Fully digital crossover

[rfbrw]

Originally posted by AndrewT

What is the bit rate in the audio channels of HDTV?

24 bits at 32 to 48 Khz

[Bitstrom]

I want the 192 kHz for DVD-audio (which I hope will be more common for music in the future) and measurements.

I don't know anything about HDTV.

[Bitstrom]

Time to search for a suitable DSP for the job and try to design (with a bit of help) a circuit that can do the search for trick.

Anyone with experience of DSP's that can help with tips on DSP's that can be good for the job?

[cph2000]

Originally posted by hjb
I had a similar set of requirements which I have found a solution for (still testing, but seems to work).

I wanted to have 2 zones of audio from WMP11 with correction filters applied to each zone. I use DRC to generate correction filters for each zone (i.e. 2 rooms being corercted for).

I have the following setup:

2 x m-audio transit USB -> 2 x DAC-AH -> 2 x Power amps

Then, I use Convolver to apply the filters and to create 4 output channels from 2 input channels (you could apply your XO here).

To connect the 2 devices into a single virtual device, i use Virtual Audio Cable as the sound device in WMP, under ASIO4ALL and use VSTHost to host the ConvolverVST plugin. Then, in VSTHost, i set the device to ASIO4ALL and the input to the 2xVAC channels and the output to the 2x2 m-audio channels (4 channels out). i see no reason why you could not connect any number of output devices in this way. regarding drift, i have not noticed any, but I am feeding to 2 different rooms so is hard to tell. I believe VSTHost has the ability to apply delays to specific channels. I wonder if the fact that I have 2 identical USB audio devices connected to the same powered USB hub alleviates. I'm still experimenting, but wanted to share.

Very nice, most people seem to rely on an application called console and a sound card driver that allows for internal routing, this rules out a number of soundcards!

I checked the home page for VAC, they reportedly support vista but no floating point formats. I was under the impressiion that vista audio is floating point.

It would be cool to have a system like yours running with media center under vista.

[Bitstrom]

Starting to look at the TAS3108.

The sub $10 price and developing tools is attracting.

[KOON3876]

Hi also AD1940 looks simple, interesting,
only cons: they (AD1940/TAS3108) will be not so powerful to execute real FIR.

[Bitstrom]

Thank you for the tip about AD1940.

About the FIR, do you mean that they are too slow to execute the math in FIR?

[KOON3876]

a little bit slow and small RAM, for long tap FIR, multi way.
example,
44.1k�~2(stereo)�~4(way)�~1024(TAP) requires 353MMAC/S
(for 96k, TAP will be 512)

I'm very wondering between TI C6713 DSK and AD1940 EVM...
AD1940 development tool looks like funny, but C6713 is more powerful.

[googlyone]

I have a design that uses the AD1940 as the DSP and CS8416 receiver chip that would do what you are after. Mostly. I also use an analog devices CODEC, as I am after anaogue output rather than digital.

If you ae after implementation of FIR filters, rather than IIR, then the AD1940 is not a good solution for you. The memory on the AD1940 is not large enough, and (as far as I can tell) the architecture of the AD1940 is not targeted at FIR filters.

That said, the AD1940 is brilliant for IIR filters, implementation of delays (the RAM is useable for true time delay independently for each output) and - well a heap of other stuff.

In my implementation I take the digital audio outputs straight to the D/A inputs off the CODEC. You would need to drive a digital output, I assume SPDIF or whatever your application needs. No big deal there.

If you are looking to build something (rather than buy a pre builtt box) then I am happy to provide you the schematics and software I use on the controller.

The second last version is here somewhere:

http://www.users.bigpond.com/anne.phil/default.htm


Phil

[KOON3876]

Originally posted by googlyone
If you are looking to build something (rather than buy a pre builtt box) then I am happy to provide you the schematics and software I use on the controller.

The second last version is here somewhere:

http://www.users.bigpond.com/anne.phil/default.htm

Phil

GrEaT�@project. Very nice to know real implementation of AD1940.
Now I'm playing with TI's 6713 DSK.
Hard to code that 6713 and compiler is very sensitive