Cool, I learned something today, and figured I would share, as others, like myself, who are not in the know, are wondering about the HDMI capacities of the I2S (aka LPCM) interface Tranquility is providing on this board.
I am sure everyone is wondering if we can use this board for multi-channel surround applications, like Dolby TrueHD, DTS HD and the such, via the HDMI input.
We certainly can, the trick is to decode the audio first. A lot of the HDMI receiver chips can accept an 8 channel (maybe more) high bit rate audio signal in I2S (aka LPCM) as Tranquility has mentioned. So if one has a Blu-ray player that has a built in Dolby or DTS decoder and can transmit the encoded raw signal LPCM over HDMI, then we can enjoy our surround sound like we have always wanted. I know the Oppo BDP103 and BDP105 can, and I am sure others can too. If you are like me, and run your Home Theatre through your PC or Mac, then all you need is an HDMI graphics card and software that decodes Dolby and DTS soundtracks. Power DVD and Total media Theatre are software packages capable of this. Of course I sure some AV receivers can do this also, but that is a little redundant, unless You wanted two rooms of surround sound!
I believe it would be possible for the HDMI input to receive a decoded Dolby Atmos signal also. Might be limited to a 5.1.2 setup, unless Tranquility can design this to accept 12 channels of hi-res audio. If this be the case, may need to figure out a way to parallel two or more of these boards together to have the ability to manage 7.1.4 multi-way speakers. For my room, 4.4.4 (front left, front right, back left, back right, 4 subs and 4 ceiling speakers) would be enough.12 channels would do it. All I would need would be an additional SPDIF output on the existing design and build my Buffalo kit as a four channel. I am only throwing this out, as the nicer Dolby Atmos AVRs have twelve channels. (Of course the crazies out there are going to go for the 34 channel rigs!) I am thinking it would be good to have this board available for the 12 channel market. (8 channel DAC and 2 assignable stereo Digital outputs)
But even as the board stands now, the sky is the limit to the audio bliss we can achieve with it...
Allen
I'm just wondering if the HDCP copy protection still applies if you decode the original data stream within your player and output LPCM over the HDMI connector. Does anyone know ?
cheers
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Tranquility,
This looks like a very nice product, spot on what I need. Sadly this comes to late for me, but maybe I get tempted anyway, let's see what you knock out of your shop. To late for me: I'm already close to finishing a MiniSharc + 8ch ESS9016 setup (no not the Buffalo DAC) to drive some active speakers.
Some questions:
I assume you'll be developing also PC software to set the filtering the DSP must perform, how will that be: An full fledged piece of software or maybe just an small program to download bi-quad parameters create by 3rd party software.
Obviously a microcontroller is included to control the sharc and ES9018 but have you also included that a display (LCD, VFD, OLED) and some key inputs are possible? and and IR remote?
Do you also include a trigger-out for switching on amplifiers?
Have you considered to make this a networked device with a web interface to do all DSP settings and control everything else. That would be kick-***.
This looks like a very nice product, spot on what I need. Sadly
this comes to late for me, but maybe I get tempted anyway, let's see what you knock out of your shop. To late for me: I'm already close to finishing a MiniSharc + 8ch ESS9016 setup (no not the Buffalo DAC) to drive some active speakers.Some questions:
I assume you'll be developing also PC software to set the filtering the DSP must perform, how will that be: An full fledged piece of software or maybe just an small program to download bi-quad parameters create by 3rd party software.
Obviously a microcontroller is included to control the sharc and ES9018 but have you also included that a display (LCD, VFD, OLED) and some key inputs are possible? and and IR remote?
Do you also include a trigger-out for switching on amplifiers?
Have you considered to make this a networked device with a web interface to do all DSP settings and control everything else. That would be kick-***.
Nice project. I'm interested if it becomes a stable product.
I'm using Hypex DLCP today whick works well and is in terms of SQ a step above miniDSP but I wouldn't mind something better.
I hope the level control on each individual channel works well. That's an important feature for active systems. Would be nice to not need pads for gain matching.
The ability to expand with more channels would be nice. If you run the multiple subwoofer approach with four subs, eight channels might not be sufficient. And same if someone wants to have active front and center speakers in a surround system.
I'm using Hypex DLCP today whick works well and is in terms of SQ a step above miniDSP but I wouldn't mind something better.
I hope the level control on each individual channel works well. That's an important feature for active systems. Would be nice to not need pads for gain matching.
The ability to expand with more channels would be nice. If you run the multiple subwoofer approach with four subs, eight channels might not be sufficient. And same if someone wants to have active front and center speakers in a surround system.
This looks really interesting. Hope this project becomes a reality.
It would be great if you could offer a complete package with all PCBs, display, pre-drilled chassis etc.
The possibillity to use external DACs for at least some of the channels would be a great option.
What is your timehorizon for this project?
It would be great if you could offer a complete package with all PCBs, display, pre-drilled chassis etc.
The possibillity to use external DACs for at least some of the channels would be a great option.
What is your timehorizon for this project?
Sorry for not getting back to you all earlier. I've just come back from Sydney and I'm not to good at punching in replies to forums using an Android smart phone.
Yes there will be a dedicated piece of software that runs on a PC and communicates with the board via a USB interface. As well the software could be made to interface to a variety of existing filter and room correction software.
Yes
Yes there is a spare port for serial coms which could also interface to a network controller or WIFI server etc.
cheers
Tranquility,
This looks like a very nice product, spot on what I need. Sadly
Some questions:
I assume you'll be developing also PC software to set the filtering the DSP must perform, how will that be: An full fledged piece of software or maybe just an small program to download bi-quad parameters create by 3rd party software.
Yes there will be a dedicated piece of software that runs on a PC and communicates with the board via a USB interface. As well the software could be made to interface to a variety of existing filter and room correction software.
Yes there is provision to drive a low cost 3.2 inch QVGA LCD display at full resolution and color. There is also an IR remote control receiver and currently the software works with the NEC IR protocol.
Yes
Yes there is a spare port for serial coms which could also interface to a network controller or WIFI server etc.
cheers
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I am using the 32 bit level control built into the ES9018 sabre DAC for both master volume and level control of all of the eight channels. It offers near bit perfect level control without sacrificing resolution.
The need for more than 8 channels is duly noted. I have some ideas for that
Also the suggestion for driving external DAC's has come up a few times but there are not many DAC's that provide the bit perfect level control that the SABRE DAC's provide which is one of the reasons why I have used this DAC and have not bothered with external connections to other DAC's. To use other DAC's and achieve the same level control would not only need the DAC's but a volume control chip as well.
cheers
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Yes it's possible to provide a kit with all of the bits needed to build it all up. Most of the boards will of course be pre-assembled because of the surface mount and fine pitch components involved. Some boards such as the audio output boards could be supplied as blank PCB's and people can populate them as needed.
Because I know how tedious and time consuming it can be to design metal work for these projects I have access to a CNC milling machine which I use for prototypes so I will be able to design the front and back panels and then provide the G-code for anyone else who knows someone that can mill out the panels for them.
Also jcga has indicated that he wants to design a real flashy case for this project.
cheers
One important feature(as others also mentioned) is the ability to adjust gain for each channel in a good way. In many systems there can be quite a big difference in sensitivity in subs compared to mid drivers. In some cases it could be 20db difference.
Maybe adding the possibillity to change the gain at each channel separately at the output board?
Also, it is important that the outputs have enough gain to drive most amps to their full potential, even if there is used quite a lot of EQ/correction filters.
The Groundsound DCN28 have a good implementation with relay based analog volume controls for each channel that can be adjusted separately for each channel(from 0 to -15db). This solution is nice, but overall gain in the system can easily become too low.
Any toughts about this?
Maybe adding the possibillity to change the gain at each channel separately at the output board?
Also, it is important that the outputs have enough gain to drive most amps to their full potential, even if there is used quite a lot of EQ/correction filters.
The Groundsound DCN28 have a good implementation with relay based analog volume controls for each channel that can be adjusted separately for each channel(from 0 to -15db). This solution is nice, but overall gain in the system can easily become too low.
Any toughts about this?
It is possible to increase or decrease the gain for each channel using the DSP.
The balanced and unbalanced outputs of the DAC are based on the design presented in the application notes for the SABRE DAC.
cheers
It depends on whether you use core access or the hardware accelerator to implement the FIR filter. For core access you can guarantee 1.25nS per tap for a 400MHz processor. For the hardware accelerator things get a bit more complex and there is a detailed explanation of it along with an example in the following document.
http://www.dspconcepts.com/sites/default/files/white-papers/Hardware_Accelerators_SHARC.pdf
This is a very interesting project, and I am definitely interested if this becomes reality!
I would wish for a flexibel signal routing e.g. the ability to mix filtered filtered signals into single output channels (useful for crosstalk cancellation). Also, it would be great with a convienient way of live switching between filter presets.
How is the work proceeding? Is there any time estimate?
Good look with this project!
I would wish for a flexibel signal routing e.g. the ability to mix filtered filtered signals into single output channels (useful for crosstalk cancellation). Also, it would be great with a convienient way of live switching between filter presets.
How is the work proceeding? Is there any time estimate?
Good look with this project!
Google did not work!
I have contacted HDMI directly, to see if they have a definitive answer on this.
HDCP is as clear as mud! I really do miss the days when You could fast forward through the FBI warnings and piracy notices! Feed lot cows with AVRs.
MiniDSP has their NanoAVR HD product and Essence has their Evolve DAC:
Evolve® HDMI 7.1 Channel LPCM DAC - Essence Electrostatic Speaker Systems
If they can do it, we should be able to with this...
I will let You know what HDMI comes up with...
Allen
I have contacted HDMI directly, to see if they have a definitive answer on this.
HDCP is as clear as mud! I really do miss the days when You could fast forward through the FBI warnings and piracy notices! Feed lot cows with AVRs.
MiniDSP has their NanoAVR HD product and Essence has their Evolve DAC:
Evolve® HDMI 7.1 Channel LPCM DAC - Essence Electrostatic Speaker Systems
If they can do it, we should be able to with this...
I will let You know what HDMI comes up with...
Allen
Count me in as interested.
I've used the MiniDSP 8x8 in the past, but I find it a bit too closed for tinkering.
I currently use Nick's Najda DSP, and I'm a very happy user. The only things I'm missing in the Najda, and that I would like to see in a new DSP project are;
- I/O boards as pluggables with ribbon cables to the main board (Which you are already doing, great!)
- Automatic preset saving to nvram/flash, so that last state/config is restored upon power loss
- A way to configure the basic everyday features through serial, i2c or spi (Volume, source selection, standby) - And possibly also the core DSP features. This would open up endless possibilities for use, for example connecting a linux SBC to it and developing a web interface for configuration.
- A better/more intutitive config application (Which I could build myself if the above option was in place). Najda's configuration application is good for punching values, not so much for listening/configuring by ear. I miss a more elegant/intuitive way to configure filters and slopes.
The things I do like in Najda and would like to see here:
- Source selection
- Analogue volume control (To avoid bit reduction at low volume), and individual analogue gain per output channel
- Optional I2S inputs for external devices (USB-I2S or small SBCs with i2s outs). I know yours has usb audio, but a separate i2s would be nice anyway.
Good luck with the project!
I've used the MiniDSP 8x8 in the past, but I find it a bit too closed for tinkering.
I currently use Nick's Najda DSP, and I'm a very happy user. The only things I'm missing in the Najda, and that I would like to see in a new DSP project are;
- I/O boards as pluggables with ribbon cables to the main board (Which you are already doing, great!)
- Automatic preset saving to nvram/flash, so that last state/config is restored upon power loss
- A way to configure the basic everyday features through serial, i2c or spi (Volume, source selection, standby) - And possibly also the core DSP features. This would open up endless possibilities for use, for example connecting a linux SBC to it and developing a web interface for configuration.
- A better/more intutitive config application (Which I could build myself if the above option was in place). Najda's configuration application is good for punching values, not so much for listening/configuring by ear. I miss a more elegant/intuitive way to configure filters and slopes.
The things I do like in Najda and would like to see here:
- Source selection
- Analogue volume control (To avoid bit reduction at low volume), and individual analogue gain per output channel
- Optional I2S inputs for external devices (USB-I2S or small SBCs with i2s outs). I know yours has usb audio, but a separate i2s would be nice anyway.
Good luck with the project!