Zynthian Audio Equalizer in 1/3 octaves

Software
1

I would like to create a single-channel device that generates a pink or white noise. The signal will be conected or disconnect to an equalizer in bands of 1/3 octaves normalized, range from 20 Hz …, 100Hz, 160Hz, 200Hz, 315Hz, 400Hz, 500Hz, 630Hz, 800Hz, 1000 Hz, … 10KHz
All of this will be implemented with Zynthian Hw. The control of the sliders of the equalizer, ON OFF of the equalizer, volume, etc., would be from the color touch screen that suits well for zynthian and would use the sound card that you have better and recommend me to purchase. I will apreciate very much your ideas of what SW we can use for loading into the raspberry, how to proceed and, if some body, is interested to develop something special for this purpose. Thank you for your help and ideas.

2 Likes
2

There is a white noise lv2 generator plugin you can enable in the webconf. There are various equaliser plugins too. I don’t know about pink noise though.

3

You could use PureData (vanilla) for creating a patch that fit your needs. I would help you with the integration on zynthian vía MIDI CC. Anyway it’s quite easy and there are some good examples in the current SD image :wink:

Also, you could use this LV2-plugin for the Pink Noise generation:

For the equalizer, you can choose the LV2 plugin you like. There are a few included in the SD image.

Regards

4

I found this:

http://www.zamaudio.com/?p=976

That includes ZamGEQ31, 31 bands equalizer with 1/3 octave per band.

I’ve been testing and it works like a charm :wink:

Regards,

5

I also have tested this combination:

  • x42 Test Signal Generator (white noise, pink noise, etc)
  • ZamGEQ31

It works as expected, and i’ve included these plugins in the new Aruk image, so the requested functionality is perfectly achievable with the new zynthian image, Aruk, out-the-box :wink:

Regards,

6

Sorry @wyleu … here the audio sample :wink:

It starts with pure pink noise and after a few seconds you can hear how the 31 bands 1/3 octave equalization works.

So yes, now you can use your zynthian for acoustic analysis of rooms, halls, etc. You still need a good measurement device, but zynthian can do half the work. Perhaps in the future we can implement the other half too :wink:

Regards,

1 Like
7

I love this! When I started working in broadcast we would equalise circuits for best audio quality using big old equalisers chained together. It was rather laborious but rewarding task; spot frequency measurements, plotting on a graph, finding inverse curves that best matched and then noting down the equaliser settings then subsequently configuring audio chains with these equalisers in circuit. At the time I was eager to use my University project to provide a solution - that is to blast pseudo random noise down the line, measure the response and perform fast Fourier transform (FFT) and cross-correlation of the source and resulting data to get the impulse response from which to derive the required equalisation. You have piqued my interest in the concept of implementing the same feature within Zynthian! (But I doubt this will make it to the top of any of my lists in the foreseeable future :wink: .)

3 Likes