MARTIN AUDIO iK81 Advanced 4 Channel Power Amplifier User Guide

Recalling Components
To recall a Component Preset (to a single output), press the

button, then use the down <> button navigate to the RECL Preset page. Using the encoder, “A” will scroll through the component presets available (as indicated by the ModulePreset.Component number and ModulePreset.Component name). When the desired component is reached, pressing will flash the Enter button. Pressing again will then recall the component preset. Note that component presets do not contain and do not disturb parameter Overlays. (See Overlays)

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See also Snapshots.
Input
AES3 Inputs
In addition to the usual analogue inputs, the Device can also accept AES3 digital inputs. When a DSP input channel is assigned to an AES3 channel, the “AES3” indicator will illuminate.
There is no standard’ for the relative gains between Analogue and AES3 so depending on the levels delivered by the audio source, it may be necessary to adjust the digital input gain trims to normalise them. It is possible to adjust the gain of the AES3 input using the Input Trim AES3 Gain parameter. For example, to achieve 0dBFS = +18dBu, set the AES3 trim to -2dB. To achieve 0dBFS = +24dBu, set the trim to +4dB. This device will automatically lock onto any sample rate within the range 28kHz and 108kHz. DanteTM Inputs Using the Dante input, it is possible to select any channel(s) as being sourced from this network. To do this, connect the audio network connection to the connection on the rear of the Device, and set the relevant Input Type menu Type parameter to “Dante”. When the Dante has been selected as part of the input routing, the “Dante” indicator above the encoders will illuminate. This indicator will come on even if there are no cables plugged into the networked audio port on the Device. As for the AES3 inputs, it is possible to set the relative gain between an Analogue input and the signals sourced from the Dante using the Input Trim Dante gain parameter. The amplifier will automatically select the correct sample rate from the incoming stream. For other details on the operation of the Dante, please refer to the relevant manufacturer’s documentation. Automatic Input Selection (Fallover) It is possible to configure the input selection to be automated. The Input TYPE screen has a Fallover parameter, which defaults to Manual, allowing you to select what Type of input you wish to use. When Fallover AES3>Analogue is selected (on an input channel which supports AES3), then the AES3 source will be automatically selected if it has a valid audio stream on it. If the AES3 stream should fail, then Analogue is automatically selected instead. When Fallover Dante>Analogue is selected (when the Dante option is fitted), then the Dante source will be automatically selected if it has a valid audio stream on it. If the Dante stream should fail, then Analogue is automatically selected instead. Similarly, it is possible to select Fallover Dante>AES3 on a channel that supports AES3 and Dante is present. TheAuto’ setting allows the highest priority input source that is active to be automatically selected, so the user could just plug a source into any input and it will be automatically selected. The priorities are: Dante first, AES3 second, Analogue third.
Note that any automatic selection will take precedence over manual selection, so if you try to manually select Dante when there is no valid Dante stream, then it will revert to the Fallover input source.
Gain and Polarity
The gain page of the input channel selected allows users to increase or decrease the amount of signal going into the selected input. Using the “SELECT” encoder to highlight the Gain value allows the value to be changed by the “ADJUST encoder in 0.2dB

USER GUIDE

steps from -40dB to +20dB. The presence of an active Group Overlay parameter is indicated by the []’ symbol (See Overlays). This page will also allow users to change the polarity of the selected input from normal to reverse and to mute the selected channel. Delay The delay page which controls the amount of delay associated with the input channel selected and is adjustable from 0 to 998ms. The delay parameter is adjustable in fine steps at low values; the adjustment becomes progressively coarser as the value increases. The presence of an active Group Overlay parameter is indicated by the[]’ symbol. See Overlays.
High Pass Filter
System high pass filtering is provided for the input signal. Filter type is selectable from 1st order, Butterworth, Bessel, Linkwitz- Riley and Hardman. Filter slopes of up to 4th order or 24dB / octave are provided. Not all filter types are available in all slopes. For example 18dB / octave Linkwitz-Riley filters do not exist.
The Hardman type filter is always described by its order as the filter becomes progressively steeper rather than following a linear slope so a dB/octave description is not accurate.
Parametric Equalisation
There are nine stages of equalisation available for each input channel, three shelving filters and six parametric filters.
FIR Shelving EQ
The Input High Shelf EQ is implemented using a Finite Impulse Response (FIR) filter, and exhibits a linear phase response; that is all frequencies are delayed by the same amount. This can be important in applications where different amounts of EQ are applied to different parts of a speaker cluster, such as to add ‘Throw’ EQ boost so that parts of cluster which are throwing further can have HF absorption correction added. If this EQ is not linear phase, then the zones where the speakers combine may suffer frequency response anomalies. Being a linear phase FIR equaliser, this necessarily introduces some latency delay, which is constant regardless of the settings. However, when the Enable’ parameter is set to “Off”, it is removed from the signal path entirely, so it does not add any latency. In this page you can change the frequency parameter from 2kHz to 20kHz, enable/disable the filter, and change the cut or boost in 0.2dB increments. The presence of an active Group Overlay parameter is indicated by the[]’ symbol being appended to the Gain value (See Overlays). The filter (and its associated latency) can be completely removed by setting the enable parameter to the “Off” position. Note that this EQ can only be used in Module Groups if set to On’. See also Latency Delay. Parametric Filters Parametric filters are defined by frequency, bandwidth and gain. The frequency is adjustable over the range from 10Hz to 25.6kHz. The bandwidth shown as Width on the screen, ranges from 0.10 octaves to 5.2 octaves. Bandwidth can be shown and adjusted as Q or Octaves (Oct). Gain is adjusted in 0.2dB increments. The presence of an active Group Overlay parameter is indicated by the[]’ symbol being appended to the Gain value. (See Overlays).
See also Bandwidth Units in Utilities.
Routing
Routing allows users to route any physical analogue or digital signal channel to any DSP input. This is effectively a matrix mixing system where all DSPs can be driven from any one input, or from pairs of inputs “1+2”, “3+4”, “1+3”, “1+4”, “2+3” or “2+4”. Summed inputs have 6dB of attenuation so that a sum of largely similar programme material remains at the correct calibrated level.

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Output
Gain and Polarity
The gain page of the output channel allows users to increase or decrease the relative signal gain for the selected output. The Gain value may be adjusted in 0.2dB steps from -40dB to +20dB. This page will also allow users to change the polarity of the selected output from normal to reverse.
Delay
The delay page controls the amount of delay associated with the output channel selected and is adjustable from 0 to 998ms. The delay parameter is adjustable in fine steps at low values; the adjustment becomes progressively coarser as the value increases.
High and Low pass Filters
High pass and low pass crossover filtering is provided for the output signal. Filter type is selectable from 1st order, Butterworth, Bessel, Linkwitz-Riley, Hardman and LIR Linear Phase. Filter slopes of up to 8th order or 48dB / octave are provided. Not all filter types are available in all slopes. For example 18dB / octave Linkwitz-Riley filters cannot be selected because they do not exist.
The Hardman type filter is always described by its order as the filter becomes progressively steeper rather than following a linear slope so a dB/octave description is not accurate.
LIR Crossover Filtering
Unique to Martin Audio, “Linear Impulse Response” (LIR) crossover filtering gives a Linear Phase crossover which has a constant delay regardless of frequency (unlike other types of crossover which delay different frequencies to a different extent, thus smearing the arrival time). The LIR crossover can thus be described as having a flat Group Delay response, and thus entirely free of Group Delay Distortion, this is exactly the same as can be provided by common FIR filtering but without the complications and disadvantages inherent with the FIR technique.
The shape of the LIR crossover filter is similar to a 4th order Linkwitz-Riley filter, and maintains zero phase difference between the adjacent bands across the crossover region to keep the polar response rock steady.
Note that very narrow bandwidths are not possible with this crossover type. If the Low Pass frequency is too close to the High Pass frequency, then the filter will mute’. Linear Phase filtering necessarily introduces delay; the laws of physics demand it. To keep this delay to a minimum, it is recommended that more conventional crossover shapes (such as Linkwitz-Riley) are used for the very lowest frequency high- pass edge, particularly if this is less than perhaps 100Hz, which is well below the frequency thought to cause audibleGroup Delay Distortion’.
This constant delay will depend on the lowest high-pass frequency used in the crossover filters in a given Drive Module.
See also the section on Latency Delays.
Parametric Equalisation and All-Pass Filters
There are ten different EQ filters; two shelving filters and eight parametric filters. Parametric filters are defined by frequency, bandwidth and gain. The frequency is controlled over the range from 10Hz to 25.6 kHz. The bandwidth, shown as Width on the screen, ranges from 0.10 octaves to 5.2 octaves. Bandwidth can be shown and adjusted as Quality Factor or (Q), or Octaves (Oct). Gain is adjustable in 0.2dB increments.
Any of the eight parametric filters can be used as All-Pass filters. When a filter is set to All-Pass mode, the Gain parameter value will show as “AllPass” on the display. This setting may only be engaged by right-clicking the EQ `icon’ in the EQ window of the Vu-Net panel.
See also Bandwidth Units in Utilities.
Limiters
The iK42/iK81 Series includes three limiters in the output signal path. Please note that whilst the Limiters in this product offer protection for amplifiers and drivers, they can never protect from all possible scenarios, therefore Martin Audio is not responsible for any damage which might occur.

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VX Limiter
This is a peak-detecting signal limiter. The VX Mode parameter determines the style of limiter. When Virtual Crossover (VX) mode is off, the limiter is controlled in a conventional manner; the only controls being Threshold and Overshoot.
The Overshoot limiter prevents the signal from exceeding threshold during the attack phase of the main limiter by more than a predetermined amount. The optimal Overshoot setting is usually about 8dB. Lower Overshoot settings will sound progressively harder’. When VX mode is engaged, the user can choose the crossover point of avirtual crossover’, which incorporates two limiters per output so the user can individually limit the drivers in a passive 2-way enclosure using individual thresholds, and optimised attack and release characteristics for each. The Threshold of the second Hi’ limiter is set relative to the threshold of the firstLo’ limiter.
This Limiter introduces some delay. In non-VX mode, this delay will depend on the lowest high-pass frequency used in the crossover filters in a given Drive Module. In VX mode, the delay is related to the Split frequency. This delay will be applied to all of the outputs in a given Drive Module to keep them in phase.
See also Latency Delays
Tmax Thermal Limiter
The Thermal Limiter is intended to protect the driver against damage due to over-heating. It models the temperature of the driver, and constrains the output signal level in order to keep the average output power below a predetermined limit, applying attack and release characteristics to go some way towards modelling the complex thermal circuit of a driver’s voice coil and magnet assembly.
Three parameters are available for adjustment:
Threshold ­ the continuous RMS voltage which the driver should be able to withstand. This is calibrated at the output of the amplifier. The Thermal Limiter can be defeated by setting the Threshold to the maximum “Off” value.
Attack ­ The time-constant of the speed at which the driver heats up (in seconds).
Release ­ The time-constant of the speed at which the driver cools down (expressed as a multiple of the Attack time).
Xmax Excursion Limiter
The Excursion Limiter protects the driver against excessive linear movement of the cone and voice-coil which could otherwise cause mechanical damage. Since this movement (excursion) is largely related to the inverse of the signal frequency, drivers are prone to being damaged by very low frequencies. This limiter is progressively more sensitive at lower frequencies and, rather than varying the gain to provide the limiting action, it uses a sliding high-pass filter to progressively curtail the low-frequency response, effectively limiting the linear excursion to below the X-max specification of the driver.
To set the limiter up, it is necessary to know the shape of the family of Excursion vs. Frequency curves of the driver for various drive voltage levels. A curve should then be chosen where the slope is high where it passes though the specified X-Max value for the driver. The peak voltage and frequency of this point should then be noted.
The Xmax limiter is usually then set up using just two parameters:
Threshold ­ the peak voltage of the point arrived at above. This is calibrated at the output of the amplifier. The Excursion Limiter can be defeated by setting Threshold to the maximum “Off” value.
Frequency ­ The frequency at which the above threshold voltage is appropriate.
A further parameter “Min” may also be available for more advanced applications. This allows the increasing limiting action at lower frequencies to level-off below a certain frequency. In most application, this would be left set to its default value of 5Hz.
Bridge
When an amplifier pair is set to Bridge Mode, it uses two amplifier channels to drive one loudspeaker with greater power. In this mode, only one set of Output controls is active per pair of amplifier channels since both of the amplifiers in the pair are driven with the same signals, as determined by the left-hand (lower numbered) channel of the pair controls. Bridge settings should be set up before recalling Drive Module Presets. Module Preset Recall will see a bridged pair of outputs as a single channel. Bridge Mode is enabled or disabled in the AMP page for a given odd numbered Output. When enabled, the Bridge indicator will be

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illuminated between the bridged channels. When Bridged, the partner (even numbered) channel will not show any signal on the limiter meter, and the Mute button will not operate, neither will you be able access any of its parameters for adjustment. The Amplifier protection indicator however will still operate.
Routing
Outputs can be driven from any DSP input. This routing is the fundamental means by which Drive Modules are created. Routing should always consume outputs consecutively alphabetically and numerically. However, non-consecutive Drive Modules may be created using manual routing and Recalling Components. See the drive module section of this user manual for more information.
Driver
The optimal drive level may be adjusted for a given driver impedance using the Load parameter. (See Load Matching). The live measured impedance value is also shown on the Driver page. Since the device can only measure this when there is a signal, the impedance is indicated as “?” when there is insufficient signal level to perform a measurement.

iK81 / iK42

USER GUIDE

Utility Pages
Screen Contrast
The Screen page in the “UTILITY” section adjusts the contrast (and optimal viewing angle) of the screen from 0-100% in 1% increments.
Stereo Linking
Stereo linking is available between DSP Drive Modules A & B and between C & D. Changing a parameter in either of the stereo linked Drive Modules will change the other linked Drive Module. Stereo linking is controlled by the STEREO page in the “UTILITY” menu.
Note: Stereo linking will only work when the linked Drive Modules are of equal size. Note: Stereo Linking state is not stored in Presets (but is stored in Snapshots)
Current Ethernet IP Address
This may be viewed in the “IP Curr” page of the “UTILITY” menu. This value cannot be edited.
IP Mode
The Ethernet IP address may be automatic “Auto” or may be a fixed static value “Static” as determined by the “IP Mode” page of the “UTILITY” menu.
WARNING ­ Do NOT use Static mode unless your IT system specifically requires it. Auto mode should always be used where possible since in this mode, the Device can always be discovered’ by the Vu-Net application. When in Static mode, the IP Address will flash on the Home screen. See also Ethernet Configurations. IP Static This allows the Static Ethernet IP address to be adjusted by the rotary encoders on the IP Static page of the “UTILITY” menu. This page will only be visible when in Static mode. Store Snapshot This page of the “UTILITY” menu allows a Snapshot of the device to be stored. See also Snapshots. Recall Snapshot This page of the “UTILITY” menu allows a Snapshot to be recalled. See also Snapshots and Aux Port. Bandwidth Units This page of the “UTILITY” menu allows the Bandwidth of Parametric Equalisers to be viewed and adjusted in either Octaves orQ’.
Aux Style
This page of the “UTILITY” menu allows the action of the Aux port to be viewed and adjusted.
See also Aux Port.
ECO
This page of the “UTILITY” menu allows the device to save power by going into a low power mode when it is not being used. Standby is a fast mode which saves some energy, but will wake-up very quickly if an audio input is detected. The associated Standby Time parameter allows the amplifier to automatically go into power-save if no audio signal has been detected for a period of time. This function can be defeated by setting the latter control to Manual. Linea would strongly advise leaving it set to automatic however as there is no negative consequence to doing this since `wake-up’ on detecting the presence of an audio input signal is instantaneous.

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The Standby Now parameter’ allows the amplifier to be put into standby mode manually when it is not being used. Sleep is a deep power save mode which saves the most energy, however it will take a small number of seconds for the amplifier to wake-up, and it may only be woken up manually (either from the Vu-Net application or by switching the device off then on again). The associated Sleep Time parameter allows the amplifier to automatically go into Sleep mode if no audio signal has been detected for a period of time. This function can be defeated by setting the latter control to Manual. External Breaker Protection (EBP) The Power (“PWR”) utility page provides access to the External Breaker Protection (EBP) feature, which allows the output power to be limited in order to prevent the nuisance tripping of mains circuit breakers or fuses when the amplifier needs to be operated on a mains supply with restricted capacity. Set the EBP value to that of the circuit breaker or fuse to which the amplifier is connected. Ethernet Ethernet configurations IP addressing in the Device can be completely automatic; No setup is required. When first installing and launching Vu-Net, the computer Firewall may ask to allow Vu-Net to access the network. NOTE: This must be allowed for both private and public networks. DHCP There are two primary IP address ranges ­ one used when there is a DHCP server, and another (Link Local’) where there is no DHCP server (so the Device and the Computer will instead use ‘Auto IP’ to allocate themselves an IP address). Both the device and the computer must be in the same IP address range. In a local network environment such as an office where there is a DHCP server, both the computer and the Device will be in the DHCP IP address range, and so will connect immediately.
AUTO-IP
The device will initially search for a DHCP server when first switched on (during which time its Online Indicator will be flashing). As it can take up to one minute to establish that there is no DHCP server available, this is the time it may take before Auto IP is entered.
Please be aware that it can also take some time from a computer being switched on in an isolated network (without a DHCP server), or unplugged from a network with DHCP to time out of DHCP searching, so it will not connect immediately to amplifiers that are already using Auto IP. The time it takes before it decides to revert to Auto IP depends on the operating system but it can take several minutes to acquire an Auto IP address.
Static-IP
If the device or the computer has a static IP address set, Vu-Net may not be able to ‘see’ the device if it is in a different IP Address range (i.e. in a different subnet). Unless there are good reasons it is best to avoid the use of static IP addressing if at all possible unless you have a comprehensive understanding of network systems.
IP Troubleshooting
If Vu-Net cannot connect to the device:
A Router acting as a DHCP server is highly recommended as this provides the most trouble-free way of administering IP addresses. Always switch on any DHCP server before connecting either the computer or Amplifier to the network.
If not using a DHCP server, check that the Current IP address in the device is compatible with the IP address of the computer. Generally, the leftmost two sets of 3 digits should be the same.
If there is no Router in the system acting as a DHCP server, wait 10 minutes (for the computer to acquire the correct IP address) and try again.
Check that the Firewall in the computer will allow Vu-Net access to the network for both private and public networks.

Snapshots
A Snapshot may be recalled either via the device User Interface, from the Vu- Net application or via the AUX port on the rear of the Device.
The snapshot menu is accessed via the utility pages. Recalling a Snapshot triggers the recalling of a Component to each input and output, and may change other device-wide settings, effectively recalling a processor-wide preset. In addition to being able to recall snapshots from Vu-Net and from the Device’s front panel, some of the snapshots are also recallable from the auxiliary port.
See also Aux Port
The parameters inside the Drive Modules are not individually stored in Snapshots. Recalling a Snapshot will merely trigger the recall of the appropriate Input and Output Components, rather than restoring the parameters that were active when the Snapshot was stored. This has the distinct advantage that the library of
OEM presets may be updated without having to be concerned about what parameters might have been saved in users Snapshots. It does however require that any existing edits to the parameters in Drive Modules are stored into Drive Module presets before a Snapshot is stored.
See also Overview of Modules Components and Snapshots

AUX Port
The AUX has two inputs, X & Y. These allow simple contact closure devices (relays or switches) or external logic signals to change the state of the amplifier as described below. Connecting an AUX input to ground (the earth symbol) will trigger it; there is no requirement for an external voltage. However, the ports can also be triggered directly by a logic signal as long as the logic low’ goes below +0.5V. Do not connect systems if their logichigh’ voltage exceeds +24V.
The AUX port may be configured to work in a number of ways by adjusting the Style parameter in the Aux page of the Utility menu:
None – No operation 2+Mute (Event or State) ­ Either Snapshot 1 or Snapshot 2 may be recalled by applying a momentary or static
connection to an Aux port terminal, or the device may be muted by Grounding both Aux port terminals 3 Snaps (Event or State) ­ Either Snapshot 1 or 2 or 3 may be recalled by applying a momentary or static connection
pattern to an Aux port terminals 4 Snaps (State) ­ One of the four Snapshots 1,2,3,4 may be selected by applying a static connection pattern to the Aux
port terminals 3+Mute (State) – One of the three Snapshots 1,2,3 may be selected by applying a static connection pattern to the Aux
port terminals, or the device may be mute by Grounding both Aux port terminals
This table shows the action taken for various Aux connection patterns in the various Aux port modes:

AUX X
Open Gnd Open Gnd

AUX Y
Open Open Gnd Gnd

2+Mute ACTION (State or Event)
No Change Recall Snapshot 1 Recall Snapshot 2
Mute

3 Snaps ACTION (State or Event)
No Change Recall Snapshot 1 Recall Snapshot 2 Recall Snapshot 3

4 Snaps ACTION (State)
Recall Snapshot 1 Recall Snapshot 2 Recall Snapshot 3 Recall Snapshot 4

3+Mute ACTION (State)
Recall Snapshot 1 Recall Snapshot 2 Recall Snapshot 3
Mute

Some of the above modes allow the AUX Port to be used either in Event mode (whereby a momentary push-button or momentary relay contact closure on one of the AUX lines will cause a Snapshot to be recalled). Or in State mode (where a rotary switch etc. connected to both of the AUX lines selects which Snapshot to use). Some of the other modes only allow State mode, requiring the connection pattern to persist in order for the Snapshot to be held as the current one.

iK81 / iK42 User Guide V1.0

iK81 / iK42

USER GUIDE

NOTE: That if the contact closure port is being driven, or if the Aux Style is set to one of the State modes, this will override the snapshot recall setting in the menu (or in Vu-Net). Also under these conditions, the snapshot menu items are not accessible, and the Home screen will show the Snapshot number as a reminder.
See also Snapshots.

Latency delay
All Digital Signal Processing, and conversion between different formats of signal ­ analogue/digital/network etc., necessarily introduce some delay (latency) to the signal path. Of course, we strive to minimise these latencies. Small as they are, it is sometimes useful to know their precise values. The following describes the principal latencies introduced by various parts of the Device product:

Input / Output Latencies

Analogue Input

0.385ms

OR

Digital input at 96 KHz sample rate 0.5ms

OR

Digital input at 48 KHz sample rate 0.66ms

Analogue Output

0.402ms

OR

AES3 Output

0.1ms

OR

Dante Output

0.5ms

Processing Latencies (limited to a minimum of 1.53ms):

Input HiShelf FIR

0.48ms (0ms if set to `Off’)

LIR Linear Phase crossover

1.19ms/Fhp(kHz), limited to 30ms maximum **

VxLim Limiter (VX mode off)

0.12ms/Fhp(kHz), limited to 1.53ms maximum **

OR

VxLim Limiter (VX mode on)

0.358ms/Fsplit(kHz), limited to 1.53ms max

** This latency figure is calculated using the crossover High-pass frequency (in kHz)

This latency figure is calculated using the Vx Split frequency (in kHz)

Important tip: The processing latency is constant at 1.53ms unless LIR crossover filters or FIR HiShelf EQs are used, so normally you would just need to add the Input and Output delays to this constant value. If LIR or FIR are in use, the Processing latency of a Drive Module may increase beyond this figure. The Drive Module Latency may be viewed on the Latency page of the relevant Input DSP channel. This can be accessed by pressing Input then down until the latency page is reached.

When LIR, is used the Vx Limiter can take the overall latency above the 1.53ms. When high pass frequency is set below 40Hz the filter will automatically revert to Linkwitz riley, this is set so that the latency will not exceed 30ms as stated.

Note that the latency reported on the Latency screen in the utilities menu does not include the Input/Output latencies.

When using input FIR filters, LIR or VX Limiters always check the view latency screen to see the latency attributed to that Drive Module.

Example:

Input/Output Analogue Input Analogue Output Processing Input HiShelf FIR (Off) LIR Linear Phase crossover (500Hz) VxLim Lim (VX mode on, 1KHz Fsplit) Total

0.385ms 0.402ms
0ms 2.38ms 0.358ms 3.525ms

Note that the latencies within a Drive Module are equalised among outputs of that Drive Module. That is, padding delay will be automatically added to some outputs such that the total latency is the same in each output of a Drive Module.

This latency equalisation does not extend outside a Drive Module, so Drive Modules are not guaranteed to have the same latency as one-another.

iK81 / iK42 User Guide V1.0

USER GUIDE

Secure Mode
When activated, this will disable all the front panel controls so they cannot affect the signal path, making the unit secure against tampering. The only option that is left for user control is snapshot recall. If this is not required then storing the same device state in every snapshot will effectively disable this feature. When in secure mode, the indicators still operate normally. To activate secure mode, press and hold the utility button for 5 seconds. To deactivate, press and hold the utility button for 5 seconds. When in secure mode, this will be shown on the display. Note that the Ethernet communications port is still active in secure mode.

Overlay Flush
If the device has been used in Module Groups, and still has an active Overlay (as indicated by the Overlay indicator), these can be removed by simultaneously pressing and holding for 5 seconds the Utility and Enter buttons. See Overlays.

Revert to Factory Settings
If you wish to erase all of your settings in the device and revert everything to factory settings, then simultaneously press and hold for 5 seconds the Up button and the Mute 1 button, then follow the prompts on the display. Only continue by pressing the Enter button if you are sure this is what you want to do. Otherwise, press the Down button to escape. Alternatively, you can access this feature from Vu-Net application using the Hamburger’ button on the bottom-right of the device control panel, selectingrevert to factory settings’.

Protection Systems
Comprehensive protection features preserve the longevity of the loudspeaker and amplifier by continuously monitoring several critical parameters, and reducing the gain, or muting the amplifier either temporarily or permanently depending on the nature and seriousness of the fault or misuse. The amplifier will recover and restart if at all possible, but may remain in shut down if a serious fault persists.
Limiters deal with routine over-driving of the amplifier, making sure that the driver(s) are not pushed too hard. The limiter indicators will warn you when the driver is being driven into limit.

Minor faults are dealt with by dimming’ the amplifier, reducing the level to a sufficient degree and for a sufficient time that the amplifier is able to recover gracefully without any user interaction. When the fault condition has passed, the amplifier will recover automatically. When the protection systems are reducing the level, this is indicated by illuminating the left-hand Amplifier channel protection indicator. This will also illuminate when the output voltage isclipping’. This indicator will remain permanently illuminated if the channel has been muted by the protection systems. The Mute button will also flash. This will usually also be indicated by a warning message on the display. Some types of protection affect all output channels, so you may see the Amplifier indicator illuminated, and the Mute button flash, on every channel.

Summary of Protection Indication
The reasons for the protection indicators illuminating are summarised as follows:

Amplifier Indicator
Amplifier clipping Amplifier clip limiting Amplifier Current limiting Amplifier VHF limiting PSU Current limiting PSU Power limiting
Thermal limiting

Driver Indicator Limiter 6dB over Thermal limiting Excursion limiting

Notes
Will show on all output channels Will show on all output channels Will show on all output channels

iK81 / iK42 User Guide V1.0

USER GUIDE

Incident Reporting

In the Vu-Net application, a coloured indicator appears on a Device Bar in the System View which displays the Incident state of the device. The Incident state may be one of three states:
Red: Fault (The device is faulty in some way and requires attention) Yellow: Check (The device may not be performing to its full and should be checked) Green: OK (The device is performing well and requires no attention)
Holding your mouse over the Incident indicator for a few seconds will show the current incident level and name.
If an incident is reported you can disable it, and all less serious incidents, by right clicking the bar in System View and selecting Enable/Disable Alarms’. Doing this will show a cross over the Incident indicator and the device will no longer report any Incidents at this level or below. If any Incidents have previously been disabled they can be enabled by using the right click context menu and selectingEnable/Disable Alarms’ again.
Any active incident will be shown on the display of the device.
A Fault state will also cause the Fault Relay to open. See Fault Relay
Fault Relay
Three connections are available via the Phoenix connector for this relay. The schematic representation printed on the rear panel shows the idle’ state of the relay (when the amplifier is not switched on). When the amplifier is switched on, the relay will normally energise. When a Fault incident occurs, the relay will be de-energised. This will allow either a Fault Incident or a loss of power to be seen as aFault’.
See also Incident Reporting
Performance Logging
The Vu-Net application allows you to inspect various performance measurements, including various graphs of performance against time, recording events over a period of up to three days. Since the amplifier cannot record any events whilst powered- off, breaks in a log due to power-downs are indicated by a break symbol || in the log.
The events recorded are:
Supply Current – How much current is being supplied to the device via the mains inlet DC Link Voltage ­ A voltage which is derived from the mains supply voltage Thermal Capacity ­ How much of the available thermal capacity has been used Driver Current (for each output) ­ The average current being delivered to the driver Driver Impedance (for each output) ­ The average impedance of the driver Protection Limiting (for each output) – How much the amplifier is `dimming’ itself in order to protect itself from potential damage
The data in the log can be exported by right-clicking on the log to launch a context menu, and selecting “copy log data to clipboard”. The data could then be pasted into a spreadsheet for further analysis. Your dealer may ask you to do this is you have experienced a problem. Alternatively, all of the operational and performance data, including the logs may be collected together into a single file by selecting File > Save Device Diagnostics. Your dealer will be able to read and interpret this data.

USER GUIDE

Vu-Net
iKon amplifiers feature an Ethernet connection to allow them to be networked together for control and monitoring of the system they are driving. This is achieved using a PC on the same Ethernet network running Martin Audio’s Vu-Net software. Vu-Net allows comprehensive control of every amplifier function;-

Vu-Net is available as a free download from the Martin Audio website. For full details of Vu-Net operation please also download the Vu-Net User Guide which shows Vu-Net operation for the iKon amplifiers and all Vu-Net enabled Martin Audio products.

iK81 / iK42 User Guide V1.0

iK81 / iK42

USER GUIDE

Processing Block Diagram

iK81 / iK42 User Guide V1.0

iK81 / iK42

USER GUIDE

Input Menu Map

iK81 / iK42 User Guide V1.0

iK81 / iK42

USER GUIDE

Output Menu Map

iK81 / iK42 User Guide V1.0

iK81 / iK42

USER GUIDE

Utility Menu Map

iK81 / iK42 User Guide V1.0

iK81 / iK42

USER GUIDE

EQ and Filter Response Graphs

iK81 / iK42 User Guide V1.0

iK81 / iK42

USER GUIDE

iK81 / iK42 User Guide V1.0

iK81 / iK42

USER GUIDE

iK81 / iK42 User Guide V1.0

iK81 / iK42

USER GUIDE

Technical Specifications

General
Number of Output channels Total power output (iK42) Total power output (iK81) Input types Control, monitoring & alarm
Energy saving modes System sleep and wakeup
Max ambient temperature (full power, no limiting)
Audio
Amplifier topology Amplifier modulation scheme Dynamic range (analogue input to speaker output) Dynamic range (AES3 or Dante input to output) Frequency response Total harmonic distortion, THD Inter-channel crosstalk (worst combination of channels)
Slew Rate Damping factor (Ref 8 Ohms) Maximum analogue input level Analogue input sensitivity range for full output Analogue input Analogue link Analogue ground scheme AES3 input
AES3 link
AES3 supported sampling rates
Digital processing
Resolution Sample rate Special functionality:

Four (iK42) or Eight (iK81) 20,000/10,000/6,000 Watts RMS (iK4220, iK4210, iK4206) 10,000/6,000/3,000 Watts RMS (iK8110, iK8106, iK8103) Analogue, AES3, Dante Ethernet, configurable function Volt-free relay and contact closure port Standby and deep sleep, both with auto-sleep timers Front panel switch, network command, contact closure and audio detection 40degC (105degF)
Proprietary 5th generation Martin Audio Class D Low feedback, multiple loop, with feedforward error correction >113dBA typ. >114dBA typ. <7Hz to >30kHz, 4 Ohms, -2.5dB. <0.05% typ, 1kHz, AES17, 4 Ohms. Better than -85dBr at 1kHz. Better than -75dBr at 10kHz. >60V per microsecond typical >800 at amplifier output +20dBu. 0dBu to +20dBu, continuously adjustable. 20k Ohm, electronically balanced. Directly connected to the analogue input. AES48 standard compliant. Transformer isolated with active cable equalisation for extended range Active signal regeneration with automatic direct bypass to the AES3 input if the unit is unpowered. 24kHz to 192kHz (auto locking).
40 bit, using proprietary LMD (Linea-Micro-Detail) algorithms 96kHz throughout Class leading limiter suite (See the `speaker protection systems’ section) Hardman crossover filters (Better out of band rejection than Linkwitz-Riley) LIR crossover filters (Linear Phase without the compromises of FIR filters) FIR Shelving EQ filters (For linear phase filtering). Overlays (Twelve additional independent overlays of EQ, Delay and Gain)

iK81 / iK42 User Guide V1.0

iK81 / iK42

USER GUIDE

Power Output iK42

Power specification
Crest Factor of 4 (12dB), 2-Ohm nominal load Crest Factor of 2.8 (9dB), 4-Ohm nominal load Crest Factor of 2 (6dB), 8-Ohm nominal load Bridged, per channel pair, 4 Ohm load 25V line (CV) operation, Crest Factor 4 (12dB) 70V line (CV) operation, Crest Factor 4 (12dB) 100V line (CV) operation, Crest Factor 4 (12dB)

RMS output power per channel, all channels driven with continuous program material and a nominal ambient temperature of 40degC / 105degF 5,000W 3,000W 1,500W 10,000W 1250W 3500W 5,000W

Power Output iK81

Power specification
Crest Factor of 4 (12dB), 2-Ohm nominal load Crest Factor of 2.8 (9dB), 4-Ohm nominal load Crest Factor of 2 (6dB), 8-Ohm nominal load Bridged, per channel pair, 4 Ohm load 25V line (CV) operation, Crest Factor 4 (12dB) 70V line (CV) operation, Crest Factor 4 (12dB) 100V line (CV) operation, Crest Factor 4 (12dB)

RMS output power per channel, all channels driven with continuous program material and a nominal ambient temperature of 40degC / 105degF 1,250W 1,250W 1,250W 2,500W 625W 1,250W 1,250W

Power supply

Topology (main power supply) Topology (auxiliary and standby supplies) Internally stored energy Mains input voltage range (automatically configured) Mains input frequency range Mains inrush current (max for <10ms)

3rd generation Series Resonant. Low quiescent Eco-Flyback. >600 Joules.
85V to 240V.
47Hz to 63Hz.
6A at 115V, 12A at 230V.

Protection systems
Note : Under all circumstances the control and protection systems will endeavour to deliver the maximum power possible for a given set of conditions, applying limiters only in extreme circumstances. Muting will only occur when a dangerous situation is detected, normal operation automatically resuming when the condition clears.

System protection Excessive output current Excessive power supply current Excessive amplifier section temperature Excessive power supply section temperature Excessive DSP section temperature Mains voltage out of range Fan speeds out of range Internal power rails out of range

Speaker protection Audio soft-clip limiter VxLim, Multiband peak limiter
VxMax, Multiband overshoot limiter Vx-Xmax, Driver excursion limiter Vx-Tmax, Driver thermal limiter (long term power limiter) DC offset protection
Excessive HF energy (VHF) limiter

Power distribution protection systems
Mains inrush current limiting (soft start and anti-surge). Mains average current limiting (mains breaker / fuse trip protection). Randomised initialisation when powered up to reduce the peak power demand in large systems.

Monitoring and logging

Supply current logged vs time

Number of power cycles counted

Supply voltage logged vs time

Number of mains brownout events counted

Thermal Capacity logged vs time Each driver current logged vs time

Fan speeds continuously monitored Fan under-speed events counted

Each driver impedance logged vs time

Various protection mute events counted

Protection limiting for each output logged vs time

Driver Impedance continuously monitored

An inbuilt alarm and notification system can be configured to indicate problems to remote devices either via the network or the

Volt-free changeover relay contacts accessibly on the rear panel.

iK81 / iK42 User Guide V1.0

iK81 / iK42

USER GUIDE

Physical
Cooling Airflow Air filtration Analogue IN and LINK connectors AES3 IN and LINK connectors Audio output connector Mains input connector Dante Primary and Secondary Relay output & contact closure inputs Front panel display Front panel encoders Front panel push buttons LED indicators Enclosure
Depth (behind rack ears) Net Weight
Options
Rear rack support kit

Variable speed fans. Front to back. Washable media, changeable without the use of tools. Genuine NeutrikTM XLR. Genuine NeutrikTM XLR. Genuine NeutrikTM Speakon. Genuine NeutrikTM 32A PowerCon. Shielded RJ45. Phoenix pluggable terminal block. Graphical, backlit, high contrast, daylight visible. Two, indented, velocity sensitive. Large, tactile, illuminated. Bright, easily differentiated Standard 19″ 2U (88mm) with handles and optional rear support system 357mm (14″). 12.5kg (27.5 pounds).
Part Number

iK81 / iK42 User Guide V1.0

References

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