PARAMETER MEASUREMENT

We can measure a full set of Thiele-Small parameters on almost any type of driver, most commonly low frequency drivers since most modeling software deals with frequencies below 250Hz. For subwoofer or bass system design, this modeling limit is usually adequate. For accurate modeling of horn loaded bass or midrange drivers, or for high frequency compression drivers, substantial additional data is required. Our LMS-VI measuring system measures parameters using the international standard 70mA signal, or at elevated levels (within the driver's linear operating range). Behaviour in the non linear region can be documented, but is not useful with common modeling software.

Perhaps you feel that the manufacturer's data is incorrect, or perhaps have a driver for evaluation which came without data. You will need the missing Thiele-Small parameters before undertaking any enclosure design. If you are on a tight budget, you can calculate the parameters for yourself (plus or minus 10%) using a few measurements with a multimeter, a power amplifier, some modelling clay (or a small sealed enclosure), a couple of calibrated resistors, and some high school calculus.

Antique drivers never had complete specifications, or may have been modified, but these can be documented. Our fee for a single LMS driver test is $30 or $50 for two units. For customers who require pair-matching or extended data, we are also equipped to measure frequency response, sensitivity and distortion. Power handling measurement is also possible but potentially dangerous, so we prefer to performed it only on expendable units.