RME experts - I need some help

[muslhead]

Circling back around. Sadly I got no answers from the Matrix or the RME forums. Everything I received was found here, as the ASR community stepped up and provided me a lot of input, things to try and potential solutions. I am extremely thankful to those that helped.
I came to the conclusion that if a $1500 streamer cant keep up with an $80 raspi when outputting to one of the most capable dacs made, its time to pack up the Matrix, slap a label on it and return it to the distributor before the return period expires. With good prior experiences with 5 Matrix products, I held them in very high regards but this exercise dropped them down a notch in my book.
Again, thanks to everyone who assisted.

 

[hearone]

Hopefully, the slow of response was due to the weekend. I did go look at your post at RME. The only RME response was that it was likely the Matrix USB compatibility. But it did not address why the Matrix worked on another streamer without problem, but not on the RME's USB. And you had mentioned DSP, the response was DSP was not the issue, since its limitations were clearly documented. The post got my curiosity about RME's ADI-2 FS DAC's DSP limitations, the RME post was right, the limitations were shocking clear : "At 48 kHz that is no big deal, at 192 kHz it already needs efficient coding and a better DSP chip."

I would have never guessed without your issue that even at 192 kHZ, it needs a better DSP chip. Got to give RME credit for not hiding the limitations. You always learn something on this forum.

 

[unpluggged]

I would have never guessed without your issue that even at 192 kHZ, it needs a better DSP chip. Got to give RME credit for not hiding the limitations. You always learn something on this forum.

There are no DSP limitations at 192 kHz on the ADI-2 Pro/DAC. They start to come into play above that sampling rate, and this is also clearly explained in the manual.

 

[muslhead]

In case my original post was not clear, i was NOT using the dsp filters of the rme but rather I use the one in jriver which is upstream of either the streamer or rme. I wanted to make sure it was clear, that the dsp chip was likely not the problem in my case

 

[unpluggged]

In case my original post was not clear, i was NOT using the dsp filters of the rme but rather I use the one in jriver which is upstream of either the streamer or rme

It does not matter. Obviously the problem is in the USB implementation of the Matrix. There are known examples (not necessarily of your particular streamer, but they are rather common, so it might be the case here also) when network activity (Wi-Fi or Ethernet) could make USB transmission unstable. Raspberry Pi 3 is a known example of this, since its network interface uses USB bus to connect to the host.

 

[hearone]

In case my original post was not clear, i was NOT using the dsp filters of the rme but rather I use the one in jriver which is upstream of either the streamer or rme. I wanted to make sure it was clear, that the dsp chip was likely not the problem in my case

Got it. Thanks. I need to do some DSP research, but am wondering if Roon/Jriver (maybe MiniDSP) might have more DSP processing without as many limitations. I like that the RME DAC has DSP loudness in particular (and some other nice DSP features). I guess one would just have to buy and experiments with your desired DSP functions and see if you can live with the reduced functions at a higher SR. It seems RME, just turns-off DSP functions as the SR goes up due to the DSP chip limitation, but they don't document which goes first and when.

I would hate to limit myself to 48 kHZ SR to be safe to have all features, if I am correctly understanding all this. Bummer... Pls correct, if wrong.

 

[hearone]

...There are known examples (not necessarily of your particular streamer, but they are rather common, so it might be the case here also) when network activity (Wi-Fi or Ethernet) could make USB transmission unstable...

Just trying to understand, is the issue related to the packet delays, retransmits/etc of typical TCP/IP packet delivers? If yes, it seems you would have have the same on TOLINK/COXAIL Or does it have something to do the aynschynorous design of USB and TCP/IP? Just asking, since today I don't see USB, but might in the future. Thanks

 

[muslhead]

Got it. Thanks. I need to do some DSP research, but am wondering if Roon/Jriver (maybe MiniDSP) might have more DSP processing without as many limitations. I like that the RME DAC has DSP loudness in particular (and some other nice DSP features). I guess one would just have to buy and experiments with your desired DSP functions and see if you can live with the reduced functions at a higher SR. It seems RME, just turns-off DSP functions as the SR goes up due to the DSP chip limitation, but they don't document which goes first and when.

I would hate to limit myself to 48 kHZ SR to be safe to have all features, if I am correctly understanding all this. Bummer... Pls correct, if wrong.

I am no expert but as i interpreted the rme manual, dsp has a limited capacity and its limits might be reached if using everything the dsp is managing. The RME has built in "limiters" to change what the device does at higher SR rates to minimize the possibility the dsp chip reaches its processing capacity. This is why, for example, they only have 5-7 bands of PEQ. More than that increases the risk of dsp overload.

Allowing roon or jriver to do the bulk or all of the filtering and management of EQ, reduces the stress on the rme chip because it "diverts" the processing power requirement needed to your pc or the roon core

I am sure someone will say what i am attempting to communicate more eloquently if what i wrote is not clear

 

[Trell]

... It seems RME, just turns-off DSP functions as the SR goes up due to the DSP chip limitation, but they don't document which goes first and when.

I would hate to limit myself to 48 kHZ SR to be safe to have all features, if I am correctly understanding all this. Bummer... Pls correct, if wrong.

@unpluggged Already replied to you that you're wrong in an earlier post, and the limitations are clearly described in the manual where you only copied one sentence. What is unclear about the limitations?

Page 16 in ADI-2 DAC FS manual https://www.rme-audio.de/downloads/adi2dacr_e.pdf: (emphasis added by me):

>>>... At 48 kHz that is no big deal, at 192 kHz it already needs efficient coding and a better DSP chip.
But at 768 kHz you need a DSP with 4 times the power of the ‘better’ one. Therefore there is no
way around disabling some functions at higher sample rates. Fortunately those limitations have
only small impact in real-world usage:

• At sample rates 705.6 kHz and up Crossfeed or EQ can be active, not both at the same time. Bass/Treble and Loudness are not available.

The high sample rates available in the ADI-2 DAC also exceed the capabilites of the digital input.
Both AES and SPDIF are limited to 192 kHz, and there is no way around it. Therefore all higher
sample rates are only usable with USB. And in iOS mode when using an iPad/iPhone with an app
that supports such high sample rates (Neutron, Onkyo HF-Player etc.). ...<<<

 

[hearone]

I am no expert but as i interpreted the rme manual, dsp has a limited capacity and its limits might be reached if using everything the dsp is managing. The RME has built in "limiters" to change what the device does at higher SR rates to minimize the possibility the dsp chip reaches its processing capacity. This is why, for example, they only have 5-7 bands of PEQ. More than that increases the risk of dsp overload.

Allowing roon or jriver to do the bulk or all of the filtering and management of EQ, reduces the stress on the rme chip because it "diverts" the processing power requirement needed to your pc or the roon core

I am sure someone will say what i am attempting to communicate more eloquently if what i wrote is not clear

Your are thinking exactly what I understand also. Even using an external DSP processor to off load the RME DSP to keep all its functions intact. Of course, two wrongs does not make a right. But it is disappointing, the DAC seemed so perfect- all-in-one DSP, HP amp and DAC. I assume at some point RME will have a family of new DACs with even higher SINAD and more powerful DSP chips (I assume DSP chips are out there somewhere), just don't know when. They move slow, but that is not necessary bad either.

 

[hearone]

@unpluggged Already replied to you that you're wrong in an earlier post, and the limitations are clearly described in the manual where you only copied one sentence. What is unclear about the limitations?

Page 16 in ADI-2 DAC FS manual https://www.rme-audio.de/downloads/adi2dacr_e.pdf: (emphasis added by me):

>>>... At 48 kHz that is no big deal, at 192 kHz it already needs efficient coding and a better DSP chip.
But at 768 kHz you need a DSP with 4 times the power of the ‘better’ one. Therefore there is no
way around disabling some functions at higher sample rates. Fortunately those limitations have
only small impact in real-world usage:

• At sample rates 705.6 kHz and up Crossfeed or EQ can be active, not both at the same time. Bass/Treble and Loudness are not available.

The high sample rates available in the ADI-2 DAC also exceed the capabilites of the digital input.
Both AES and SPDIF are limited to 192 kHz, and there is no way around it. Therefore all higher
sample rates are only usable with USB. And in iOS mode when using an iPad/iPhone with an app
that supports such high sample rates (Neutron, Onkyo HF-Player etc.). ...<<<

Actually, I am not wrong.

I just did not want to quote the whole DSP limitations in the manual. 48 kHZ as no big deal is pretty low to lose no functions, so thought that the 192 limitation was clear enough just by that sentence. The limitation only get worst by quoting more- you would need a 4 times better DAC than the non-existent "better" DAC. Wow! That some limitations- we need more than 4 times better.

The limitation of the DSP are very clear, as stated- at 192 you start hitting them, so "I" would be limited to 48 kHZ to use the DAC with no "limitations", since that is the only SR that it does not have limitations. Sorry, for the confusion. I used the word "limitation" in two contexts. I just expected more for a DSP DAC. My bad, I guess. But glad your are happy within the limitations and enjoying it.

Cheers!

 

[Trell]

I just did not want to quote the whole DSP limitations in the manual. 48 kHZ is pretty low, so thought that limitation was enough. Sorry. The limitation of the DSP are very clear, as stated. I just expected more. My bad, I guess. But glad your are happy within the limitations and enjoying it.

Cheers!

Of the sample rates the ADI-2 DAC supports (44.1, 48, 88.2, 96, 176.4, 192, 352.8, 384, 705.6 and 768 kHz) only 705.6 and 768 kHz have some limitations, and for my use that's perfectly fine as I don't have any content above 192 kHz, in fact, almost all is 44.1 kHz.

That is, as the manual says, only when using USB as SPDIF (as a protocol) supports max 192 kHz.

 

[Trell]

Your are thinking exactly what I understand also. Even using an external DSP processor to off load the RME DSP to keep all its functions intact. Of course, two wrongs does not make a right. But it is disappointing, the DAC seemed so perfect- all-in-one DSP, HP amp and DAC. I assume at some point RME will have a family of new DACs with even higher SINAD and more powerful DSP chips (I assume DSP chips are out there somewhere), just don't know when. They move slow, but that is not necessary bad either.

That's only the case when using sample rates of 705.6 and 768 kHz. Do you have any content that is recorded, mixed and mastered at those sample rates?

 

[Trell]

Actually, I am not wrong.

I just did not want to quote the whole DSP limitations in the manual. 48 kHZ as no big deal is pretty low to lose no functions, so thought that the 192 limitation was clear enough just by that sentence. The limitation only get worst by quoting more- you would need a 4 times better DAC than the non-existent "better" DAC. Wow! That some limitations- we need more than 4 times better.

The limitation of the DSP are very clear, as stated- at 192 you start hitting them, so "I" would be limited to 48 kHZ to use the DAC with no "limitations", since that is the only SR that it does not have limitations. Sorry, for the confusion. I used the word "limitation" in two contexts. I just expected more for a DSP DAC. My bad, I guess. But glad your are happy within the limitations and enjoying it.

Cheers!

Now you’ve extensively changed your post that I replied to, after I posted it.

Oh well, you’re still wrong and still misunderstands what’s written in the manual that I quoted here in context.

When you double the sample rate you typically need to double the DSP requirements, so for 768 kHz = 4*192 kHz you need four times the DSP power compared to 192 kHz. This is not specifically for RME but general. A more powerful DSP costs more money to buy and implement, which increases the retail price. So here there is a trade off that RME made on focusing on real-world usage.

The limitations for the ADI-2 DAC DSP does definitely not start at 192 kHz but at 705.6 kHz. It’s right there in the manual. Let me quote that limitation yet again:

Page 16 in : https://www.rme-audio.de/downloads/adi2dacr_e.pdf

>>>

• At sample rates 705.6 kHz and up Crossfeed or EQ can be active, not both at the same time. Bass/Treble and Loudness are not available.

<<<