The Babyface pro FS has a USB B (printer style) output to a USB-A into the host computer. That’s how my RME Fireface UCX connects to my host computer which controls the routing within the RME device (i.e. a 2-way USB protocol). I guess a mac mini has multiple USB-A connectors and one of these would output to the dac - hopefully someone will correct me if I’m wrong!
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EDIT: The diagrams show an RME device suggest using optical input into the Babyface. If you can get into the mac mini via ethernet to Roon then that’d be different to getting into the mac via the RME unit. I get the impression they don’t wamt to talk directly to units such as my Melco (I thought they would but they don’t seem to think that it’s possible, which is why I need to use a USB to S/PDIF protocol converter (my Chord MScaler) to get into my RME Fireface UCX. I believe someone uses an RME Digiface USB rather than a babyface.
Every day learning more…
I can’t leave Aurender out of the equation (I just bought it). apparently the simplest way is to have Roon and use the Mac Mini.
unfortunately I had not considered buying Bacch4mac, but probably would have thought of investing the money in another way.
The basic Bacch4MAC has no RME BabyFace FS. It is introduced in Audiphile Edition to allow custom filters for your room DSP and ear shape since it converts analog mic inputs into digital and allows the mini to compute the filters. Most mini have USB A,B, and C I/Os
I am also struggling what to do. Putting a high end streamer in front of the Mac mini is pointless, all the benefits are gone with it. It will no longer make a difference if you stream directly from the Mac mini.
But despite being a digital the source there is allot of quality differences, thinking of power supply, caps, cpu etc. This this is a dilemma for me.
(The Bacch SP is beyond my reach unfortunately, with that it is possible)
But if I buy the BabyFace to connect the Aurender for the basic version, would I lose quality if I later pass the signal through the Mac Mini?
or does it not make sense to spend money on that interface if I will have the basic version?
I’m worried that I spent on a better quality streamer, and then put the signal through the Max Mini. For basic reasoning, will I lose sound quality by doing that?
Bacch SP is also out of my budget.
I had a similar struggle about three months ago. I was streaming Roon using an Auralic Aries G1 supported by a Matrix DDC/LPS/RAL HDMI combo that provided I2S to my DSD DAC MK1 and later DSD DAC MKII. I was quite pleased with the results. Nonetheless, I was intrigued by what I was reading about the BACCH system and what other early users were reporting. I bit the bullet and ordered an Audiophile+ configuration fully expecting the improvement in sound stage to be dramatic but likely at the expense of compromises in tonality. I had the same concerns you are now having about introducing a Mac Mini into the mix and all the attendant noise that would bring.
So here’s my experience… as expected, the soundstage was expanded (breadth and depth) considerably. Locations of the performing personnel was much better defined - the “air” was definitely there! In general, the listening experience was much more immersive with BACCH. Live recordings, acoustic combos and electronic music provide the most dramatic effects. Much to my surprise, there was no compromise in tonality that I could detect. That said, the positives of what BACCH provides was so impressive that I would have accepted some degradation in tonality if present. The fact that such a compromise wasn’t required was an unexpected bonus.
To provide some context, I want to mention that the Mac Mini I’m using (M2) was bought specifically to run BACCH. During the initial setup, Edgar neutered many of the Mac Mini functions unneeded by BACCH. Streaming via Roon is provided via a Nucleus and running the Roon Daemon on the Mac Mini. I physically have the Mac Mini and BabyFace located on a bottom shelf in my rack as distant and isolated as I can make it. I’m using a pretty good USB cable - Shunyata Sigma - for connectivity to the DSD DAC MK II. The room is acoustically treated and configured for “mid-field” listening. The combination of all these factors made the decision to keep the BACCH system obvious and render the Auralic Aries G1 surplus.
My suggestion to the curious continues to be starting with the software-only Intro package. At $980, it’s a relatively inexpensive way to see what BACCH can do with your system and room. If you are happy with the results, you can stick with the Intro package (many have done just that) or move up to one of the Audiophile packages where custom filters and the ability to interface with other sources become part of the mix. If the latter, 100% of the Intro package price is applied to the upgraded package. If you aren’t impressed by the Intro package, it can be “returned” for a 100% refund. In my experience, no tweak I’ve applied has come close to the sonic improvements provided by BACCH.
I just got an answer from Theoretica.
The BACCH4MAc Intro does not come with any hardware. Without additional hardware you cannot connect your disc player or the Aurender streamer to the Mac mini. However, you can log in to your Tidal account on the Mac and stream directly through the BACCH-dSP application on the Mac to your PS Audi DAC through USB.
If you like what you hear, and later decide to upgrade to the Audiophile edition, there are ways to connect the Aurender streamer to the MAc (e.g. via minidSP’s USBSTREAMER B).
I have the hardware version, BACCH-SP adio. Mine has an EXCELLENT DAC inside it. It can also act as a Preamp with no degradation. Edgar is of the opinion that the Roon Server source isn’t that important. I understand his point of view but don’t share it. I use either a Pink Faun or a Grimm MU1 as a Roon source. I connect my MU1 via SPDIF. My BACCH can also serve as an endpoint for Roon. I have used it that way without complaint. I prefer letting the MU1 be my endpoint. Edgar will let you try the basic software version, or any version, and when you decide to go up the ladder you get full credit for what you had previously. So maybe try the software version and ask questions then?
Edgar is as smart as they come. Trust me, if the MAC had any deficiencies, he wouldn’t be using it. I fully, fully, fully understand the fears of adding a MAC to your audio path. I totally get it. I can’t give you an answer myself as to why it shouldn’t and doesn’t matter. But he can. I am fairly certain that if you find you don’t like it you’ll get your money back.
I read your experience very carefully…
I think I will opt for the audiophile option. Since the only way to check the experience of the basic version is to log in to Tidal on the mac mini, and skip Aurender (which doesn’t make any sense). Based on Theoretica’s recommendation, I bought a 2018 Mac Mini with I7 16GB RAM running the latest Apple OS.
I’ll see when I pull the trigger. Thanks
I would love to have the BACCH-SP, it must be wonderful!!! you are right about buying a version and doing all the queries. I will listen to Don Edgar 
I’ve been following this with much interest as I also await delivery of my DSD Mk2.
I have a large room where my audio resides, being an open plan lounge-dining-kitchen area. I listen in both the lounge and kitchen. I suspect the BACCH will be much better in the sweet spot of the lounge, and that I’d have to turn off the DSP when listening from the kitchen. What sonic penalty is there when using the BACCH in “bypass” mode versus running a USB direct from Roon Nucleus + (as with my setup) to DSD Mk2?
No big deal at all. The sweet spot effect is noticeable and very enjoyable. But without the filtering in place it’s just the great system you loved before adding BACCH. It’s just very enjoyable (the BACCH Filter). I’m not ever certain it needs to be bypassed.
For what it’s worth, I haven’t found a downside yet. It’s just very easy to listen to.
Which makes me wonder, is there anyone on this forum who tried BACCH and did not like it?
Raise your flipper!
If you decide to go forward with it, check out the “What are you listening to - (BACCH Edition)?” thread and the playlist that @Steve08226 and @aangen have curated for some suggested tunes that help demonstrate what BACCH processing is all about.
Thanks @aangen
What puzzles me is that means Nuc > USB > DSD Mk2 will sound the same as Nuc > Mac (BACCH) > DSD Mk2 when the filtering in the latter is switched off.
People are splitting hairs over the sound signature of elite USB cables and yet the second pathway, with a Mac computer between two USBs is supposed to sound the same as one USB. Surely the path that the electrons take through the Mac is not as pure as direct? I can understand that the BACCH processing overwhelms any difference a USB may contribute.
I guess that brings up another question - is the sound quality poorer when out of the sweet spot of BACCH with it on, compared with no BACCH filtering? That is the likely situation when I’m listening to music, but moving around the kitchen.
BTW, I don’t question your observations at all, just trying to reconcile how it works. I really appreciate all the contributions!
this forum is a bad influence 
, of course I’ll move on.
I appreciate the help on the subject. I’ll take a look at the thread you mentioned.
Cheers
My kitchen and dining area is off the main listening area and forward of sweet spot by 20 feet and gets music through a six foot wide open door right of right channel.
Having Bacch DSP engaged improves intelligibility of vocals, realness and live music sound of instruments. Tonality and timber and has more articulation in the bass. Eliminating cross talk both in room and adjacent rooms improves sound outside sweet spot since room bass loading masking other frequencies also goes down.
Is bass still good? Yes I believe better. It was enough that I had fixed a mix drink for my wife using a blender in the kitchen that has a power stand by switch one switches on then one must hit pulse or high and low buttons. The volume was set at Bacch optimized level. The streamed music hit a deep bass note and the blender was still in power stand by and the vibration caused blender high switch to flip it on. This surprised my wife who couldn’t figure out what happened and was startled by an appliance seemingly having a ghost operator . To me the bass hit and glasses rattling in cabinet then blender switched itself to high explained it all. So I don’t think you will miss out on anything.
The sound quality is not poorer but to fully experience the immersive sound stage you need to be in the sweet spot (or directly in front or behind it). Unless I’m doing some A/B comparisons of a filter versus bypass, I just leave BACCH engaged. If I’m seriously listening from my sweet spot, I’ll use a filter with head-tracking activated. If I’m moving around in or out of the room, I’ll use a filter without head-tracking. As Al mentioned in his post, when out of the sweet spot, your system will sound very similar to what it does without BACCH.
I don’t disagree with you that the path through the Mac Mini shouldn’t sound as good; however, in my experience it does. I think there are a number of other factors that come into play when using a filter such as the adjustments it makes for your room’s acoustic characteristics. I think this benefit is highly underrated or overlooked. I’m an EE and have resigned myself to check my diploma at the door when entering my listening room. Many things we experience in this hobby don’t seem logical but are undeniable (save for members of a select forum - but we won’t go there 
).
Yep.
Fun though…
totally, already thinking about what else to update in the short term 