http://www.cirrus.com/en/products/pro/detail/P1117.html
this chip is very very interesting for its capability
since i have not find ANY existing product that does what i want
( decode surrround with recent formats and output multiple digital channels seperatly )
i am looking for alternatives
anyone has every played with DSP chips ?
i believe that we require licenses for decoding the different formats?
hard to obtain for personal use? expensive?
any other options ?
thanks
this chip is very very interesting for its capability
since i have not find ANY existing product that does what i want
( decode surrround with recent formats and output multiple digital channels seperatly )
i am looking for alternatives
anyone has every played with DSP chips ?
i believe that we require licenses for decoding the different formats?
hard to obtain for personal use? expensive?
any other options ?
thanks
In my previous job, I had worked with this Cirrus DSP family to develop a OEM DSP board.
Frankly to say, don't think of using these chips for DIY purposes.
Maybe you'll be able to buy one of these DSP somewhere but then don't forget that hardware design covers only a few percent of the project. The big deal is software.
The available datasheet covers maybe 10% of the chip actual features and all the real interesting information to be able to develop such a decoding application is available only through NDA.
I don't even mention DTS/Dolby fees ; you need to pay them before beeing able to request documentation
What exactly are you looking for ? I think I could be of some help
Frankly to say, don't think of using these chips for DIY purposes.
Maybe you'll be able to buy one of these DSP somewhere but then don't forget that hardware design covers only a few percent of the project. The big deal is software.
The available datasheet covers maybe 10% of the chip actual features and all the real interesting information to be able to develop such a decoding application is available only through NDA.
I don't even mention DTS/Dolby fees ; you need to pay them before beeing able to request documentation
What exactly are you looking for ? I think I could be of some help
Ah oui ??
Well what i am really looking for is the ultimate ...
seperate digital output of surround signal chanels
what would be the best is probably to hack an Home theater receiver that already features all that is required
( matrix, volume, I/O )
and use the digital from the DSP instead of letting it pass throuh the DAC/S
Serais tres apprecie si tu pourrais m'aider sur ce probleme, car je vais avoir besoin de realiser ce fait avant que ma piece et mon "setup" de cinema-maison
soit complete .
do you want me to email you ?
thanks
Well what i am really looking for is the ultimate ...
seperate digital output of surround signal chanels
what would be the best is probably to hack an Home theater receiver that already features all that is required
( matrix, volume, I/O )
and use the digital from the DSP instead of letting it pass throuh the DAC/S
Serais tres apprecie si tu pourrais m'aider sur ce probleme, car je vais avoir besoin de realiser ce fait avant que ma piece et mon "setup" de cinema-maison
soit complete .
do you want me to email you ?
thanks
From a hardware point of viewn this DSP features :
- one spdif input (with regular 2 channels PCM or compressed content such as Dolby Digital, DTS, MPEG audio etc...)
- one 7.1 PCM input (4 I²S lines)
- one 7.1 PCM output (4 I²S lines)
- one 2.0 PCM output (aka downmixed content of the 7.1 output)
I²S n°1 is for Front Left and Front Right
I²S n°2 is for Surround Left and Surround Right (lateral speakers)
I²S n°3 is for Center and Sub
I²S n°4 is for Rear Left and Rear Right (back speakers)
Volume control is available from -96dB to +24dB. You can trim channels, activate matrix decoding etc...
Do you only require access to I²S signals from the surround speakers ?
What is exactly your application (sorry for being curious
)
- one spdif input (with regular 2 channels PCM or compressed content such as Dolby Digital, DTS, MPEG audio etc...)
- one 7.1 PCM input (4 I²S lines)
- one 7.1 PCM output (4 I²S lines)
- one 2.0 PCM output (aka downmixed content of the 7.1 output)
I²S n°1 is for Front Left and Front Right
I²S n°2 is for Surround Left and Surround Right (lateral speakers)
I²S n°3 is for Center and Sub
I²S n°4 is for Rear Left and Rear Right (back speakers)
Volume control is available from -96dB to +24dB. You can trim channels, activate matrix decoding etc...
Do you only require access to I²S signals from the surround speakers ?
What is exactly your application (sorry for being curious
)I would like to have access to all of the seperate digital channels once decoded from the surround signal
then use multiple DCX2496 units for Xover and split signals to send to correct destination
output that in digital from the DCX toward some superior DACS and then to amplifiers
my setup will include :
sub
front left and front right
surround left and surround right
rear center
so i need a chip with code that will permit remixing and setup without a center channel
and will work with the rear channel also
I'd also like to be able to have multiple inputs, switch
and control volume of the input sound
( total volume control wich would affect all the digital outs )
Do you believe it is possible to find a receiver that already has all the required code in it, using the CS497xx chip, and then hack it up ??
then use multiple DCX2496 units for Xover and split signals to send to correct destination
output that in digital from the DCX toward some superior DACS and then to amplifiers
my setup will include :
sub
front left and front right
surround left and surround right
rear center
so i need a chip with code that will permit remixing and setup without a center channel
and will work with the rear channel also
I'd also like to be able to have multiple inputs, switch
and control volume of the input sound
( total volume control wich would affect all the digital outs )
Do you believe it is possible to find a receiver that already has all the required code in it, using the CS497xx chip, and then hack it up ??
I am not familiar with DCX2496 but I doubt it has I²S inputs. You certainly need to feed him with SPDIF.
Thus you need 4 DIT chips (Texas, AKM or Cirrus) to convert the 7.1 I²S decoded channels to 4 SPDIF stereo lines(ignoring center channel is just a matter of phantom mode and DSP setup, no difference on the hardware) .
The easiest way would be to open a 7.1 AVR and :
- find it's DACs (it's recommended to mod the Amp near the dacs, not close to the DSP)
- find their datasheets
- find the 4 I²S lines
- design a small PCB with DIT chips
- drill the backpannel of this AVR to get all 7.1 decoded preamp digital outputs
Don't forget to check whether the volume control is analog or digital
Thus you need 4 DIT chips (Texas, AKM or Cirrus) to convert the 7.1 I²S decoded channels to 4 SPDIF stereo lines(ignoring center channel is just a matter of phantom mode and DSP setup, no difference on the hardware) .
The easiest way would be to open a 7.1 AVR and :
- find it's DACs (it's recommended to mod the Amp near the dacs, not close to the DSP)
- find their datasheets
- find the 4 I²S lines
- design a small PCB with DIT chips
- drill the backpannel of this AVR to get all 7.1 decoded preamp digital outputs
Don't forget to check whether the volume control is analog or digital
Hey! you do believe it is possible ?
would you help me out ?
i do not have the necessary knowledge to do such things...but i do posess the GUTS required
Do you believe that any of the current DSP chip sends out I²S signal to their DACS ?
what if they use a single DAC that does multichannel conversion, will it also use multiple I2S lines?
btw please explain the meaning of :
I2S
DIT chip
if you can point me in the right direction,
i usually understand pretty quickly once i have all the required information
would you help me out ?
i do not have the necessary knowledge to do such things...but i do posess the GUTS required
Do you believe that any of the current DSP chip sends out I²S signal to their DACS ?
what if they use a single DAC that does multichannel conversion, will it also use multiple I2S lines?
btw please explain the meaning of :
I2S
DIT chip
if you can point me in the right direction,
i usually understand pretty quickly once i have all the required information
I dont see the point in using a specific transmission protocol for AVR manufacturer. Thus yes it will be I²S (or Left Justified maybe)
Please review the datasheet of this chip
http://focus.ti.com/docs/prod/folders/print/dit4192.html
You will understand what spdif and i²s are all about.
i think so
What about using a computer with appropriate sound card?
Use VST plugins in a "realtime virtual rackmount".
It WILL do the trick. Even if it's not "full realtime": when you need multichannel at an event you don't use Dolby anyway... (good old Behringer ADA8000... stack them up, add ADAT ports to a digital Yamaha mixing desk => standard setup.) You should be able to do that with Linux too, with a RT kernel. Search "ubuntu studio".
Use no hard drive but Compact Flash (IDE compatible), choose a portable computer processor with adapter and adequate fanless cooling (maybe adapting an old "alpha PAL" heatsink. DC/DC power supply. Won't make any noise, should fit a 3u rack. BTW, cheaper than developping your board.
If you need, make a firewire card with comprehensive chips and ready made drivers. Output i2s on balanced LVTTL trhu good connectors. Or output i2s, i8s, LJ, RJ.. Anything you want.
The computer will also do the job of crossover, filtering, and any additional DSP you may like.
Your project is exciting anyway. Good luck if you keep working on it. One of my teachers, Jean Pierre Lafont (who made the mixing desks for BBC, 20th century fox, Disney etc...) left the game when it came to digital desks: you have to be a full team of engineers, otherwise the chip no longer exists when you have finished making the software. But that's for a full mixing desk, a channel splitter should be doable.
Nicolas
Note: The product you're looking for may exist. Yamaha makes a series of DSP machines for speaker processing in large venues. If it has Dolby decoding option...
3000$
Use VST plugins in a "realtime virtual rackmount".
It WILL do the trick. Even if it's not "full realtime": when you need multichannel at an event you don't use Dolby anyway... (good old Behringer ADA8000... stack them up, add ADAT ports to a digital Yamaha mixing desk => standard setup.) You should be able to do that with Linux too, with a RT kernel. Search "ubuntu studio".
Use no hard drive but Compact Flash (IDE compatible), choose a portable computer processor with adapter and adequate fanless cooling (maybe adapting an old "alpha PAL" heatsink. DC/DC power supply. Won't make any noise, should fit a 3u rack. BTW, cheaper than developping your board.
If you need, make a firewire card with comprehensive chips and ready made drivers. Output i2s on balanced LVTTL trhu good connectors. Or output i2s, i8s, LJ, RJ.. Anything you want.
The computer will also do the job of crossover, filtering, and any additional DSP you may like.
Your project is exciting anyway. Good luck if you keep working on it. One of my teachers, Jean Pierre Lafont (who made the mixing desks for BBC, 20th century fox, Disney etc...) left the game when it came to digital desks: you have to be a full team of engineers, otherwise the chip no longer exists when you have finished making the software. But that's for a full mixing desk, a channel splitter should be doable.
Nicolas
Note: The product you're looking for may exist. Yamaha makes a series of DSP machines for speaker processing in large venues. If it has Dolby decoding option...
3000$
NeoY2K : please point to this yam product
price is not a problem here ...
Just for quick show ..this is my new house
HT's room ..here you can see the front wall that has embedded ( 2"foam/8"concrete/2"foam) IB sub array
( the garage is used as the rear chamber,
wich is reached through a 10'high 2'wide concrete chamber/port )
so back to topic,
i will read the article.
i do not want to use a computer as the only source,
i find the ability to switch different sources
with an HT receiver very interesting
like connecting and old game or stereo source and beeing able to have it matrix it back to use all the speakers ..and do multiple source swith
( also video switching .. )
What do you suggest as far as digital signal goes?
my only fear here is the jitter that will be introduced from using so many conversion and going through so many chips ..
what would be the ideal path ?
we could start from there and then make the required compromises to attain my goal
price is not a problem here ...
Just for quick show ..this is my new house
HT's room ..here you can see the front wall that has embedded ( 2"foam/8"concrete/2"foam) IB sub array
( the garage is used as the rear chamber,
wich is reached through a 10'high 2'wide concrete chamber/port )
An externally hosted image should be here but it was not working when we last tested it.
so back to topic,
i will read the article.
i do not want to use a computer as the only source,
i find the ability to switch different sources
with an HT receiver very interesting
like connecting and old game or stereo source and beeing able to have it matrix it back to use all the speakers ..and do multiple source swith
( also video switching .. )
What do you suggest as far as digital signal goes?
my only fear here is the jitter that will be introduced from using so many conversion and going through so many chips ..
what would be the ideal path ?
we could start from there and then make the required compromises to attain my goal
thinking of it ...broswing products through internet..even went as far as looking at DOlby's solutions for theaters and such
at the end, the reason why i want digital outputs,
is to use the DCX for crossovers in the digital domain,
since it will be easily tunable, and lossless
and with the number of drivers i'll have,
and the quantity of possibilites, using analog crossovers is just way out of the question
i am also a bit frustrated about using analogue crossovers when eveyrthing CAN be digital
( way simpler though for stereo system )
So if i'd find an home theater receiver, comercially available, that has similar crossover options as the DCX units ..it would render all those efforts pointless.
But i have yet to find any unit that has anyhting more than " 30-350-80-120hz" sub X-OVER option
as i said before, having alot of components and chips in the line won't probably help with distortion ( jitter )
so a single component with potent recent DACs would replace ALOT of the units i plan on using
( is there any recent receiver with real high quality DAC sound ?? haven't heard any good reciever up to now,
but haven't checked any for 2-3 years so .. )
at the end, the reason why i want digital outputs,
is to use the DCX for crossovers in the digital domain,
since it will be easily tunable, and lossless
and with the number of drivers i'll have,
and the quantity of possibilites, using analog crossovers is just way out of the question
i am also a bit frustrated about using analogue crossovers when eveyrthing CAN be digital
( way simpler though for stereo system
)So if i'd find an home theater receiver, comercially available, that has similar crossover options as the DCX units ..it would render all those efforts pointless.
But i have yet to find any unit that has anyhting more than " 30-350-80-120hz" sub X-OVER option
as i said before, having alot of components and chips in the line won't probably help with distortion ( jitter )
so a single component with potent recent DACs would replace ALOT of the units i plan on using
( is there any recent receiver with real high quality DAC sound ?? haven't heard any good reciever up to now,
but haven't checked any for 2-3 years so .. )
JinMTVT said:
Hi,
I was not telling you to use the computer as a source, but only as the DSP box. Running a PC with a RT Linux Kernel isn't very different from having a µC running any RTOS (maybe Linux in some cases...) with a DSP. But on a computer, everything has really been done. The only thing you have to do is parameter what DSP you want it to do, and tell it to launch the program at boot.
You could enter the computer in digital or analog if you want. Just choose a soundcard. You may want to do a little bit of programming to add some controls on the rack (switching between digital and analog in/out, and changing the processes inside). Shouldn't be that hard.
Dolby receiver Digital out => Computer => SPDIF(i2s?) digital outs => DAC
or
Stereo (analog)=>Computer=>SPDIF outs => DAC
Etc...
But I don't really see the point in making multichannel from stereo.
http://www.yamaha-europe.com/yamaha...er/30_speaker_processors/10_SP2060/index.html
I don't see anything for Dolby but you may have to ask them if they have plugins.
They also have Ethersound DSP, look at it.
EDIT: sorry, it's in french, search the ref in english
coloradosound said:
Dolby and DTS licences are (too) expensive. For example, just being able to get the right to start a Dolby-based design costs you $5k. Well, that was 5 years ago when we start working on that DSP solution.
DTS : higher bitrate thus higher fees
: $10kAnd this doesn't include latest HD decoders such as Dolby Digital True HD etc...
Chips vendors such as Cirrus Logic won't sell you those chips, even if you buy 500 pces. The reason is that software covers 90% of the project developpement and that software means bugs means technical support. Cirrus Logic will not support you and the DIY community.
Now, you can still try to buy a OEM board. Try :
- vinci labs
- momentum data systems
- i-lab america
- yba
i'm with John...
beeing there, i'd rather have all the power options that a recent receiver provides
( myriad of inputs including hdmi 1.3, main volume,
all the surround decoding and matrix options )
so that beein said,
how do we choose the "corrrect" avr ??
and we still have to debate, what is the best path??
i am seriously worried about the excessive jitter
from all the conversions and spdif chips ...
do you believe it will be an issue ?
how long of cable can we safely run I2S lines on before getting some signal distortion ?
beeing there, i'd rather have all the power options that a recent receiver provides
( myriad of inputs including hdmi 1.3, main volume,
all the surround decoding and matrix options )
so that beein said,
how do we choose the "corrrect" avr ??
and we still have to debate, what is the best path??
i am seriously worried about the excessive jitter
from all the conversions and spdif chips ...
do you believe it will be an issue ?
how long of cable can we safely run I2S lines on before getting some signal distortion ?
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