The miniDSP 8x8 is a great board and assumed to be targeting DIY’ers in kit form. However, as neat and easy to use the plugin may be, it does not allow to do much extra with the board other than crossovers or similar. What a waste!
I plan to use mine for a LXMini2 front speaker pair (three drivers) and a LXmini 2-way centre so the 8 outputs are perfect, only three inputs required. The plugin is ok for this but I also want to implement a few other features, such as tilt control, etc. Using the plugin’s four config’s is clunky at best, waiting for the dsp to be reloaded whilst listening to clicks is hardly user friendly!
My solution uses SigmaStudio to give me freedom of design and a Teensy 4 to setup the DSP and DAC instead of the on-board PIC microcontroller. As well as setting up the CODEC and DSP on startup, the Teensy can then provide remote control receive and control any DSP functions via the multipurpose I/O lines.
Some other uses could be to configure the analogue inputs in stereo pairs and switch between them for seamless source selection, something else the plugin does not allow for. I think 192KHz sampling rate should also be possible without having to restrict to just 2 analogue inputs with the 4x8 plugin.
Hardware modification of the board consists of adding just one resistor where there are already pads available, all other connections can be made via existing headers. Warranty of the board is assumed to be null and void once one starts to mess with it!
Project is still a work in progress but board analysis is complete and the basics are all now working. The concept is to keep the onboard PIC in permanent reset mode by pulling down the /MCLR pin via the PIC programming header on the board. This means the board has 100% backwards ability to stock mode of working. Via I2C, DSP reset and CODEC reset it is possible to program the board from the USBi SigmaStudio interface for development and then a Teensy for the final version, although the CODEC setup is only via the Teensy so a workaround is required when working with USBi.
Ok, sufficient for a first post, but if anyone has an interest in this project I’m happy to share details.
I plan to use mine for a LXMini2 front speaker pair (three drivers) and a LXmini 2-way centre so the 8 outputs are perfect, only three inputs required. The plugin is ok for this but I also want to implement a few other features, such as tilt control, etc. Using the plugin’s four config’s is clunky at best, waiting for the dsp to be reloaded whilst listening to clicks is hardly user friendly!
My solution uses SigmaStudio to give me freedom of design and a Teensy 4 to setup the DSP and DAC instead of the on-board PIC microcontroller. As well as setting up the CODEC and DSP on startup, the Teensy can then provide remote control receive and control any DSP functions via the multipurpose I/O lines.
Some other uses could be to configure the analogue inputs in stereo pairs and switch between them for seamless source selection, something else the plugin does not allow for. I think 192KHz sampling rate should also be possible without having to restrict to just 2 analogue inputs with the 4x8 plugin.
Hardware modification of the board consists of adding just one resistor where there are already pads available, all other connections can be made via existing headers. Warranty of the board is assumed to be null and void once one starts to mess with it!
Project is still a work in progress but board analysis is complete and the basics are all now working. The concept is to keep the onboard PIC in permanent reset mode by pulling down the /MCLR pin via the PIC programming header on the board. This means the board has 100% backwards ability to stock mode of working. Via I2C, DSP reset and CODEC reset it is possible to program the board from the USBi SigmaStudio interface for development and then a Teensy for the final version, although the CODEC setup is only via the Teensy so a workaround is required when working with USBi.
Ok, sufficient for a first post, but if anyone has an interest in this project I’m happy to share details.
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Further to the above, I've been thinking about an example demo project as my real project for the LXmini crossover and filtering cannot be exposed here as this would go against the contruction plans licencing.
The attached block diagram shows a 4 x stereo input to 2-way active main speaker outputs with the addition to drive four subs with individual filtering using, say, the output of MultiSubOptimiser or similar. Remote and local controls to be supported, together with a small display - I have a 1.54" 256x256 colour LCD module here, so that's what it will be!
This will be a skelton SigmaStudio project for the user to tweak as required and an Arduino sketch for the Teensy.
The attached block diagram shows a 4 x stereo input to 2-way active main speaker outputs with the addition to drive four subs with individual filtering using, say, the output of MultiSubOptimiser or similar. Remote and local controls to be supported, together with a small display - I have a 1.54" 256x256 colour LCD module here, so that's what it will be!
This will be a skelton SigmaStudio project for the user to tweak as required and an Arduino sketch for the Teensy.
Hi Bill,
I'll be posting details shortly. In the meanwhile, if you haven't already then set yourself up with the following:
Account with login to Analog Devices and download SigmaStudio.
Arduino environment with Teensy addins from PRJC.
Teensy 4 module, ideally with pins or solder in your own headers, a prototyping block and some jumper wires, mostly pin to socket, some pin to pin.
I'll be posting details shortly. In the meanwhile, if you haven't already then set yourself up with the following:
Account with login to Analog Devices and download SigmaStudio.
Arduino environment with Teensy addins from PRJC.
Teensy 4 module, ideally with pins or solder in your own headers, a prototyping block and some jumper wires, mostly pin to socket, some pin to pin.
The connection points are shown in the attached pdf.
Software to follow when I've tidied it up and added some example control features. Currently it configures the board in a basic in to out mode, decodes remote and sets up the display.
My current lash-up:
Software to follow when I've tidied it up and added some example control features. Currently it configures the board in a basic in to out mode, decodes remote and sets up the display.
My current lash-up:
Attachments
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Project document has now been updated to include the software instructions. Software is in the zip file attached.
Should be sufficient information to get up and running. I would suggest the project is not at beginner level, but not at a particularly advanced level either.
Anyone already familiar with Arduino would be off to a good start. Add familiarity with SigmaStudio and you will be off to a flying start!
Please post back here if I've missed something and also to let me know if this has been useful.
Should be sufficient information to get up and running. I would suggest the project is not at beginner level, but not at a particularly advanced level either.
Anyone already familiar with Arduino would be off to a good start. Add familiarity with SigmaStudio and you will be off to a flying start!
Please post back here if I've missed something and also to let me know if this has been useful.