fred_france
Active member
Hello,
I am a beginner in the world of Teensy, and I bought a version 4.0 + the audio adapter.
I want to experiment audio filters (bandpass, high pass, low pass).
For this, I want to use an FIR filter, but I can't seem to get any valid response curves.
To start, I tried the example provided in Audio / Effects / Filter_FIR, and I measured the frequency response of the low pass filter: the shape is correct, but I only have -10dB of attenuation at 2Khz instead of -60 dB as advertised in the demo sketch.
Moreover, I tried to generate my own tables of coefficients with a tool (http://t-filter.engineerjs.com/), by setting: 44117hz, 200 taps, and changing "static int" to "const short ”, the results curves are catastrophic.
I noticed that the examples found on the internet are for a Teensy v3.x and not for v4, maybe some settings need to be adapted for my version 4?
thanks a lot for your help
(sorry for my bad english)
I am a beginner in the world of Teensy, and I bought a version 4.0 + the audio adapter.
I want to experiment audio filters (bandpass, high pass, low pass).
For this, I want to use an FIR filter, but I can't seem to get any valid response curves.
To start, I tried the example provided in Audio / Effects / Filter_FIR, and I measured the frequency response of the low pass filter: the shape is correct, but I only have -10dB of attenuation at 2Khz instead of -60 dB as advertised in the demo sketch.
Moreover, I tried to generate my own tables of coefficients with a tool (http://t-filter.engineerjs.com/), by setting: 44117hz, 200 taps, and changing "static int" to "const short ”, the results curves are catastrophic.
I noticed that the examples found on the internet are for a Teensy v3.x and not for v4, maybe some settings need to be adapted for my version 4?
thanks a lot for your help
(sorry for my bad english)