Visual Acoustic April 2026

Acoustic Calculators

Room Modes

Calculate axial, tangential, and oblique standing wave frequencies for any rectangular room. Identify bass buildup, nulls, and problematic mode clusters that colour your low-frequency response.

RT60 Reverberation Time

Estimate reverberation time using the Sabine equation. Assign materials to each surface and compare the result against ideal RT60 values for studios, classrooms, offices, and concert halls.

Delay Time (BPM to MS)

Convert any tempo to millisecond delay times for straight, dotted, and triplet note values. Copy precise values for delay, reverb pre-delay, and modulation sync in your DAW or hardware.

Decibel (SPL)

Combine multiple sound sources logarithmically, calculate inverse-square-law attenuation over distance with hearing safety indicators, and convert between dBV, dBu, and volts.

Sound Wavelength

Find the wavelength and quarter-wavelength absorber depth for any frequency in air, adjusted for temperature. Includes a reverse mode and reference table of common musical frequencies.

Frequency to Note

Convert any frequency in hertz to its nearest musical note and cents deviation using 12-TET equal temperament. Supports adjustable A4 reference pitch and includes a reverse note-to-frequency lookup.

Helmholtz Resonator

Design a Helmholtz resonator or panel absorber for targeted low-frequency acoustic treatment. Calculate resonant frequency from cavity volume, neck dimensions, and panel mass for DIY bass traps.

Critical Distance

Calculate the critical distance where direct and reverberant sound are equal in a room. Essential for optimal speaker placement, microphone positioning, and acoustic measurement accuracy.

Speaker Crossover

Calculate passive crossover component values for loudspeaker systems. Supports Butterworth and Linkwitz-Riley topologies in 1st through 4th order for any crossover frequency and impedance.

Sound Transmission Loss

Calculate the transmission loss of walls and partitions using the mass law. Compare single-wall and double-wall constructions, and estimate STC ratings for soundproofing and noise isolation.

Equal Loudness Contour

Calculate perceived loudness in phons and sones from frequency and SPL using ISO 226:2003 equal loudness contour data. Understand how human hearing sensitivity varies across the frequency spectrum.