Good Day,
I have finally been able to get my collection of 300+ LP’s and Cassettes converted to digital MP3’s. I wanted to put a few CD’s together for the car and when I burned the music CD, the volume levels are not the same from track to track. Is there a way using Audacity to even them out so I do not have to turn the volume up and down in the car?
As you can probably tell I am very new at the digital music mixing and burning my own CD’s. Thank you for any assistance in this matter.
Mark
Does your car stereo pay MP3s from a disc, or are you making audio CDs?
If you are making audio CDs with 10 or 20 songs on a disc, you can adjust the volumes by ear, which is best. In this case, run the Amplify effect on each file separately and leave the default which will normalize (maximize) the peaks at 0dB. (This will not equalize perceived loudness, it’s just a starting point). Then if they are not equally loud, choose the quietest sounding track and adjust the louder tracks down to match (by ear).
A couple of notes…
Since many (most) commercial releases are already normalized/maximized, and since many quiet sounding songs have maximized 0dB peaks, many people are disappointed to find that MP3Gain tends to lower the volume of many (most?) tracks. …Since you can’t you can’t boost the volume of these quiet tracks without distortion, the only way to match volumes is to reduce the louder tracks. You can adjust-up the MP3Gain target volume, but if you choose the “don’t clip” (don’t distort) option, you don’t leave MP3Gain much room to work and many files won’t be adjusted and MP3Gain won’t be as effective.
If you are making regular audio CDs, it’s best to avoid MP3, because MP3 is lossy compression. You may not notice the quality loss (especially with high-bitrate, high-quality, compression settings) but it’s good practice to avoid unnecessary lossy compression. (There is WAVgain which is like MP3Gain for WAV files if you want to take advantage of automatic volume adjustment without the lossy compression.)
If you do want MP3s, It’s also best to avoid editing MP3s, because the file gets decompressed when you open it, then it goes through a 2nd lossy compression step when you re-export. So, do all of you volume adjustment and other editing before making an MP3 once as the last step. (MP3 gain makes the adjustment without decompressing, and there are special-purpose MP3 editors that can do some limited editing without decompressing/re-compressing.)
And just FYI - “Equalization” (such as Audacity’s Equalizer effect) normally refers to frequency adjustment (similar to bass & treble control with multiple frequency bands.) So, let’s just say “volume matching”. 
Some people misuse the term “normalization”, but regular normalization doesn’t correlate well with perceived loudness.
Thank you DVDdoug for the response.
My care Infinity player says it plays MP3’s but when I burned a Data CD of just MP3’s it would not read them. So I figured I had to go to the ‘Burn Music CD’
So there is no way withing Audacity to set the to adjust the mp3 files except by manual hearing and using the Amplify effect on each individual MP3 File, is that correct?
I tried listening to through Audacity and the ones that are lower volume sound just the same as the ones that are normal. But when I listen to the CD I burned as a Music CD you can defiantly hear the difference.
So other than using the MP3Gain you mentioned, and may make some volumes lower as you stated, is there any application that will allow me to make all of the MP3’s the same so I do not have to go through each one"
Mark
There is a Nyquist plugin here that uses a “similar” algorithm to replaygain: ReplayGain plug-in Make sure you get the “New Version” in that post. See here for how to install Nyquist plugins: Missing features - Audacity Support .
You could automate processing of the files in Audacity by adding the replaygain plugin to a Chain. See Chains - for batch processing and effects automation - Audacity Manual.
But you will lose quality this way because Audacity must re-encode the files, and it will be fairly slow. It would be better to use MP3Gain for greater speed and because you will not lose quality.
Not all CD burning software may necessarily recognise the replaygain changes that MP3Gain makes.
CDBurnerXP is one that I know recognises replaygain: CDBurnerXP: KB7: Using Replay Gain.
Gale
Thanks Gale! I didn’t know (or I’d forgotten) about the ReplayGain plug-in.
My care Infinity player says it plays MP3’s but when I burned a Data CD of just MP3’s it would not read them. So I figured I had to go to the ‘Burn Music CD’
Did the data CD work on your computer?
So… if you are making an audio CD, you should avoid MP3. If it’s “too late” and you don’t want to go the trouble of re-recording, that’s up to you.
If you use the Audacity ReplayGain plug-in and you are making an audio CD, export to 44.1kHz 16-bit WAV (the same underlying PCM format as audio CDs). Do this even if you are starting with MP3s to avoid the 2nd lossy compression step.
Note thata MP3gain makes adjustments in 1.5dB increments (due to limitations of the MP3 format). The Audacity plug-in will be able to make finer adjustments since it’s not working on the compressed MP3 data. But with any of these tools, the computer algorithm may not “work perfectly”… Even if you asked two people to adjust two or more files for “equal loudness”, they might not agree… And it can get very complicated for more dynamic songs with loud parts and quiet parts…
Not all CD burning software may necessarily recognise the replaygain changes that MP3Gain makes.
CDBurnerXP is one that I know recognises replaygain: > CDBurnerXP: KB7: Using Replay Gain> .
Actually, MP3Gain (and WAVgain) changes the actual MP3 volume, so it works on EVERYTHING. ReplayGain and Apple’s Sound Check use metadata to adjust the volume at playback-time, so these variations require an application that supports it. Of course, the Audacity plug-in can be used to “permanently” change the file, so it doesn’t depend on application support.)
I tried listening to through Audacity and the ones that are lower volume sound just the same as the ones that are normal. But when I listen to the CD I burned as a Music CD you can defiantly hear the difference.
That’s weird! Maybe there’s something different about the sound environments, or the quality or your car speakers vs your computer speakers/headphones, or maybe you’re listening at a different volume… Something that makes it easier to hear loudness differences in your car compared to your computer.
That would obviously be best but if you want the MP3 files themselves to be volume adjusted as well, you’d have to adjust those in a second process (ideally in MP3Gain, not Audacity).
I know that WAVGain re-encodes the WAV file, though that doesn’t matter for WAV for most practical purposes since WAV is lossless (WAVGain does have dither options).
I understand that MP3Gain modifies the global gain field in each MP3 frame, which can only be in 1.5 dB steps, correct? So as you say, every MP3 player will respect that and modify the gain accordingly.
But does every CD burning software look at the MP3 frames and adjust the volume of a stream being burnt to an audio CD? I’ve never tested it, but I guessed not. What do you think?
However as well as modifying the frame gain, MP3Gain also adds what I assume to be replaygain metadata. Here’s an example from a file I just passed through MP3Gain now:
REPLAYGAIN_TRACK_GAIN.-0.565000 dB
REPLAYGAIN_TRACK_PEAK.0.955816
If so, a CD burner that respects ReplayGain should always be able to burn an audio CD correctly from an MP3 encoded by MP3Gain.
Gale