels for the correct mapping of your
particular system.
First select a speaker from the image of the vehicle in the top left corner, then select an output
mapping from the drop-down menu in the middle of the screen to select the channel output you
have connected for that particular speaker. Repeat this for each speaker and its corresponding
output channel.
When running a component speaker system with a passive crossover, only select one of the
speakers in the cluster. It is not important which speaker is chosen, as this is only the mapping
stage. Crossover settings will allow for correct settings for this type of speaker system.
Next, you will need to allocate the appropriate input mappings to each speaker. For each
speaker, simply select the speaker image in the top left corner, and then click the appropriate
‘Input Mapping’ options for each speaker. If multiple input mappings are selected, these sources
will be combined and summed.
Wiring channels vs GUI channels mapping

Page 12
GUI Amplifier
Channel 1 500W
Channel 2 175W
Channel 3 175W
Channel 4 175W
Channel 5 175W
Channel 6 300W
Channel 7 300W
Channel 8 175W
Channel 9 175W
Channel 10 4V Preout
Mono Inputs
After mapping your speakers, you can then adjust the mono input gains and delay using the
“Mono Inputs” panel which will be displayed on the right-hand side of the configuration tab.
Figure XX - Mono Input adjustments

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Phone, Nav, PDC and Chime Gain Adjustments
This can be used to independently adjust the gains of the input sinks such as phone, navigation,
PDC, and chimes. Each manufacturer has different configurations for their mono inputs so
please reference the table below when adjusting your phone, nav, pdc or chime gains.
Vehicle Phone Nav PDC Chimes Voice
BMW Sink 1 Sink 2 Sink 4 Sink 3 Sink 2 (same as
Nav)
Audi Sink 1 Sink 2 NA NA Sink 3
Porsche Sink 1 Sink 2 NA NA Sink 3
Mercedes Sink 1 Sink 2 NA NA Sink 3
Landrover Sink 2 Sink 2 (same as
Tel)
Sink 3 Sink 4 Sink 2 (same as Tel)
Jaguar Sink 2 Sink 2 (same as
Tel)
Sink 3 Sink 4 Sink 2 (same as Tel)
Aston
Martin
Sink 1 Sink 2 Sink 3 Sink 4 Sink 2 (same as
Nav)
Toyota Sink 1 Sink 2 Sink 4 Sink 3 Sink 2 (same as
Nav)
Mini Sink 1 Sink 2 Sink 4 Sink 3 Sink 2 (same as
Nav)
Delay
The delay slider can be used to fine-tune the mono input processing delays in your mObridge
device. This can help alleviate echo issues in certain vehicles while using your mObridge device
to play audio on phone calls. The delay will be active on all mono inputs.

Page 14
Saving Setups & Presets
The K2 MOST25 8.1.1 Amplifier will automatically save setups upon shutdown of the MOST
system. This needs to happen ‘gracefully’ - meaning that the user cannot just pull power from
the unit, as this will not work.
The K2 MOST25 8.1.1 Amplifier has four different presets and these can be tuned individually.
The channel mapping is consistent across all four presets. These can be selected with the drop-
down menu in the top right corner as shown below.
Figure XX - Saving tuned settings
You can save a backup of all of your presets by simply selecting ‘File->Save As’’ on the top
menu bar as shown in the above screen. This will save a backup (.rax file) of your setup across
all four presets. This file can be used to load in saved settings later on.
It is also possible to select these presets using specific commands in the head-unit of your
vehicle. This varies depending on your vehicle make, and head-unit system. Please check the
support documentation on the mObridge website to find the vehicle-specific instructions.
● K2 MOST25 8.1.1 Amplifier
If there are no vehicle-specific instructions for your vehicle make, the preset can generally be
changed using the Logic7 Surround controls as shown in the images below.

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Figure XX - Using L7 Surround Mode to change presets
Figure XX - Using Professional Radio Surround Modes to change presets