I am reading this book Designing Audio Effect Plugins in C++: For AAX, AU, and VST3 with DSP Theory. Here I implemented the Flanger effect. Quick summary: A flanger effect is basically a echo effect but the delay parameter is changed with an LFO oscillator to give the "flanging" sound.
Here is the graph:
My problem is this version of flanger only has the following properties:
In modern DJ equipments you see flanger with options such as "1beats,2beats,4beats...". What I noticed is The smaller lfoRate is the longer my flanger effect becomes. So If I set lfoRate around 10.26, my flanger becomes 1/8beats flanger. The book does not mention anything related to this. So I wonder what is the relationship between lforate and "Xbeats" of flanger. Lets say that my music is 128 bpm, is there is a special formula which is used to calculate lfoRate so that I have 4 beats flanger?