DIY digital xover, what do you think?

[bogicp]

Hi all,

Ok, I'm probably... hm, but never mind, what do you think about this?



I see that almost all things needed for xover already exist and because tools for FPGA are free of charge, why not ?

Any opinions will be highly appreciated.

Best regards,

boggy

[ShinOBIWAN]

The Spartan DSP is used in the RME HDSP series. Very good DSP.

[bogicp]

Hello ShinOBIWAN,

Thank you for your reply,

Originally posted by ShinOBIWAN
The Spartan DSP is used in the RME HDSP series. Very good DSP.

Actually, Spartan isn't dedicated DSP chip, it's FPGA - a Field Programmable Gate Array, they can do all digital tasks if you program it for this and if chip size is large enough for your tasks.
You can put in same chip, for example, 8bit microcontroller, DSP core, USB core, UART core, etc..
etc...
All wiring you can do inside chip, and this can be very, very fast...

Yes, it's used also in Apogee, Lynx, ... devices.

You cannot expect to have DSP functions for free of charge, but you can do it by yourself for free of charge ... with dedicated DSP chips you must buy programming tools... with FPGA you may use free tools...
This is some of more reasons why FPGA

Best regards,

Boggy

[ShinOBIWAN]

Originally posted by bogicp
Hello ShinOBIWAN,

Thank you for your reply,




Actually, Spartan isn't dedicated DSP chip, it's FPGA - a Field Programmable Gate Array, they can do all digital tasks if you program it for this and if chip size is large enough for your tasks.
You can put in same chip, for example, 8bit microcontroller, DSP core, USB core, UART core, etc..
etc...
All wiring you can do inside chip, and this can be very, very fast...

Yes, it's used also in Apogee, Lynx, ... devices.

You cannot expect to have DSP functions for free of charge, but you can do it by yourself for free of charge ... with dedicated DSP chips you must buy programming tools... with FPGA you may use free tools...
This is some of more reasons why FPGA

Best regards,

Boggy

I always thought FPGA stood for Flat Pin Grid Array and was used as a term for surface mounting CPU's in PC's to the mothermoard ala. SMD.

Consider me re-educated

The Spartan is indeed a very flexible chip and the quality amd speed isn't bad either My RME HDSP3264 and HDSP5264 continue to impress me. They are used as a software based XO with FIR filters and DRC.

How much is Spartan charging for the FPGA? Are they demo boards? What about SHARC's?

[bogicp]

Originally posted by ShinOBIWAN


I always thought FPGA stood for Flat Pin Grid Array and was used as a term for surface mounting CPU's in PC's to the mothermoard ala. SMD.

Consider me re-educated

No problem

The Spartan is indeed a very flexible chip and the quality amd speed isn't bad either My RME HDSP3264 and HDSP5264 continue to impress me. They are used as a software based XO with FIR filters and DRC.

How much is Spartan charging for the FPGA?

At http://www.nuhorizons.com you can find XC3S1500 in FG456 package for about $80, for other devices (smaller packages, for example, are cheaper) you may contact it. Other providers for Xilinx devices are Digikey (they don't have Spartan3 devices) and Memec.

Are they demo boards?

Yes, look at link

What about SHARC's?

You must buy Analog Devices software tool for SHARC. Xilinx provide software tool for free (you can use it for maximum Spartan 3 with 1,500,000 gates chips, and this is enough for most of applications)

With FPGA you must buy only chips, not tools.

With FPGA you can do DSP more efficiently than with dedicated DSP chips, but FPGA DSP isn't easy to program in copy/paste sense from some vendor's examples. But loudspeaker crossover DSP needs are very simple. You can do IIR, FIR, some delay etc... that's all. But you can do more complicated things with FPGA in crossovers... if you have needs or curiosity for it.

You can write program for FPGA in vhdl, and in this form, source can be shared with others.




Best regards,

boggy

[paulb]

Originally posted by bogicp

You can write program for FPGA in vhdl, and in this form, source can be shared with others.

Where do you find vhdl source for these types of filters? Is there a users group or something through Xilinx?

[wigginjs]

This project goes over my head in terms of complexity, but I'm going to be following this thread and just thought I'd show my interest. Sounds really neat and if it gets to a point where there is a kit or something I'd most likely be interested in trying it out.

[bogicp]

Originally posted by paulb

Where do you find vhdl source for these types of filters? Is there a users group or something through Xilinx?

I can write vhdl for crossover purposes, other things already exists in some level of completness at Open Cores .

Best regards,

boggy

[bogicp]

Originally posted by m0tion
This project goes over my head in terms of complexity,

I understand you, but this idea (free and open digital crossover is in my mind for a long time), and I cannot find any other thing for loudspeakers with same flexibility,
If I understand good loudspeaker problems, most of it are in crossover section and drivers... in other cases we cannot do much more than we do today.

but I'm going to be following this thread and just thought I'd show my interest.

Thanks.

Sounds really neat and if it gets to a point where there is a kit or something I'd most likely be interested in trying it out.

If people are interested for this project, it's not that hard work to prepare some quantity of PCBs, with vendor lists you can buy parts. etc. With some documentation... this is almost a kit.



Best regards,

boggy

[paulb]

Originally posted by bogicp
I can write vhdl for crossover purposes, other things already exists in some level of completness at Open Cores .

At that site I see this: "This page is here because the site administrator has changed the configuration of this web server. Please contact the person responsible for maintaining this server with questions. "