freeDSP - an open source 2-in 4-out digital crossover board

I really don't understand your point, who cares about witch OS to use to reach the target?

The OS is part of the system - and we want to be able to control and modify that part too.

Most important thing is to make something yourself, DIY. also who said that minidsp is cheap?

Exactly - so the DIY aspect should cover the OS too. It has nothing to do with price or money.
 
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How would you get Sigma Studio to run under Linux and if not who would write it to run under Linux ?

cheers

As discussed earlier, AD already wrote a linux network utility, whereby linux runs a network service that SigmaStudio can connect to remotely. The linux box is connected to the AD DSP and actually controls the device, and SigmaStudio just sends data/conifig/commands to the linux server via TCP/IP.

What this means is that all that is missing for full support in linux is the GUI.

As discussed, it is quite possible that the Windows GUI could be run in WINE, and then connected to the linux network service running on the same box (localhost).

I suppose you have to be a bit of a network nerd to see how this might work, but if I test it and confirm it to work, I will post simple instructions.
 
I just discovered freeDSP, and I am wondering the following since I am pretty unclear on the specifics.
I was looking at the datasheet for the ADAU1701, but most of it is above my knowledge level.
http://www.analog.com/static/imported-files/data_sheets/ADAU1701.pdf

1. Is it correct that the the six connections of the freeDSP are 2x RCA unbalanced analog stereo inputs and 4x RCA unbalanced analog stereo outputs?
2. Is it possible to feed the freeDSP an I2S audio source to the DSP for the outputs?
3. Does anybody anticipate that the noise floor might be at? I found this thread in which a diyaudio user posted miniDSP noise floor measurements:
http://www.diyaudio.com/forums/minidsp/251361-minidsp-2x4-noise-floor-2.html
 
Hey diynube,

thanks for your interest in freeDSP.

To answer your questions:

1. Yes it's 2 in, 4 out. But you could wire it in sigmaStudio to be 1 balanced in, 2 balanced out.

2. Yes that's actually possible. You could e.g. put a spdif-to-i2s board on top of the freeDSP to get digital inputs.
One of our students just designed a i2s-DAC board for freeDSP, too :) I'd you need more outputs.
3. I'm not quite sure about noise floor measurements, we will do them in the near future. MiniDSP uses the same DSP, so maybe it's not too bad as a noise floor reference.

enjoy your Christmas holidays! :)
 
Hey diynube,

I'm not quite sure about noise floor measurements, we will do them in the near future. MiniDSP uses the same DSP, so maybe it's not too bad as a noise floor reference.

As a perspective buyer of FreeDSP I would want to adress these issues vs MiniDSP.
I would buy two boards to be used as an active 4 way crossover.

The Noise floor
Maximum output voltage 0.9V
48kHz sampling rate, I think a minumum 96kHz for hi res audio.
Linux support

To adjust paramiters on the fly, without an aditional $80 for the USBI, are there alternatives?
I know that the sampling rate is done, what about the other points?
Would the ADAU1452 adress these issues, and future proof,then I would be prepared to pay more.



Many thanks
Ian
 
The first run of pre-orders just finished, that's the reason why you can't order any freeDSP-kits on our website anymore. Because this is a spare-time project for us, we cannot store pre-packed kits until someone calls us to buy them ;-)

For adjustments on the fly, I just heard about a cheap alternative for the USBi-programmer, somewhat like a USBi-clone.

You could buy the module on eBay: CY7C68013A 56 EZ USB FX2LP USB2 0 Develope Board Module Logic Analyzer EEPROM | eBay

And then refer to these topics:

ELEKTOR FORUMS • View topic - ADAU1701 Universal Audio DSP Board

https://ez.analog.com/thread/11612?start=30&tstart=0

USBee SX/ZX Hack - Project Server

USBee AX Pro reprogramming | Bits and Bytes

I just took a look into the ADAU1452, sounds pretty interesting. We will do some testing with it and try it out :)
 
I run SigmaStudio on a Windows XP virtual machine through linux. I know this isn't the principled solution you're after but its very practical. Using the Oracle distribution of virtualbox there is even USB support so you can flash MCUs using the USB JTAGS etc. It works really well.

The now legacy XP is so lightweight and near enough free (license from old pc) these days that I think its a no brainer unless you have a particular (idealogical?) reason not to. Its a handy tool for SigmaStudio and occasionally Powerpoint if I need to edit someones presentation without having the format messed up by LibreOffice.
 
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I run SigmaStudio on a Windows XP virtual machine through linux. I know this isn't the principled solution you're after but its very practical. Using the Oracle distribution of virtualbox there is even USB support so you can flash MCUs using the USB JTAGS etc. It works really well.

The now legacy XP is so lightweight and near enough free (license from old pc) these days that I think its a no brainer unless you have a particular (idealogical?) reason not to. Its a handy tool for SigmaStudio and occasionally Powerpoint if I need to edit someones presentation without having the format messed up by LibreOffice.

Certainly this is the best option and one that I have considered, but I'm limited by the fact that I would like to use a rather modestly-powered netbook for this purpose. I use VirtualBox for other purposes on much more powerful systems and I love it, but on an Atom N270 with 1GB RAM... :eek:

P.S. Ideologically speaking, I do still think it is silly that SigmaStudio requires Widows. Seems to me like a huge "miss" on the part of AD.
 
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For adjustments on the fly, I just heard about a cheap alternative for the USBi-programmer, somewhat like a USBi-clone.

And then refer to these topics:

ELEKTOR FORUMS • View topic - ADAU1701 Universal Audio DSP Board

https://ez.analog.com/thread/11612?start=30&tstart=0

Interesting to see that Analog's BrettG at least is eager to open the USBi firmware now, but they are still having discussions with the legal department.

Forget the drag'n drop DSP - instead of SigmaStudio it would be better to develope an open source alternative. One way could be some kind of Python generator like what Next DSP's Mark Seel used with Wavefront DSP:

https://sites.google.com/site/nextaudiodsp/

See the nextdsp.zip package there. The idea is to write blocks or modules which can then be compined and loaded to DSP. The code generation uses python yield generator keyword, see Improve Your Python: 'yield' and Generators Explained for an introduction to python generators.
 
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Unfortunately there is no documentation on ADAU1701 assembler language (machine code), SigmaStudio is only way to program the chip:

https://ez.analog.com/message/117495

However, it would be possible to design an algorithm in SS and the update the parameters (like biquads for the filters) to the DSP separately once the parameter location has found from the generated code.

Actually when you to the Action -> Export System Files you will get the file name <project name>.params which contains all needed information to upload new parameters for EQ's etc. It's just that you have to generate the .hex file for each different flow in SS. You event get the header files for C.
 
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