All About HDTracks Hi-Res Audio Files

Questions to answer:

  1. Can you hear the difference in hi-res files?
  2. Are the hi-res files worth the extra cost?
  3. Can/How do i play hi-res files in iTunes or on my iPod/iPhone/iPad?

First, here’s why i’m doing this:

I purchased two of my favorite albums from HDTracks.com over the past few months just to play with and see if i can hear the difference between these files and those i ripped from CD’s as Apple Lossless (ALAC) files.

The two albums i purchased are:

Kind of Blue

“Kind of Blue” by Miles Davis (one of the best jazz albums of all time)

Jazz at the Pawnshop

“Jazz at the Pawnshop” (an album widely praised by audiophiles for its sonic awesomeness)

 

 

 

 

 

 

 

 

 

 

Both of these are albums i’ve owned in several versions over the last 35 years from vinyl through CD and then remastered CD and now in hi-res audio files. I know and like the music very well.

So . . .

1. Can you hear the difference in the hi-res files?

I’m listening with my desktop computer/iTunes and also on my iPod Classic (7th gen) as sources through a Fiio E09i headphone amplifier and AKG K550 headphones with Alpha Pads. Yes, it’s not end game high end audio equipment, but it is decent audio equipment.

In order to be sure that I am comparing apples with apples, I took the hi-res files from hdtracks.com and converted them to standard Apple Lossless (ALAC) files using the process listed below in the answer to question 3.

The answer for me, with my equipment and hearing is an absolute NO. I suppose it is possible that someone with better “ears” and better equipment might be able to hear a difference. However, thorough research in multiple audio forums and articles seems to say that at best, more than 99% of listeners can not tell any improvement in sound quality of the same exact mastering of a musical file based solely on the resolution of the file.

2. Are the hi-res files worth the extra cost?

Unless you are one of those in the less than 1% who can hear a difference, the answer is often (but not always) NO.  As an example of the cost difference, the remastered CD for Kind of Blue costs $7.29 on Amazon.com and $24.98 on hdtracks.com. That means that a hi-res audio file costs more than 3 times what the CD costs for an audio difference that almost no one can hear. HOWEVER, please note that most people can hear the difference between an MP3 file of 256 kbps or less and an ALAC or hi-res file from the same master on good audio equipment.

However, there are several reasons you might, perhaps, want to buy the hi-res file anyway. It might be possible that at some future time audio equipment will be able to play the hi-res files in a way that could make the audio difference hearable. It’s also possible that you have exceptional hearing and are one of those who truly can hear the difference. However, the most likely reason to go with a hi-res music file from hdtracks or from Pono would be because the music files have actually been remastered using superior mastering techniques to those of the commonly available CD version of an album. This actually does happen. Better mastering is often a good reason to buy a high resolution file instead of the CD. BUT, buyer beware. that the mastering actually has to be better than that found on the normal CD and there is no guarantee that just because it is a hi-res file, it has been remastered in a better way. In fact, this is usually not the case. Improved mastering by a good engineer can make a very audible difference, and in those cases, the high resolution file actually does sound better even to my ears on my equipment.

An example in point is the high resolution version of Jazz at the Pawnshop. This album has been remastered many times and the differences are audible, but NOT because of the high resolution files, but because of the mastering techniques used. If you take the newest, best mastered version, and down sample it to standard 16/44.1 CD resolution, there is no audible difference between the hi-res file and the standard file, to me, and to almost all listeners. However, the sound of the newest remastered file in both hi-res and standard is better than the earlier versions, and those were good, in fact, better than good.

3. Can/How do i play hi-res files in iTunes or on my iPod/iPhone/iPad?

Have you ever wondered how to convert hi-res 24/96, 24/192 or other hi-res files to versions playable on an iPod or iPhone? Me too. So i spent a few days doing a lot of googling and reading and then trying the stuff i read. I’ll give you the end result so you won’t have to do all the research.

I am using dBpoweramp R15.3 for all my bit rate and bit depth conversions. There are other programs which can do this, but i’ve been a dBpoweramp user for many years and their software works great and their support forum https://forum.dbpoweramp.com/forum.php is excellent with answers often supplied directly by the software author. The software isn’t free, but it is worth the cost.

I am working under some assumptions:

  1. You want to use the high resolution file in iTunes and possibly on an iPhone/iPod/iPad.
  2. You want the best sounding version of the file possible.

If that applies to you, here is the process to accomplish this. Follow these steps, and do them in this order. Doing these steps out of order can lessen the quality of the audio and/or cause artifacts to be inserted into the music.

Get the file as an ALAC file or convert a FLAC file to an ALAC file.

High resolution files are almost always available as ALAC or FLAC.  There is no reason to get any other file format. Trust me on this. If you want to play your files in iTunes, get an ALAC file. iTunes will not play FLAC files. If you already have a FLAC file, it can easily be converted to an ALAC file using the convert option of dBpoweramp. Make sure you have the codecs installed (they are free) for both FLAC and Apple Lossless. Then right-click on the file and select convert. Choose Apple Lossless as the file type to convert to. Presto-Chango, you end up with an ALAC file!

Convert the sample rate to one which can be used in iTunes or on an Apple device.

The highest sample rate which an Apple device can use is 48 Khz. If playing the file on an Apple device is your goal, then you want to down sample the file to 48 Khz or less. If you want to play the files only in iTunes (either on your PC. Mac or via an external DAC) you need to convert to 96 Khz or less.

You can purchase FLAC and ALAC files at 44.1, 48, 88.2, 96, 176.4, 192 and 384 Khz. Here is the important key: you want to down sample your file to an even multiple of either 44.1 Khz or 48 Khz. This is important. Let me give you some examples:

If your file is 384 or 192 you can convert it down to 96 or to 48. Those sample rates are exact multiples of 48 so when you down sample them, no interpolation is done, it’s an exact division and you will get a new file free of artifacts and errors. If your file is 176.4 it can be down sampled to 88.2 Khz or 44.1 Khz without error or artifacts.

Itunes can play 96, 88.2, 48 and 44.1 Khz files. Any Apple device (iPod, iPhone, iPad) can play both 48 Khz and 44.1 Khz files.

For maximum compatibility, convert your files down to either 48 Khz or 44.1 Khz, which ever is an even multiple of your original file. This keeps the process clean and error free and will give you a file playable on any Apple device. Remember that 99% of us can not hear any audible improvement for a file higher than a 48 Khz sample rate, so my advice is to down sample to 44.1 or 48 Khz (which ever is an even multiple) and not worry about the higher resolution numbers. You won’t hear the extra information, and the higher resolution files take up MUCH more disk space.

To do this in dBpoweramp, go to the add DSP box and select Resample and then click on the settings button and select either 48000 or 44100. You will have to change this setting whenever you start with differing sample rate original files.

If you are going to “volume normalize” using EBU R128 or ReplayGain, do that now.

I am a fan of EBU R128 volume normalization. What is that? Have you ever been frustrated by playing songs in a playlist in iTunes or on your Apple device when one song is quiet and you have to reach and turn up the volume and then the next song blasts your ear drums? Volume normalization fixes that problem.

Apple has a way of doing this called Sound Check. If you enable this feature in iTunes and on your Apple device, then every song you add to iTunes will be adjusted to a common volume level and when played back on an Apple device, you shouldn’t have to keep reaching for the volume control.  Sound check has a few flaws: 1) better methods of analyzing files have been developed which do a significantly better job of matching (normalizing) volumes and 2) this ONLY works when you play back a file on an Apple device. Sound check has two advantages: 1) it does not alter the original volume of the file, it just adds a tag to the file which tells the Apple device how much to raise or lower the volume and 2) you can turn off sound check if you ever want to.

ReplayGain uses a better algorithm for adjusting the sound level. It also works on non-Apple devices, but not on all devices. In order to use ReplayGain, you need to use a program outside of iTunes. dBpoweramp can use the ReplayGain algorithm in its Volume Normalize DSP (digital sound processor).

The best method of Volume Normalization is relatively new and is known as EBU R128 or simply R128 for short. Its algorithm is an improvement on ReplayGain and it works extremely well. I use R128 on all of my music files and i use the dBpoweramp volume normalize DSP to do this whenever i rip a CD or convert a music file. Simply add the Volume Normalize DSP to your conversion setting in dBpoweramp after the resample DSP and then click on the settings button and select EBU R128.

Lastly, convert your bit depth from 24 down to 16.

This should be the very last step in any file conversion. iTunes will play 24 bit files. Apple devices claim they will play 24 bit files, but in reality they do not. They simply lop off the extra 8 bits to get from 24 bits to 16 bits, adding distortion to the music playback. You do not want that to happen, so you should convert 24 bit depth files to 16 bit depth files using a process known as dithering (and selecting triangle for the dither method). I won’t go into the whys and wherefores concerning dithering and why you should use it, but you should.

Let me briefly explain bit depth. When listening to a music file, every file has something called Dynamic Range. Dynamic Range is the difference (measured in db’s) between the loudest sound in a file and the quietest sound in a file. The maximum dynamic range that most humans can hear is 100 db. 16 bit depth files contain 96 db of dynamic range. This is very close to the maximum a human can hear. 24 bit depth files contain 144 db of dynamic range, far more than a human can hear. 24 bits are used when mixing and mastering digital files by engineers in order to allow for extra headroom to avoid clipping. That is a valid reason for using 24 bit files, but a reason which disappears when the file is finally mastered in its last step. Recording engineers use dithering to turn their 24 bit master into a 16 bit master ready for making a CD. You should also use dithering to convert from 24 bits to 16 bits.

Since we are dealing with final files, and since no Apple device will correctly play a 24 bit file without actually cutting out 48 db (144 db – 96 db) of dynamic range in a very harsh manner, we should make converting our music file to 16 bit the last step we take.

Using dBpoweramp, add the DSP Bit Depth to your conversion step. Click on the settings button and select triangle as the dithering method. Using dBpoweramp, you can do each of these steps one at a time. or you can do them all at once. However, dBpoweramp will execute the DSP steps in the order they are entered. You absolutely should drag and drop them so that the Resample step occurs first, volume normalization second, and bit depth is the last DSP.

If you have any questions about any of this information, please leave them in a comment to this blog post.

 

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