Managing Volume: ReplayGain(RG) / MP3Gain / Sound Check (iTunes)

ReplayGain(RG), MP3Gain, Sound Check (iTunes)
These features are used to normalize the audio files, I mean music files.
I’m gonna sum up the data I’ve collected, thereby comparing one another.

This document is not perfect and I want you to get more information from professional articles.
I’ll have this document get fixed afterterwards.
Also, pointing out any of the errors is always welcomed.


< ReplayGain(RG) >

This technology is done by analyzing the internal volume of a music file.
Then, by calculating the difference between the volume and the target volume, the number is put in the tag of the file.
When a music player or a device plays the file, it reads the tag of it.
If there’s a RG data and the player notices it, the difference is applied to the output volume when the player is playing the file.
This means that RG tag does not change the sound wave of an audio file.
All the analized data are put in the tag and this means that if you remove the tag, then the analyzation is gone.
Then the file will become the one which was like before the RG analyzation.


< MP3Gain >

The core algorithm is the same as ReplayGain.
MP3Gain is a program designed to apply the RG technology to MP3 files.
Because RG just calculates the difference of the file volume and the target volume and then put the result in the tag, it supports all file types.
However, the problem is that the music player should be able to read and use the RG result.
Years ago, old devices and programs could not read and apply the RG analysis result in the tag.
So the analyzing was no use.
In order to solve this problem, MP3Gain was developed.
It uses the RG algorithm and applies the result to the actual audio file.
It does not just add some number in the tag, but it really changes the actual volume of a file.
Because the process is done by really changing the sound, this program only supports MP3 files.
Other file formats require different ways of processing, so there are similar programs such as AACGain for other formats.

In the official site of MP3Gain, it says that the program does not change the original file.
It’s a half truth.
It actually changes the internal volume of a file and then adds a tag about the amount of volume change.
The type of the tag is APE.
When you want to remove the change, MP3Gain reads the tag and redo the change.
But when you remove the APE tag after changing the volume once, the audio file cannot get back to the original state by itself, if you don’t remember the original volume or the amount of change made by MP3Gain.
To add, it is a small defect that MP3Gain can only change the volume by 1.5dB.

< Sound Check (iTunes) >

Sound Check is a feature provided with Apple’s iTunes.
The basic mechanism is just like ReplayGain.
iTunes automatically calculate the volume of any files such as AAC and MP3.
Then, iTunes add a tag to the file about the difference of the volume level compared to the target leve.

There are some disadvantages.
Because it’s Apple’s own technology, the tag made by Sound Check is not always applied to devices or programs that are not made by Apple.
Also, while the Sound Check is done relatively quickly, the analysis is not that accurate.
iTunes’ target level cannot be changed manually by users in a normal way.
Lastly, because the volume change is done on files one by one, you cannot do an ‘Album Gain’.

However, all the defects can be solved if you use a program named iVolume.
You can do ‘Album Gain’, you can change the target volume as you want, and the analysis is done quite specifically.
iVolume can be used freely, but to remove some inconvenience you should pay for the app.
The first defect can be solved when you change all your devices to those made by Apple. lol


Managing AAC files: Rip music from a CD

It can be said that aac codec surpasses mpeg-3 codec in all aspects.
This means that there is no relative disadvantage of using aac files instead of mp3 files.

There are many softwares that can be used to make aac music files.
But because aac is a lossy codec, the encoding algorithm is important.
Roughly, iTunes uses its own encoder and all other programs use Nero encoder.
According to analyses Nero encoder is inferior than iTunes encoder especially when using the VBR settings.

So it is the best to use iTunes when making aac music files.
The trouble is that there are some codecs that iTunes does not support, such as flac.
In this case, it’d be better to convert flac files to alac files.
This is okay because both of them are lossless codecs.
When flac files are converted to alac files, they can then be converted to aac files using iTunes because iTunes support alac codec.

Anyway, in this post, I’ll introduce you the way of ripping music from a CD and get aac files.
I’ll not use the default settings and change them a little bit.

Insert a CD in a odd drive.
iTunes will show you the track list automatically.
If you want to change artist, album title, track title, etc, you can change it now.

Now, let’s change the rip settings.
Press “Command + ,” and click the import setting or you can just click the same button provided in the CD track list screen.

Select AAC encoder.
Let’s change some specific settings.
Go to user setting.

It’s true that AAC codec has good quality compared to its small size, but the default setting is not enough.
It is better to set the bitrate to 256.
This setting is known to be similar to the quality of when using mp3 codec with the bitrate of 320.
VBR setting will keep the file size shrinked.
Nero encoder is not preferred when creating aac files because its VBR algorithm is not efficient enough.
HE encoding is the latest setting but because it pursuits even smaller file size by sacrificing the sound quality.
So let’s not choose it.

Save all the settings and let’s rip the music off!
Extracted aac files will be automatically added to the iTunes library.

Get guitar chords easily with Chord Tracker by Yamaha

Chord Tracker by Yamaha is an app for a musician who wants to get chords of a song.
It’s for iOS (iPhone/iPad) and it’s free!!
It can be used simply just by choosing a song, but it also has advanced features for those who want even more.

This is the app’s icon.
App Store link is:


When you start the app, you can see the artists’ list.
The songs you play with the stock music player are all shown in the list.


When you choose a song, wait for a sec.
After the loading, the app automatically gives you separated measures.
You can start from any bat you want.


You can get even more details of a chord.


Tap the share button for more features.
You can send the analysis to a musical instrument and also add the song to favorites.


Let’s tap Chord Analysis Settings.
In the Re-analysis, you can change the tempo and the meter.
Changing the tempo, you can get even more chords for a specific measure.
For example, if there is a chord change in a certain measure, you can only get the first chord with the Original setting.
If you change the tempo, you can also get the second chord of that measure.
Changing the meter seems to be not necessary for rock music.


With Detail Settings, you can shift the beat and change the key.
The first feature is necessary when the automatically devided measures do not fit the real beat.
The second feature will do a lot when you use a capo.

Managing AAC files: Lossless to AAC

Recently, I’ve been changing all my music files from MP3 to AAC.
To be specific, I’m encoding my FLAC files and ripping CDs to AAC files.
You should not encode MP3s directly to AACs because they are both lossy codecs.
Some data are gone when you create MP3 files, and when you convert them again to AACs even more data will be lost.
That is no use and the output can never be better than the source.

Therefore, you should get some original files.
Lossless files like WAV, FLAC, ALAC are good sources, and you can also use your own CDs.
In this post, I’ll show you how to convert music files to AAC files.

AAC files are better than MP3 files because,

  • they are compressed more
  • their VBR is more efficient
  • they can take the advantage of AAC bypass when your bluetooth devices support AAC codecs

When your bluetooth devices all support AAC codecs, you can get better battery life and even better audio quality.

From now on, I’ll convert FLAC to AAC.
I’m going to use XLD(X Lossless Decoder).
It seems to be developed by a Japanese.
It is a light and handy tool, and the output is in good quality.

Also, the recent update is 20151128 which means the developer is hardworking. lol
You can download the installer at the Official site.
I’m now using MBPr OS X 10.11.1 Yosemite.

After the install, start the app.
Nothing happens!
But the app is running in the dock bar.

You can also find it running in the upper left corner of the screen.
Go to Preferences or use the shortcut “Command + ,”.

Our purpose is to convert files to AAC.
So set the output format to AAC.

Click the option which is at the right of output format.
Using the settings below, you can get the same output when you’re using iTunes to rip CDs and get AAC files.
I’m suggesting these settings and I believe it will provide you with the most efficient output.

Let’s convert files.
Move to a folder where FLAC files are located.
Select all files using the shortcut “Command + a” or by dragging.

Right click and choose XLD in the app list.
You can also do the same thing by drangging the files and putting them on the XLD icon in the dock.

Files are being encoded fast.

When it’s done, you can get these M4A files.
AAC is the name of a codec and the container’s name is M4A, so don’t get embarrassed.

Now, move the lossless files to the safe place, and use the M4A files created.
You can put them in the iTunes library or use any other devices/programs to listen to them.