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A multi-channel interface from PC - the Missing Link

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I decided to start a new thread on this, as I have noticed that a lot of members are struggling finding a current viable solution to this matter in regards to streaming multi-channel sound out from our PCs to our Twisted Pair Audio products.

My goal for this thread is to get this information consolidated here, maybe even with some build links, photos, etc, to help others figure out what would work best for their given build be it Buffalo or Opus.

I personally would like to find a solution that would work for both 1 eight channel configured Buffalo III DAC, 4 two channel configured Buffalo IIISEs, or even 8 monos for the dreamers out there. I would imagine that the interface for all these arrangements (including Opus) should be the same: at least Eight I2S lines.

These are the options I know of so far:

1 - MiniDSP USBstreamer: Does not seem to be the best "match" out of the box. But it sounds like it can be used with the Cronus Re-clocking module and one of the Isolator modules if one was willing to "modify" the USBstreamer. I personally do not feel too comfortable doing a mod like that, but others of You might be.

2 - USBPAL: Requires a "licensing" scheme.

3 - Tapping I2S lines off a PCI-e Sound Card and using Teleporters: I know some people have done this with the Asus Xonar DX cards, and I am sure it can be done with the newer Asus Essence STX cards, using the daughter board pin outs:

http://www.diyaudio.com/forums/digital-source/138585-xonar-deluxe-pin-outs.html

If on a budget, one could buy just the 2 channel version Essence and run their DACS off the daughter board pins (2 - 6 channels) and use the main channels of the Essence for subs or surrounds.

My concern with this option are the drivers and if I am doing the Buffalo an injustice running off the 24-bit I2S lines and opposed to 32-bit.

Also, I am wondering if there are any other CURRENT PCI-e sound cards that would work like this.

4 - Cronus Re-clocker: I read that this module has multi-channel capacity. Are there other options other then MiniDSP? Maybe something with BeagleBoard?

I am not the most savvy understanding everything about jitter, clocks, ground isolation and the such. This is the main reason I bought a kit. I wanted a proven design I could assemble, and learn as I go, and if I so desire, try out different I/V stages.

Having said that, it seems people are pretty fired up about the possibilities with the Cronus Re-clocker modules. How much of an improvement does it offer over tapping I2S lines with the Teleporters?

thoughts anyone?
 
- I2S transfers 2 channels at once, so it should be enough to have 4 I2S lines for 8 channels
- ES9018 in Buffalo DAC accepts only 32 bit I2S. but it might contain only 24 valid bits
- Cronus is only for I2S sources that can be slaved from external clock; source must not use its own clock if it is connected to Cronus.

I'm not sure how you define the "PC", but if it is enough to have Linux operating system, then it can be done using BeagleBone Black and Hermes-BBB. See the link below.
 
Time for more research...

Thanks for the clarification, Miero.

- I2S transfers 2 channels at once, so it should be enough to have 4 I2S lines for 8 channels

Cool, 8 channels is enough for my current needs of running either a 4.4 system or 2-way mains 4.2 system. However, I am open to the possibility of having more channels, say for future multi-way FIR cross-overs for a 7.1 system. I am sure others may be interested in these possibilities also, if any are available.

- ES9018 in Buffalo DAC accepts only 32 bit I2S. but it might contain only 24 valid bits

I will need to double check that Asus Essence Card. Possum on the Twisted Pair Forum posted that the Asus Xonar card worked for his Buffalo quadraphonic rig.

USB to I2S for Buffalo III multichannel - General Questions - Twisted Pear Audio Support

-
Cronus is only for I2S sources that can be slaved from external clock; source must not use its own clock if it is connected to Cronus.

This is an area I am not too knowledgeable in. It is actually hard to say if I want a source clock or not, considering I am running multi-channel, multi-way DSP sound from JRiver. My main concern is that my speakers remain in time with each other. (see specifics to my system below).

I'm not sure how you define the "PC", but if it is enough to have Linux operating system, then it can be done using BeagleBone Black and Hermes-BBB. See the link below.

I have considered a Linux OS, but due to the multi-use aspect of my HTPC (games, video editing, graphic arts, surfing, etc), I think Linux is going to be way too "tweaky" esp for my family! :eek:

But it is good to know that BeagleBone Black is a multi-channel option for those users that have a Linux based PC.

My system in a Windows 7 OS, which I will soon be "cornered" into updating to Windows 10 as Mircosoft will be discontinuing support for 7 next year. I really wish I could go Linux, but it is just not user friendly with a lot of the software and games we play.

I use JRiver as my player and run all my FIR filters thru its DSP engine. JRiver also works for games and streaming video online with its WDM driver. For this application I use IIR filters to avoid audio latency.

My personal goal is to get my configured 8 channels of audio out of JRiver, preferable ASIO, to my Buffalo configuration.

I am wondering if BeagleBone Black can be configured to daisy chain off my windows PC. JRiver does have a Linux version. If that could be ran on the BeagleBone, and the media streamed from my Windows PC, that could be another option. As You can tell, I really have no idea what BeagleBone is, so time for some research...

In the meantime, I would like to continue to explore options for a Windows Based PC, as I believe there are others who are interested also.

Miero, how is your system set up? Are You running Multi-channel?
 
Some findings...

BeagleBone seems pretty interesting. It is well documented setting it up as a stand alone music player. But I am not finding any information setting this "open source" board up as strictly a "link" between my PC and Buffalo III. I would think that it could be done. However, this seems to be the "long way around" to achieving my goal.

I also looked into the Asus Essence STX sound card. It would appear that the Essence internally works in 24-bit. However, the input PCI-e signals to the card can be either 16-bit or 32-bit:

Asus ASIO Control Panel

So if I was to go this route, I would be looking at a lot of bit changes: Source: 16 or 24-bit ---> 64-bit DSP ---> 32-bit PCI-e ---> 24-bit IS2 ---> 32-bit Buffalo (if possible). I as far I understand, the Buffalo will adept to any incoming bits on the IS2 inputs, but is limited to 24-bit if using S/PDIF (stereo only). Again, this does not seem "ideal".

At this point, I am debating on assembling my Buffalo III as a two channel kit with S/PDIF. I can get the Asus Essence, ran my subs and surrounds off that, and run my main channels thru S/PDIF to Buffalo III. Definitely not ideal but at least doable until a working multi-channel solution is available...

There has to be a way to do this that is reliable and does this DAC kit justice.

I welcome anyone to share their successful build regarding this matter.

Thanks,
 
I'm not sure how you define the "PC", but if it is enough to have Linux operating system, then it can be done using BeagleBone Black and Hermes-BBB. See the link below.

Thanks miero, very helpful. I didn't know this was possible.

From mieros BBB webpage:

"The BBB has 4 serializers and each one is capable to generate:
- one stereo I2S channel
- one mono DSD channel
- one stereo SPDIF channel

Using the "serconfig" option the different serializers can be enabled
and thus allows to change channel number and its offset.

Possible values for each serializer:
M ... I2S/DSD mode
I ... I2S only mode
D ... DSD only mode
S ... SPDIF only mode (exclusive, cannot be combined with I2S/DSD) -- Notice: does not work in botic5
R ... record mode (I2S only)
- ... disabled serializer

Examples:
MMMM ... 8ch I2S output or 4ch DSD output (default)
I--- ... 2ch I2S output on mcasp0_axr0 pin
-I-- ... 2ch I2S output on mcasp0_axr1 pin
--I- ... 2ch I2S output on mcasp0_axr2 pin (old default)
---I ... 2ch I2S output on mcasp0_axr3 pin
DD-- ... 2ch DSD output on mcasp0_axr0 and mcasp0_axr1 pins
MM-- ... 4ch I2S output or 2ch DSD output on mcasp0_axr0 and mcasp0_axr1 pins
--MM ... 4ch I2S output or 2ch DSD output on mcasp0_axr2 and mcasp0_axr3 pins
S--- ... 2ch SPDIF output on mcasp0_axr0 pin
-S-- ... 2ch SPDIF output on mcasp0_axr1 pin"
 
Found another PC option: Pink Faun I2S Bridge

For those of us not willing to part with our PCs, what do you guys think of this option? (scroll to the lower half of the screen for English)

I2S Bridge

a TNT review:

[Review] Pink Faun I2S Bridge - Computer to DAC Interface

This is basically a PCI-express card that outputs I2S via HDMI cable to a DAC capable of I2S. 2 and 8 channel versions are available. It mentions having its own power supply (still looking for pictures of that) and its own internal clock. Just need a raw HDMI socket to hook into the Buffalo I2S inputs. Bear in mind, the HDMI is mainly used in this case as a means to transfer the audio signal, it is not tied down by HDCP limitations. Phew! This seems to work on a similar concept as the teleporters, but different in that it only "transmits" with no "receiver" on the DAC side.

It only supports up to 32bit/192kHz, and only has drivers for Windows 7 and 8.1 (hopefully 10) systems. It sounds like they are working on Linex drivers.

It is a little pricey and a challenge to source (esp the 8 channel version) :(, but this seems like one of the best possibilities so far.

Would this interface well with the Buffalo?
 
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Does BBB have enough power to do linear phase filters and other heavy processing on 8 channels?

Long story short, with lower sample rates the BBB can do a good amount of work. With higher sample rates the BBB ARM chip can be challenged. While some 2 ch FIR applications have been reported on the RPi, I haven't heard about audio FIR being done on the BBB. IIR with 8 channels is very possible.

Frank
 
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BTW, Allen... I learned a lot setting up a BBB, and am also considering options for the workstation that contains my DAW. We tend to think of this grade of workstation as omnipotent, so it is surprising and fun when a little ARM board like BBB comes along and kicks-butt simply using clock-switching! It means we have the choice of dedicating an inexpensive processor to a function rather than relying on the workstation as a 'master source'. ...will watch the thread to see how you progress... How are you weighting the compromises between multi-function flexibility vs output quality?
 
This idea is theory and not tested, yet!

1. The BBB has an USB-OTG-port. Using the ALSA USB-Audio-Class-2.0 driver on the USB-OTG-port will make the BBB a USB-Audio-Class-2.0 audio-interface. The audio can be grabbed via an ALSA device.

2. The Botic I2S-driver seems to be capable of up to 8x 24bit@192 kHz output-channels on 4 GPIO ports.

If you use jackd to connect the ALSA USB-device with the ALSA I2S-device you have a 8-channel USB-to-I2S audio interface and you can even enable jacknet for network audio. ;)
 
The search continues...

Thanks for the suggestions, I have been busy building a First One Amplifier designed by diyAudio member Lazy Cat, so excuse my late response. (Working two jobs and running a part-time business does not help) My gut is telling me I am going to want to get this project going next after I hear my new amp. ;)

Unfortunatly the ExaU2i is not in production any more but it might be possible to ask exaSound Audio Design > Home for one.

I have not looked into this yet, but I will. Little worried about pricing, seeing the cost of their other products. :xfingers:

BTW, Allen... I learned a lot setting up a BBB, and am also considering options for the workstation that contains my DAW. We tend to think of this grade of workstation as omnipotent, so it is surprising and fun when a little ARM board like BBB comes along and kicks-butt simply using clock-switching! It means we have the choice of dedicating an inexpensive processor to a function rather than relying on the workstation as a 'master source'.

Long story short, with lower sample rates the BBB can do a good amount of work. With higher sample rates the BBB ARM chip can be challenged. While some 2 ch FIR applications have been reported on the RPi, I haven't heard about audio FIR being done on the BBB. IIR with 8 channels is very possible.

I think that is what is holding me back with BBB. The concept is good, but it can not do what my PC can do running DSP in JRiver. But, I am guessing it is a matter of time when something like BBB will have the processing power to do intensive DSP. The Cat's Meow with be running 4 or more BBB's, each one running a pair of 4-way FIR EQed speaker systems for a 7.1 system and maybe a second stereo rig in another room. Need a lot of DACs for that mind You. :)
This idea is theory and not tested, yet!

2. The Botic I2S-driver seems to be capable of up to 8x 24bit@192 kHz output-channels on 4 GPIO ports.

There is some potential for BBB if this can be done, but it still seems the long way around to me, esp having to learn Linux and all of that. At 24 bit, I would prefer to tap off the ASUS sound card.

...will watch the thread to see how you progress... How are you weighting the compromises between multi-function flexibility vs output quality?

That is the challenge, I should not need to compromise in this case. JRiver handles the multi-function aspect quite well and the quality is there, it is getting that quality out to the DACs, and have it work as "integrated" as the on board sound. The software and 32 bit capacity is there as Potential available to be used...

At the moment, I am leaning towards building my current buffalo III kit as a four channel DAC, mainly because this version of the board is designed to be a multi-channel version. If I really like it, I will build a Buffalo SE version later for my main front channels, and use the four channel version for surrounds and subs. I do not have my speakers built for my 4.2 system yet, so as of today, I only need four channels for mains and subs. :D

So far, I am leaning towards the ASUS card, the ExaU2i (if available) or the Pink Faun ($$$)... My concern, is by the time I get this all working, I could have bought a ExaSound 8 channel DAC. I really hope the Twisted Pair version is worth the extra effort. ;)
 
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Thoughts on this new creation from DIYinhk...

I got my first One v1.4 Power Amp built. :D An Amazing Amp, to say the least. I can definitely hear differences in DACs, DSP configurations, phase and timing nuances, etc. This amp is not for the faint of heart, it will reveal issues in speakers and source, but in a graceful, smooth way. :hbeat: It is like playing a DVD on a 1080 plasma TV over HDMI. Better yes, but one does hunger for a Blu-ray source. :)

Given that, my on-board Realtek Audio is not acceptable at all. :eek: Thankfully, my M-Audio Fast Track Pro is worthy enough. Finally got it to work ASIO. I am limited to four channels with it, which almost gets me by now, if one of the channels was not blown. :eek: (Later on, I plan to investigate ways to fix that.) It does have a SPDIF out, so I could run my Buffalo out on that (2 channel build) and have the other two channels for subs or surrounds (if I fix the blown channel).

Ideally, I still want at least eight channel capacity. I found this USB board from DIYinhk. It uses a XMOS chip like the MiniDSP. There are claims of successful builds with ES9018 multi-cahnnel DACs, so this might be the ticket:

XMOS Multichannel high-quality USB to/from I2S/DSD SPDIF PCB - DIYINHK

diyAudio thread about it:

http://www.diyaudio.com/forums/vendors-bazaar/283283-new-xmos-multichannel-pcb.html

Not sure if this can stream eight channels of 32 bit over USB, as the information on the product site states 16/24 bit, but yet in the thread above, it is mentioned that it does indeed support 32 bit. But the communication is not clear (or my understanding :eek:). I am thinking the 32 bit is over the I2S outputs. I will dig a little deeper and get back to You.

Thoughts anyone? Dare I be a "guinea pig" for this board? Price is reasonable. But do not want to be penny wise, dollar dumb either! :dodgy:

Allen ;)
 
Starting the Buffalo Build...

Due to issues I am hearing from my current DAC, :( I am taking the plunge and starting my Buffalo Build. :) The First One amp I built is quite the game changer, no turning back now. :D

I am going to start with the standard stereo build for now. I want to be sure this is the DAC for my system, before I commit to a multi-channel build. Looking at the design of the boards, and how it all fits together as a whole, it really is designed as a two channel kit. Multi-channel is indeed possible, with massive layout compromises, at least in terms of using one DAC module for 3 - 8 channels. The designers have always promoted using several DAC modules for multi-channel rigs. We will see, as I build up my confidence, I still may be willing to retro-fit this build into 4 channels. I would like to get the basics covered first, especially considering there are several output stage options for this module: IVY, Legato, and even the glass audio "Unbalancer" (tubes).

I will be trying SPDIF first, as I already have that board. If I decide to go all the way, I am leaning towards using the teleporters and maybe the ASUS sound card on the PC side. I think USB is causing issues with my current DAC, so I am feeling a little skeptical using that kind of interface, at least until I understand what is really going on.

I am starting a new thread for my build, with photos, and will post a link for those interested.
 
The search for the link continues...

I figured I would post a quick update post on where my Buffalo adventures are going...

First off, I did get the Buffalo III kit assembled and working (Wow, has it been that long since I posted :eek:)

Here is the link to the build, which needs to be brought up to date too :eek:

http://www.diyaudio.com/forums/twisted-pear/294644-visual-buffalo-iii-building-journey.html

I have been spending the last four months doing a lot of listening, enjoying an old music and movie collection that all seems new. :hbeat: There has been a lot of EQ tweaking and new lessons learned. It is amazing how much less DSP I need now with the Buffalo DAC. DSP can be used to cover up the weaknesses in a rig as well as bring out the best. Thankfully, I can focus more on the latter now. ;)

So it is safe to say, I definitely want to go the full multi-channel route with these Buffalo DACs. My current plan is to procure two more Buffalo kits, as the funds allow and build a six channel DAC. If I need two more channels, I will split my current Buffalo III into the four channel version.

So now that brings us back to the "missing link" - a way of getting the six to eight channels out of the computer to the DAC.

I have been digging a little more into this to narrow things down.

First off, the ExaU2i is not available and as far as I could understand, it did not pass DSD signals. In fact, I believe that is why they quit production, as they where planning a DSD unit. If I feel brave, I may post on their thread, because the ExaU2i was exactly what I wanted, apart from the lack of DSD. (more on DSD below).

Then there is Pink Faun... a broken link...

Here is a new link to the Pink Faun:

Welkom bij Pink Faun | Pink Faun

I can not find the multi-channel version available anymore. That really concerns me. I guess multi-channel designs come and go...

So what is available, today, on the market in 2017:

Not too much really.

There is still the Asus Essence STX II with teleporters. This is the most obtainable and proven method so far. Again, a no go for DSD.

Secondly, there is the DIYinhk board. With the latest drivers, it can support up 24 bit/192. It also claims "PCM 768kHz and DSD1024 can also be supported with external 45.1584Mhz 49.152Mhz clock and customized firmware." I would assume (a dangerous thing) that it supports lower rates of DSD with the supplied firmware. I will be confirming this if I go this route. I also need to find a suitable power supply for this board, as it needs 800 mA max at 3.3 volts. What bothers me with this board is the sheer lack of documentation and questionable support I witness on the thread here at DIYaudio. The best information on this board has been provided by member DimDim.

Ian is creating a multi-channel FIDO board with state of the art clocks to add to a USB board like the DIYinhk. The boards are works of art and I think they would take the Buffalo boards to a whole new level. Yet, it would appear that new firmware would need to be written if using with the DIYinhk board. But seeing that the DIYinhk board is the only one marketed right now, maybe a programmer will step up to the plate.

http://www.diyaudio.com/forums/digi...project-ultimate-weapon-fight-jitter-433.html

As far as DSD is concerned, I have never heard it, not been able to as I do not have the hardware for it. So I really do not know if I want this feature or not, yet, I will not know until I hear it. I know there is not much available on DSD, but that could all change. Look what happened to DTS when blu-ray came out. So I am mainly interested in DSD for the flexibility.

As far as clocks go... I do know they make a difference. I can hear a difference on SPDIF between my motherboard output and the M-Audio output. The M-audio has a leaner sound with a tad more "air" around instruments. It is very, very subtle and in this case, is not a difference I would want to spend money on. On the other hand, I like the passion I see in Ian's boards, so I will be keeping an eye on that project, to see where it goes. Maybe he could design a USB board to go with his FIDO.

As of today I would still say, the search for the missing link continues... as in there is not yet a "complete" kit one can buy and assemble. Thankfully, I have plenty of other DIY audio projects to finish before procuring more DACs and building this interface. One such project, is putting my existing Buffalo in its modu HiFi case I received yesterday. The trick is planning this out right, as I hopefully got a case big enough to house all three completed Buffalo kits. ;)

I have been contemplating trying the Broskie Unbalancer as an output stage also. Might only be able to fit one DAC in the case then. :D
 
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I look forward to Russ' post! :)

@ArtsyAllen, I'd be interested to read of your uses for DSP. I'm running three BIIIse/Legatos via teleporters from my BBB. The BBB pulls stereo from the server and then actively divides it for multiple amps and their drivers. I've had some success with various IIR and simple FIR filters in the BBB. My next goal (though on the back burner for now) is to experiment with more powerful externally-processed FIR phase correction filters at the server level. These would "pre-treat" the stereo PCM signal that subsequently is processed by IIR filters at the level of the BBB.

Be aware that the BBB can output 8 channels of PCM but only 4 channels of DSD - it cannot render 6 DSD channels if you were to generate those signals in a PC. There is some interest by a few brave users to employ the BBB as a network audio adapter to render DSD as produced by HQPlayer software. This software can convert PCM to DSD (in hopes of eliminating some sources of noise). That work is ongoing - I'd be a contributor in that effort but for my 3-way active speakers...
 
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