I use a Raspberry Pi 4 + Intona High Speed USB-Isolator + Musical Fidelity M6srDAC with async USB mode. No noise, no clock issues, virtually no jitter. The sound is so much better and clean now than before w/o a bridge or w/o the isolator. I believe in that setup even the audiophile low noise power supply I use could be spared.
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I’ve been lurking on these pages watching this whole thread with interest.
I felt compelled to write a pretty long missive - if only to stimulate others to go and study the subject matter they are commenting on - it’s aimed at the whole thread and no one individual.
I’m relatively new to Roon, only having started using it in January this year.
I am a convert, and have moved my various (3) systems to Roon from Volumio.
In what will turn out to be either a great move or folly - I have also paid for a lifetime subscription to Roon.
As what I like to think of as a “music first” audiophile - I’m more interested in what my own ears perceive and the music - than I am in what a marketing led journalist may tell me is better… but the important thing is the music - not just the kit that is used to get it.
I am an engineer (C.Eng and MIEEE) with over 130 patents granted during my career. In my early years worked in the recording industry repairing and updating mixing desks and all sorts of associated equipment.
I’ve made many of my own amplifiers and preamplifiers, and even built my own ladder DAC back in the early 90s.
I was around when the real change to mastering for CD rather than Vinyl started. That coincided with my engineering career being in digital signal processing (although my work is/was mostly in healthcare).
Audio-wise I am now very fortunate after many years of hard work to be able to afford a decent all digital setup - with a minimum box count, and the best bit being that others far brighter than me did all the hard work to make it so good.
I have a set of Kii Three speakers, Innuos Zenith SE and Phoenix with a Kii Controller as my primary system. All 3000+ of my CD’s are ripped (Red Book standard) to FLAC and stored both on a NAS and on the Zenith. The Zenith is also my Roon Core on a hardwired network with CAT6 cable. I also play some hi-res files that I picked up along the way, and stream both Tidal (including MQA) and Qobuz in their maximum resolution formats.
I also have a Raspberry Pi 3B+ with a HiFi Berry Digi +Pro running Ropieee which connects via SPDIF to a Graham Slee Majestic DAC and Solo Ultra Linear headphone amp that drives a pair of Beyerdynamic T1’s (2nd gen) and others including a pair of 1770’s and 770’s. I guess the habits of a studio life die hard, with Beyerdynamic headphones and AEG microphones being in the majority here.
I also have another more recent Raspberry Pi 4 running Ropieee which connects via USB to either an Audioquest Dragonfly Red or an Onkyo DAC-HA200 which can be used with a range of IEM’s or many of the other headphones from my relatively large collection (about 20 pairs).
I have not got the spectrum analyser out (yet) on any of this but these are my subjective conclusions from my ears (not golden by any means):
Using each of the sources direct to the Kii Three’s and with nothing else in the signal path there are (unsurprisingly) differences between a) The Zenith SE and Phoenix, b) the Zenith SE on its own, c) the Raspberry Pi 4 using USB and d) the Raspberry Pi 3B+ with the HiFi Berry Digi +Pro.
Set a) has perfectly “black” quiet points, a tall and very wide soundstage with excellent clarity, depth and what I would consider to be near perfect reproduction across the range of frequencies. Let’s face it - a system that retails for over £25k needs to be pretty special. It is.
The attack and decay particularly in complex orchestral or large band groups is excellent allowing you to pick out individual instruments in amongst what would be normally quite a confusing picture. It shows up poor recordings and bad mixes, being quite brutally honest in its reproduction. It’s occasionally like being there, but Although it’s incredibly engaging to listen to and very relaxing, it’s not what I would ever describe as a warm reproduction (often with harmonics) that some people seem to gravitate to. That’s not wrong - just different.
Set b) mirrors many of the points from set a) - but if there is a criticism the soundstage isn’t quite as tall or wide and the decay from very complex pieces may not be quite as fast. Otherwise, it’s still pretty special.
There is very little between c) and d) with the latter seeming to just get ahead on clarity and handling of complex “big” soundscapes as generated in some electronic music and movie themes.
Both Raspberry Pi iterations perform way, way better than the price point might lead you to expect, and as in most things where we seek perfection, there is a law of diminishing returns as you get further and further towards Nirvana (the place not the band). So the Pi’s are really good, but there is a very clear difference between a)/b) and c)/d) that you’d probably expect.
The Kii threes do intrinsically tidy up their input signal and reduce any jitter, so I can’t say that I’ve heard anything untoward from the Raspberry Pi’s as they do their stuff, no matter whether they are using SPDIF, optical or USB.
The sound stage from both c) and d) isn’t anywhere near as expansive, and nor does either resolve the picture to place musicians within it accurately - in comparison to system a). However, make no mistake, both RPi setups are far better at doing all of that than either a relatively new Lenovo Laptop or a Mac Mini - both of which I have also tried on the same system.
The Pi’s are in my opinion also almost an order of magnitude better than the excellent Chromecast Audio - a fantastically convenient device for some applications.
I think it’s fair to say that the system sounds better on USB using the Raspberry Pi 4 rather than the Raspberry Pi 3 on USB (no HAT) but it is hard to pinpoint exactly why. To my ears it just felt that the Raspberry Pi 3 was battling through some “mush” in comparison to the ease at which the Raspberry Pi 4 was operating.
My conclusion is that it’s hard to go wrong at almost any system level by using a Raspberry Pi as a streamer.
They’re really very good, and probably far better than they ought to be considering the low price of putting together a reasonable one. In my view it has made other streamer and DAC manufacturers step up their game to try and differentiate from this $130 upstart. That’s a good thing.
Using something better than the standard wall wart power supply as used with most Raspberry Pi implementations will almost certainly bring you additional sonic benefits, and I recommend the 5V 3A iFi power supply, because yes, I could hear an improvement - notably a clearer background.
So a penultimate comment from me is on the “bits are bits” statements we have seen here and elsewhere.
So aren’t bits just bits?
Well, yes they are - technically but in this engineer’s view (and it’s only my view) the issue is not only the bits, but the TIMING of when exactly those bits are supposed to be there. That’s a measure both of how clean the waveform is (nice square edges, limited hysteresis and a fast rise and fall) and just how much noise is interfering with the “threshold” (the point at which a voltage rise or fall is recognised as a 1 or a 0).
The point at which that threshold is reached is when the digital signal processor actually recognises it and it is this timing that in my view is CRITICAL.
More importantly than my opinion, psycho acoustic studies tell us that the human ear/brain is INCREDIBLY sensitive to these timing differences - particularly when both ears are in use.
It’s what helped us survive being eaten at some point in the dim past.
For those who want to know more, a quick Google of “Intraaural Time Differences” will open a whole new world. A long time ago, I worked on some hearing test equipment for those with cochlear implants and I did a fair bit of reading around this topic. Some people have spent a lifetime studying just one small aspect of psychoacoustics - so a few comments in a forum barely scratches the surface…
Should small factors like jitter, electrical noise, processing/clock/timing variables combine to create or exaggerate even a small delay effect - which causes the timing to be off - we will probably notice it.
Some studies have demonstrated that at certain frequencies the human ear/brain can detect frequencies with a difference of just 1Hz, and timing differences of under 50 micro seconds or 50 x 10 to the -6. It may be smaller, but physiological measurements at that speed get more difficult.
So yes, bits are bits, but the accurate delivery and processing of these bits and their relationship to the clock signal and how they are perceived by the human ear is why digital audio engineering is just so fascinating and why such debates and myths carry on on forums like this.
My advice - do your own research and make your own mind up.
A last word here for Ropieee, a superb piece of free software that makes creating a Roon endpoint and maintaining it an absolute breeze.
Thanks to the diligence of its creator, it just keeps getting better with added features.
If you use it, I urge you to donate something to the creator so that it can just keep getting better, and so that support can continue.
Whatever happens - just enjoy listening to music.
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Nice write-up, David. Thanks.
Probably more than that, if you are using the built-in DAC and preamp in the CCA, less so if you are using the optical digital out from the CCA.
The thing is, in a modern DAC, this is entirely under the control of the DAC. How the bits are delivered to the DAC is insignificant, so long as you don’t have buffer underflow. The DAC buffers them and controls their entry to the D/A processor.
A much more interesting and highly variable thing to look at.
What do you attribute this to?
Amen to that. Here’s the donation link.
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Wholly agree - optical out is the best way, although I breathed new life into an old Bose Sound Dock using a CCA puck and it’s 3.5mm adaptor… a bit of a fiddle to find the right I/P pins - but it works!
Indeed true, although the threshold trigger point (and how it is affected by external factors such as noise and jitter) are determined by design. That “trigger point” can be affected by noise and even clock harmonics and bus noise. I guess most modern DAC’s are on chip, so there is less of an issue, but if I had a few years with nothing better to do I might look at what would be needed in an ultra accurate but low noise audio DAC - although it would probably end up costing a fortune!
I think that it might be noise on the power supply line from a poorly functioning switched mode supply, probably built down to a price rather than up to a standard. A good switched mode supply well implemented shouldn’t leak transients onto the power line to any level that would make a difference. A linear power supply with a toroidal or encapsulated transformer almost always outperforms the standard wall warts, but again - there are bad linear supplies too. Not everyone wants additional room heating…
I think that’s what ESS Technologies and Asahi Kasei Microdevices are doing, isn’t it? Take the new dual chip 4191/4498 combo from AKM, for instance.
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I saved the best for last @Bill_Janssen…
Music itself is subjective, and my old ears are not as good as my younger ears once were. Rifle shooting (army and otherwise) plus a lifetime in industry before health and safety make my own ears less good at determining outcomes of changes and tweaks. I now find I need a few days to determine any sonic changes - against a few minutes when I was younger!
Human hearing and the psychoacoustic challenges audio equipment manufacturers are trying to address mean that the debate about measurement and perception will probably go on long after I’m pushing up the daisies and I’m only 57!
In my view, unless you want to really start chasing down the laws of ever diminishing returns (and I have gone as far as I think I want to (barring a set of BXT’s for the Kii Threes) - then a well set up RPi running Ropieee or similar on USB from a Pi4 or using a HAT on the earlier models will get you a heck of a long way along that route, potentially giving you more cash to spend on amps/speakers or lunch.
I’d still buy my Zenith SE and Phoenix (second hand as I did) just because the Kii’s can reveal the differences quite well. I’m not sure many systems would - unless they’re as brutally honest with the signal. Some people hate that.
I don’t.
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IMHO, at least 50 percent of what people think they hear is not real. They expect something to sound better, so it does.
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Interesting - I’d love to see the evidence for that which someone else has done properly.
Where is that info?
For my input - I stuck an iFi wall wart on the old Tektronix oscilloscope here and there was certainly a flatter DC line (less ac frequency component on it) than the standard Pi version.
I looked at the ground line too - and yes, there is some very low level components on there but it was below the sensitivity of the scope and my setup.
In any case - for a relatively low cost DC supply that’s handy - I haven’t found a better one in the same price range. Have you?
I do have a really nice 5v 5A linear supply that would work - but it’s relatively big, and I only have one, and something similar is expensive. I might build my own once I have determined the permanent placements for all the Ropieee endpoints.
Look forward to seeing the articles/evidence about the effects on sound quality together with your recommendations for a better PSU for the money. Thanks!
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Hi Jim,
So what exactly is your point here?
I just go with what measurements and my ears tell me. I encourage everyone to experiment for themselves and not just to listen to those who say a lot and do little!
We all have different systems and tastes - and I guess that’s why the world is such an interesting place.
Blind testing is the only way in which we can subjectively gauge performance. You will note though that Psychoacoustics was touched upon in my response. It might be worth reading up on that - it’s a fascinating topic.
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My point is obvious. Expectation bias is a real thing.
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Indeed it is. Another reason why I always try and do my own research before buying/using. If that involves dusting off an old oscilloscope - then so be it.
Interestingly - I have chosen to use RPi’s as Ropieee endpoints for most of the locations I listen to music in. These are not expensive hi-end streamers and I make the point in my original post and responses that for the money - they’re really hard to beat.
The DAC I use for my “best” headphone setup is one that I still find (for my ears) that I prefer the sound of. It’s really not mainstream and does not do MQA or even the higher rates (downsampling is used) - but the Graham Slee Majestic DAC seems to work very well with his Solo headphone amp. I have tried various other DACs at increasing cost - but I have yet to be convinced of the further expense for very minimal gain.
I was just curious why you decided to chime in with your comment when it didn’t materially add to the thread? I guess you just wanted to educate everyone?
Perhaps your expertise and experience could voice an opinion on the topic here?
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I’ve been a member for years on the Martin and other acoustic guitar forums, and there’s a certain trust/respect that members give each other concerning what we hear, regardless of accepted norms/measurements/consensus.
If a member says they were at a shop and played such and such guitar that cost $X, and they were surprised it sounded and played as well as some other guitar that was priced at $10X, rarely if ever does someone say “There’s no way that’s true, the expensive one uses better wood and measures better so you’re wrong.”
Or conversely, if they thought the $10X one sounded and played better, nobody would say, “well, you just want it to sound better because you expect it to because it costs more. Or because it has an adirondack vs a sitka spruce top. It’s confirmation bias.”
Everyone’s ears hear things differently. What is crystal clear and accurate to one, is tinny and brittle to another. What’s lush and complex to one, is muddy and vague to another.
Yeah, I get that acoustic guitars are different than amps or speakers or power supplies, but there’s no getting beyond the fact that different people do hear things differently. Gotta respect that.
Interesting how different it is on audio forums.
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I have assembled 3 RPi4’s running RoPieeeXL, one with a screen and battery powered. I sold one and use two of them, one with a Meridian Prime Headphone Amplifier and Power Supply and one with a Dragonfly Cobalt. I use them with AEON and Sony WH1000XM3 headphones. Both of these DAC’s are MQA as I use both Tidal and Qobuz.
People chime in all the time. This is an internet forum. I’ve posted in this thread 6 times. There are moderators to keep things in line.
Yes, I agree. I’m a bit shocked actually about the negativity on this forum in particular.
I’m new(ish) to Roon and to the use of the RPi as part of an audio system, although I know one of the RPi creators well - as a good friend and fellow engineer. We’ve been discussing my journey of discovery in audio streaming using the RPi and it’s great discovering new things that not even he envisaged for RPi.
I’m not at all new to audio or audio recording/reproduction however and the style of dialogue in industry forums and professional audio engineering forums is a long way from what we see here.
It is a shame that some feel the need to personally denigrate because all it does is create an echo chamber of the same opinions - and in the end this just kills respectful comment. That means that people like me will vote with their feet and won’t consider further active participation where it’s not wanted.
I think the professional music/industry forums will remain my choice.
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@David_Ford. Keep providing your perspectives… Some of use value peoples experiences and actions. Every day is a learning day and I in general agree with your first post.
As someone who has also built audio equipment (as a hobbist) yet expecting little SQ difference yet hearing a good steps
… Measure and hear are key.
As you say, do your own research and listen… In full agreement.
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Here you go, measurements of the IFI PS are included in the review.
Check out SBooster PS’s. They are clean and provide excellent results. Not the same money obviously. https://www.sbooster.com/
Hi David,
I wasn’t trying to be negative.
I had just recently learnt of the AS measurements on the iFi power supply, so I thought it was important to share this information in the context of the subjective feedback you provided.
Too many mainstream audio companies market their products, with an ability to improve sound
quality, yet when independently measured the opposite seems to be true. I.e. higher distortion, more noise, etc. Dac’s, power supplies, USB noise/recovery devices, etc are all good examples.
I’m the first to support everyone having a subjective opinion, but measurements should be equally valid and not seen as confrontational.
But…, I also know measurements aren’t everything. Sometimes measurements don’t correlate with good sound. Point in case; I own a Firstwatt F7 amplifier, which deliberately introduces 2nd and 3rd harmonic distortion… for ‘improved’ musicality. No issues here, it sounds amazing, but Firstwatt are open with this methodology and approach.
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Thanks. I think that’s all anyone should do. Too much store is placed in those who make unqualified and subjective assessments, post only part of the picture or take selectively from genuinely researched articles - often missing the point entirely.
You could spend a lifetime trying to correct this. I won’t attempt that here.
I had been warned by a pro-audio friend of mine who once had a successful consumer audio store - that there were a lot of “armchair warriors” in the sector. It’s a shame the “Audiophile community” gets so fixated and polarised - and I guess it’s because the level of hype and marketing in this sector often defies logic (and the science) which in turn leads to some of the consumers believing the hype over the science. There seems to be a lot of pseudo science practised too, with meaningless graphs or measurements that look impressive - but then you realise that these either have no reference, calibration or even in some cases - understanding of the magnitude (or not) of the results.
Me, I’m for my own research, my own practical tests (usually over months), bench analysis (where I have the kit available) and then long-term use and review.
I think I’ll revert to lurking and reading about the excellent Roon software here - and save my contributions on audio recording and reproduction for more professional and authoritative environments. I am sure it will also help my blood pressure and sanity.
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