# How to make log-Mel spectrogram?
**URL:** https://discourse.julialang.org/t/how-to-make-log-mel-spectrogram/97927
**Category:** General Usage
**Tags:** question, machine-learning, dsp, audio
**Created:** [April 26, 2023, 4:08am UTC](https://discourse.julialang.org/t/how-to-make-log-mel-spectrogram/97927 "2023-04-26T04:08:02Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@jling](https://discourse.julialang.org/u/jling)
#### Post date: [April 26, 2023, 4:08am UTC](https://discourse.julialang.org/t/how-to-make-log-mel-spectrogram/97927/1 "2023-04-26T04:08:03Z")
The eventual goal is to make a pure Julia Whisper inference, but got stopped before 1st step.
Most ingredients of the spectrogram is simply a combination of hanging window and stft:
>
in Julia, we can find them in DSP.jl([Periodograms - periodogram estimation · DSP.jl](https://docs.juliadsp.org/latest/periodograms/#DSP.Periodograms.spectrogram))
but where can I find the mel filterbank matrix? which is some audio specific scaling model
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### Author:  [@rafael.guerra](https://discourse.julialang.org/u/rafael.guerra)
#### Post date: [April 26, 2023, 7:11am UTC](https://discourse.julialang.org/t/how-to-make-log-mel-spectrogram/97927/2 "2023-04-26T07:11:46Z")
To make a log-Mel spectrogram from a DSP spectrogram, I believe you need to transform the frequency axis according to the [Mel-scale formula](https://en.wikipedia.org/wiki/Mel_scale) and display the amplitudes in dB.
Linking also this [“related” thread](https://discourse.julialang.org/t/plotting-a-spectrogram-using-dsp-jl/58013).
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### Author:  [@pywugate](https://discourse.julialang.org/u/pywugate)
#### Post date: [June 19, 2024, 4:09pm UTC](https://discourse.julialang.org/t/how-to-make-log-mel-spectrogram/97927/3 "2024-06-19T16:09:05Z")
You can also take a look of [MFCC.jl](https://github.com/JuliaDSP/MFCC.jl) , [MusicProcessing.jl](https://github.com/JuliaMusic/MusicProcessing.jl) and [SpeechFeatures.jl](https://github.com/lucasondel/SpeechFeatures.jl)