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XO4 Audio Management System


  • 4 inputs and 8 outputs - native processing now runs at 96k resulting in wider bandwidth (over 30kHz)
  • Improved converters - lower noise and improved distortion figures.
  • Bigger 2x24 character display with new low profile buttons.
  • Auto switching power supply works across the world on all voltages
  • XO4A - Audiocore compatibility (Not available in the standard XO4), control up to 32 processors remotely via 3 Pin-XLR standard signal cable, using RS485 (wireless adaptor available).



DP4 Remote application offers the possibility to remote control up to 32 XO4A Loudspeaker Management Systems from your iPhone® or iPod Touch® or iPad®.  DP4 Mini is also available as a shrunk down application that allows read only access.


The XO4 is a 4-in 8-out audio management system from XTA, in collaboration with Funktion One, offers advanced processing capabilities and improved performance along with extra features as standard.

  • 4 inputs and 8 outputs - native processing now runs at 96k resulting in wider bandwidth (over 30kHz).
  • Flexible routing matrix - in addition to standard fixed configurations such as 4 x 2 way (standard configs are still implemented), any output may be fed from any input or the sum of inputs. Edit buttons show routing instantly when pressed.
  • Extended processing capabilities - 9 (previously 5) full bandwidth parametric bands available on every output, all switchable between PEQ, high and low shelving responses.
  • Input EQ is now offered as standard - 8 bands of fully parametric EQ on each input channel.
  • Further extended processing capabilities - crossover filters on each output now offer 48dB/Oct. responses, on top of the previously available 1 to 4dB/Octave options. A gentle 6dB/Octave roll-off response is also now included.
  • Legendary XTA program limiters with automatic and manual time constant facilities.
  • New additional ''D-Max'' limiter with look ahead processing allows attack time of standard limiter to be optimised for best audio quality, whilst still being able to set a ceiling on the maximum output of any channel.
  • Delay memory allows for up to 650mS from any input to any output - extra fine delay resolution on outputs for driver alignment, in 30nS (0.1mm) steps!
  • Extended memory capacity - user memories now extended to a maximum of 55 which may be Input data, X-over data or both.
  • Library manager software available for design of OEM presets - design your crossover live whilst connected to the unit, and lock out any parameters as required to stop end user adjustment/viewing. No practical limit to the number of presets that may be stored (over and above the user memories).
  • Improved converters - lower noise and improved distortion figures.
  • AES Input accepts AES rates from 32k up to 192k via a sample rate converter. Front panel indication of AES selection and AES lock status.
  • AES Output (available special order as a product enhancement) sample rate fixed at 96k.
  • Familiar 226 style user interface with enhancements including menu shortcuts and quick access triple press editing to get the job done quickly. ALL functions are available though the front panel interface - NOTHING is just a remote facility.
  • Bigger 2 x 24 character display with new low profile buttons.
  • Auto switching power supply works across the world on all voltages. 


4 electronically balanced
Impedance: >10k ohms
CMRR: >65dB  50Hz - 10kHz


8 electronically balanced
Source Imp: <60ohms
Min. Load: 600ohm
Max. Level: +20dBm into 600 ohm
Frequency Resp:
±0.5dB 20Hz-20kHz
  -3dB @ 32kHz
Dyn. Range: >116dB 20Hz-20k unwtd
Distortion: <0.02%@1kHz +18dBm
Maximum Delay: 650 mS 
Min Step Size: 0.3 µS
Input Gain: +6dB to -40dB in 0.1dB steps
Output Gain: +15dB to -40dB in 0.1dB steps and mute
Parametric Equalisation**
8 Sections per Input, 9 Sections per Output 
Filter Gain:  +15dB to -30dB in 0.1dB steps
Freq. Range: 19.7Hz - 32kHz, 1/36 octave steps
Filter Q / BW: 0.4 to 128 / 2.5 to 0.008
 (Sections switched to shelving response)
Low Frequency:  19.2Hz - 1kHz
High Frequency: 1kHz - 32kHz
Shelf Gains: ±15dB in 0.1dB steps
High and Low Pass Crossover Filters
   1 of each high & low pass filter per output
  Bessel / Butterworth 6/12/18/24/48dB per octave
  and Linkwitz-Riley 12/24/48dB per octave
Look ahead output limiters:
Threshold:  +22dBu  to -10dBu
Attack Time: 0.3 to 90 milliseconds
Release Time: 4/8/16/32 x Attack time
 Automatic time constant facility also included
'D-Max'' clip limiters:
Threshold:  +2 dB to +12 dB above standard limiter
Release: Slow/Medium/Fast/Automatic
Display:  2 x 24 Character LCD
Input Meter:  2 x 4 point, -24dB to digital clip
Output Meter  8 x 4 point, -24dB to +4dB into limit
Inputs:  3 pin female XLR
Outputs:  3 pin male XLR
External:  9 pin DEE connector (RS232)
 3 pin XLR I/O (RS485)*
Power:  3 pin IEC
Power: 60 to 250V ±15% @ 50/60Hz

 3.3kg Net, (4.7kg Shipping)

7.25lbs Net, (10.3lbs Shipping)

Size: 1.75''(1U) x 19'' x 11.8''
 (44mm x 482mm x 300mm) excluding connector
Latency: 1.5mS (analogue in - analogue out @ 96kHz)




















































































* Only operational when AudioCore compatibility option has been included
** Extended EQ Pack adds the following response types: Band pass; Notch; All pass; Phase; Elliptical Hp/Lp; VariQ (Resonant)

Due to continuing product improvement the above specifications are subject to change.

Units will be supplied in boxes of 5, wrapped, and with foam inserts, ready for OEM packaging.   
They may also be supplied in single plain brown boxes, wrapped and with foam inserts.

User Manual
A generic manual will be issued on disc upon completion of the product specification for editing as required. XTA will not include individual manuals with each unit package.

AudioCore Compatibility
XO4A Version is network ready with enhanced communications (now running at up to 115k for faster downloads and high resolution remote metering) – control up to 32 processors remotely via our world famous AudioCore package, either via a standard balanced line (on RS485) or connected to the network via our Walkabout WiFi kit.
Extended EQ Pack
A suite of additional EQ responses to facilitate precise crossover designs and construct higher order crossover filters – see Key Features section for more details.

Technical Drawings:

XO4 Audio Management System Technical Drawing
All dimensions in mm and inches © Copyright Funktion One Research Ltd 2000 - 2024

Downloadable Files:


Product in Action: