How to shrink ONLY spikes of a wave form?

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mattad
Posts: 49
Joined: Wed Jun 28, 2006 10:24 am

How to shrink ONLY spikes of a wave form?

Post by mattad »

At first have a look at the sample waveform of a song:

https://snipboard.io/T3kO0Z.jpg

As you can see there are many almost silent parts and some spikes in between.

I want to reduce ONLY all spike heights (=volume) by lets say 20%.
Therefore I could mark each spike as an interval and reduce the volume accordingly.

However this is somehow tedious.

I guess there is a way to let GW do this in one step for all spikes.

What I need is a function "search all 1 second intervals, then check if the volume in each interval is above 0.8 on the left scala and if yes reduce it by 20%"

How can I achieve this in Goldwave?
DougDbug
Posts: 2172
Joined: Wed Feb 16, 2005 3:33 pm
Location: Silicon Valley

Re: How to shrink ONLY spikes of a wave form?

Post by DougDbug »

The waveform looks fine to me...

You can use the Compressor/Expander effect with the Reduce Peaks preset.

Dynamic Compression makes the loud parts quieter and/or the quiet parts louder. Limiting is a kind of fast compression that "pushes down" the peaks. Compression and limiting is one of the most commonly used effects in audio production (along with equalization and reverb). Almost every professional recording has some compression.

Mostly compression and limiting are used to reduce the loud parts/peaks and then "make-up gain" is used to bring-up the overall loudness.

IMO - Many modern recordings are over-compressed to "win" The Loudness War and the constant-loudness makes the music boring.

Expansion is the opposite and it makes loud parts louder and/or quiet parts quieter. It's rarely used except for noise-gating. A noise gate is a downward-expander that makes the quiet parts quieter or kills the quiet parts completely.

(GoldWave sometimes gets compression and expansion mixed-up but the presets names/descriptions are correct and that should keep you on the right track.)
mattad
Posts: 49
Joined: Wed Jun 28, 2006 10:24 am

Re: How to shrink ONLY spikes of a wave form?

Post by mattad »

Thank you. It looks good.

Qne more related question:

How can I tell GW to enable "Compressor" radio button by default?

Currently always "Expander" is set when dialog is called and I always have to switch manually to "Compressor"
DougDbug
Posts: 2172
Joined: Wed Feb 16, 2005 3:33 pm
Location: Silicon Valley

Re: How to shrink ONLY spikes of a wave form?

Post by DougDbug »

Like I said, in GoldWave sometimes those names are WRONG! Just start with one of the presets and those buttons will be set correctly.

First off the correct terminology - Dynamics relates to the difference between the loud & quiet parts, or high & low levels. We often say "dynamic range" or musicians say "dynamic contrast." In the context of music dynamic contrast is a better description. Or you might just say, "That song is very dynamic", or "That song has no dynamics".

Or you might say, "That song is very compressed", but that would relate to processing of the recording rather than the original musical performance.

And to repeat - Compression reduces the dynamic contrast by making the loud parts quieter and/or the quiet parts louder. Expansion increases the dynamic contrast by making the loud parts louder and/or the quiet parts quieter.


That's the dictionary definition, but GoldWave gets it wrong half the time!

This is confusing, so hang-on and, I hope I get this right... :twisted:

What it GoldWave seems to do is - "Compressor" affects sounds above the threshold and "expander" affects sounds below the threshold.

If you select "boost quiet parts" the "expander" button is selected. But that's NOT REALLY expansion, it's compression (reduction) of the dynamic range. "Boost quiet parts" also shows-up as "expander" and this time it's true... You are increasing (expanding) the dynamic range.

Anything that says "quiet parts" is labeled (or mis-labeled) "expander" and anything that says "loud parts" is labeled (or mis-labeled) "compressor".

The multiplier and compressor/expander settings together determine what GoldWave is REALLY doing.

In GoldWave "compressor" means it's working above the threshold (louder parts) so a positive multiplier is actually expansion (boosting the loud parts) and a negative multiplier is compression (reducing the loud parts).

In GoldWave "expander" means it's working below the threshold (quieter parts) so a positive multiplier is actually compression (boosting the quiet parts) and a negative multiplier is expansion (reducing the quiet parts).




...Although GoldWave gets gets the names/descriptions wrong, most compressors don't even give you the option of boosting quiet parts, and expanders are fairly rare too, so I'm going to complain too much about the wrong terminology.


P.S.
Just in case I got any of that wrong, and to make things easy on yourself - Start with one of the presets and trust the descriptions. Those are correct! Then, you can play with the settings and it's best to just ignore the compressor & expander buttons.
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