Frequently Asked Questions

A. More information

mp3TrueEdit™ an affordable MP3 audio editor - key benefits
  mp3TrueEdit™ can be used for podcasting, creating a ringtone or an audio greeting or message, editing mp3 and AAC* recordings such as lectures, meetings, band rehearsals or choirs etc.  It allows you to quickly find and edit the audio that you need and all this without losing any audio quality!
  The original quality of the MP3 or AAC audio is retained.
  Record from your audio input to MP3 or AAC files from within mp3TrueEdit™ (may require an additional download).
  Built for quick and easy editing of MP3 and AAC files.
  Easily view and find sections of audio.
  Edits can be undone or re-done quickly and easily.
  Opens very large audio files quickly and easily.
  Uses familiar cut, copy, paste, delete and crop operations.
  Saves disk space as it avoids having to create large intermediate files.
  Adding effects such as fade in/out and volume increase/decrease.
  Create projects that allow you to save your work and export edited audio with no quality loss at all!
  Normalization and silencing audio and inserting silent sections.
  Exports MP3 and AAC files with tag information.
mp3TrueEdit™ Systems Requirements
Windows Apple macOS iOS Android
Windows 10 (1809 or later) macOS 11 and above iOS 14.0 and above Android 8.0 and above


*Supported Formats

1) mp3TrueEdit™ is specifically written to handle MP3 and AAC files which are the most popular and most compatible audio formats.  However, it does not currently support the ‘MP3 Pro’ or ‘MP3 free format’ versions of MP3 which are not widely used.
2) The supported AAC files are those with extensions .aac, .m4a, .m4b, .m4r and .mp4 which contain AAC audio can also be edited without quality loss in mp3TrueEdit. Currently only unprotected AAC LC mono and stereo files are supported (the most popular AAC format).


B.   General questions

1. Question: What do you mean when you say there is no quality loss if we use mp3TrueEdit™?

When you use mp3TrueEdit™ in knows about the internal structure of the MP3 and AAC file formats and can directly edit the information that it contains without having to decompress and recompress the audio.  This prevents a loss in quality and also saves on disk space and time because of the following reasons:

  • Firstly, if the MP3 or AAC files were to be decompressed to its uncompressed (PCM) format before editing you would not lose any quality but it would take around 10 times more disk space and it would take some time to do the decompression process. 
  • Then if you wanted to save/export your edits back to an MP3 or AAC file then you would need to recompress back to MP3 or AAC again this would take some time and would also degrade the quality of the audio.
  • This is because when you compress (or recompress) audio to MP3 or AAC you will always lose some quality because MP3 and AAC audio compression will always sacrifice some quality in order to gain a greater reduction in file size.
  • In addition mp3TrueEdit™ is also designed to prevent any invalid or corrupt audio from being generated when joining or splitting MP3 files so you are not limited to where you can make your audio edits. 

2. Question: Can mp3TrueEdit™ edit other format files apart from MP3 and AAC files?

No. mp3TrueEdit™ is specifically written to handle MP3 and AAC files which are the two most popular and compatible audio formats. There are other audio editors that can handle various other audio formats. mp3TrueEdit’s focus is on editing MP3 and AAC files using a quick and easy to use interface and saving your edits back MP3 and AAC without losing any of the original file’s audio quality.  However, it does not currently support the ‘MP3 Pro’ or ‘MP3 free format’ versions of MP3 which are not widely used.  Also AAC file support is currently limited to AAC LC, mono and stereo files the most popular AAC format.

C.   Specific questions on the mp3TrueEdit™ application

1. Question: Where can I find the installed help documentation?

You can view the complete user manual in PDF format.  By using the ‘Help | View Manual (PDF)...’ menu commands.  This is also available using the PDF link at the top of this tutorials page. Please note that on Windows systems you will need to download the free PDF viewer application from Adobe to view the PDF manual using this link:

2. Question: I tried to join two audio files and I received this error message: “Incompatible audio file cannot be loaded into project.: ...”. Why is that?

You can join audio files only if the file format (MP3 or AAC) and file compression settings are compatible, that is, the sampling frequency (expressed in Hz) must be the same and mono and stereo formats cannot be mixed with each other. If the bit rate is different, it is still compatible but the exported MP3 or AAC file will be converted to a variable bitrate (VBR) file format.  If you receive this error message you can still work around these incompatibilities by converting the file you want to append to the same format as the current project's settings. This can be done using the built-in Convert command where the the necessary project settings to convert to can be seen in the bottom status bar of our desktop or mobile apps.

3. Question: Why are the ‘Play’ or ‘Play Selection’ buttons sometimes disabled?

Check if you are in a paused mode. If you are, click on the Stop button first, and then click on the ‘Play’ or ‘Play selection’ button. You will also need to select the desired audio before pressing the ‘Play Selection’ button.

4. Question: I clicked on the audio display screen to indicate the start position to play (marked by a dotted green line). Yet why when I clicked on the play button, it is playing from a different start position?

In order to listen to from your desired position, you need to move the vertical red play position line by pressing either the Left or Right arrow keys on your keyboard to the desired start position. Then click on the play button. The dotted green line is used for selecting a part of your audio for editing.  You can also use other keyboard shortcuts on Windows and macOS to move more than one frame at a time.  Please see the installed user manual under the “Keyboard shortcut commands” section.  You can also use the mouse to move the ‘Play position scrollbar’ to the desired start position. 

5. Question: I clicked on the audio display screen and a vertical dotted green line appears. What does this line indicate?

When you see a dotted green line – this shows the start and end are at the same time position. You basically have not made a selection to edit - so nothing can be copied or any effect applied.

6. Question: I clicked on the audio display screen to make a selection of the audio to edit, but all I am getting is an alternate red or green dotted line. What does this line indicate? 

If you see an alternate red or green dotted line, this indicates that the current play position (which is the red line) and the current zero width selection (green dotted line) are both overlapping each other. So you have not made any selection, yet. Please refer to mp3TrueEdit™ manual section ‘Selecting audio’ for more information on how to select an audio section for editing.

7. Question: When exporting a file or some tracks why do I get the error message: ‘The file is already in use and cannot be overwritten’?

When you are editing using mp3TrueEdit™ you are not allow to save any changes made to any of the source files that you have opened, which is a sensible approach to take. In this way, the content of the source files are retained. If you are carrying out a lot of changes, its best to save your edits as an mp3TrueEdit Project file (.mteproj format) by clicking on Save or Save Project As. This will allow you to save all your edits in one file. Once you have finished your editing session, you can export to the audio file format using the Export All As, Export Selection As or Export Tracks buttons. However, if you are only making a small edit, you can still use the Export All As button to save an edited audio file in another filename.

8. Question: How do I find out the format and characteristics of an MP3 or AAC file?

When you open an MP3 or AAC audio file in mp3TrueEdit™, you will see the format and characteristics of the opened file and all your current edits.  This comprises of the MPEG Layer 3 or AAC format, average bitrate, sampling frequency, stereo/mono format and the current total duration (hours: minutes: seconds) of the edits in your project file.  You will find this on the status bar shown at the bottom right hand corner of the application. An example format would be: MPEG1/Layer 3 -192kbps – 4410 Hz – Joint Stereo - 00:02:49.

9. Question: I can’t hear some parts of my lecture/meeting recording very well, how can I increase the volume of the quiet sections (such as people asking questions)?

To increase the volume to the maximum level without distorting the quality, first select the section to adjust. Then click on the Normalize button to display the normalize dialog.  You are then able to select the target volume that you wish to normalize to which is expressed in decibels. A value of 0dB represents the maximum volume that can be played back without distortion and the more negative the value the quieter the sound will be played back.

10. Question: I have an MP3 file that I want to use for a ringtone but how do I remove the quiet intro and make the rest of the ringtone louder so I can hear my phone ringing?

If you only want to use a small part of an MP3 or AAC track to turn it into a ringtone then you can follow these simple steps:

  • First use the Open command to open the source MP3 or AAC file which you may have ripped or downloaded previously.
  • Then simply select the audio that you want to use using the cursor to click and drag from the start to the end of the selection you want to make.
  • Then you can press the Play Selection button to preview your selected audio.
  • If you want to adjust your selection you can use your mouse to drag the start or end positions of your selection.
  • You can then use the Crop command to edit only the selected audio.
  • Then you can use the Select All followed by the Normalize commands to normalize to a ‘Target Level’ of 0dB which will increase to volume to the loudest level it can be without distorting.
  • You can then select Export All As to save your MP3 or AAC audio for using as a ringtone on your phone or any other device or application.

You will need to consult your phone’s user manual on how to transfer the exported MP3 or AAC file to your particular make and model of phone.

11. Question: Why do the blue volume bars appear higher when I paste from one file to another when the sound volume seems to be at similar levels?

The blue volume bars in the audio display screen are only an indication of the volume levels of an MP3 or AAC file.  They do not always closely represent the actual volume level of the decoded (decompressed) audio that you will play back through your speakers.  What the blue bars represent is actually a specific piece of information that is found in the MP3 and AAC file formats (the global_gain) this is used because you can obtain a useful representation of the volume levels without having to decode the entire compressed audio file which could take some time depending on the size of your audio file and the processing power of your computer.

12. Question: How can I search through a large file for the audio that I want?

First of all you will find it easier if you zoom out to the maximum level by repeatedly pressing the Horizontal Zoom Out keyboard command (see below).  Alternatively in the Options dialog you can set the Appearance (tab) ‘Horizontal Zoom’ value to 1.

Then you can use the mouse to scroll the ‘play position scroll bar’ to view and find the audio that you want.  You can press the ‘space’ key at any time to play and pause the audio at the ‘current play position’ red vertical line marker.  On Windows you can also use your keyboard Play/Pause and Stop media keys at any time.  You may also find it useful to consult the user manual for a list of other keyboard shortcuts for navigating and selecting audio.

13. Question: How do I make a section of an MP3 or AAC file completely silent so that this cannot be heard or recovered when exported?

To make the currently selected audio completely silent without affecting the total length of the audio file or project you can use the following steps:

  • Select the audio you wish to make silent using any of the selection methods.
  • Click the Silence button to make that selected audio completely silent.
  • You will notice that silenced audio is shown in the audio display screen as a light grey-blue color.
  • You can also remove any previously applied silencing of audio by selecting it and clicking the Remove Silence button.

Unlike normalizing or reducing the volume the Silence command completely removes audio from the exported audio files and it will not be recoverable by any other tool.

14. Question: On Windows I don’t seem to be able to record to MP3 with a bit rate higher than 56 Kbit/sec.

mp3TrueEdit™ is able to use the built in ACM MP3 encoder that comes with Windows but this may require the latest version of Windows Media Player and/or additional configuration changes to be made to the Windows ACM settings. 

  1. If you are using Windows XP then you may need to download and install the latest version of Windows Media Player using the following link:
  2. Then if you are still only able to record at 56 Kbit/sec on Windows XP, Vista, 7 or 8.  You may need to change your windows registry settings to allow the MP3 encoder that comes with the latest Windows Media Player to be used by mp3TrueEdit™. UPDATE: The best way to achieve this is to download and install the latest version of mp3TrueEdit from our downloads page.

15. How do I download the LAME MP3 encoder to use with mp3TrueEdit™?

NOTE: The LAME MP3 encoder is now bundled with mp3TrueEdit and does not need to be downloaded or configured.

External links disclaimer:
Please note that external links from this website are provided for additional information only. C2 Solutions Limited makes no representations or warranties about any other site that you may access through this site. When you access a non-C2 Solutions Limited site, you are accessing an independent site over which C2 Solutions Limited has no control or responsibility. You do so at your own risk. The presence of links to non- C2 Solutions Limited sites does not imply that C2 Solutions Limited endorses or accepts responsibility for the content or use of such sites. Views expressed by individuals or companies on external webpages linked to by us are not necessarily those of the C2 Solutions Ltd. itself.

16. Sandboxing Support Should Have Minimal Impact

The latest version of mp3TrueEdit sold via Apple's Mac App Store is required by Apple to support sandboxing.  Although sandboxing has now been implemented in mp3TrueEdit it is possible that this may impose some additional restrictions on users as to where and how MP3 and AAC files and mp3TrueEdit projects are accessed. For the moment it is recommended that if possible all MP3 and AAC files that need to be edited are stored somewhere under the Music folder and also that all mp3TrueEdit projects (with the file extension .mteproj) are also stored under the Music folder.  It is also recommended that exported audio files and tracks are also saved to a folder somewhere under the Music folder.  If you do need to open or save MP3 or AAC audio into other folders this is also possible.

Should you need to transfer a set of MP3 or AAC source audio files and a project file (.mteproj) that has been used to save the edits on these files to another machine then we recommend that you save your project file in the same folder as the source audio files.  If however the source audio files are in separate sub-folders then we recommend that you save your project file to the folder above all your sub-folders containing the source audio files.  If transferring to a computer running macOS then you should copy the set of folders containing the source audio and project file somewhere under the Music folder of the new machine.  When opening a transferred project and source files you may then be prompted with the message "file fragment   not found! Do you wish to search using a relative path?" if you click Yes the project will be updated with the new location of the source files and you can continue editing on the new machine.