Tag: DSP

Spotify segment analysis player in Max

Echo Nest API audio analysis data is now provided by Spotify. This project is part of the internet-sensors project: https://reactivemusic.net/?p=5859  and updates the 2013 Echo Nest project described here: https://reactivemusic.net/?p=6296

 

The original analyzer document by Tristan Jehan can be found here (for the time being):  https://web.archive.org/web/20160528174915/http://developer.echonest.com/docs/v4/_static/AnalyzeDocumentation.pdf

This implementation uses node.js for Max instead of Ruby to access the API. You will need set up a developer account with Spotify and request API credentials. See below.

Other than that, the synthesis code in Max has not changed.  Some of the following background information and video is from the original version. ..

What if you used that data to reconstruct music by driving a sequencer in Max? The analysis is a series of time based quanta called segments. Each segment provides information about timing, timbre, and pitch – roughly corresponding to rhythm, harmony, and melody.

spotify-synth1.maxpat

download

https://github.com/tkzic/internet-sensors

folder: spotify2

files

main Max patch
  • spotify-synth1.maxpat
abstractions and other files
  • polyvoice-sine.maxpat
  • polyvoice2.maxpat
node.js code
  • spot1.js
node folders and infrastructure
  • /node_modules
  • package-lock.json
  • package.json
dependencies:
  • You will need to install node.js
  • the node package manager will do the rest – see below.

Note: Your best bet is to just download the repository, leave everything in place, and run it from the existing folder

authentication

You will need to sign up for a developer account at Spotify and get an API key. https://developer.spotify.com/documentation/general/guides/authorization-guide/

Edit spot1.js replacing the cliendID and clientSecret with your spotify credentials

node for max install instructions (first time only)

  •  Open the Max patch: spotify-synth1.maxpat
  •  Scroll the patch over to the far right side until you see this green panel:

  • Click the [script npm init] message – this initializes the node infrastructure in the current folder
  • Then click each of the 2 script npm install messages –  this installs the necessary libraries

Instructions

  •  Open the Max patch: spotify-synth1.maxpat
  •  Click the green [script start] message
  • Click the Speaker icon to start audio
  • Click the first dot in the preset object to set the mixer settings to something reasonable
  • open the Max Console window so you can see the Spotify API data
  • From the 2 menus at the top of the screen select an Artist and Title that match, for example: Albert Ayler and “Witches and Devils”
  • Click the [analyze] button – the console window should fill with interest data about your selection.
  • Click [play]
  • Note: if you hear a lot of clicks and pops, reduce the audio sample rate to 44.1 KHz.
Alternative search method:

Enter an Artist and Song title for analysis, in the text boxes. Then press the buttons for title and artist. Then press the /analyze button. If it works you will get prompts from the terminal window, the Max window, and you should see the time in seconds in upper right corner of the patch.

troubleshooting

If there are problems with the analysis, its most likely due to one of the following:

  • artist or title spelled incorrectly
  • song is not available
  • song is too long
  • API is busy
Mixer controls

The Mixer channels from Left to right are:

  • bass
  • synth (left)
  • synth (right)
  • random octave synth
  • timbre synth
  • master volume
  • gain trim
  • HPF cutoff frequency
You can also adjust the reverb decay time and the playback rate. Normal playback rate is 1.

programming notes

Best results happen with slow abstract material, like the Miles (Wayne Shorter) piece above. The bass is not really happening. Lines all sound pretty much the same. I’m thinking it might be possible to derive a bass line from the pitch data by doing a chordal analysis of the analysis.

Here are screenshots of the Max sub-patches (the main screen is in the video above)

Timbre (percussion synth) – plays filtered noise:

Random octave synth:

Here’s a Coltrane piece, using roughly the same configuration but with sine oscillators for everything:

There are issues with clicks on the envelopes and the patch is kind of a mess but it plays!

Several modules respond to the API data:

  • tone synthesiszer (pitch data)
  • harmonic (random octave) synthesizer (pitch data)
  • filtered noise (timbre data)
  • bass synthesizer (key and mode data)
  • envelope generator (loudness data)

Since the key/mode data is global for the track, bass notes are probable guesses. This method doesn’t work for material with strong root motion or a variety of harmonic content. It’s essentially the same approach I use when asked to play bass at an open mic night.

additional notes

Now that this project is running again. I plan to write additional synthesizers that follow more of the spirit of the data. For example, distinguishing strong pitches from noise.

Also would like to make use of  the [section] data as well as the rhythmic analysis. There is an amazing amount of potential here.

Building SoapySDR and CubicSDR with Linux

How to build SoapySDR and CubicSDR from source in Ubuntu 20.04

After unsuccessful attempts to compile SoapySDR and CubicSDR on Mac OS and Windows, I was able to get it running in Ubuntu 20.04.  The whole process took about 2 hours but could be done in less time if you know what you are doing.

It wasn’t really necessary to install CubicSDR to test SoapySDR. But CubicSDR is the only SoapySDR app that consistently works when it comes to devices, I/Q, files and TCP frequency control.

After completing this install I was also able to compile and run the SoapySDR example code here:  https://github.com/pothosware/SoapySDR/wiki/Cpp_API_Example

Build

There are excellent instructions at the CubicSDR wiki on github: https://github.com/cjcliffe/CubicSDR/wiki/Build-Linux

I also added the rtlsdr driver and the airspyhf driver. Instructions for rtlsdr are on the wiki. Instructions for airspyhf are below. You can add these drivers/libraries at any time, after SoapySDR is installed.

There were several missing libraries – described here.

hamlib

Hamlib is an option in CubicSDR. It was included because we’re using it to send frequency data to the devices via rigctld. You’ll need to install hamlib before you try to compile CubicSDR

Instructions and source code here: https://github.com/Hamlib/Hamlib

Instructions are somewhat vague. Here’s what I did.

Install libtool:

sudo apt install libtool

Clone the repository, build, and install:

git clone https://github.com/Hamlib/Hamlib.git
cd Hamlib
./bootstrap
./configure
make
sudo make install

airspyhf

airspyhf library code from Airspy. Instructions here: https://github.com/airspy/airspyhf

This is what I did, if I can remember correctly. You may need to install libusb, but if you have done all the stuff above you probably already have it.

git clone https://github.com/airspy/airspyhf
cd airspyhf
mkdir build
cd build
cmake ../ -DINSTALL_UDEV_RULES=ON<
make
sudo make install
sudo ldconfig

SoapyAirspyHF

Now you can add the Soapy AirspyHF drivers. Instructions here:  https://github.com/pothosware/SoapyAirspyHF/wiki

git clone https://github.com/pothosware/SoapyAirspyHF.git
cd SoapyAirspyHF
mkdir build
cd build
cmake ..
make
sudo make install

 

Max8radio CubicSDR I/Q prototype

Another working prototype with Max and CubicSDR

Now working some better… The Max SDR patch is receiving an IQ audio stream at 96 KHz from CubicSDR and sending frequency data to rigctld daemon via a python script that recodes OSC to tcp data.

repository: https://github.com/tkzic/max8radio

Files:

max8sdr1.maxpat

py3rigctl2.py (python script)

Instructions:

Basically the same as instructions in the previous prototype here: https://reactivemusic.net/?p=19995

make sure to start the rigctl daemon before CubicSDR

 rigctld -m 1 4532 & 

And make sure there is some audio gain on CubicSDR

But… There is only one Max patch now and – after you start the rigcltd daemon, you need to run the python script in the max8radio folder like this:

python3 py3rigctl2.py

The most important thing is to start CubicSDR first before you run the Max patch. Make sure to get everything working correctly. Then start the Max SDR.

In CubicSDR make sure you only have one “modem” running – otherwise the IQ data stream will be a complete mess. Als0 make sure that the audio sample rate in CubicSDR is set to 96 KHz. It will revert to 48 KHz. everytime you load the program. You can use the ‘bookmarks’ from a previous CubicSDR session (lower left part of the screen) to load a previous session with the same parameters.

These are the necessary settings:

  • I/Q modem
  • Audio out: Existential Audio Inc. Blackhole 2 ch.
  • Audio sample rate: 96 KHz.
  • Rig Control Menu: enable rig and follow rig should be ‘checked’
  • Frequency should equal Center frequency and the V delta lock toggle should be on
  • Demodulator Gain level should be very low to prevent excess AGC (upper right corner)

Actually if you have loaded everything ok in a previous session, try this:

  • get the rigctld daemon running from the command
  • load CubicSDR
  • First thing: click ‘enable rig’ under rig control (this will probably load some crazy frequency like 145 Mhz
  • Then in the bookmarks (lower left) double click on your previous session, under ‘recents’ for example: 7007MHzI/Q – this should restore almost all the settings.
  • Then change the audio sample rate to 96 KHz if needed.
  • If the input to Max seems wrong, try clicking the S  (over near the top right)  to solo the modems. There may be more than one going.

Max settings

  • Set audio input to Blackhole 2ch @ 96 KHz. (to match output from CubicSDR
  • Click the ‘flip IQ’ toggle – for some reason CubicSDR sends out the I/Q signal flipped
  • The arrow key tuning and all other tuning methods should work now

Notes

One of the problems with CubicSDR is sometimes you’ll accidentally change something and all the settings go crazy.

note: I tried a new version of CubicSDR (2.6) from the sdrplay website. It would not detect any connected devices or audio drivers.

Once you get it working, the audio quality inside Max is excellent – using the Airspy HF+

RF noise reduction

image001

Notes

RF mixer simulation in Max

Audio simulation of an RF circuit.

Screen Shot 2015-03-29 at 4.49.36 PM

The simulation serves no purpose, but its fun. There are 4 versions. I think the third one sounds best (rf-mixer-sim3.maxpat). Its interesting to hear how much spectral distortion happens from multiplying sawtooth waves.

Screen Shot 2015-03-29 at 4.46.55 PM

Download

https://github.com/tkzic/max-projects/

folder: rf-mixer

patches:

Note: please set the signal vector size to 1 (or as low as possible) and enable overdrive and audio interrupt

Screen Shot 2015-03-29 at 5.22.30 PM

Four versions:

  • rf-mixer-sim.maxpat (initial attempt)
  • rf-mixer-sim2.maxpat (uses sah~ and rate~ objects)
  • rf-mixer-sim3.maxpat (uses gate~ objects with a phasor~ clock)
  • rf-mixer-sim4.maxpat (bandpass filter on RF input)