High Quality Audio - Very Confused

Richy1984

Active Member
I will soon be purchasing a Naim Uniti 2, PMC Twenty 23 Speakers and iPad and want to set myself up to be able to listen to high quality audio :)

If someone could help with a few questions that'd be great!...

1. What does 16bit/44.1kHz or 26bit/192kHz actually mean in simple terms?
2. What do I need (programs etc) to be able to download or stream high quality (i.e. above CD quality) audio?
3. Is Spotify anygood? I was considering it until I read the max sound quality was 300kbits which as far as I can tell is still way off even CD quality? :rolleyes:

Cheers in advance for any help.

Richy
 

MaturityDodger

Well-known Member
I will soon be purchasing a Naim Uniti 2, PMC Twenty 23 Speakers and iPad and want to set myself up to be able to listen to high quality audio :)

If someone could help with a few questions that'd be great!...

1. What does 16bit/44.1kHz or 26bit/192kHz actually mean in simple terms?
Imagine the audio signal as being a wave on a graph.
The first number (the number of bits) is the resolution on the Y-axis.
The second number (the sample rate) is the resolution on the X-axis.
16/44.1k is the format that audio CDs use. This means that there are 44100 samples per second. And that for each of those samples there are 2^16 (=65536) possible values that the sample could have.

2. What do I need (programs etc) to be able to download or stream high quality (i.e. above CD quality) audio?
You don't need anything special to download audio files. Just take a computer on the net and buy them.
but for streaming, you need both a server and a streamer.
Your uniti is a streamer. So you just need a server.
you can stream music from online sources, and pay for the privelege. I've never used this.
Or you can set up a server at home. A NAS (network attached storage) is the best thing in my mind. £3-400 for a decent box and hard drives. You put your music on this, run server software on it, and the streamer plays them.
These files can be ripped from CDs, or downloaded. You can then use your iPad as a controller.

But you don't necessarily need to stream at all. If you put your files on a USB device (including the iPad itself) and plug it into the Uniti, then the Uniti can read and play them directly. An iPad is a very expensive way of buying digital storage though if that's all you're going to use it for!

3. Is Spotify anygood? I was considering it until I read the max sound quality was 300kbits which as far as I can tell is still way off even CD quality? :rolleyes:
Never used it, sorry.
 
Last edited:

Doomlord_uk

Well-known Member
CD Audio's 16bit 44.1kHz encoding is enough to perfectly encode all audible sound (with a dynamic range less than 96dBs); there is however some advantage technically to working with higher sampling rates when converting back to audio, and higher bit-depths permit greater dynamic range (which again can help when converting to an 'analogue' volume level too, for instance).

[Edit] - CD audio IS high-quality audio. :)

300kb/s is quite a high-bit rate for a compressed audio stream using a codec like MP3. It should be all but inaudbily different from standard uncompressed CD audio.

If you want to find out what Spotify is like, try it :) You need a Facebook account to register and there is a 30-day free trial of the Premium service.
 
Last edited:

Richy1984

Active Member
Thanks for the replies guys. So...

1. What audible benifits does a greater no. of samples / higher sample rate give once you go above CD quality?
2. What sites are best to purchase & download high quality audio files?
3. Finally, doomlord; how can a 300kbps stream be inaudibly different from CD, if its bit rate is considerably lower?

:rolleyes:

Audioenthusiast; I was considering a ipad as there is a very good app that works with the Uniti. I realise it isnt the cheapest way to store audio but I love the sleak look of the ipad and the way it works with music (artwork for albums etc). Although I will consider other means.

Richy
 
Last edited:

Steven

Senior Moderator
3. Finally, doomlord; how can a 300kbps stream be inaudibly different from CD, if its bit rate is considerably lower?
Have a read of my waffle here: http://www.avforums.com/forums/stre...ising-cds-codecs-formats-software-needed.html. Generalised however, we all have different ears and equipment etc
3. Is Spotify anygood? I was considering it until I read the max sound quality was 300kbits which as far as I can tell is still way off even CD quality?
There are two general schools for Spotify (a) general stream everything or (b) use it to discover new music, out there songs only

As for quality, think that lends itself to prev paragraph. Have a modest budget bedroom myself so am happy with Spotify quality (noting I only have a free account, which has reduced bitrate). Would not know how it sounds on a better setup
 

MaturityDodger

Well-known Member
Welwynnick said:
Other way round.

Time is the independent variable, which is the x-axis, and amplitude is the dependent variable, which is the y-axis.

Isn't that the same as what I said? Because sample rate is the time-related thing and bit depth is the amplitude-related, so I think that's the same?
 

andy1249

Distinguished Member
300kb/s is quite a high-bit rate for a compressed audio stream using a codec like MP3. It should be all but inaudbily different from standard uncompressed CD audio.

Apple marketing speak , you may not notice on the very below average and grossly overpriced ipods, but you certainly will with any kind of half decent separates unit. Apple cornered the market for mp3 and insist on selling this compromised format as good enough , so whether it originated with them or not they most certainly deserve the lions share of the blame.

One thing I know for absolute sure that will show mp3 and any other lossy file format up for the compromised rubbish it is , is the Naim unit the OP is planning on using.

Here are the facts, Lossy compression , regardless of bitrate , is Never as good as CD.
MP3 vs AAC vs FLAC vs CD | Stereophile.com

Yes CD has a much higher bitrate , thats because with lossy compression , up to 90% of the data is thrown away , they supposedly use Psychoacoustics to throw away the parts you wont miss !!!
Rubbish , and the better the gear you have the more that becomes glaringly obvious.
 

andy1249

Distinguished Member
1. What audible benifits does a greater no. of samples / higher sample rate give once you go above CD quality?

There is quite a marked difference with the right material.
DVD audio and SACD were two formats that had 24bit 96khz sampling on most titles. If you can get hold of some samples of the same material in high res and CD format you can judge.
SACD is still around , niche market of course , and mostly classical titles

2. What sites are best to purchase & download high quality audio files?
Ive used this site ,
https://www.hdtracks.com/
The majority of titles here are ones that existed on DVD audio and SACD at some point or another , the content is exactly the same.

3. Finally, doomlord; how can a 300kbps stream be inaudibly different from CD, if its bit rate is considerably lower?

It cant , see my above post for the details , and to see just how different they can be try some material on your Naim in both lossless and lossy formats. I pretty much guarantee you'll be cursing the format after this.

My personal worry is that because everyone gleefully seems to swallow the Apple kool aid , that soon this is all you'll be able to get , and that would be an absolute disaster !
 

Richy1984

Active Member
:thumbsup:Thanks for all the advice people!

So in summary, lossy formats (MP3 etc) as I thought are to be avoided and are pretty rubbish, but designed purely to give a small file size. Lossless formats however are better.

I intend on using the ipad for travelling (which I do a lot with work), not just for music.

So my thoughts are that I'll transfer my CDs to the Ipad (in apple lossless format) and then use the Naim n-stream app to play the lossless files via the Naim Uniti 2.

I've also got the option of USB with the Naim Uniti 2 too. So I can start delving into the world of higher quality files. Although am I right in thinking USB is limited to 24/96khz quality?

Then ibn future I'll look at building up a library of higher quality files and get a NAS drive.

Do my plans sound reasonable?

Can't wait to get the system now!
 
Last edited:

Doomlord_uk

Well-known Member
Interesting article from Stereophile. What's notable is that the thrust of the article is that MP3/lossily compressed audio is not 'CD quality' - and that's plainly true as the graphs show. What's interesting is that the noisefloor remains at or below -80dBs - IOW pretty well inaudible.

MP3 is an essential element of the music world now, and always will be. At least I hope so. Perhaps the key reason I say this is that there is a wealth of otherwise unobtainable/OOP tracks that can only be found online via 'illegal' download sites. Napster, the original one, was a treasure trove of new music finds, but also remixes and remakes, vinyl rips, cassette transfers and even off-air recordings - many of which will never find their way into 'official, legal' download service's servers. Say no to MP3 and you shut the door quite firmly on a vast and vital seam of music.

And if you say no on 'sound quality' terms, then I suppose you will also be saying no to FM, DAB, vinyl, cassette and internet radio. All because you believe you *have* to listen to 'high quality' audio?

Buying a hifi should allow you to enjoy your music as much as possible, but it should never circumscribe your choices nor dictate your tastes in music.

MP3s: Just Say Yes! :thumbsup:
 
Last edited:

noiseboy72

Distinguished Member
The other advantage of having a 24 bit convertor on a 16 bit signal - as many CD players and amps do, is that the least significant bits output by the devices are often not that accurate. By using a long bit length, the Least Significant Bits are thrown away and at least in theory should sound better.

The idea behind sample rates that allowed the audio spectrum above audible range to be reproduced. @ 44.1Khz, the maximum frequency is a little below half the sample rate, or about 20KHz. This is just above the normal hearing range of young people and well above that of old farts like me! Rupert Neve was one of the main drivers of using high sample rates to improve high frequency performance. 24/96 is pretty much the de-facto standard for studio recordings, although live concerts and TV recordings captured off the MADI digital desk stream will probably be 24/48 or 16/48 as this is more usual for live applications.

There really is no such thing as "Lossless" audio compression. The ear can perceive the "simplified" signal, with compressed recordings sounding muddled and lacking in punch. Your proposed system will highlight these shortcomings, but you can of course buy some really beautiful recordings from Linn Records and others.

Spotify offer a higher quality paid for service, but it is still not really hifi. Fine for some late night low level listening, but compare it to the original CD and you will find it wanting.
 

Doomlord_uk

Well-known Member
There really is no such thing as "Lossless" audio compression.
What do you mean? Of course there is such a thing. Almost any data can be losslessly compressed ('packed' in computer jargon) and then perfectly reconstructed again. That's how ZIP files work on PCs, for instance. Lossless audio files are about, typically, 50% compressed but when unpacked give back 100% of the original data.
 

noiseboy72

Distinguished Member
Try zipping a wav file. It does not get very much smaller...

Any form of audio rather than data compression - IE: using algrythms to shrink the audio using psycoacoustic techniques rather than just removing unused data tags and more efficient code structure is audible given the right system. MP3 is just one example.

You cannot compare zipping a file to MPEGing it. The technique is entirely different and the end result is not the same either.

I have never seen an MP3 player that works with zip files. I think the reason being that pure data compression is not as efficient on audio as it is on documents.
 

BlueWizard

Distinguished Member
Extending what DoomLord_UK has said. Indeed file compression like ZIP absolutely can NOT change the data contained in the file. You can NOT have a compression logarithm altering your Word or Excel files.

But find and load a TIFF file or RAW photo file into your Photo Editor, then save a copy of it in JPG format. Then reload so you have both the TIFF and JPG in the Editor, Zoom in, and compare the detail. The JPG, close up, is going to look pretty bad.

At normal Zoom, the JPG sort of blurs or blends the image together and you brain tends to smooth out any inconsistencies. That is because the JPG has, in a sense, thrown a lot of data and details away. This is the method used for Audio Compression. The final 'picture' can be blended together by you brain to smooth out what you hear, but data WAS Lost.

Lossless formats are more like ZIP files. You get less compression because you have to retain 100% of the data, but you still do get worthwhile degree of compression.

As another test, RIP a file from a CD into WAV format, then re-save it as FLAC format, then re-save the WAV as MP3 format, and notice the huge difference in file sizes. WAV is HUGE. FLAC is Large. MP3, compared to the other two, is positively tiny. Something had to happen to make the MP3 so very small, and what happened was, they threw a whole bunch of information away. The FLAC is large because, despite compression, 100% of the data was saved.

Steve/bluewizard
 

Richy1984

Active Member
and as far as I am aware from reading the threads and websites people have posted, apple lossless like flac allows for some compression of the data, but doesn't lose any quality of the original cd format. Correct?
 

Doomlord_uk

Well-known Member
apple lossless like flac allows for some compression of the data, but doesn't lose any quality of the original cd format.
Correct. That is what LOSSLESS means :)

In contrast, LOSSY compression causes information to be lost. It is not recovered during rebuilding the original WAV (CD) file. However the nature of the loss is controlled such that its effect is, or should not be, audible. This is why MP3s sound as good as they do, which is pretty damn good, considering the level of compression acheived.
 

BlueWizard

Distinguished Member
and as far as I am aware from reading the threads and websites people have posted, apple lossless like flac allows for some compression of the data, but doesn't lose any quality of the original cd format. Correct?


There are two formats from Apple, one is ACC (I think) which is a lossy compressed format, and the other is typically referred to as Apple Lossless. One would assume it is called "Apple Lossless" because no data is lost. The Apple Lossless is the preferred format for high quality listening.

MP3 and ACC are fine for an iPod player as these are typically used outside or in other noisy areas that prevent full fidelity anyway. For causal listening ACC and Hi-Bit MP3 are fine. But for serious home listening, you definitely want Lossless files, and now that they are become more available, if possible you want high bit and sample rates. (24b/96k, etc...)

I believe, if you join HDTracks.com, you can download a free sample pack of Hi-Res audio files. I don't think membership costs anything, nor are there any buy requirements. You simply have your necessary data on file should you decide to buy something.

Do keep in mind there are no hardware players for High Resolution computer download files. That is, yes, there are Hi-Res BluRay, and SACD, but these are not computer download files. Digital technology has outstripped hardware technology, and making hardware players like SACD requires that all players conform to a fixed standard. Where as, computer based files and players have the versatility to adapt to any new file format that comes out. And most streaming player, like Sonos or Logitech, play multiple common formats.

Fix hardware standards like SACD are simply too ridge to work in the modern world. Though I think both SACD and BluRay still have market potential as the world moves beyond the iPod Generation. The iPod Generation is growing up and as such there standards are becoming much higher, and they are demanding better sound quality.

Since BluRay player are likely to become common in every home, that represents a widely accepted standard that has outstanding audio quality. There are already a few Artist experimenting with BluRay-Audio releases.

SACD is already established but appeared on the cusp of digital downloads, that the prevented its wide acceptance. However, there are far more titles available than people imagine, and it is NOT simply limited to Classical music.

Here is a pretty extensive list of available SACD Titles -

SACD at Music Direct

Just to list the first few artists you will find at this link - Pink Floyd, The Beach Boys, Cat Stevens, Stevie Ray Vaughn, Santana, Billy Joel, Jame Taylor, Miles Davis, etc.... Admittedly, you probably won't find One Direction or Justin Bieber but do you really care?

I believe the world is certainly moving to pure digital files with no physical format. That allows for tremendous versatility in playback since it is mostly computer driven.

However, I haven't completely given up on physical formats. Both BluRay and SACD have tremendous potential as multi-channel ultra High Resolution audio playback, and the ability to include video at no substantial cost to audio bandwidth.

CD could have had a longer life if they had tried to improve and maximize its sound quality rather than taking the good enough attitude that is seems they have taken. Modern CD is driven my marketing and not by sound quality, which is sad.

Of course, that's just my opinion.

Steve/bluewizard
 

Avi

Distinguished Member
1. What audible benifits does a greater no. of samples / higher sample rate give once you go above CD quality?

That may depend on the DAC processes and the digital filters characteristics a particular product employs with native 44.1/48kHz material. Some of the these processes are bypassed with higher sample rate material.

Material may be interpolated or decimated from a master with a different native sample rate. The "sound" of the end result may vary even with the same source material depending on the sample rate conversion (SRC) characteristics employed.

It's also possible to compare how identical source material may sound different after SRC using SRC software that enables custom filter characteristics. Audiofile Engineering's sample rate manager has optional customisable characteristics using iZotope's routines for example.

Some key characteristics of popular SRC solutions used in the music industry can be found here - SRC Comparisons.

Avi
 
Last edited:

Richy1984

Active Member
Here is a pretty extensive list of available SACD Titles -

SACD at Music Direct

Just to list the first few artists you will find at this link - Pink Floyd, The Beach Boys, Cat Stevens, Stevie Ray Vaughn, Santana, Billy Joel, Jame Taylor, Miles Davis, etc.... Admittedly, you probably won't find One Direction or Justin Bieber but do you really care?
Can you play SACD on any CD player? i.e. coudl i play it on my naim Uniti 2 or do you need a specific hi quality CD player?
 

andy1249

Distinguished Member
SACD needs an SACD player , there are many types of SACD disc , there is SACD hybrid , which has a CD layer , that will play on any CD player but is no different to the CD.

There are SACD only disks , containing just a DSD layer , that needs an SACD player , and there are multichannel discs , which need an SACD player.

There are many universal disc players on the market , probably the best of them at the moment is the Oppo BD 95, both in terms of performance and in terms of cost.

Short answer , no you cannot play High res SACD content on a CD player.
 

GuitarBizarre

Active Member
Try zipping a wav file. It does not get very much smaller...

Any form of audio rather than data compression - IE: using algrythms to shrink the audio using psycoacoustic techniques rather than just removing unused data tags and more efficient code structure is audible given the right system. MP3 is just one example.

You cannot compare zipping a file to MPEGing it. The technique is entirely different and the end result is not the same either.

I have never seen an MP3 player that works with zip files. I think the reason being that pure data compression is not as efficient on audio as it is on documents.

*most* files don't get much smaller when using zip. Thats because it is a poor compression format. There are better alternatives available like RAR or 7ZIP.

I just compressed a .wav file of 171MB with each of those to see the results. I chose the highest compression rate (slowest but most effective compression), on each.

wav - 171MB
zip - 129MB (75% of original size)
7zip - 107MB (62% of original size)
rar - 105MB (61% of original size)

Decompressing those would return a .wav file that was 1 for 1 and 0 for 0 exactly the same as the source material.

This effect would be MORE pronounced on longer material, especially with 7zip, due to the way that 7zip doesn't compress the whole file if there is repeated data. It compresses only UNIQUE data, and then reconstructs the file based on where it nows that data is repeated. On files where data is repeated a lot (for example, archives of romhacks, where the files are largely the same with minor differences added), 7zip can reference huge swathes of repeated data and in so doing achieve extremely high compression rates, all while still being able to return a 1 for 1 and 0 for 0 identical result upon decompression.

Audio data of course isn't optimized for that sort of compression, so FLAC, being a lossless codec is slightly better than these for reducing filesize, but is still regardless an entirely identical result to the original wav. It does not use "psychoacoustics" as you claim, nor is the difference audible if the data is read perfectly. (Which in a computer it always is, and in a transport it isn't necessarily, giving the FLACs the "audible advantage" there, should you have golden ears and a hifi system to make the dalai lama jealous)
 

Mark.Yudkin

Distinguished Member
General data compression algorithms such as ZIP or RAR will yield less good results than algorithms targetted at the specific redundancies of the problem domain, because of the necessary generality. In audio, the word packing is generally used for lossless compression algorithms.

FLAC (Free Lossless Audio Codec) is one example of an algorithm targetted at LPCM packing. Its popularity is due to the first word in the name - no license fees need to be paid for the intellectual property.

The other commonly used packing algorithms in products are:
  • Meridian Lossless Packing (owned by Meridian), used on DVD-A and as the base for Dolby TrueHD on Bluray
  • MPEG-4 Direct Stream Transfer (Moving Picture Experts Group, ISO/IEC 14496), used to compress DSD on SACD
  • DTS-HD Master Audio (Digital Theater System), used on Bluray
  • Apple Lossless Audio Codec (Apple, now royalty-free), used within Apple's product world
 

The latest video from AVForums

Star Wars Andor, Woman King, more Star Trek 4K, Rings of Power & the latest TV, movies & 4K releases
Subscribe to our YouTube channel

Latest News

Google set to launch the Pixel 7 and Pixel 7 Pro smartphones
  • By Ian Collen
  • Published
Focal launches Bathys noise-cancelling wireless headphones
  • By Ian Collen
  • Published
Formovie Theater UST projector hits the UK
  • By Ian Collen
  • Published
Sonus faber unveils new flagship Arena speaker series
  • By Ian Collen
  • Published
Sharp showcases its upcoming 4K TV and audio line-up
  • By Ian Collen
  • Published

Full fat HDMI teeshirts

Support AVForums with Patreon

Top Bottom