Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion HiFi & HT Chat Cleaning the bits

David is active on the Roon forum where you are guaranteed to be attacked by Vigilante Snake Oil Police (VSOP) as soon as you post anything suggesting that networks might influence sound. So he has taken his 3-tier Roon and Diretta project private, to avoid being harassed by self-proclaimed experts who think they know better than the rest of us and are compelled to set us straight. His overview is posted above in this thread.

He turned me on to Audiolinux in early 2024, and I implemented their Diretta function-and alerted him to the benefits- shortly thereafter. We use Roon Server running on that OS with Host (together with Roon as I have been doing on my Intel NUC) or with Host on a separate RPi (as he has implemented, believing that it further cleans the stream) and Target on a third machine.

Audiolinux has a menu system which makes it easy to install Roon or LMS or HQPlayer etc, so you don’t have to use Diretta with Roon. But I like it, and had wished for better SQ so here we are…

Thanks for this OldDog. A lot of good stuff to think on. I need to find David's thread. I've seen that Roon forum and know what you mean.
Does David replace the NUC with a less noisy host (Pi)? If so, how to add the NUC for Roon Core without stirring noise back in?

Sorry mods if this is too far from the original post about switches.

springlike

I can't see why these posts shouldn't be allowed, it’s in the HiFi & HT Chat section.

I'm quite interested myself how this stuff would actually hang together since I would want to keep Roon as the front end UI. I'm pretty sceptical on these sort of optimisations, I personally haven't had much joy with upgraded cables etc. As someone mentioned Diretta themselves don't do themselves any favours with the available documentation.

But from a practical standpoint, if I can get a sensibly priced Pi based alternative to an "808.6/ID42", I'd be in, even if the performance is break even. The old Meridian hardware is all obsolete now so need a plan B for when the inevitable happens.

Cheers
Greg

What is 3-tier Roon? How does it fit with host-target?

It is not possible to run Roon Core on a Pi, (https://community.roonlabs.com/t/roon-server-on-raspberry-pi/243501/15).

So do the 3-tiers refer to a NUC and 2 pi?

Springlike: Yes, you could run Roon core on a RPi5 if you have a small library and don't use DSP. I wouldn't because I'm in love with my custom convolution filters from homeaudiofidelity.com. An Audiolinux license allows multiple installations at the same location, so I have it running on a Gen7i7 NUC (with Roon Server and Diretta Host), a RPi4 Target and now a second RPi4 which will take the Host function away from my NUC once I implement David"s instructions to create a new, optimized network connection between just this new Host and my existing Target. That will be a 3-tier Roon setup: PC for Roon Server > Host > Target

David uses a generic PC running Audiolinux (which is very quiet and more powerful than any Pi) with Roon Server. He hands off first to a RPi4 Host using a USB3-to-ethernet dongle and then over a short ethernet cable from the Host's RJ45 port to his RPi4 Target.

Hello Greg: Technology marches on, and M's electronics are not keeping up. Except, I hope, inside the XE speakers. I addressed this issue in a past thread: https://www.meridianunplugged.com/u...;Main=35762&Number=318968#Post318968

Thanks OldDog, that clarifies things.


I think David's instructions are here:
Introduction
Instructions

After trying to understand this, (a lot), my rough plan would be to try it in stages beginning with the target. That would be an RPi endpoint to replace my MS600 and connect to the master speaker by SPDIF instead of SpeakerLink.

All being well at that stage, the next stage might be the Roon server running under Audiolinux on my i7 NUC, and then learning how to configure Diretta.

Glad you found David’s project info. It was the Allo DigiOne HAT (SPDIF output for Raspberry Pi) that got me started on this road. For $125 plus the cost of the Pi running a free OS such as DietPi, it can be amazingly competitive sonically with a 218 if given great power. https://allo.com/sparky/digione.html

Should you progress to Audiolinux and Diretta, David has written a driver for HATs like this.

If the MS600 has Comms out, you could leave it connected to the BNC on your speakers for control while music flows from the Pi.

What power supply do you use for your digione? I see allo.com recommend shanti which seems very reasonable.
Alternative to the digione could be pi2aes from pi2design.com for not many more $.

Shanti has two separate 5v rails which is most appropriate for their DigiOne Signature transport, with a “dirty” SBC galvanically isolated from a “clean” SPDIF HAT.

This is a terrific sounding combination which could, in theory, use either Audiolinux or GentooPlayer OS to implement Diretta at some point. I’ve not personally done it that way because I had moved on from 5200SE to DSP9 by the time I left Roon’s RAAT for Diretta, and the 9s take AES/EBU (not SPDIF).

EDIT: Actually, the 9s can be made to use SPDIF -but it’s a more complicated setup and I like the sound of AES.

A short digression into the difference between SpeakerLink and AES/EBU.

The difference in cable and connectors is well known. The difference in the protocol seems to come down to whether MHR (Meridian High Resolution) is being used or not. Is it correct to say if MHR is not used, all else being equal, (cabling and connectors are impedance matched and wired correctly), then for audio only, (not comms), SpeakerLink and AES-EBU are identical. But if MHR is used, then, (and only then), they are not identical because SpeakerLink audio is encrypted in a proprietary way.

So now it goes to when if ever MHR is used nowadays. Is it something used by some Meridian devices? Or was it always something on the way towards MQA, and later superseded? I can't find out. Anyone know?

As I remember, when high resolution audio was in its infancy there was a requirement from the MPAA that it could not be transmitted ‘in the clear’ to stop it being copied. Meridian’s solution was to encrypt the stream using MHR algorithm.

The need to keep hirez audio encrypted is a bit quaint now. However, a byproduct of the encryption process is apparently to increase entropy in the signal, which improves jitter handling AIUI. I assume why this is still the approach taken.

Your understanding of the story, Ian, matches mine in that required encryption turned out to have a serendipitous sonic benefit. I never quantified that claim since my source electronics today (with standard AES/EBU) are so different from my Meridian (with MHR) products. I believe that all M digital outputs are encrypted.

I can confirm that the XLR-to-RJ45 wiring was straightforward, and sounds really good.