Woofer Box and Circuit Designer - The most accurate Sealed, Vented, and Passive Radiator modeling tool available - Complete with amplifier modeling and the ability to include room and baffle effects in the response
Software and Measurement-less Design Tutorial By Dave Dal Farra:
How to Design Loudspeakers without Performing Measurements "Simple Loudspeaker Design": Download a Presentation / Overview of how to design loudspeakers without performing measurements HERE; Download a zipped directory containing all the necessary software applications and demo files HERE
MicHeight - Spreadsheet that aids measurement microphone set-up. Provides valuable information such as FFT window size and resolution and floor bounce and standing angular locations.
Software By Charlie Laub:
Active Crossover Designer (ACD)- A set of tools for designing active loudspeaker crossovers using a series of linked Excel spreadsheets. Complete control of transfer function using pole and zero notation. Generates "advanced biquad" coefficients for the MiniDSP crossovers (original ACD version) or for the LADSPA plugins ACDf and mTAP (new ACD-L version). Core tools are extensible via extensions.
LADSPA plugins - LADSPA plugins are used to implement first and second order filters as IIR digital filters under a LADSPA host such as ecasound. Inspired by the ACD filter set, you now can use an inexpensive ARM or mini-PC to implement a crossover using Linux audio processing. Also includes a multi-channel fraction delay line, and OnOffDelay, a plugin to control external equipment via GPIO pins in response to the audio signal - useful for controlling power supplies, speaker relays, soft start, LEDs, etc.
Power Supply Capability and Design - a tool for designing linear unregulated power supplied used to power class-AB power amplifiers. Includes a model of the transformer that accounts for voltage sag with increasing current draw based on Antek AN series transformers. Choose capacitor ripple voltage, nominal speaker load, and number of channels and see the power potential that the supply can support. Great for making choices about transformer VA rating, total capacitance used, etc.