A dramatic improvement in sound quality

Audio Gear DACs
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I am standing baffled before a phenomenon for which I can’t really find an explanation. I have been a Volumio Premium subscriber for quite a long time, and until now, I had been using Volumio not on a Raspberry Pi, but on a Laxton MiniPC. I was completely satisfied with the system’s quality, and although I had a few problems, I always received help for them, for which I thank you here as well.

A few years ago, I tried installing Volumio on a 2005 Mac Mini. It was successful, but it came with many problems: it couldn’t see the Wi-Fi, there were shutdown and startup issues, etc. So, I returned to the Laxton MiniPC, which was connected to an SMSL Sanskrit MKII DAC, and it sounded excellent. The Mac Mini ended up functioning as an internet radio in the garage. Updates were turned off on it, so I occasionally brought it into the house to update.

Meanwhile, the SMSL Sanskrit was replaced with an SMSL S1 DAC, which caused no problems whatsoever for Volumio.

However, two days ago, I brought the Mac in to update it. For this, I disconnected the Laxton, and the Mini took its place. When it started playing after the update, I was astonished. The Laxton also sounded beautiful. But what this ancient Mac produced… well, it left me speechless. It was as if I had replaced everything with a better system. With the Mac, the soundstage opened up, it gained depth; the music wasn’t just coming from the speakers, but also from around them! Musical details emerged that I hadn’t really heard before. My wife even put down her newspaper and asked in surprise: “What did you do? This sounds somehow different, it’s a more beautiful sound.”

I started interrogating the Volumio system hiding in the Mac, and a series of surprises hit me: For example, that little white remote control works with it; it shuts down and starts up properly, something it only used to do if I unplugged the power cord from the socket. The previously lame Wi-Fi also works now. However, the previously working analog output has disappeared; it can’t be found. And there was an annoying bug too: the fan was running at full speed. I fixed this by opening the Mini and cutting power to the cooler. I checked, and the CPU didn’t heat up beyond 40°C.

I quickly reconnected the Laxton and listened to the same albums I had listened to before. Yes, I heard correctly: the music had retreated back into the speakers and became somewhat boring; that intangible, different, better, more beautiful sound was gone. My wife even said: “Put the other one back, but make sure to clean the dust off it properly first.”

Now I’m sitting here, wondering what causes this magic. Is it the more powerful Core 2 Duo 2GHz processor? The 4GB of RAM? Or perhaps the better state of the USB port’s clock? Because in the Laxton, only a 1.6 GHz Celeron processor and 2GB of RAM were working. Both machines connect to the internet via a Gigabit LAN cable, and the Volumio settings are exactly the same on both machines.

So, what is the reason for this dramatic improvement in sound quality? Can anyone pin this down, put a finger on the exact cause?

But guys, all my recognition and praise for your work. This Volumio is a gem. Oh, and one more thing: the built-in CD drive works too!

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Did you try SMSL Sanskrit MKII DAC back? Maybe, new DAC makes the difference?

And what about Volumio version? One of my volumied Mac Mini 2008 has recently lost access to internal sound card. Probably, it silently upgraded its Volumio, and the new version has problems with the hardware.

I own three such Mac Minies (2008), but can’t say they produce remarkably beautiful sound. They connected to SMSL Sanscrit 10th mkII and Loxjie D40.

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One possibility is that your Laxton MiniPC may be producing a lot of electrical noise (RF, EMT, and ground noise created by the motherboard and power supply) that is carried by the USB cable to the DAC. The digital data itself may still be transmitted correctly through the USB cable, but the electrical noise can affect various circuits in the DAC. The Mac Mini very likely emits lower noise compared to many PCs.

Noise carried by USB cables is a topic discussed in the audio community, and there are USB accessory devices available to isolate and filter electrical noise. Higher quality DACs have noise isolators built into their USB interface.

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Thanks for your post! It was an interesting read, and it confirms what we consistently found out @ Volumio: the electronic layout of the streamer indeed affects sound quality. There are various factors involved, among the many:

  • Noise management in the various buses (Ethernet, USB, etc), this affects the overall noise floor that gets sent downstream in the chain. This affects details of the reproduction.
  • Jitter management, some systems are less prone to jitter to be sent downstream, this affects the “musicality”

Now, it’s hard to say if the MiniPC you were starting from was really low on these parameters and the Mac Mini is instead just better (but not overall better) or if the Mac Mini is exceptional in these parameters.

But this proves, once again, that “bits-are-just-bits” is just an inaccurate oversimplification of how digital playback works.

Thanks for sharing your story

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"I think I’ve figured out the solution! The LaxtonPc is a cheap office mini-pc originally, and its USB ports’ clock signal and noise filtering leave a lot to be desired. This, in turn, apparently affects the sound produced by the DAC.

On the other hand, the Apple product was originally designed for media consumption, and its USB port emits a more precise clock signal and produces significantly less noise.

I also conducted an experiment, which yielded interesting results as well: I have an adjustable linear power supply that I finished building a few weeks ago; it has very low noise because I intended it for a RIAA correction stage. But this power supply is capable of 90 Watts of power with negligible heat at 18.5 Volts. This is the operating voltage for both devices.

Well, the Laxton benefited the most from the power supply swap, but I wouldn’t call the change dramatic, it simply sounded better. The MacMini also benefited from it and revealed an even more detailed soundscape to me.

From this, I’ve drawn the following conclusion: Volumio is a top-tier system, truly an audiophile-quality streaming interface. That is undeniable. But for the capabilities of this excellent software to truly shine, it matters a great deal what kind of hardware we run it on and what electrons we feed that hardware.

I can’t comment on the other properties of the USB port because I’m not an expert. But after this, if anyone in my circle is considering streaming, I would recommend Volumio without hesitation, but I would immediately add: they should be very careful about what they install it on, because good hardware can bring out the most from this system

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