M
MarK_o

  • Feb 6, 2021
  • Joined Jan 24, 2021
  • 0 discussions
  • 0 posts
  • In Guitar Multi-FX processor

    Nice one, I finally made a phase-vocoder based time freezer, inspired to a variety of Electro-Harmonix effects.
    We'd like to have a library of effects among the examples, these should be mostly about the DSP and as less as possible about interfacing with it, with a clear interface so that they can be easily re-used by others as building blocks.
    It is going to be challenging to find the appropriate format, though, and my TimeFreezer, for one, is nowhere close to these specs as of now, but if anyone is interested in contributing or pitch in as to what format it should have, feel free to do so.

    I will open a dedicated thread later, but I am leaving this as food for thought ...

  • In Guitar Multi-FX processor
  • In Guitar Multi-FX processor

    Thanks. I'll move it to YouTube and see if I can get it to embed that way.

    giuliomoro What's the ethernet cable for?

    There is a metal tab on the front of the case that doesn't allow enough clearance for the USB cable. I was too lazy to disassemble everything when I discovered this so I started drilling the metal tab with Bela inside. As sound judgment would have told me, the drill slipped when it got through the metal and the bit tore off the USB connector. Now I have to use Ethernet to connect to Bela. I haven't inspected it closely enough to determine whether the USB connector tore up traces so I'm still holding onto hope I can repair it. For now I'm glad the BBB has a LAN port and that it is default configured for DHCP to obtain an IP address from my router.

    How do you power the unit?

    Currently I have a 5V wall-wart that I hacked from a cell phone charger or something. Not having a compatible jack I just stripped the wires and soldered them to the bottom of the Beagle board.

    That is a funny case! How many of the pots did you connect?

    The funny case is my experimentation chassis that I have had for years. It used to be a crazy analog envelope filter that I had disassembled to clean up, but then I never finished re-wiring and it sat in my junk box for years. It makes a really nice home for R&D on Bela.

    I have 8 of the pots connected but my current code uses a maximum of 7. I have it in my mind to reserve at least 1 analog input for the purpose of being able to connect external modulation sources. I have one plan to inject noise from a digital output through a resistor to the output of a Crybaby type wah then T that back into the Analog Input (AC-coupled). My circuit simulations indicate I can use the output impedance of the wah to get a spectral noise power density profile that I can process in software so the standard wah can be used as an expression pedal simply by connecting the output to Bela.

    I'm trying to decide whether I want to claim 1 more analog input for a voice channel for a vocoder, or whether to simply dual-purpose the 1 analog input. The other pots will be used for external analog pre and post-amps (input level & output level adjustment).

    Did you add a high-impedance buffer in front of Bela's input? Or do you drive the guitar through a non-true-bypass pedal before hand?

    A high-impedance buffer is on my todo list, but currently it's being driven through my amp's effects loop, so it's being driven by a relatively low-impedance source in the video. I have also connected directly to Bela input from my guitar and, as you observed in another thread, it sounds fine. I can detect the change of sound of my guitar somewhat but it's pretty subtle.

    giuliomoro though it makes me a bit seasick when your delay affects the pitch

    My wife thinks the same thing. It was a more extreme way of demonstrating envelope control on the LFO rate. It sounds more like a chorus effect when adjusted to sane amounts and the envelope pitch control helps it sound less mechanical.

    ...or if you're talking about the more extreme pitch change where the envelope was effecting delay time directly, this again can sound very pleasant when less extreme settings are used.