PRAXIS is a sophisticated audio measurement system, utilizing higher quality Windows sound hardware, for professional use. It operates within 32-bit Windows operating systems (Windows98 and above) to provide full-featured customizable measurements of loudspeakers, transducers, electronics, room acoustics, and vibrating systems.  

The system is deep and powerful and encapsulates very complex processes. Yet it is an easy system to use. Praxis was designed with the intention that the user need face no more complexity than is necessary to accomplish the needed measurement. Depth and power are there when you need them, but they do not block your way.

Praxis is able to make use of calibration files for transducers, and can calibrate around the measuring soundcard (using the AudPod device) to provide data in terms of physical units such as Volts, SPL, or Pascals.

Praxis provides a wide selection of stimulus types and acquisition types for exceptional versatility. Its data graphing and formatting capabilities are unequaled anywhere. Unlimited overlayed plots can be generated, and you can use custom backgrounds, markers with search and tracking functions, fully adjustable scaling and grid settings, weighting functions, fixed and flexible width time data windows, and much more. The measured data, once collected, can be modified or transformed via a set of powerful operations for in-depth analysis or interpretation.

Detailed calculation of room acoustics characteristics (such as Schroeder curve, STI, Objective Clarity, RT60, etc.) is provided along with efficient, wide dynamic range measurement capabilities using techniques such as logarithmic sweeps (chirp).

The Praxis measurement system provides for intelligent automation, through its support of visual Scripts. A Script is an application (program) that can run within Praxis, complete with a Graphical User Interface, and is able to operate the Praxis measurement system's main features (as well as doing other general computer operations). Included is the Liberty Script Designer, a visual RAD development tool (patterned after Borland's Delphi system) to streamline development of custom Praxis Scripts.

Praxis operates in one of two modes:

The Full operating mode, in which all capabilities are enabled. This mode requires purchase of the AudPod with the Praxis Software, and provides you with the most useful audio measurement tool available.

And the Free (or Demo) mode, which is provided free of charge (except shipping), and allows inspection formatting and printing of Praxis-obtained data. Demo mode also provides several useful measurement functions, including Thiele/Small parameter measurement of woofers, and RTA monitoring of audio signals. And, of course, Demo Mode also allows you to explore the features of Praxis.


Praxis is able to generate and acquire audio data in 16bit and 24bit formats, and at sample rates to 96kHz. It can operate with one or two channels in input and output. Praxis generates its stimulus data in real time, rather than being constrained by finite pre-generated wave files -- it can, for instance, continuously generate "live" a multitone signal set containing over a hundred simultaneous sinusoid tones, each with selectable frequency, level and phase.

Praxis is a very versatile measurement instrument. The many possible combinations of its Stimulus, Acquisition, and PostProcess types, and the nearly infinite extensibility provided by Praxis' Scripts, prevent a full listing of its capabilities from being presented here.

However, some of the more obvious applications of Praxis include:

Hardware and Software Requirements

Soundcard requirements:

Software requirements:

Windows 98SE, ME, 2000, XP, or later (Windows 95 or NT not supported except for demo mode).
Windows 2000 or XP preferred.

Computer Hardware Requirements:

Praxis relies on the horsepower of your main processor (which is also busy running the Windows OS), so faster is better! The following are minimum and recommended characteristics of a computer for Praxis:

Design Goals and Philosophy

Two characteristics stressed heavily during Praxis' development were (1) Flexibility and (2) Ease of Use.

Flexibility of course makes the program more valuable and promotes its adoption for more purposes. It also allows the program's capabilities to remain up to date.

Ease of Use means less time spent in support calls for both the developer and the user. This is an important consideration when the staff is as small as Liberty Instruments' staff!

We address Flexibility by enabling very adaptable graphing windows ("Plots"), by providing a wide array of stimulus, acquisition, and postprocess types, and by opening up an entire API ("Application Programming Interface") for controlling Praxis from user-writable scripts.

We address Ease of Use by providing extensive Help features (such as this file) and manual, and by designing the controlling forms to, as much as practical, show controls and options only when they could be relevant to the operation being performed. For instance, the Configuration Forms for the various Acquisition types will change depending on the chosen Stimulus and Acquisition, to show only the relevant controls for the situation. And you can hide these Configuration windows when further adjustment is not needed, and quickly bring them back up when you need them.

Praxis is designed assuming the time-honored laboratory sequence of:
1) Stimulate the device being tested: "Stimulus"
2) Record the device's response: "Acquisition"
3) Transform and interpret the response, in relation to the stimulus: "PostProcess"

To these, Praxis adds another layer of control: "Scripting", which is somewhat like having a laboratory assistant available to do the tests over and over again, to modify the process depending on results, and to further transform the results to new data forms as they are developed.  The Liberty Script Designer allows you to visually program the system to create powerful extensions and automations which run within PRAXIS.   Scripting also, of course, allows development of easy-to-perform measurement processes to minimize the required skill level of a measurement operator.