Utility to balance volume in MP3 file with varying volume?

[Muse]

I have MP3 gain and have used it occasionally for years. I used it to boost the volume on relatively quiet MP3s I've made of radio broadcasts. I just downloaded and installed the most recent edition.

I'm doing something different right now, though and wonder if this or another utility will help. I'm making voice recordings, around an hour, that will have fairly widely varying volume. If the speaker walks to the other side of the room and faces in the other direction (the recorder will remain in the same location), the levels will diminish considerably compared to the rest of the recording. Is there a utility that will boost the volume in those "quiet passages?"

I figure that Protools would do that, and I have access to it at the radio station I work at but Protools has to be overkill for this.

 

[abaez]

This is called normalization, I'm sure there is some option in your program to do this.

 

[Phynaz]

Audacity

 

[Muse]

Originally posted by: abaez
This is called normalization, I'm sure there is some option in your program to do this.

I installed Audacity and Normalization doesn't seem to be what I want here. AFAICT, that will equalize maybe the average volume for a number of audio files. I ran it on a 2.5 minute test recording of my voice where I walked into and out of various rooms, leaving the recorder in one location and it didn't help. What seems to work is selecting portions of the recording that obviously have low volume and using the Amplify effect, leaving the Allow Clipping checkbox unchecked (the default), and using the offered amplification setting (Audacity seems to supply a reasonable setting, such as 9.2 db depending on the nature of the selected portion of the file). The results seem pretty OK, maybe close to as good as I can hope for. I'm recording in MP3 using 128 kbps and 44.1 khz encoder settings. I might be better off recording in WAV and converting to MP3 later. Someone at Rockbox Forums appears to think so. For one thing he tells me that Rockbox's (and probably my iRiver H140's) MP3 encoder isn't very good and is likely to produce artifacts. I'm pretty inexperienced in these things. Anyway, I don't expect state of the art recordings in this particular usage.

 

[Evander]

The Levelator was made for this purpose:
http://www.conversationsnetwork.org/levelator/
I have it installed but haven't used it yet, but it's free

Audacity might be good enough, but you don't want normalization, you need to select "effect -> leveller" and play around with the settings.

And yes, you should record to wav first, not mp3. You will decrease sound quality if you reencode an mp3 (sort of like making a copy of a copy of an audiotape). What many consider to be the best mp3 encoder is called LAME. It is free and works with many programs (including Audacity, but you have to download LAME seperately and configure Audacity to the LAME directory). And I don't know if you know this already, but if you are encoding voice to mp3, there is probably no need to encode the mp3 in stereo. For example, so called "cd quality" mp3 is 128kbps stereo, but if you don't need stereo you can use 64kbps mono for the same quality. So a 10 minute recording will take up only 5 megs of space instead of 10 megs at 64kbps mono.

Here's another tip- while mp3 is the best for compatibility, there are other formats that are more effecient for low bitrate, voice encoding. For example, speex:
http://speex.org/
or wma professional or Nero HE-AAC digital encoder (all of these are free). You can encode for example at 24kbps and still get good quality at a fraction of the size of mp3. But most people aren't so familiar with these files and might not know how to play them on their computer (and may well not be able to play them on a portable audio player). But I thought I'd point this out to you as another option.

 

[Muse]

Originally posted by: Evander
The Levelator was made for this purpose:
http://www.conversationsnetwork.org/levelator/
I have it installed but haven't used it yet, but it's free

Audacity might be good enough, but you don't want normalization, you need to select "effect -> leveller" and play around with the settings.

And yes, you should record to wav first, not mp3. You will decrease sound quality if you reencode an mp3 (sort of like making a copy of a copy of an audiotape). What many consider to be the best mp3 encoder is called LAME. It is free and works with many programs (including Audacity, but you have to download LAME seperately and configure Audacity to the LAME directory). And I don't know if you know this already, but if you are encoding voice to mp3, there is probably no need to encode the mp3 in stereo. For example, so called "cd quality" mp3 is 128kbps stereo, but if you don't need stereo you can use 64kbps mono for the same quality. So a 10 minute recording will take up only 5 megs of space instead of 10 megs at 64kbps mono.

Here's another tip- while mp3 is the best for compatibility, there are other formats that are more effecient for low bitrate, voice encoding. For example, speex:
http://speex.org/
or wma professional or Nero HE-AAC digital encoder (all of these are free). You can encode for example at 24kbps and still get good quality at a fraction of the size of mp3. But most people aren't so familiar with these files and might not know how to play them on their computer (and may well not be able to play them on a portable audio player). But I thought I'd point this out to you as another option.

Thank you!

I've been using the LAME encoder for years (mostly with Total Recorder Standard Edition, which I use all the time!).

Thanks for the link to the leveller. I'm definitely going to try that! Tomorrow I'm making my first voice recording in my yoga class and probably to MP3, unless I have a few minutes to experiment with WAV recording. I'm real busy today. Probably next recording I'll do WAV and then work out some compression after leveling later.

 

[Muse]

I recorded this morning in WAV, about 1/3 a GB of data for the 1:04 file. Installed the Levelator. It's about as easy to use as you can imagine. You drag and drop a file onto it and in the case of this file about 5 minutes later the output file was there alongside the original WAV file, only "output" was added to the file name.

It seems to have done its job very nicely. Now I'll experiment a bit with compressing the leveled WAV file into something that sounds the same to me but takes up relatively little space.

The recording sounds very good. I can understand the instructor practically all the time, even though the room has terrible acoustics, undoubtedly due to the fact that all four walls are glass (mirrors on 3 of those sides).


Edit:

Originally posted by: Evander

Audacity might be good enough, but you don't want normalization, you need to select "effect -> leveller" and play around with the settings.

I don't see a leveler effect in Audacity.

Edit2: It's a good thing I recorded to WAV this morning. The Levelator works only on WAV or AIFF files, evidently.

 

[ShawnD1]

post deleted.


Do these linked programs level the volume across 1 file or across several files? I'm having trouble getting files to normalize from song to song.

 

[ManBearPig]

mp3gain

 

[Evander]

Originally posted by: Kazaam
mp3gain

Didn't read the first four words of the post didja?

Glad to hear levelator is working well for you.

In case you still have some mp3's you previously recorded and want to use in levelator, you can still do so by first converting to wav. There are numberous utilities to do this, personally I like dbPowerAmp where I just have to right click the mp3 and select "convert to wav"

1/3 of a GB for a 64 minute- you recorded in monaural (not stereo) right? If so OK, otherwise that figure doesn't sound right- a stereo wav at 44.1 khz uncompressed (PCM) would take up twice that space.

For next time, the audacity leveller effect is located as shown here:
http://img152.imageshack.us/im...565/clipboard01ru1.jpg
that's from version 1.35 beta, but don't think it's any different in older versions.

If you want to compress the wav using next-gen codecs, my personnal recommendation is the free nero he-aac codec, even music at 44.1 khz 24kbps sounds pretty decent. Speex and wma pro I haven't really messed around with, but he-aac has more widespread compatibility.

 

[Muse]

Originally posted by: Evander

Glad to hear levelator is working well for you.

In case you still have some mp3's you previously recorded and want to use in levelator, you can still do so by first converting to wav. There are numberous utilities to do this, personally I like dbPowerAmp where I just have to right click the mp3 and select "convert to wav"

1/3 of a GB for a 64 minute- you recorded in monaural (not stereo) right? If so OK, otherwise that figure doesn't sound right- a stereo wav at 44.1 khz uncompressed (PCM) would take up twice that space.

For next time, the audacity leveller effect is located as shown here:
http://img152.imageshack.us/im...565/clipboard01ru1.jpg
that's from version 1.35 beta, but don't think it's any different in older versions.

If you want to compress the wav using next-gen codecs, my personnal recommendation is the free nero he-aac codec, even music at 44.1 khz 24kbps sounds pretty decent. Speex and wma pro I haven't really messed around with, but he-aac has more widespread compatibility.

I downloaded 1.2.6 Audacity a few days ago and it doesn't have Leveller. 1.3.5 is beta. Looks to be a new feature. Well, The Levelator seems to work very well and is as easy as you could hope for.

Right now I figure I'll stick with MP3 because I'm fantasizing about supplying other attendees of these yoga sessions with the files at some point. Either posting them for download or selling them a CD for a buck (with the instructor's permission, of course). The yoga instructor is going to leave town this summer, with no immediate plans to return, although many of us have put our addresses on her email list.

Yes, I recorded in mono. To me the 30 MB MP3 I wound up with sounds just like the WAV file. I figure there's a good chance all the sessions remaining will fit on one CD.

 

[nakedfrog]

Dynamic range compression/compressor in Audacity?