Any advice on how to eliminate noise from NAS?

[RichardT]

Hi everyone,

 

I'm setting up my first computer-based audio system and would be very grateful for your help.

I'm trying to eliminate noise which appears to be coming from my Raspberry Pi 3 NAS.

 

At the audio end there is DAC fed by an Allo USBridge signature which is connected to the network via ethernet.

Whilst testing the system, I used my laptop to host the files (on an external HDD connected via USB). Things sounded good.

 

Then I switched to using my Raspberry Pi 3 to host the files and there was a clear drop in sound quality. The Pi was connected to the network via ethernet and the files were hosted on an HDD directly attached to the USB ports. I've changed the Pi to connect via WiFi as I've read that the Pi3 ethernet port is shared with the USB ports so that could have been a source of noise. I've also put chokes on the power lead to the Pi and the HDD USB cable. There is some improvement, but using the laptop as the NAS still sounds better.

 

What is my laptop likely to be doing better than the Pi? Are there any other tweaks I could make to the Pi that might improve the situation?

Or is the Pi fundamentally dirty, in which case what would you recommend to use as NAS in a high quality audio system?

 

Many thanks for your ideas.

[RichardT]

Hi Dave,

 

Thanks for the advice. Good to know I'm not the only one.

 

In my case, it isn't lifeless music (I've had that when using a standard pi to stream to the DAC - not a great idea). In my case it sounds slightly harsh. It's the sort of sound I've previously found cured on other pieces of kit with a better power supply or a ferrite choke.

 

Before I give up on the pi and try something like you suggest, I've ordered one of the iFi low noise power supplies for the pi to see if that resolves it. I'm hoping so as I hadn't budgeted on spending much on the NAS.

 

Thanks again.

 

[RichardT]

1 hour ago, jcn3 said:

 

 

Is the hdd powered by something other than the pi? I don't think the pi has the ability to power peripherals (like hdd) unless the power requirements are very low. 

Hi - the HDD is powered just by the pi. I've often read that the pi may lack the power to do this but have never had a problem on several pi 2s and 3s with standard power supplies. I suspect the drives I've tried are not too power hungry. I've managed to see it fail when trying to use battery power for a pi and it was very obvious...

 

So I think this is working ok.

 

Although I did wonder if a powered usb port might help my problem. Could the power draw of the HDD on the pi generate noise??? I hesitated to try this as that would add another potentially noisy switched mode power supply to the system. But I might come back to this. Thanks.

[RichardT]

7 hours ago, davide256 said:

Never got much joy out of Pi3b+, always sounded “dirty” on USB out even with a $400 LPS. Pentium NUC was far more satisfactory for UPNP streaming. Best not to put drives in your USB out device, USB boot is electrically quieter, just do UPNP streaming for least(quietest) CPU activity

I agree. I also tried a nice LPS with the pi when it was in use as my streamer (so connected via usb to the DAC). The LPS definitively improved things, but only so far.

 

With the Allo usbridge signature that I'm now using as a streamer, there was still a massive improvement in sound quality when I removed the usb HDD from it and fed it via ethernet (using upnp as you suggest).

 

But that still leaves the problem of what to then use as a NAS, given my experience that this also affects the sound quality... I'd naively hoped that with this many layers of abstraction the quality of the NAS would be of little consequence. The Intel NUCs are certainly attractive but I bet they don't all sound the same given what I've learnt to date. It seems to be a bit of a lottery.

 

It sounds like you've been happy with the NUCs though so that's another thing I can try - thanks.

[RichardT]

2 minutes ago, Cebolla said:

What UPnP/DLNA media server are you using on the RPi?

 

Has the RPi's UPnP/DLNA media server been configured to transcode the audio files it is providing over the network for the Allo Signature USBridge Player being used as the UPnP renderer/streamer?

 

Normally the only way the UPnP media server can affect the audio files being streamed is if it is transcoding them to another audio format and/or changing the audio resolution. Otherwise, the audio files should arrive at the USBridge UPnP renderer unaltered.

I'm using miniDLNA on the Pi. There is no transcoding going on so, as you say, theoretically the data should arrive unchanged. But that's just theory! There is clearly noise being generated somewhere at the Pi (which is absent when using my laptop) and this is affecting the quality of the data being received by the USBridge.

 

I've read articles describing some significant differences in sound quality from changing NAS setup. This one is particularly depressing:

http://www.enjoythemusic.com/hificritic/vol5_no3/listening_to_storage.htm

 

6 months ago, before I started setting this system up, I remember discussing with a friend that I didn't see how anything in the system before the DAC should affect the sound. It's all just 1s and 0s right? I seem to have got that a bit wrong...

[RichardT]

21 minutes ago, Cebolla said:

Are you running miniDLNA on the laptop too? Otherwise there is potential for the same file not being treated the same in your comparison if you are a using a different UPnP media servers.

That's a very good point.

On the laptop I'm running Ubuntu 20.04. It appears that this uses Rygel under the hood for UPnP, so that is different.

I'll try Rygel on the Pi and / or miniDLNA on the laptop and see if the difference disappears...

Thanks.

[RichardT]

9 minutes ago, davide256 said:

Thanks for the article, even on this site few want to go down the rabbit hole of NAS differences

Yes - it is definitely a rabbit hole. I suspect we can apply the usual rules of clean power supplies and isolating signals from dirty electronics as much as possible, but beyond that it's anybody's guess what NAS setup will sound better.

 

Whilst reading about this I've come across the idea of using a dedicated network switch to host the NAS and streamer rather than having them both connected directly to the router as I have at present. Have you, or anyone else, done this and noticed any difference in sound quality? If I understand correctly, it should help eliminate interference that might arise from the router and increase the potential network bandwidth available between the NAS and streamer.

[RichardT]

1 hour ago, davide256 said:

I have NAS, server, and ripper PC on an Etherregen switch, largely because I can get reliable throughput in excess of 100MB/sec that way for DSD files

with all on the GigE ports. Audio playback can be erratic if your data has to pass through a router and be affected by its state of activity vs just passing data between MAC addresses on a switch. Can't say that one needs to spend on an Etherregen, I suspect a simple Cisco Catalyst GigE switch would do just fine

as the FE one I tried worked well when doing only PCM

Thanks.

I wish you hadn't introduced me to the idea of the Etherregen switch! I'd love to hear what difference that makes - it'll depend on how dirty the ethernet clock is in the first place I guess. I've heard dramatic improvements in the past from inserting a high-quality reclocker in a digital stream before it hits a DAC (but that was coax or optical). I can see how the same principle could apply.

[RichardT]

3 hours ago, clipper said:

USBridge Signature user here.

 

You could use something as simple as this as a NAS: https://www.synology.com/en-us/products/DS118.  It's about $220 US, I think.

 

I use something similar, and power it with a linear power supply.  

 

I am an EtherREGEN user also.  Great product.

 

This isn't what you asked about, but I concluded that the software you run on the USBridge Signature really matters.  If you have a chance, give GentooPlayer a try.  

Many thanks for your advice. I have only used moode on the usbridge so far. I've got a spare sd card so will give Gentoo a go - it looks massively configurable so that'll keep me quiet for a while.

 

If etherregen is all it claims to be, then so long as the NAS has enough power to meet the bitrate, the NAS I use shouldn't affect sound quality. But, again, that's theory and I'm sure in practice things might be different. Have you ever used a different NAS with the etherregen to see if there is any change? For instance, does switching back to a non-linear power supply on your NAS affect sound quality? (Although I suppose that could indirectly create interference in the system via power lines)

 

The purpose built NAS units are designed to provide enough power for video transcoding which is of no interest to me. An old NUC like davdie256 mentioned would have more than enough processing power for a fraction of the price, but would consume a lot more electricity than the NAS example you provided.

 

Thanks again for your advice. I think I need to get hold of one of these etherregen switches to hear what it does. I think they provide a 30 day money back guarantee so I'm only gambling the postage to the UK.

[RichardT]

5 hours ago, clipper said:

The only 2 NAS units I've used are very similar to each other (Synology DS115J and DS116).  For my needs (I don't need to do RAID or anything, and I really only use the NAS to hold music), the smaller and less powerful NAS units are perfect because they're easier to power with a reasonably priced linear power supply.

 

Switching back to the stock power supply results in a drop-off in sound quality (with my equipment, my ears, etc.).  

 

 

Thanks, that's very helpful. I've read that others also continue to hear improvements to the sound by tweaking components upstream of the etherregen.

 

I've got plans to try a cheap little switch I've dug out that I can power with the secondary linear supply on the usbridge shanti LPS. The iFi supply for the pi has arrived too. This'll hopefully give me an idea of where most of the trouble is coming from.

[RichardT]

10 hours ago, clipper said:

You're welcome.

 

Yes, I hear improvements too from other tweaks in the network chain, such as:

JCAT network card in music server, powered by a linear power supply,

Cable modem, router, and switches powered by linear power supplies,

Dedicated switch (only 2 ports used, one connected to another network switch, the other connected to a fiber media converter),

Fiber connected between fiber media converter and EtherREGEN A side, Ethernet connected between EtherREGEN B side and USBridge Signature, and

EtherREGEN synced to an external clock.

 

Good luck with the stuff you're trying.

 

Wow - it's a bottomless pit! I'll start with the stuff nearest USBridge and work backwards...

[RichardT]

4 hours ago, One and a half said:

@RichardT, add in a pair of DX-ISO-PLUS filters in the Ethernet cable from the NAS to the chain to the audio endpoint. You may need several, their price is inexpensive and worth every penny. The noise reduction is quite dramatic.

Many thanks for that - another interesting option and a lot less pricey.

I'll add those to the list of bits to try out.

[RichardT]

This morning I've had chance to try a cheap (£10) switch that I had lying around powered by the Shanti LPS rather than sending everything via the router.

The improvement is already significant.

Even using the original SMPS supply with the switch is an improvement over not having the switch at all, but the LPS on the switch makes the biggest difference.

Thanks everyone so far for all your pointers - it's very helpful as this is a minefield.

I'll hopefully get chance to do some more listening over the next few days.

[RichardT]

For the benefit of anyone else following a similar path...

 

Today I had the opportunity to see if adding the iFi power adaptor to the Pi3 NAS improved the sound so it could compete with my 8 year old laptop with standard power brick as the NAS (not a fancy machine and storing the music on the same external HDD I used on the pi).

 

In short, no, it still fell well below par. The laptop sounds sweeter, warmer, more detailed, more open and most significantly has much better dynamics. I remain staggered that the NAS can have this much effect. The rest of my system isn't massively high end either ( amp, DAC and speakers are all worth less than £1k each).

 

As a result, I shall look into getting a second hand NUC and trying that with a linear power supply. I wonder if the pi 4 would have been more acceptable as I understand that it no longer shares the same bus between the usb and ethernet connections.