Thiele-Small Driver Measurement
With the Woofer Tester 2, measuring a driver's Thiele-Small parameters is easy. Q/FS, Vas and motor parameters are measured with a single click of a button.
Vas can be measured with the Delta Mass, Delta Box or Efficiency method. The tester's sophisticated model takes phase-plug area into account as well.
For Impedance & Phase testing, a fast, under 1 second, test mode is available. This is useful for crossover design or a quick, production line test of a driver. Various Impulse, MLS, Noise, Sine, Chirp test signals are available in fast mode. Note that this mode is not as precise and is not recommended in a final speaker design. Additionally, the Woofer Tester 2 allows you to see the Cms trend versus drive level.
Single-Button Q/FS, Vas Thiele-Small Parameters
& Motor Parameter Tests
Click image to enlarge
Advanced Thiele-Small Simulator & Box Analyzer
The Woofer Tester 2 includes an advanced Thiele-Small Simulator that models Frequency Dependent
Inductance and vastly improves measurement results over existing methods.
The Box Simulator models vented, sealed, band pass and passive radiator designs. Additionally,
it calculates box, port and stuffing losses and measures response, impedance, phase,
velocity & Xmm. The advanced features in the analyzer allow you to account for room or
car pressurization effects, as well as vent resonances otherwise known as pipe organ effects.
Driver compression effects can be selected from the Test Environment, AC compression measurement table, or a
manufacturer's data sheet.
The Woofer Tester 2 introduces a new way to conduct box alignment that takes the guesswork out of using Fsb, Ha and Alpha values... only to find that the finished box doesn't produce the expected response! Our new method automatically aligns the simulator to the measured in-box impedance data and finds the effective box size, tuning and losses. In addition, it can be turned around to refine your driver parameters if they have shifted due to drive level, temperature, break-in or box and driver interaction.
As shown in the two graphs below, the simulated and actual results match closely and produce
superior results to any traditional method using Fsb, Ha and Alpha (those are provided as well).
Auto alignment works for both sealed and vented boxes, even when the driver and box interaction has shifted the initial design parameters.
32 Dual Data Buffers for Testing and Overlays
The large number of dual data buffers available enables you to construct intricate graphics overlays and setup complex testing scenarios. Each data buffer stores two data points; hence the name 'dual buffer'. The data points stored can either be Impedance, Phase, Response, Displacement or Velocity and are indicated in the Info column of the Overlay setup control (pictured below).
All data buffers are controlled from the Overlay setup control. To write to any buffer, simply select it from the list. With an additional click, name it as you wish. Then, select the checkbox on the left to display the data in the Overlay window. Easy!
Response and phase offsets as well as phase wrapping and polarity are also set here. You can either manually enter them or use the offset calculator, which automatically finds the difference between the desired and measured value for you!
Setup Control Window
The Setup Control window lets you configure your test environment. Test signals, buffers, sampling rates, graphing options and data buffers are all controlled from here.
Speaker Builder's Toolkit
Also included in the Woofer Tester 2 are a number of tools to help you with your speaker design.
One of them is the Air Core Inductor Design tool that calculates the
layers, number of turns, DC resistance, weight and length of wire required.
Another capability allows you to measure small and large capacitors. The capacitor measurement alignment tool measures and nullifies the tester's parasitic components. This enables the measurement of capacitor values less than 100pF.
For oval shaped drivers, there is an ellipsoid calculator that calculates the correct driver area. This is important for
measuring Vas correctly, as applying a circular diameter to an oval driver yields incorrect results.
Atmospheric conditions have an impact as well and the Woofer Tester 2 allows
you to adjust them to fit your environment by entering temperature, barometric pressure and humidity values.
Zobel Compensation Networks and T/S Tank Circuit
As part of the more advanced crossover design features, the Woofer Tester 2 can be used to find a Zobel Compensation Network, and it includes a T/S Tank Circuit calculator as well. While simple, off-the-shelf
crossovers designs assume resistive loads, they ignore the fact that all speakers have some amount of voice coil inductance. A Zobel Compensation Network accounts for voice coil inductance making a speaker appear resistive.
The T/S tank circuit calculator is used for simulators that model driver impedance as RLC components.
Crossover Component & Cable Measurement
The Woofer Tester 2's large dynamic range and utmost precision allows it to measure impedance and phase continuously from 1 to 20 kHz with 5-digit accuracy typical when used at full scale.
With electrical ranges of 100 pF - 1000 uF, 100 nH - 10 H, 10 milliohm - 100 kohm range, 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