SQ Of Native WAV Files vs Flac Converted to WAV on the Fly Files

Posted by: nigelb on 07 September 2017

I have finally got round to getting a NAS installed for primarily backing up CD rips held on my UnitiServe. Having been replaced by the Core, I might move the UnitiServe on and possibly replace it with a Core at some point. In this scenario, I would need the NAS to act as a music server in the interim, possibly installing Asset. If the NAS does a good job as a server, I might dispense with a Naim ripper/server altogether and rip the odd CD from my iMac. This could help fund another upgrade I am considering.

As most of my CD rips on the US are currently WAV files, I will need to convert these to Flac before copying them to the NAS, if I want to use the NAS as a server (because my understanding is that the metadata on WAV files gets screwed up on a NAS). The NAS (QNAP with possibly Asset UPnP server software) would then be set to convert Flac to WAV on the fly when used as a music server. I understand that once the WAV files on the UnitiServe have been converted to Flac, it is a tricky (certainly lengthy) process to convert them back to WAV. So if I go ahead with the NAS as a server, my understanding is that I will no longer be able to stream native WAV files and will have to move to streaming Flac converted to WAV on the fly from both the NAS and UnitiServe, unless the UnitiServe keeps both a WAV and a Flac version of each file which I doubt.

It is possible I have misunderstood this entire process, but assuming I am correct, my question is if anyone has detected any deterioration in SQ between streaming native WAV files vs streaming Flac converted to WAV on the fly files? If so, is the difference of any significance in your opinion? My streamer (or is it renderer) is a NDS.

Posted on: 07 September 2017 by DrPo

Hi Nigel, I cannot comment about SQ differences btw WAV and FLAC (I cannot differentiate) but about the WAV metadata - this is NOT an issue, I have WAV files with properly displayed metadata on my NAS.

G.

Posted on: 07 September 2017 by nigelb
DrPo posted:

Hi Nigel, I cannot comment about SQ differences btw WAV and FLAC (I cannot differentiate) but about the WAV metadata - this is NOT an issue, I have WAV files with properly displayed metadata on my NAS.

G.

Hi DrPo, thanks for the quick response. What NAS and UPnP software are you using?

Posted on: 07 September 2017 by ChrisSU

I converted my US rips from WAV to FLAC some time ago, and convert to WAV on the fly - I can't hear any difference between this and straight WAV on my NDX. You could always convert one or two albums, and see if you hear a difference on your more resolving NDS. before taking the plunge.

You are right to think that Unitiserve CD rips stored as WAV will not have metadata readable by other devices, and the workaround of converting to FLAC on the US is the way to go. You can always convert back to WAV (or any other format) at a later date if you need to.  

Posted on: 07 September 2017 by nigelb
ChrisSU posted:

I converted my US rips from WAV to FLAC some time ago, and convert to WAV on the fly - I can't hear any difference between this and straight WAV on my NDX. You could always convert one or two albums, and see if you hear a difference on your more resolving NDS. before taking the plunge.

You are right to think that Unitiserve CD rips stored as WAV will not have metadata readable by other devices, and the workaround of converting to FLAC on the US is the way to go. You can always convert back to WAV (or any other format) at a later date if you need to.  

Thanks Chris. I had thought to try a couple of albums first but the nServe UI seems only to offer a mass WAV to FLAC conversion of all files unless when I hit the convert button it then offers me albums to select. I just wanted to check things out before I hit the convert button you understand.

I suspect there is little or no difference in SQ of native vs converted WAV files but Naim do say native WAV is best for SQ. They even state this on one of the nServe screens when you get close to the conversion screen. But if I want to use the NAS as a server, I don't see I have any choice unless DrPo has found a way of storing WAV files on his NAS without corrupting the metadata.

Posted on: 07 September 2017 by Eoink

WAV files created on Naim ripper/servers come with a proprietary tagging method which uses an external file. I believe that converting to FLAC then adds the metadata to the FLAC files as "normal" tags.  I retagged my files when I moved to a NAS, the metadata had been pretty random as I just fed disks in and ripped when I got the HDX, so tags were inconsistent. I stayed with WAV, but embedded ID3 tags into the files using mp3tag.

Posted on: 07 September 2017 by Eoink

I believe Naim's point is on the streamer itself. The extra processing effort taken to convert FLAC to WAV on the streamer has an effect (maybe noise floor raised?), so the SQ is impacted. Converting on the fly on the NAS should have no impact, as when it gets to the streamer it's a WAV stream no matter what the format on the disk on the NAS, and should be identical to the same stream coming from a WAV file as they're both lossless sets of the same data.

Posted on: 07 September 2017 by Adam Zielinski

Nigel - personally I cannot hear a difference between a FLAC and WAV. 

I even switched the transcoding off, as I noticed the transcoded WAVs had a bit of a strange sampling frequency to them.

Posted on: 07 September 2017 by nigelb

Hi Adam, thanks for the reply.

I notice you have both a UnitiServe SSD and QNAP NAS. Are these used as separate servers for your (many!) separate systems? If the QNAP is used as a server, what UPnP server software are you using? If both are servers, do you notice any difference in SQ between the US and the QNAP?

Posted on: 07 September 2017 by Adam Zielinski
nigelb posted:

Hi Adam, thanks for the reply.

I notice you have both a UnitiServe SSD and QNAP NAS. Are these used as separate servers for your (many!) separate systems? If the QNAP is used as a server, what UPnP server software are you using? If both are servers, do you notice any difference in SQ between the US and the QNAP?

QNAP NAS is a repository for the files (Downloads and Rips). UnitiServe SSD administers the ripping process and acts as my UPnP server accross the network.

I also keep an active copy of MininServer installed on my NAS, as a backup (you may recall my thread 'Dead Uniti Serves Society...' ). 

I actually prefer the 'sound' of my UnitiServe 'serving' the files, rather than files being served by the MinimServer. There is some subtle difference, but I think and I'm just trying to justify keeping the US 

Posted on: 07 September 2017 by DrPo
nigelb posted:
DrPo posted:

Hi Nigel, I cannot comment about SQ differences btw WAV and FLAC (I cannot differentiate) but about the WAV metadata - this is NOT an issue, I have WAV files with properly displayed metadata on my NAS.

G.

Hi DrPo, thanks for the quick response. What NAS and UPnP software are you using?

QNAP running Asset and minimserver. I think WAV metadata is also supported by Twonky after some version. I use mp3tag to edit metadata on my PC.

The catch might be that I dont use Core or Serve. If you stick to a NAS WAV metadata is not an issue. 

Posted on: 07 September 2017 by Pev

Same here - have flac on my Qnap NAS and convert to wav on the fly in the NAS - to my ears it sounds as good as native wav. I did compare some years ago and found I preferred wav to flac marginally.

Posted on: 07 September 2017 by ChrisSU
nigelb posted:
ChrisSU posted:

I converted my US rips from WAV to FLAC some time ago, and convert to WAV on the fly - I can't hear any difference between this and straight WAV on my NDX. You could always convert one or two albums, and see if you hear a difference on your more resolving NDS. before taking the plunge.

You are right to think that Unitiserve CD rips stored as WAV will not have metadata readable by other devices, and the workaround of converting to FLAC on the US is the way to go. You can always convert back to WAV (or any other format) at a later date if you need to.  

Thanks Chris. I had thought to try a couple of albums first but the nServe UI seems only to offer a mass WAV to FLAC conversion of all files unless when I hit the convert button it then offers me albums to select. I just wanted to check things out before I hit the convert button you understand.

I suspect there is little or no difference in SQ of native vs converted WAV files but Naim do say native WAV is best for SQ. They even state this on one of the nServe screens when you get close to the conversion screen. But if I want to use the NAS as a server, I don't see I have any choice unless DrPo has found a way of storing WAV files on his NAS without corrupting the metadata.

You can convert individual albums or tracks if you want to. On N-Serve for Mac, if you Control-click on an album, you'll see the option 'Encode to' in a drop-down, then select FLAC. If you use a PC, I presume the DTC has a similar option.

Posted on: 07 September 2017 by Simon-in-Suffolk

If your transcoder is working correctly there is no difference at all, and I measured it once, and I could see the streamer had no possible way of determine whether it was a native wav or transcoded was and the data appeared the same on a network trace (of the initial packets I measured) .... HOWEVER, the interframe timing from the media server to your Naim streamer can subtly affect SQ... a bit like the effect you obtain from using different Ethernet switches ... and transcoded wav on the media servers I played with changed the inter frame timing compared to native wav streaming and as such a slight SQ signature change could be detected... I found feeding an off board DAC from the streamer mitigated this differences to the point of being very marginal.

 

Posted on: 07 September 2017 by nigelb

Thanks for all your replies, very helpful.

Posted on: 07 September 2017 by Bart
Eoink posted:

I believe Naim's point is on the streamer itself. The extra processing effort taken to convert FLAC to WAV on the streamer has an effect (maybe noise floor raised?), so the SQ is impacted. 

There is a big leap in that little word "so."  You state it as if it's a fact.  Many have reported that they cannot hear a difference resulting from said "extra processing effort."  I am among those who cannot hear a difference.  Yet I do let my nas do the conversion, rather than the Naim player.  Why -- not because it sounds differently.

Posted on: 08 September 2017 by hungryhalibut

Nigel, you have it exactly right. If you intend to put the albums on the nas and use it for streaming it's essential to convert to flac first. I converted 2,000 albums before selling my Serve. About 30 missed the conversion process and ended up on the nas as separate tracks. Reassembling 300 tracks was a pain - just think what over 20,000 would be like. Once on the nas, set Asset to transcode to WAV, which to me sounds better. If you have an iPad and put the nas on the screen as a link thing, you can also put Asset there, so you can control it from the iPad. I've not explained that well, but hopefully it makes sense. 

Posted on: 08 September 2017 by nigelb
Hungryhalibut posted:

Nigel, you have it exactly right. If you intend to put the albums on the nas and use it for streaming it's essential to convert to flac first. I converted 2,000 albums before selling my Serve. About 30 missed the conversion process and ended up on the nas as separate tracks. Reassembling 300 tracks was a pain - just think what over 20,000 would be like. Once on the nas, set Asset to transcode to WAV, which to me sounds better. If you have an iPad and put the nas on the screen as a link thing, you can also put Asset there, so you can control it from the iPad. I've not explained that well, but hopefully it makes sense. 

I understand perfectly and that all sounds like good advice. Yes, I really don't want a huge retagging/reassembling task so I will certainly convert WAV to FLAC before copying file to the NAS. I don't have anywhere near 2000 albums so my tidying up task should't be a lengthy as yours.

Thanks

Posted on: 08 September 2017 by Eoink
Bart posted:
Eoink posted:

I believe Naim's point is on the streamer itself. The extra processing effort taken to convert FLAC to WAV on the streamer has an effect (maybe noise floor raised?), so the SQ is impacted. 

There is a big leap in that little word "so."  You state it as if it's a fact.  Many have reported that they cannot hear a difference resulting from said "extra processing effort."  I am among those who cannot hear a difference.  Yet I do let my nas do the conversion, rather than the Naim player.  Why -- not because it sounds differently.

Possibly just a badly written point by me. I was trying to explain that Naim's reported preference for WAV over FLAC was at the streamer/renderer end, not on the NAS end. Some people believe they can hear a sound difference, some don't. I wasn't trying to make a definitive statement about the sound quality, although I can see how it read that way, I was trying to explain that even if you believe there is a sound difference on a Naim streamer betweeen FLAC and WAV it won't show up if the FLAC is transcoded on the NAS.

I stuck with WAV as storage is so cheap and I needed to retag most of my music (about 1,2000 albums) anyway, so was "happy" to spend my time doing so when I moved from HDX to NAS. If I'd had a fantastically organised metadata set on my HDX then I'd have done some serious listening tests between FLAC and WAV and probably format converted, instead I added ID3 tags to the existing WAV files using mp3tag.

Posted on: 08 September 2017 by ChrisSU
Eoink posted
I stuck with WAV as storage is so cheap and I needed to retag most of my music (about 1,2000 albums) anyway, so was "happy" to spend my time doing so when I moved from HDX to NAS. If I'd had a fantastically organised metadata set on my HDX then I'd have done some serious listening tests between FLAC and WAV and probably format converted, instead I added ID3 tags to the existing WAV files using mp3tag.

Jeeeeesus H Christ, you retagged 1200 albums manually!!!! I was bored out of my mind after I did a 12 album box set.

Posted on: 08 September 2017 by nigelb

Taking EOINK's point about taking the conversion demands away from the Naim streamer and having the NAS do the FLAC to WAV 'on the fly' conversion work, I presume that a basic QNAP NAS (model TS-251A-2GB RAM with 2 x 2TB WD Red hard drives) with Asset UPnP will be capable of doing this conversion work, even on large hi-res files?

That brings be to one last question. So far we have been talking about backing up and streaming UnitiServe CD rips (from a UnitiServe) from a NAS. Are there any complications to consider when backing up hi res downloads and streaming those from a NAS? All my hi-res music files are in WAV format. Do I need to convert these to FLAC also before copying to a NAS? I have MinimServer and copies of the WAV hi res downloads on my iMac so might be able to do the conversion work on that.

Sorry for the basic questions but I am still new to NAS installation.

Posted on: 08 September 2017 by Eoink
ChrisSU posted:
Eoink posted
I stuck with WAV as storage is so cheap and I needed to retag most of my music (about 1,2000 albums) anyway, so was "happy" to spend my time doing so when I moved from HDX to NAS. If I'd had a fantastically organised metadata set on my HDX then I'd have done some serious listening tests between FLAC and WAV and probably format converted, instead I added ID3 tags to the existing WAV files using mp3tag.

Jeeeeesus H Christ, you retagged 1200 albums manually!!!! I was bored out of my mind after I did a 12 album box set.

Not quite manually, sitting on the sofa pointing mp3tag at each folder in turn, then modifying the tags if needed to keep consistency. It took every evening I was in for a month, sanity kept (given the starting point that might be doubtful) by listening to music and treating myself to a half bottle of fine Burgundy or claret most evenings.

Posted on: 08 September 2017 by Eoink
nigelb posted:

Taking EOINK's point about taking the conversion demands away from the Naim streamer and having the NAS do the FLAC to WAV conversion work, I presume that a basic QNAP NAS (model TS-251A-2GB RAM with 2 x 2TB WD Red hard drives) with Asset UPnP will be capable of doing this conversion work, even on large hi-res files?

That brings be to one last question. So far we have been talking about backing up and streaming CD rips from a NAS. Are there any complications to consider when backing up hi res downloads and streaming those from a NAS? All my hi-res music files are in WAV format. Do I need to convert these to FLAC also before copying to a NAS?

Sorry for the basic questions but I am still new to NAS installation.

I download most of my hires as WAV, these tend to come with the tagging embedded in the files as ID3 tags, so that's properly delivered by a NAS to a streamer. I find the Qobuz WAV files can be slightly oddly tagged.

Posted on: 08 September 2017 by ChrisSU
Eoink posted:
ChrisSU posted:
Eoink posted
I stuck with WAV as storage is so cheap and I needed to retag most of my music (about 1,2000 albums) anyway, so was "happy" to spend my time doing so when I moved from HDX to NAS. If I'd had a fantastically organised metadata set on my HDX then I'd have done some serious listening tests between FLAC and WAV and probably format converted, instead I added ID3 tags to the existing WAV files using mp3tag.

Jeeeeesus H Christ, you retagged 1200 albums manually!!!! I was bored out of my mind after I did a 12 album box set.

Not quite manually, sitting on the sofa pointing mp3tag at each folder in turn, then modifying the tags if needed to keep consistency. It took every evening I was in for a month, sanity kept (given the starting point that might be doubtful) by listening to music and treating myself to a half bottle of fine Burgundy or claret most evenings.

I thought alcohol might have been involved!

Posted on: 08 September 2017 by hungryhalibut

If the downloaded WAV files are properly tagged they will be fine - it's just the Naim rips that cause issues. 

We have a Qnap 253A and it converts 192k albums on the fly quite happily. One nice thing about the 253 (the 251 may have this, I don't know) is that you can plug a USB drive into a socket on the front, press a little button, and it backs up with no need to open the computer or schedule tasks. You just need to set it up in the Qnap first, which takes a few seconds, then it works fine. Of course, you can simply plug it into your computer and when you transfer the files to the nas you can copy them to the USB as well. It's all very easy. 

Posted on: 08 September 2017 by ChrisSU
nigelb posted:

Taking EOINK's point about taking the conversion demands away from the Naim streamer and having the NAS do the FLAC to WAV 'on the fly' conversion work, I presume that a basic QNAP NAS (model TS-251A-2GB RAM with 2 x 2TB WD Red hard drives) with Asset UPnP will be capable of doing this conversion work, even on large hi-res files?

That brings be to one last question. So far we have been talking about backing up and streaming UnitiServe CD rips (from a UnitiServe) from a NAS. Are there any complications to consider when backing up hi res downloads and streaming those from a NAS? All my hi-res music files are in WAV format. Do I need to convert these to FLAC also before copying to a NAS? I have MinimServer and copies of the WAV hi res downloads on my iMac so might be able to do the conversion work on that.

I run Minimserver on my Synology DS115 backup NAS, and that will transcode on the fly with no issues, so your QNAP should be fine.

The automatic backup from your US only does CD rips in the MQ folder, so you will need to add a downloads folder to your backup NAS and use a separate backup process for this. (Maybe you are already doing this?) To serve these backups to the streamer, you then need to point your server at both (backup) folders. It will be able to transcode Hi-Res FLAC to Hi-Res WAV on the fly, unless you configure the server to do something different.