# Allocation-less, perhaps planned, Constant Q transform

**URL:** <https://discourse.julialang.org/t/allocation-less-perhaps-planned-constant-q-transform/111694>\
**Category:** Signal and Image Processing\
**Tags:** dsp\
**Created:** [March 16, 2024, 12:04pm UTC](https://discourse.julialang.org/t/allocation-less-perhaps-planned-constant-q-transform/111694 "2024-03-16T12:04:22Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Benny](https://avatars.discourse-cdn.com/v4/letter/b/49beb7/32.png) [@Benny](https://discourse.julialang.org/u/Benny)\
**Post date:** [March 16, 2024, 12:04pm UTC](https://discourse.julialang.org/t/allocation-less-perhaps-planned-constant-q-transform/111694/1 "2024-03-16T12:04:22Z")

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I’m reading up on FFTs and STFTs again for 1D real data, and eliminating startup work and allocations with rFFT plans looks promising. I’m also interested in spacing the frequency bins logarithmically like how musical pitches are, but I can’t find an up-to-date ready-to-use option for planning constant Q transforms, let alone a real one. I’m reading that it can be computed with FFT, but I lack the fundamental knowledge to implement it. Any pointers will be great.

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**Author:** ![rafael.guerra](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/rafael.guerra/32/216610_2.png) [@rafael.guerra](https://discourse.julialang.org/u/rafael.guerra)\
**Post date:** [March 16, 2024, 1:40pm UTC](https://discourse.julialang.org/t/allocation-less-perhaps-planned-constant-q-transform/111694/2 "2024-03-16T13:40:57Z")

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Check this:  
[GitHub - r9y9/ConstantQ.jl: A fast constant-q transform in Julia](https://github.com/r9y9/ConstantQ.jl)