Audacity, how to remove a spike

[vpelton]

Audacity, how to remove a spike

I had a spike in my file. Most of the file was at about 0.4, but the spike was about 0.6 . Because of this, I could not amplify the file enough. To my ears, I couldn't hear anything louder at the spike. What is the easiest way to remove the spike?

This is what I did, but I had to try a few times before it sounded ok so would like an easier way. I zoomed in a lot, selected just the spike, then did effect; amplify with -9 dB.

[TriciaG]

That's it. If you have one spike, that's the way to fix it.

If you have a bunch, use the Compressor effect. But that's overkill for one spike.

[vpelton]

Thanks. To be specific, what I did was select where the spike began at the zero crossing, continued to where it crossed zero again, then continued to pick up the negative spike until it did its final zero crossing. Is that what I'm supposed to do? Or, do I just select the part that's over say, 0.4?

Also, I looked at compressor. It has tons of options. Is there a writeup describing what I should set each value to? This is for future reference in case I need it.

[annise]

You really need to experiment with most Audacity tools when you need them.
step 1 - save your file outside Audacity , I tend to use flac
Step 2 try the effect, listen to result
Step 3 edit undo
repeat 2 and 3 till the result sounds right.

Anne

[TriciaG]

Depends on your spike. I was picturing a blast of a vowel, not a plosive. If it's a plosive, you can sometimes use the High Pass Filter to shrink it rather than Amplify. But yes, use the whole S-curve.

Here's a video for compression. http://www.youtube.com/watch?v=wJ3lOTDsN6c

My default settings are as follows:
Threshold: -17 to -13 dB (this number can be varied a lot)
Noise Floor: -40 dB
Ratio: 2.5:1 to 4:1
Attack: 0.2
Decay: 1.0
NO checks in the check boxes

High Pass Filter, I use about 150 Hz threshold and 12 dB rolloff (I think those are the terms).

[vpelton]

Thanks, that helps a lot. Just one more question. To figure out the Threshold value, you suggest, say -17. But how do I look at the track to see how high the spikes are? It goes only between -1.0 and 1.0 .

Plus, are spikes sometimes good? Maybe you want to be loud at some point. Don't want to have a monotone.

[TriciaG]

I don't know how to figure out how high the spikes are in order to use it for the threshold. Like Anne said, experiment with it. The lower the absolute number (-13 being lower than -17), the less recording will be compressed.

Spikes can be good, to emphasize things. But in my listening experience, I don't like some phrases really loud compared to the neighboring recording. It's startling. Intensity of voice, IMO, is better than straight volume in most cases.

[vpelton]

Thanks to everyone. I know enough now to get started.

[annise]

It is posible to sound louder and softer without higher and low spikes. Play with Audacity running and watch what happens. You can do more things with your voice than you realise you can do

Anne