Make a spectrogram of any audio file online: log or linear frequency scale, adjustable range, a hover readout, and PNG download. Free, no upload.
The spectrogram tool draws a picture of the sound in an audio file. Time runs left to right, frequency runs bottom to top, and brightness shows how loud each frequency is at each moment. The whole file is analysed on your device, so a short click in a long recording still shows up. Hover over the image to read the exact time, frequency, and level under the pointer, click anywhere to play from that point, and download the result as a PNG with its axes included.
The logarithmic scale spaces frequencies the way hearing does and suits music and speech; linear gives every kilohertz equal height, which makes it easy to see where the high frequencies stop. That is the usual check for a lossy file dressed up as lossless — an MP3 saved as WAV or FLAC shows a flat ceiling, often around 16 kHz. A larger window separates notes that are close in pitch but blurs timing; a smaller one does the reverse. Your audio never leaves your device. What is a spectrogram explains what the shapes mean, and for a live view of sound as it happens, use the spectrum analyzer.
Time runs from left to right and frequency from low at the bottom to high at the top. Brighter areas are louder. A steady horizontal line is a constant tone such as mains hum, a vertical stripe is a short broadband sound such as a click or drum hit, and a stack of evenly spaced horizontal lines is a pitched note with its harmonics.
It can show strong evidence. Lossy encoders remove the highest frequencies, so a file that was once an MP3 or AAC usually has a sharp, flat cutoff, often between 16 and 19 kHz, even if it has since been saved as WAV or FLAC. Switch to the linear scale to see it clearly. A genuine CD-quality file normally carries content up to about 22 kHz, though some recordings are simply dark, so a cutoff alone is not proof.
It sets the trade-off between pitch detail and timing detail. A large window such as 8192 separates frequencies that are close together but smears short events sideways. A small window such as 1024 shows precisely when a sound happens but makes each frequency band thicker. 2048 is a balanced default for most audio.
Logarithmic, the default, gives every octave the same height from 20 Hz upward. That matches how we hear pitch and leaves plenty of room for bass, voices, and the notes of instruments. Linear spaces frequencies evenly from 0 Hz to the top of the range, so the bass is squeezed into a thin strip at the bottom while the highest frequencies take up most of the picture. Use linear when you are inspecting the top end, such as an encoder cutoff or a high-pitched whine.
Hum shows as a steady line at 50 or 60 Hz, depending on the local power grid, often with fainter lines at its multiples. Hover over it to read the frequency, using the logarithmic scale and a 4096 or 8192 window for precision. Heavy clipping often appears as bright vertical smears reaching high into the treble on the loudest moments. The dB in the readout is relative to the loudest point in the file, not to full scale, so it cannot confirm clipping on its own.