We have 5 used XTA DP448 available.  They are in great condiition. They have the usual rack scratches and usage marks from mounting etc but as you can see they have been very well looked after. 
 
XTA DP448 4-in 8-out Signal Processor
 
As the demands placed on professional audio systems continue to steadily increase, so must the technology be advanced to maintain the expected quality and useability. Based on a completely new processing platform, running at a native sample rate of 96kHz, the 4 Series set a new standard in terms of performance, flexibility, and ease of use.
 
Using the latest digital signal processing and high sample rates would be wasted if attention is not paid to capturing the signal as faithfully as possible, and reproducing it accurately. The range uses high-performance 24-bit converters on the inputs and outputs, running at 96kHz to give a bandwidth of over 30kHz and a dynamic range in excess of 116dB.
 
With two or four fully balanced inputs, and up to eight fully balanced outputs, it also offers greatly increased flexibility. Now it’s possible to realise (for example) four two-way monitor systems, or your favourite DP226 configuration with an additional stereo processing channel, all in a single 1U unit.
 
With multiple inputs and outputs, the 4 Series are able to offer much more than a simple crossover system. To make configuration as simple as possible, a selection of templates are available to set the system up, taking care of routing and selecting useful crossover points.
 
However all of this is easily adjustable, including the routing. Any output may be fed from any input, or combination of inputs, forming a completely flexible matrix.
 
The 4 Series processing platform has been designed to operate at a native sampling rate of 96kHz, and also be powerful enough to cope with the additional inputs and outputs. Available on each input channel is a 28 band graphic equaliser, in addition to 8 bands of fully parametric equalisation. Each output path features up to 9 parametric sections, in addition to the crossover filters which themselves now offer slopes from 6dB/Octave up to 48dB/Octave.
 
All parametric sections can be reconfigured to many alternate filter behaviours, including the familiar high and low shelves and notch filters, but along with bandpass, elliptic and variable ‘Q’ shapes, and phase adjustment, in 2 degree steps. Each output also features a combination of limiters – a limiter which is designed to protect individual drivers from over-excursion/over-driving, and an additional look-ahead “D-Max” limiter for added safety.
 
Add to this sub-millimetre accuracy when introducing time alignment with completely flexible ganging of all channels, and it can be seen that a member of the 4 Series will fit the bill in any system configuration.