
Loudspeaker design tools
Well, at least something to experiment with loudspeaker design in mind.
Calculators and visualization

Sound wavelength calculator
Convert sound wavelength to frequency, or frequency to wavelength
Sound wavelength calculator
Vertical reflections calculator
Play with simple vertical reflections, floor bounce and ceiling bounce.
Vertical reflections calculator
Listen
Try crossover filters on headphones
Try ideal IIR filters as two way crossover on headphones.
Try crossover filters on headphones
Try group delay on headphones
Try audibility of group delay on headphones.
Hear group delay on headphones
Try stereo image sharpness
Try effect of frequency response balance to stereo image
Stereo image sharpness test