Sound Quality difference between inputs

Just adding to the above, the difference is also clearly audible on my 272, although not as obvious as on the Qb.

best

David

A lot of people say that the sound from a USB stick is the best you can get. I've never bothered to try it though. Everything sits on the nas and it gets to the 272 and Qb over a couple of wires.

I haven't noticed it because I use uPnP as recommended by Naim. They don't reckon all that much on USB and your findings appear to support this.

Harry posted:

I haven't noticed it because I use uPnP as recommended by Naim. They don't reckon all that much on USB and your findings appear to support this.

I thought that was USB from a computer (which Naim don't support apart from on the V1) rather than a USB stick Harry.  

Thanks both. I only tried it because the Qb is to take on holiday with us mainly and I hoped to avoid taking a NAS with us too. All of this will need to be re-evaluated!

My friend with the NDX told me he first noticed that the USB input sounded worse when he took some files along to listen to loudspeakers at his NAim dealer. The dealer copied the files to the store's US and they instantly sounded much better.

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David

If you are are only taking it on holiday, a USB stick should be fine. I'm not sure how you'd control the Qb though as it needs a network, unless you can choose tracks with the optional remote control. 

Hungryhalibut posted:

If you are are only taking it on holiday, a USB stick should be fine. I'm not sure how you'd control the Qb though as it needs a network, unless you can choose tracks with the optional remote control. 

Ah well I have thought about that. One of the places has wifi and so I can just plug the Qb into the router and use my iPhone to control it. The other one doesn't so what I am going to do is take an old router with me and set up a small wifi network for the same purpose. It won't be connected to the Internet but will be ok for controlling the selection of tracks on a USB stick.

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David

I don't know if I can hear a similar difference on my uq2, i will have to go back and compare now.  But I love your dedication to the Naim cause, even taking your Qb on holiday with a router for company!

DC71 posted:

But I love your dedication to the Naim cause, even taking your Qb on holiday with a router for company!

This year I told myself that it was fine to not have music while we were away because, although I always do all the cooking when we eat in while on hols, I could always listen to the radio while I cooked. But for different reasons radio reception was terrible in both places and I ended up trying to make out the music through a noise like "frying tonight". Hence the Qb.

And if it's good enough for HH.........

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David

We always have the Qb playing when cooking and we wouldn't be without it. Our next holiday is Vienna, where the State Opera will have to make do, as the Qb would take us over the weight limit. Perhaps Naim should make a Qb carry bag from Bentley leather car seat offcuts. 

Good plan HH. Perhaps we should make a joint suggestion via the Customer Portal!

Maybe this thread is small enough to ask you whether your ear is showing any improvement yet? I do hope so.

best

David

Hungryhalibut posted:

A lot of people say that the sound from a USB stick is the best you can get......................   

I think this is something Huge & myself have said,  we use it as a benchmark tool to hear what the player supposed to sound like when (e.g.)  the user was playing wireless or a network/ethernet question/problem.  If there is no SQ difference between USB & UPnP then you are good to go etc..  This is true with my NDX so the OP report is a bit concerning;  the first thing that comes to mind is to question the USB as its been reported here on odd occasions that a specific USB brand or format or something is better/worse than others.

My experience of HiRes tracks on a USB thumb drive fed directly into the front of both my SuperUniti and NDS was very noticeably worse than the same thumb drive loaded into my MAC then subsequently transferred to NAS and then streamed back. Can't explain that, but difference was not small. 

How about the same file copied from the MAC>NAS route onto USB ??  Again I question the pedigree of the USB or its format as this is absolutely not as I have experienced.  

Hi David, as discussed on other threads it would be very suprising if no sound difference was apparent between USB and UPnP (and SPDIF andYoslink). Way back when Naim first introduced USB memory interfaces for audio playback there was discussion on the forum about different types of USB memory sticks/chipsets sounding different (and on the NDAC the front and rear USB port sounding different)

So it might be worth trying a different USB memory stick vendor/memory size to see if you get any improvement? You can perhaps think of the USB memory stick equivalent to the NAS/UPnPmedia-server/switch/Ethernet-lead combo .. and we know how many variables exist there.

Simon

Thanks Simon

i agree that it would be surprising if there were no difference in SQ, but the difference I am talking about is in no way subtle, noticed by my wife instantly for example, even though she didn't know what I was doing.

i will try another memory stick, although this is a good, branded, fast one with lots of free space.  And I don't see why different memory sticks should make any difference because presumably the Naim box fills up a buffer from the input media and plays the music from the buffer?

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David

Oh dear, bits are bits  again.

Huge posted:

Oh dear, bits are bits  again.

Once they are inside the Naim's electronics, then yes they are of course.

What did you think, that each bit carries a special identifier of its origin maybe?

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David

No, bits are voltage levels, and as such can carry things other than the digital data along with them (RFI, jitter, frame rate variations, switching noise variations etc.) and these can interfere with the DAC and/or with the analogue electronics.  It's all been covered at length several times before.

Huge posted:

No, bits are voltage levels, and as such can carry things other than the digital data along with them (RFI, jitter, frame rate variations, switching noise variations etc.) and these can interfere with the DAC and/or with the analogue electronics.  It's all been covered at length several times before.

I recognise all of that but, with respect, I don't think you are appreciating the point I am making. The file on a memory stick is transferred by the Naim device into a buffer and that removes all of those extra pieces of unwanted information, replacing them with its own set of noise, jitter etc. So all I am saying is that unless one believes in a sort of audio homeopathy, memory sticks that aren't stuffed full and don't have errors should sound the same when plugged into the same Naim input and playing the same audio file.

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David

"No, bits are voltage levels, and as such can carry things other than the digital data along with them"

Well, they involve voltage levels, but more precisely they are voltage thresholds.  Below a certain value (and the value varies depending upon the transport mechanism you are thinking of) they are taken to be 0, and above a certain level they are taken to be a 1.  So if the 'on' voltage is, say, 5 volts or more and the off is, say, 1 volt or less then noise of even as much as 2 or 3 volts doesn't affect the bit stream.  In practice the levels are usually lower, and so closer together, but chosen so that the probable noise levels are smaller than the threshold difference.  So unless you are injecting very large noise levels (unlikely) then the noise should not matter.  

Dave - i think you and Huge might be agreeing with each other .. possibly... from a binary data representation i don't think there is any real debate that binary data gets meaningfully corrupted. However the noise and coupling of a USB memory stick or USB memory device can pollute the host platform with good old fashioned analogue measures of power line and ground plane modulation and electro magnetic  field strength, albeit by a tiny amount affecting SQ performance. Naim, I believe had this in mind, when they introduced the option to disable Apple device charging through the USB port... Now I suspect the USB memory stick/thumb drive has a a tiny load compared to an iPod or iPhone, but it does have a clock and digital electronics - USB is a relatively loose interface standard - I can  certainly understand why different memory stick chipsets and design may load or couple differently to the host. 

Dave another thing to try that I believe  illustrates the coupling idea . .get an NDAC - use a memory stick to play a file. Compare on a revealing system the NDAC front and rear USB port when playing back a file. Do they sound the same? 

Beachcomber posted:

"No, bits are voltage levels, and as such can carry things other than the digital data along with them"

Well, they involve voltage levels, but more precisely they are voltage thresholds.  Below a certain value (and the value varies depending upon the transport mechanism you are thinking of) they are taken to be 0, and above a certain level they are taken to be a 1.  So if the 'on' voltage is, say, 5 volts or more and the off is, say, 1 volt or less then noise of even as much as 2 or 3 volts doesn't affect the bit stream....

I do apologise for being a pedant but when digital data is 'carried' along in a serial fashions in say USB, Ethernet and SPDIF for example, NRZ Manchester encoding is used (polar and non polar depending on application and transport type). This means a voltage value doesn't itself represent a digital binary value ... the mapping of the binary value  is dependent on it and the previous state-values... So a 1 or 0 can be represented by various differing voltages when transmitted.

I would have thought that NRZ (and even NRZI) and Manchester are mutually exclusive...  NRZ sending the data 00 will show no transitions in voltage, whereas with Manchester you would see 3 transitions for that same data.  This is necessary because the clock signal is included in the data stream, in effect.  A 0 is denoted by a transition from high voltage to low, and a 1 is denoted by a transition from low to high.  Thus to show a 0 the voltage must go from high to low, then back up to high all within the bit frame.  NRZ transmitting 00 would stay low for both bits.  The problem with NRZ is that a series of 0s or 1s will show no transition at all, and so synchronising the clocks at each end can be problematic.  The advantage of Manchester encoding is that there is at least one transition for each bit, so the clock is in the data stream.  The point that I was trying to make, though, is that whichever encoding method you use, that absolute voltage is not particularly important - it is the difference between voltages that matters, and there has to be a sufficient change in voltage to count as information about the data.  Noise, within limits, doesn't affect things.  If the noise is sufficiently high then a 1 might be mistaken for a 0, of course.  Theoretically (and in practice) error checking and correction will catch this.

How many times do you find that a file transmitted over ethernet, or wi-fi has been corrupted?  I haven't spotted this yet.  If you copy an audio file over ethernet from one computer to another, you will almost certainly find that it is a bit-perfect copy.  The bits copied do not have noise imposed on them.

Synchronising the clocks (which is fairly simple with Manchester encoding) is important.  But again, problems here will usually be sorted out by the error checking.  Hence your Word document transmitted over ethernet or the internet will arrive at the other end as a perfect copy.  

So as far as I can see there are only two kinds of problem that an audio signal can encounter which would change the music.  One is that the noise on the wire somehow gets into the analogue side of things without affecting the bit stream (because the bit stream will not be affected by the noise) - and this surely comes down to the design of the receiving equipment, and TBH I doubt that is an issue.  The other is timing - if the signal is so bad that much work or re-transmission of data is required, then you will potentially get gaps in the data stream received.  That would depend on the buffering used.  It takes a lot longer to play the music than it does to transmit it, so with sufficient buffering (probably not very much) then any problems caused by errors in the transmission should be solved before that part of the music is played.  

I know there is more to it than that of course.

Beachcomber posted:

... One is that the noise on the wire somehow gets into the analogue side of things without affecting the bit stream (because the bit stream will not be affected by the noise) - and this surely comes down to the design of the receiving equipment, and TBH I doubt that is an issue.  ...

Not in audio gear, but in scientific instrumentation I've actually seen this happening.  The problem is real, and in the real world it's hard to solve.