Fixing variable sound level (DJ Mix)

With a DJ mix where some songs are louder than others and also some songs that are too loud but adjusted (during recording), what would be the best way to even this out?

Full Project

I’ve tried zooming in and normalizing (no dc offset, -6 dB sometimes) as picture below, but I can spend hours on this but there’s not much effect on an 80 minute project.



I’ve thought about normalizing to +6 to get rid of the peaks but that sounds like it will just cut the peaks out and make them clip.

Actually, Normalize won’t clip unless you insist that it does. Normalize is a global volume control. Everything goes up or everything goes down. Audicity’s version of Normalize affects left and right differently, so it can create more problems than it solves.

You want one of the compressors. The volume compressors, not the digital compressors like MP3. Those are the tools that can change the characteristics of a show depending on loudness.

If you aren’t using Audacity 1.3.6, you should be. The effects and tools are much better than they were were in 1.2.

I’m looking for a good compressor to simulate a radio station. No luck yet (they pay multiple thousand$ for theirs) but I did see a multi-band compressor in 1.3.6 that I really want to mess with. Properly adjusted, those things can eliminate bass tone pumping which a simple, single compressor can do by accident.


There is a new version of Chris Capel’s Dynamic Compressor available here:
It works superbly well on Classical music and should also work well with other types of music.

This is what it looks like after using the compress dynamics (with the default settings). I haven’t had a listen yet but I’ll post back once I have to see how it sounds.

It looks like it created a few peaks. Are there recommended settings to prevent this?

What I’m wanting to do is bring down the loudest parts of the project and then normalize to bring everything up as a whole automatically (which I was doing by hand).

That is what it is all about.

Music is supposed to have peaks - it is only the recent fashion for compressing the life out of music that has produced music without peaks. Have a read of this article:

If after that you still want to squeeze a bit more volume into your recording, then you will need to use a “limiter” after using the compression. There is a plug-in called “fast lookahead limiter” (which I believe is included in the plug-in pack on the main Audacity web-site) that will do that.

<<<There is a plug-in called “fast lookahead limiter” (which I believe is included in the plug-in pack on the main Audacity web-site) that will do that.>>>

Ooooo. This is me writing that down. That could be part of the answer to this…


I’ve listened to it now and it seems like the highs were amplified, the mids were a bit muddy and the lowend was amplified but sounds a bit square. Also it seems like a lot of the pops and clicks on the vinyl were amplified. Are there any recommended settings for this compressor? Are there any other look-ahead compressor/limiter recommended?

The other dynamics compressor that I use is “SC4”. I think it’s one of Steve Harris’s collection.

I’m now looking at your original question…

So this is a DJ mix that you made?

It’s probably too late now for this particular mix. The method you need to use is to keep each song on its own track and adjust the level of each track (you can use the volume slider on the track) so that they sound the same loudness. Do not worry about it being as loud as possible, or if one track “looks” louder than another, at this stage you should only be concerned with how it sounds.

When the tracks are perfectly balanced, save the project - if you are using 1.3.5 or later you will be prompted to choose whether to save all the audio files in the project, to which you should choose “Yes - safest”.

Then close Audacity (this will release RAM memory and delete unused temp files).

Then Open the project in Audacity and save it again with a new name (the first saved project is now a backup that you can go back to if necessary).

Now Mix the tracks together, and only then should you be looking at maximising the volume.

Is a dynamic compressor the same as a look-ahead compressor?

It’s a live mix so this isn’t going to work. I have a number of mixes that have already been recorded so I’m looking for something that can run on them. The compressor I used did make everything a bit more consistent but I don’t want to amplify pop/clicks

“look ahead” has slightly different meanings depending on whether you are talking about compressors or limiters.
The collective term for all of these kind of effects is “dynamic processor”, in that they adjust (process) the dynamics (changes in amplitude/volume) in one way or another.

Compressors will operate over relatively long time periods and adjust the output level of a signal so that the average level does not go up and down as much as the input level. In other words, the range of loud to quiet of the music is reduced (compressed) so that it is more even. There are many variations on this idea, and many compressors offer a whole load of adjustments so that the sound engineer can tailor the effect to suit their needs. The most common adjustments are attack and decay times and the compression ratio. Learning to use compressors effectively requires a bit of research and a lot of practice.

Limiters generally operate over much shorter time periods - the easiest type to understand is the “brick wall limiter”. This effect gets its name from the idea that it creates an immovable barrier to prevent the signal from going above a set “limit”. It is similar to “clipping” except that the distortion that it introduces is more gentle (it rounds off the clipped peaks rather than clipping them flat) and so is less obtrusive.

“Look-ahead” with compressors is when the compressor will look to see what signal is coming and will start to compress the signal in advance of the rise in amplitude of the incoming signal. This does not necessarily mean that output peaks will never exceed a particular level (that’s what brick wall limiters do), but it means that the reduction in volume will begin before the arrival of an increased input level.

In that case it will probably be best to use the envelope tool to adjust the volume of each section so that each song is at the appropriate level.

When you have done that, Mix and Render the track, then Normalize to -1 dB, then use the fast lookahead limiter with a boost of around 3 to 6 dB and a maximum level of -0.3 dB (figures are approximate, but I think this is the sort of thing that you are looking for.)

Can’t you just use the Envelope tool as you would the master volume knob on your mixer? Though, instead of avoiding red lights, you’d be, in essence, normalizing the volumes.

But please, do keep in mind that differences in dynamics are important.

How do you mean exactly?

I’m going to point you to another thread that deals with this…

I posted this for a completely different reason, but I got to mess with this tool last night and it did a very remarkable job. I used essentially the default numbers and I’m planning on using the tool like that this weekend.

If you follow the developer’s narration, he was making a lot of the same program performance decisions that you are asking about. It’s extraordinarily difficult to get a compressor to do this job without seeming to be doing anything at all.

One of his notes had to do with the older existing compressor tools in Audacity. He didn’t like them very much because they made many wrong philosophy decisions. That’s what got my attention. I didn’t like them, either, and for those exact reasons.


Carol752, if you wrote anything I missed it. I only see a quote :confused:

I gave the compressed version another listen in the car and noticed that during parts of the song where the bassline drops out all of the high end gets really loud (ambient synths etc). So the compressor, with the default settings, isn’t going to work. Does anyone know if there are alternate settings that would prevent that?

Also, is there anything like the envelope tool, but automated for bringing down the louder parts (say anything that 2x or 1.5x louder than the everything else around it)?

I tried out the envelope tool and the result of 5minutes or so of work is about half a second worth of audio:

Zooming out you can quickly multiply the amount of work it would take to get just 5 seconds done:

Are there any plugins that can do this automatically?

I think what you need is a multi-band compressor. I don’t know of one for Audacity, but it’s easy enough to reproduce the effect, and although it is a bit more work than just running a compressor at its default settings, it is considerably quicker than manually entering thousands of envelope points.

To produce a simple multi-band dynamic compressor effect:

In this case we will just use two bands, bass and treble, though the method can be expanded to more bands if you wish.

  1. Open Audacity and Import your audio track.
  2. Select the entire track and duplicate it (Ctrl+D)
  3. Use the highpass filter set to your chosen cross-over point (say 800Hz) and a roll-off frequency set to 3B per octave (this is actually 6dB per octave in current Audacity versions).
  4. Use the lowpass filter on the other track with the settings identical to what you used in step 3.
  5. Apply dynamic compression (use your favourite compressor with whatever settings you require) to each track individually.
  6. Listen to both tracks together, and if you like it, Mix and Render. If it’s not quite right, use “Undo” and go back to step 3.

The advantages of multi-band compression are that you can apply different compression amounts to different frequency bands. Also, if there is a heavy bass hit, with normal (single band) compression, this will cause all of the audio to dip in level, making a noticeable drop in the upper frequencies. Using multi-band compression, this undesirable side effect is avoided.

Nice one, I’ll give this a shot. is 800Hz the recommended frequency for splitting the two bands? Is there a benefit to doing 3 or 4 bands as opposed to 2? If so what frequencys do you suggest splitting at?

It all depends on the music.

It’s best to try and keep the crossover frequencies out of the most critical frequency bands otherwise you can get strange phasing effects. Also, if you use more bands, then you will need to use sharper cut off frequencies in the high/low pass filters, but that can cause resonance to occur close to the cut off frequency.

4 frequency bands is likely to be the maximum that is useful, but often a simple 2 band will provide just as good results with a lot less effort.

A good compromise would probably usually be 3 bands, somewhere around 20Hz to 400Hz, 400Hz to 3kHz, 3kHz to 20kHz. If you have,say, a synth bass track that is pumping out a lot at around 300 Hz, then you might find it better to push the lower crossover frequency up a bit, say to around 600Hz, or if you have a lot of deep bass below 100Hz, then you may find that a simple 2 band split at around 300Hz with a sharp cut-off does the best job.

Practice on short samples and keep a note of your settings, after a while you will probably find that you have certain favourite settings.

Remember that while you have the frequency bands split you can also adjust the levels of each band.

This is getting seriously surreal. Is there any reason we’re not using the multi-band compressor built into Audacity 1.3.5?

Effect > Apple: AUMultibandCompressor

That tool can have serious musical mix problems, but it does smash everything down to a straight waveform on the TimeLine. More importantly, did you try that custom compressor tool I mentioned in an above post. If all you want to do is retain the character, flavor, texture, and presentation of the original performance without the loudness variations, that’s exactly what that tool does.

Pull down the two sound clips and compare them. I know it’s not screaming rock or dance music, but work with me here. The abrasively loud segments are pushed down and the orchestration is pushed up. You can listen to that whole hour-long show in the car without touching the volume control.

Once you get it that far, you can apply more effects, but if you’re mixing dance music, you don’t want to take any more moxie out of the performance than you have to. I don’t like dance music that’s been sterilized.

You can continue to mess with the performance waveform by waveform, but you’ll continue to have musical problems if you’re zoomed in that tight. Loudness and volume happen in a much broader and sloppier way.

Do you have your “before” performance posted somewhere? Try not to digitally compress it. That can cause problems with sound experiments.