Audio Effects DSP Board

[markseel]

That's awesome - those multicolor LED's look fantastic.  It would be really cool to have a box with maybe three of these, some foot-switches, and MIDI output to the FlexFX board.  The cap-sense is really interesting too.

Over the weekend I came across these:

http://www.ebay.com/itm/1-3-Annular-LED-Ring-Display-Green-Bars-Red-Dot-Rotary-Encoder-or-Clock-/251437248842?hash=item3a8ad3f14a:g:saQAAOxyrM5TJHaW

Nice.  Maybe those could be combined with the free electron's PSOC solution.

[markseel]

The FlexFX digital board layout is complete and ready for a prototype production run!

[imaradiostar]

Looks good! Is it going to Osh?

Is there a mating board with a pair of AK4556's and a regulator for 9v guitar input? Should I design one?

What about a bluetooth module? That of course assumes a mating software tool. I'm assuming your USB based application could be adapted to bluetooth. I know a guy that writes android code for a living, maybe I could recruit him.



Jamie

[markseel]

I can't sent this to OSH I don't think unless they're able to place that BGA on the board for me.  I'll check.

http://Is there a mating board with a pair of AK4556's and a regulator for 9v guitar input? Should I design one?

I'm designing an audio board but it's not exactly like the one you're describing.  I'd be more than happy to collaborate on that.  Do you do PCB layout?  If not I can design the PCB and put it up on OSH Park.

http://What about a bluetooth module?

Totally agree that BLE would be a good way to control effects.  I've done BLE firmware development on various embedded projects so happy to help with this if folks are interested.  The board's UART TX/RX can be used to comminate with a BLE module that runs a complete BLE stack (like the BlueGiga BLE112/BLE113).  You can program these and have them exchange data with the DSP board via those UART lines.

http://I know a guy that writes android code for a living, maybe I could recruit him.

That'd be cool.  Same with iOS.  I'd like to be able to control the effects/DSP board from a mobile app.

[imaradiostar]

In all honesty I've not done any real digital board design in Eagle or the like. I seem to recall using PCB123 or somesuch but that was ages ago. I've designed quite a few stencil transfer jobs and even produced the artwork using vizio so that they looked nice but that's nowhere near the same thing. I've only recently started again on that sort of work once I realized that Osh is so cheap and can do a four layer board.

All bluetooth posturing aside- I think your idea is good and the best way to get traction is to get it built and working. A computer based interface and dev environment was your goal anyway, right? Forget bluetooth, get it built.

One thing I HAVE done, though, is solder BGAs. I have an oven at work. We'll talk.

Jamie

[markseel]

For my effects I'm doing this:

Mono Input --> Digital Preamp * 2 --> Graphic EQ * 2 --> Modulation * 2 --> Mixer/Spatializer --> Cabsim --> Stereo Output

There's two preamp/EQ/modulation blocks so that they can be run in parallel and mixed to create a thicker sound. 

The digital preamps model 3-stage triode gain stages.  Each 3-stage preamp feeds a 9-band graphic EQ for final tone shaping.  The EQ's frequencies and gains can all be adjusted (so an EQ's frequency bands can be tailored to shaping interests).  And those two then each feed separate 3-voice modulators (chorus/flanger/delay).  So two independent effects chains.

Both preamp/EQ/modulator effects audio paths feed a mixer and spatializer (mono to stereo conversion).  The mixer allows the two preamp/EQ/mod paths to feed a left channel and right channel cab simulator with the desired mixes.  The spatializer allows the use of a single preamp/EQ/mod channel to feed stereo cab sim's (mono-to-stereo conversion).  Using a mono cab sim vs stereo cab sim allows for longer IR's.  And using one preamp/EQ/mod rather than two also allows for larger cab sim IR's.  The cab sim IR length grows to water MIP's is available after configuring the preamp/EQ/modulator effects.  Also; the preamp or modulator for each effects chain can be enabled/disabled - further freeing up MIP's for longer IR's.  Therefore the IR support ranges from 10 msec to 80 msec depending on effects configuration.

The preamp/EQ/modulator effects are fully parameterized.  There's a total of ~70 parameters ...

Preamp: 10 for each of the 3 preamp stages
GraphicEQ: Final gain, 9 band frequencies, 9 band gains
Modulator: 9 for each of the 3 voices

... allowing the effects designer to experiment and create something new, or to model something that already exists.  A GUI app to aid with this is in the works.  All parameters are accessable via USB MIDI and/or serial UART MIDI.

[markseel]

These IR's are in WAV format.  This board and effects framework will support them at the 48 kHz sample rate.
https://www.celestionplus.com
https://www.celestionplus.com/ir-overview/

[dapeegoo]

Hi Mark,

I just sent you a PM. Are you selling your IR loader pedal yet? Would love to try it out!

[orbitbot]

I also do Android (amongst other) programming for a living, so I could probably chip in somewhere or at least give a codebase a lookover. I have just gotten started on doing embedded & audio stuff so that territory isn't as familiar yet. Regarding the whole bluetooth implementation idea though, do you all feel this is an appropriate action to take at this point in time? Reading through the post history I get the feeling that perhaps the main board should get onto solid ground and into end users hands before its that feasible to start tweaking (I see Android & BT functionality as something further down the line).

[markseel]

Are you selling your IR loader pedal yet?

Not yet.  After I have enough money to make the prototypes and prove that the HW design is correct then I'll look to produce these in larger quantity.  Hopefully soon!

... do you all feel this is an appropriate action to take at this point in time?

Not for me as I'm focused on getting the XMOS board and the effects/cabsim SDK finished.  The board is fairly basic - USB, DSP, and I/O's for I2S, I2C, and UART.  One could add support for a external BT or BLE module though.

[markseel]

Prototype boards are in production!
Should be ready for testing in 1 to 2 weeks.

[markseel]

Prototype boards are back and ready for testing.
32 cores and 2000 MIPS in a small package!

[Ice-9]

These are looking great Markseel, I look forward to your testing results.

[micromegas]

Those boards look nice indeed! Lots of power in such a small package

[markseel]

Board works    Can load and run firmware via JTAG.  Next up I'll finalize the development kit for a first release (it's in Github if you want to see a prelim version).  Will also have a stereo cab simulator (impulse response convolution) ready soon as an example app for the dev kit.

[Ice-9]

Board works    Can load and run firmware via JTAG.  Next up I'll finalize the development kit for a first release (it's in Github if you want to see a prelim version).  Will also have a stereo cab simulator (impulse response convolution) ready soon as an example app for the dev kit.

Great progress, please count me in for a board when you are ready to release them Mark,   

[markseel]

Will do.  Hopefully we can get lots of folks interested in order to decrease the cost per board.

[micromegas]

Will do.  Hopefully we can get lots of folks interested in order to decrease the cost per board.

I am definitely interested in one

[orbitbot]

I'd also be interested in a board when the time comes along, although I'm still a bit wary of construction complexity and screwing up something expensive while trying to DIY. Which is to say that I'm a bit price-sensitive, but following the development with great interest A Kickstarter or something as mentioned earlier in the thread sounds like a reasonable approach to me.

[markseel]

... a bit wary of construction complexity and screwing up something...

Can you elaborate on that?  Maybe there's something we can do to make adoption easier.  The boards will be fully assembled so you'd have to add mounting screws and a 100-mil pin header or perhaps solder wires to the header holes.

Also, a cheap guitar/analog interface board is in the works so then you'd just have to connect it to the XMOS board and wire up your audio jacks and switches and what-not.  Thoughts?