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Hi-end DSP based multi-channel integrated Preamp/Crossover/DAC project

Really looking forward to this project!

What sort of buffered components will be used for the analog outputs? opamps on removable sockets by any chance?

It was tough fitting all eight IV converters into the allocated space so all OPAMPS are 8 pin SMD SOIC devices. I would have liked to have used DIL packages but space was at a premium. Perhaps I could have an option with unpopulated opamps and you solder your own in but then the board would be untested so that is not such a good idea.

Alternatively I could offer different boards with different opamps but that would require different board runs.

cheers
 
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Hello

Just got a run of pcbs made from a new supplier that I have not used before and the quality is very good. These are the Digital Audio IO board and is now a 4 layer board ;) Will be looking to submit some of the other boards as they are finalized in the coming weeks.

cheers

An externally hosted image should be here but it was not working when we last tested it.
 
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I will look foreward on the time you will sell your Boards. Important for me is a powerfull FIR Engine. This time i use, like many others, the Najda Board from Nick. A Great tool but one thing i miss is the use of FIR Filtering with 192kHz Sampling Rate. With my Board i can only run 48kHz Sampling Rate!

Hope your Board can more?
 
Wow!

Haven't been really looking for this - but I found it. Wow!

This seems to be the upgrade I've been starting to envision, without really thinking somebody is just about to actually make it happen. Ride on, David!

Am currently using the Nayda DSP, which is great, but there was no reaction to my suggestions and wishes lately. Besides all the hardware upgrades and hopefully nice software implementation, I am looking forward to be able to loop through the miniDSP Dirac board, as already mentioned by others.
But if you could manage to implement Dirac functionality into your DSP (as mentioned in post 148), that would be awesome!

Then I was speculating lately, if there could be any solution to servo control my open baffle woofers - and it just so happens, that you are the man for this as well! Now it can't be a coincidence anymore : )

And since I've been just about to upgrade my sub amps and power supplies, I'd like to know if I could afford your servo's. Please pm or email me for this, to stay on subject in this thread.
Please supply me with the following information:
- is a specific amp and power supply essential components of your servo, or can I use my own?
- can the integration of your servo into my system profit from using your DSP, by simplifying setup and/or hardware, or are they separate entities
- can I afford it?

Am excited already!
Cheers,
Abel

Here's a pic of my setup ...
 

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Haven't been really looking for this - but I found it. Wow!

This seems to be the upgrade I've been starting to envision, without really thinking somebody is just about to actually make it happen. Ride on, David!

Am currently using the Nayda DSP, which is great, but there was no reaction to my suggestions and wishes lately. Besides all the hardware upgrades and hopefully nice software implementation, I am looking forward to be able to loop through the miniDSP Dirac board, as already mentioned by others.
But if you could manage to implement Dirac functionality into your DSP (as mentioned in post 148), that would be awesome!

Then I was speculating lately, if there could be any solution to servo control my open baffle woofers - and it just so happens, that you are the man for this as well! Now it can't be a coincidence anymore : )

And since I've been just about to upgrade my sub amps and power supplies, I'd like to know if I could afford your servo's. Please pm or email me for this, to stay on subject in this thread.
Please supply me with the following information:
- is a specific amp and power supply essential components of your servo, or can I use my own?
- can the integration of your servo into my system profit from using your DSP, by simplifying setup and/or hardware, or are they separate entities
- can I afford it?

Am excited already!
Cheers,
Abel

Here's a pic of my setup ...

There is already a thread dedicated to the DSP servo

http://www.diyaudio.com/forums/subw...-gain-servo-controlled-woofer-controller.html

The work on the DSP servo sub is ongoing but has been put on the back burner for a while whilst I focus on the DSPXO board. One of the problems with the DSP servo sub is that the setup may too convoluted for some diyers so more work needs to be done on it.

cheers
 
One more vote for version without Sabre DAC's :). Started to Build LX521 and this will be perfect fit over miniDSP 4x10Hd.

May consider looking at supporting other DACs later on but one of the attractions of the Sabre DAC is its 32 bit volume/level controls for all 8 channels which is not available on other DACs. This avoids the need for post analog processing after the DAC output. However it is possible to implement this on the DSP with other 32 bit DACs.

cheers
 
Total number of taps depends on the sample rate and the tap rate which is 1.25 nS per tap for this dsp. This gives us a total number of taps of:-

4K taps @ 192KHz
8K taps @ 96KHz
16K taps @ 48KHz

but that is with the core running flat out processing the FIR and not doing much else. Distributed over 2 channels you can divide those figures by 2. With 1:4 decimation it is possible to achieve 16K taps at 192KHz or 8K per channel for stereo or 2K taps per channel for 8 channels.

Now it is possible to offload the FIR's onto the accelerator which requires almost no core intervention and has similar tap execution time to the core. One can expect a similar tap execution time but there are some other overheads involved with this. I am still looking into the pros and cons of this feature. I wrongly assumed that I could process 8 channels concurrently with this feature but there are only 4 MAC units assigned to the whole of the 32K taps and not to each 1K segment as I initially assumed :(

cheers

Hi
Any progress regarding FIR implementation choices?

How is decimation going to be implemented?
Will the FIR filter have to compensate for (or at least take into account) the rolloff of the antialiasing filter, like in the Four Audio HD2 processor?

Thanks
 
Hi
Any progress regarding FIR implementation choices?

How is decimation going to be implemented?
Will the FIR filter have to compensate for (or at least take into account) the rolloff of the antialiasing filter, like in the Four Audio HD2 processor?

Thanks

Depends how the decimation is done of course. One way to do it is to incorporate your crossover filters (low pass) before the FIR so that it removes most of aliasing components which then makes the decimation a simple process.

cheers
 
May consider looking at supporting other DACs later on but one of the attractions of the Sabre DAC is its 32 bit volume/level controls for all 8 channels which is not available on other DACs. This avoids the need for post analog processing after the DAC output. However it is possible to implement this on the DSP with other 32 bit DACs.

cheers

Which volume control option is better in regards to sound quality, DSP or DAC? Internal volume control on the Sabre is ok.
Also, are you buffering/reclocking the digital inputs?
 
Which volume control option is better in regards to sound quality, DSP or DAC? Internal volume control on the Sabre is ok.
Also, are you buffering/reclocking the digital inputs?

If it's a 32 bit DAC and 32 bit DSP then it will have the equivalent performance of the Sabre DAC in terms of digital resolution. However if it is a 24 bit DAC then there is higher quantization errors for a given attenuation.

cheers