Life of Pi

[terrybooth]

Whoa! Lets get give some proportion to this.
The PI is a computer; it’s not some magical bit of electronics that outshines any other computer when it comes to audio; all computers can deliver bit perfect audio to a dac.
What is special imo is the price and the simplicity of the motherboard. It’s still just a computer.

The dacs; yep they give outstanding performance for the money but there are better dacs in just about every respect.

I’m not knocking the PI and\or the many dacs that can be stacked directly on the PI board.
but the hype is more than the product and that’s not so good.
The point for me at least is you would be very hard pressed to equal the two combinations I’ve heard for the money and that I am afraid is as far as it goes.

I’m listening to my my music centre and Benchmark dac still because it’s better. Yes it costs ridiculously more money but it is better without a doubt.

If others prefer or consider the PI equal or better than their flagship CD players and tweaked dacs then I say this says more about the shortcomings of the original kit and not so much about the PI and dac combo.

I totally agree that we should avoid the 'best thing since sliced bread' but this is all about a journey and not about arriving.

Fretless is telling us that he found his Pi/HiFiBerry Dac sounds different/better. This I think is significant because the Pi is only acting as a transport here - all the analogue stuff is happening offboard, so if 'all computers can deliver bit perfect audio to a dac', why does this sound different? (Note I say different, not 'better' at this point.)

If I can briefly describe my digital journey.

Starts with a 'flat earth' system and a Naim CDI
This sounded 'OK' but not 'better' than the analogue system (probably due to background brainwash).
With a house move and family, the system languised plus I didn't pay for the 6 monthly tweak/upgrade that was necessary to keep me happy with it.
I built a CD system with 'spare' kit. The CDI migrated to that.
This became the system I listened to music on.
I heard a rumour that John Farlowe was going to go back into production (I have Exposure Amps) a bit of googling brought me to NVA and eBay to a secondhand AP50.
I remember a friend telling me that rather than 'source first', a CD system needed 'better' amplification (pick the bones out of that statement from someone who was also 'flat earth), so the amplification started to be beefed up and I started to 'get' what NVA was about.
CDI went and TFS came. Did it sound 'better' probably not much but one thing I found was that a ripped CD sounded better than a played CD.
TFS was augmented by an outboard DAC at the suggestion of the TFS maker - first one, NAH, second one, yes better.
TFS was OK but felt really 'clunky' to me and I found what appeared to be an approach based on 'minimalism' which is what I like about NVA.
In particular, I was attracted by this claim: https://volumio.org/raspberry-pi-i2s-da ... s-so-good/
So, I've spend many hours trying to figure what sounds better. Certainly the Pi plus external DAC isn't wonderful (this appears to be down to the implementation of the USB bus on the Pi). To me, the PI doesn't sound worse than the TFS, so the TFS was sidelined.
And now, I'm playing around with the power supply to see if that makes a difference to me.

Back to the computers. The Intel x86 architecture one architecture, the Pi is a different architecture. They apparently do things differently. Is one better than the other for music reproduction: I don't know. Put on top of that, the operating system; does that make a difference in sound quality: I think it does but I haven't found differences in the Pi world (then I haven't tried). However, the most important thing for me in the Pi world is that is is all open-source and that is a great environment for experimentation and development: it makes the journey more interesting for me.

[Fretless]

Terri-fic (!) story, and nice to compare one's own experiences with somebody else's.

I spent several years pretty well only listening to music via a (windows) PC and spent a lot of time and effort experimenting with music compression formats and media playing programs. Since then I have been actively busy to combine the computer and audio systems. Hobby & curiosity.

It is interesting that the Pi sounds so much better than the Sonos; the same files are being played through the same system. So the only conclusion is that the Sonos is mucking up the data signal somewhere in between it coming in as network information and being output as an SP/DIF audio stream.

Next experiment will be to compare the Pi against my ASUS (windows) netbook which has a USB link to the same Musical Fidelity M1DAC. Although I know that USB audio can suffer from 'Jitter' where the data signal goes out of synch and can be heard as a veiling/loss of focus in the audio.

[terrybooth]

Next experiment will be to compare the Pi against my ASUS (windows) netbook which has a USB link to the same Musical Fidelity M1DAC. Although I know that USB audio can suffer from 'Jitter' where the data signal goes out of synch and can be heard as a veiling/loss of focus in the audio.

Did something similar when I had the TFS running into an outboard DAC. (Although the laptop was using Win 8 and the TFS Win 7). Interesting to hear your version of this experiment.

[Welder]

Oh dear, I didn’t do that very well did I. My apologies. I’ll blame a day of Spanish builders.

I’m not knocking any of this and I totally agree about the fun of discovery and all the Open Source comments Terry has made (I spent months with a scalpel and a soldering iron cutting up various mother boards got from scrap and mates so I could find out what was required for audio and what just added unnecessary complexity and I struggled with Linux and still do). I’m not bragging about my system either. I like it and I built a fair proportion of it over the years; not just chucked money at it and bought the monthly favourites.

My point was and still is a few of the more vocal on a number of forums have it seems finally accepted that file based audio with one of those horrid computer thingies can, and often does, sound better than the thousands of pounds worth of previously prized and bragged about battle ship construction CD players and odd looking dacs with glass bottles sticking out the top.
We are talking about a computer and a dac chip here basically; nasty plasticy thingies that cost pence compared to 'real Hi Fi’. Some, not here I might add, have got rather carried away in their enthusiasm and now the combo that triggered the conversion is THE answer for file based audio.
Well, it isn’t is it. There are lots of dirt cheap fantastic sounding dacs out there, lots of different MOB’s and lots of different ways of connecting all the pieces together. They all do that transfer of digital signal thing equally well these days , I would argue, that’s the point about digital and that’s the point that is largely being overlooked. Sure, there will always be small issues such as perceived differences in the performance of various operating systems, power rail noise, dac performance, etc, but this is all about digital signal transfer and that is pretty much a done deal as they say.

Now if we could all stop saying silly things about letting the music through and start talking about signal processing we might make some progress and concentrate on the shouty end of the system.

I hope this comes over a bit better than my last post.

[_D_S_J_R_]

If the Sonos doesn't 'sound' quite as good, could it be in the analogue outputs? Please forgive my ignorance if I have this wrong...

[Fretless]

If the Sonos doesn't 'sound' quite as good, could it be in the analogue outputs? Please forgive my ignorance if I have this wrong...

I was using the digital coax output of the Sonos Connect in this system, so all it was doing was converting the computerised data files of MP3 and FLAC format into an SP/DIF stream (same as a CD player) and outputting that to the M1DAC. Shouldn't be too difficult for it - no analogue filtering or anything. I even disabled the onboard Wifi link so all power could be utilised by the procesing chips.

The sonic difference is marked. The sound produced when the Pi replaces this link in the digital chain is clearer, more dynamic, better depth in the sound field & image. Like I said earlier, it's like my M1DAC had been swapped for something far more expensive.

[Fretless]

Got me thinking, that last question and I think I have worked out what the Sonos Connect is doing that causes the slight degradation in signal quality.

(those not interested in techno-babble need read no further)

The Connect is a clever little thing. It inputs digital data (wired and wireless) and outputs both a digital and analogue signal which can be fixed volume, but also variable volume. It also communicates with other Sonos devices in an apart ('Sonosnet') network.

What it can also do is input analogue audio - from a CD player, for example - and act as a remote-controlled pre-amp. But the analogue signal from the CD is first converted into digital, as it can also be accessed from other Sonos devices in the network. So somewhere there is an interim phase within the Sonos where a data-stream/signal gets manipulated. Possibly (I'm guessing here) as an analogue signal.

This would mean that an incoming FLAC stream gets converted to analogue, processed for volume, and then converted again to a digital SP/DIF for output.
Certainly the Connect's analogue output has a very clear sound, and I have a second Connect directly driving my old NVA stereo A40 amp in the living room and that sounds very pleasant.

As the Pi B+/Hifiberry Digi+ combination only does a single conversion (FLAC => SP/DIF) then this could explain why the sound is that much better. The integrity of the original data stream is preserved.

Theoretically then, the Sonos Connect's analogue output ought to sound approximately the same as a Pi/Hifiberry DAC with analogue RCA output - but the digital output from the Sonos goes through a re-encoding phase and an accompanying slight loss of quality.

[Fretless]

Now if we could all stop saying silly things about letting the music through and start talking about signal processing we might make some progress and concentrate on the shouty end of the system.

I hope this comes over a bit better than my last post.

Completely agree, cheers

[terrybooth]

With the IQAudio DAC, I find that it sounds better with the volume control disabled in Volumio. The HiFiBerry Digi doesn't, I think, have this option.

[Fretless]

With the IQAudio DAC, I find that it sounds better with the volume control disabled in Volumio. The HiFiBerry Digi doesn't, I think, have this option.

You're right, Terry. The volume controls in Volumio do not work with the Digi+ output.

This only reinforces my ideas about the Sonos Connect where the digital output volume could be varied - something which I believe happens in the analogue domain before the sound signal is digitalised again for re-transmission as a data stream to the rest of the Sonos system and the onboard digital outputs.