Included with The Woofer Tester Pro:
• Test unit
• CD-ROM with Software
• 2 Measurement Microphones & Cables
• 1 USB A/B cable
• 2 RCA Y-cables
• 1 10-ohm 10 watt Calibration Resistor
• 1 0.5 ohm 10 watt Current Sense Resistor
• Low-power Banana/Alligator test leads
• Downloadable User Guide
• Free Software Upgrades & Support

System Requirements:
• Pentium 450 MHz or faster
• USB Port
• Windows® XP, 2000, Me or 98SE

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Description

High Power Test Port

Being able to measure and quantify Thiele-Small and box tuning data at higher power levels is a major step in designing higher quality speakers. The Woofer Tester Pro enables designers to see these effects at a fraction of the traditional cost. The high power impedance and phase test port extends the Woofer Tester 2's small signal milli-amp level tests to the multi-ampere Xmax level where many drivers begin to distort and fail. The graphs below illustrate the effect drive level has on the base Thiele-Small parameters.

                       Idrive vs. Fs                                           Idrive vs. Vas
Click image to enlarge
                       Idrive vs. Qts                                           Idrive vs. BL



Thiele Small Testing over a Dynamic Range from Microwatts to 200 Watts

With the unparalleled accuracy of the WTPro, driver characteristics can be measured over a dynamic range that extends from microwatts to over 200 Watts. Drive levels are limited only by your amplifier. See the FAQ on Cms Non-Linearity

Test modes

The Woofer Tester Pro supports MLS, Step, Noise, Chirp, Continuous Sine and Pulsed Sine modes for accurate as well as fast testing. High precision measurements are crucial for modeling and the Continuous Sine mode provides the best signal to noise ratio. With the WTPro, results are as accurate as .02%. Continuous Sine mode is best used for close microphone response or within an anechoic chamber.

The WTPro fast test modes are intended for real-time analysis (RTA). The Woofer Tester Pro conducts fast tests in under 1 second. A range of test signals is available, since not all signal types yield the best results. For example, the step mode favors lower frequencies and is best suited for woofers, while MLS is better suited for midranges and tweeters.

Advanced Thiele-Small Simulator & Box Analyzer

The advanced Thiele-Small simulator in the Woofer Tester Pro supports all box types - Vented, Sealed, Band Pass and Passive Radiator. Using Frequency Dependent Inductance modeling, results are improved over the traditional, flat model. The simulator calculates Response, Impedance, Phase, Velocity & Xmm of all Radiators.

The Box Analyzer automatically finds box alignment and losses with the built-in Auto-Align feature. It calculates box, port and stuffing losses and models the effects of room/car pressurization as well as vent resonance (pipe organ effects). Import your data from the WTPro Test Environment or the manufacturer's data sheet. This includes the T/S versus drive compression data.

Compare simulated to real-time response with extreme precision (< 0.5dB error) as shown in the graph below:



In-Air Acoustic Response

The WTPro measures in-air acoustic response with MLS, Noise, Impulse or Chirp in real-time allowing you to easily position speakers perfectly in the room. Simply move the test microphone around the room and watch the response on the screen. For Best noise rejection (Sweep and collect), use Sine and Pulsed Sine modes. Reject room reflections using a Time Window (MLS and Step) and create Cumulative Spectral Decay and Waterfall Plots.



Interactive Crossover Design (ICD)
The Interactive Crossover Designer in the WTPRo software greatly speeds up crossover design time by allowing you to simulate various crossover designs without actually having to build them! Designs are entered via an ICD circuit file, which is converted into filtered left and right test signals. The test signals are then used to excite two drivers connected directly to an amplifier. The results of the simulated crossover match the physical crossover to fractions of a db, as shown in the graph below.



To find the optimal crossoverpoint, the ICD also measures Acoustic Distance to <.1mm and finds Delta Phase at the crossover frequency. Decide on crossover topology based on Driver Delay and Phase.

             Amplitude of both Channels                          Delta Phase at XO frequency


         ICD filter overlay, Left-Right Pan


Crossovers are also affected by voice coil alignment. The ICD control window also includes a time delay option to test these effects without having to physically move the drivers.

To protect your tweeters during the design phase, the software can also accommodate a tweeter protection circuit. The User Guide has instructions on how to build the physical tweeter protection circuit.

Harmonic, Inter-Modulation & SINAD Distortion Measurement

The WTPro includes various distortion measurements: 1st through 6th Harmonics on a relative or absolute level vs. frequency, inter-modulation distortion as well as Signal to Noise and Distortion Ratio (SINAD). SINAD can be viewed as Signal Relative To Drive Signal, Oscilloscope or Lissajoux.

Tweeter Response & Harmonics 1-6 on Absolute Scale         SINAD at 1 kHz Shown as Lissajoux Pattern


AC & DC Thiele-Small Model Compression

The Woofer Tester Pro can also measure T/S models while stepping through DC bias or AC drive level. This can reveal suspension and motor mechanical offsets, or provide compression modeling information. The XY plot tool compares any parameter pair.


         Cms versus Xmm Displacement                    BL versus Xmm Displacement


Using Distortion for Voice Coil & Suspension Analysis

Harmonic distortion of the 2nd-6th harmonics versus DC bias reveals suspension and voice coil offsets but it also indicates acoustic quality.



Thiele-Small Parameters vs. AC Drive Level

The XY comparison tool can be used to compare any two Thiele Small parameters. Each measurement can also be selected into the simulator (a pulldown in the simulator) to generate an AC response for each point. That is, driver compression is revealed.

         Vas (Liters) versus AC Current Drive                    BL versus Xmm Displacement


Crossover Component & Cable Measurement

The WTPro's large dynamic range and utmost precision allows it to measure impedance and phase continuously from 1 to 20 kHz with 5 digit typical accuracy when used at full scale. With the low power port covering a rang up to 3 mA and 4 Amps for the high power, a huge dynamic range is possible. The low power port supports 100 pF - 1000 uF, 100 nH - 10 H and 10 milliohm - 100 kohm RLC measurement range, but it easily measures speaker cables as well.

Change in Inductance of 36" Leads Open/Closed            10 ohm cal resistor: 1 milli-ohm/div, 1-20 kHz
50 milli-ohm/div