Help With Highly Dynamic Audio Recording.

I would like some help with a problem I having when recording a music lesson.
I record my music lesson, but the volume when my instructor and I speak is often very low, but
when we start to play our guitars, it’s too loud for my recorder.
When I import my recording, you have to strain to hear what we are saying, but when we start
to play our instruments, it’s so loud it can blow out the speakers.

How can I limit the “dynamic range” of my recording?
Use a compressor? Limiter? Volume increase with limiter?
My recorder has a gain switch on the side to increase the sensitivity of the microphone, so you can hear us talking properly,
but then the guitar music just overwhelms the recording.

I am lost with all the effects that are available and would like to get some recommendations, or possibly
some links to where I can see some examples.


The proper solution would be to wear headset microphones plugged into a mixing desk and another microphone for the guitars. Pan the vocal microphones extreme left and the guitar mic extreme right (or the other way round). Adjust the gain so that you get a decent level on each channel, then after recording use Audacity to split the left right channels and convert to mono. Then use the Auto-Duck effect to mute the vocal microphones while the guitars are playing.

Another less effective solution would be to record with AGC (Automatic Gain Control). Some recorders have AGC built in and it automatically adjusts the recording level according to how loud the sound is. The main problem with this is that it takes time for the AGC to adjust, so the first few seconds of the guitars will be horribly distorted until the AGC has reduced the gain. Similarly the first few seconds of voice will be inaudible while the AGC is turning the recording level up.

An alternative to “fix” the problem after recording would be to use a huge amount of dynamic compression. The original recording level needs to be set to the (loud) guitars. Applying dynamic compression with a high compression ratio. If you use the dynamics compressor that is included in Audacity 1.3.11, try these settings:
Threshold -60
Noise Floor -80
Ratio - 10:1
Attack time - 0.1
Decay Time - 1.0

The limitations are that the voices will “fade in” gradually (though these settings make it as fast as possible) and the sound quality will be adversely affected. The background noise (noise floor) will also rise substantially as the voices fade in.

“Chris’s Dynamic Compressor” often gets recommended as a cure all for uneven volume problems but is unlikely to work well with such extreme differences. With optimum settings it will even out the volume effectively, but there will be a much longer fade-in/fade-out time (several seconds) than using the built in compressor.

Steve Harris’s “SC4” compressor is another compressor but it does not have “lookahead” so there will be a sudden “blip” if the guitars start suddenly.

Yet another method would be to record at a level suitable for the guitars and manually split the recording each time the recording changes between guitars and voice. The voice sections can then be moved to a separate track and amplified. This process can be streamlined by marking sections with labels and “Edit menu > Labelled Regions > Split Cut”, then pasting to a new track, but it will still be a lot of work.

Beyond all this, you have not mentioned what you are recording with. Is your recorder/microphone capable of recording the guitars without distorting?

Here’s a rather unconventional method that may work better than compression (though not as good as using headsets and a mixer).

Make your recording with the recording level set for the guitars.
Select the track in Audacity and press Ctrl+D (duplicate track).
Select the top track and from the effects menu select “Auto Duck”.

You may need to tweak these settings but try:
Duck amount = -24
Minimum Pause = 1
Outer Fade = 0.2 (both)
Inner Fade = 0.0 (both)
Threshold = -30

If the voice becomes silent, raise the Threshold setting (try -12).

Then delete the lower track and Amplify the remaining track.

This is probably the most effective method for a “post production” fix.

compression will help

move the mike closer to your mouths to get voice louder
and turn away with your back to the mike when you play to lower the guitar volume

use two mikes - one voice one guitar - mix them later on


Tell us how everything is connected. If you only have one microphone and you’re trying to talk over a rock-crusher guitar amplifier, that’s never going to work very well.


one mike then
use the turn away method

i think they implied acoustic

if its electric
turn off the amp
and use a di
turn the volume down!
and crank it up in the mix

My guess is that loopster is having an electric guitar lesson and has a recorder running during the lesson so that he can listen to it again later but does not want to be messing around doing anything that detracts from the lesson. I doubt that the problem would occur with acoustic guitars. I would further guess that they do not want to be fiddling around with multiple microphones or spending time adjusting the recording levels during the lesson. These requirements make it impossible to get a “good” recording, but my guess is that “good enough” will do. Assuming that my mental picture of the scenario is close to reality, the “Auto Duck” technique described in my previous post will probably be a good option. (has anyone tried it? It’s a neat “trick”)

If loopster returns to this forum topic it would be interesting to hear what the actual recording situation is like and if any of the suggestions are useful. It’s probably not worth pursuing conjecture further.

Sorry to leave some many helpful people hanging.
In my environment I am taking a one hour guitar lesson with an instructor. I don’t really have the time or room to come in and have a perfect setup for recording.
I come in, plop down my recorder, (Zoom H2), and start recording. I have tried some different recorders and it usually comes out the same. Our talking comes out very weak, and the guitars are overwhelming. It’s hard to tell the instructor to speak up and play softly.
I am currently using the dynamic compressor that comes with audacity and only tweaked the first setting to .6 instead of the default .5. Then I export to MP3, copy it to my iPhone and listen to in on the way to work. It is very helpful as many times he speaks of music theory, asks questions and points out small things that I could be doing better. I get a lot of information in one hour and it’s easy to forget it all.
Thanks for your help, it seems to working at an acceptable levels now…


Huh. Chris’s compressor would probably work fine if you just decreased the release width, and perhaps even increase the release exponent. Of course, you have to lower the floor enough and give it a compress ratio of around .8-.9. That should take care of it.

turn the gain down so the h2 does not clip
you can fix the voices in audacity later
and bring up all the guitar/speaking to the same level for playback

if it is acoustic then put the mike on a stand near mouth level
as close as feasible. the difference in distance to the guitar will give you another 12-20 db of help.

If you are getting reasonable results using the Audacity compressor, then as pdf23ds has said, you are likely to get good results with Chris’s Dynamic Compressor.

Worth noting that in addition to the suggested settings for this particular task, pdf23ds has recently announced new documentation that explains how to use Chris’s Dynamic Compressor.