Compressor with slow attack vs expander

[sir-haver]

Hey guys,

Just something that confuses me, if you're using a compressor to make your kick more punchy, by having a slow attack you let the transient through and then compress what comes after, aren't you actually expanding the dynamic range? Isn't it the same as using an expander to boost the transient of the kick (provided that you gain match between the two methods) ?

Thanks

[lfm]

When passing threshold and attack with knee is done, it decrease amplification with ratio, this total is compression, depending on setting for threshold and attack. And also how short the sound is, percussive or a lasting note.
- attack is the time until the knee start working to decrease amplification with an envelope over to the final amplification while above threshold.
(some compressors put the number for attack in ms and might be after the knee is done, just a definition thing)

And I would call it medium attack to get punch. You put the brakes in the middle of skin movement, kind of.

When short attack a lot of vibration from skin is reduced to almost nothing on output.
- make up gain decide how loud that is
When long enough attack to get all vibration through you get no audible effect for a percussive sound.
- so balance between threshold, ratio and attack decide resulting punch

So my view is that punch is created stopping skin vibration a little bit. A bit of attack through and then put the brakes on the rest. So the sound depend much apon the knee in this process, so why some compressors work well for drums like 1176 type and others not.
- how the envelope of knee is, decide the sound and brings character

Unless you stop some part of skin movement in output signal there is no compression. And very different if lasting notes or percussive stuff.

From your questions it sounds like the part after attack is compression, but look at the full process as compression instead. The signal going into compressor is a certain level. It cuts of some transients reducing output level if setting for punch, but never expand level. All this if level ever go beyond threshold.

[DMG68]

I understand what you’re saying. I think it partly depends on your release time as well. A quick release on compression brings up the quieter sounds after release, once you apply make-up gain. It all works together, attack time, gain reduction, release time and make-up gain. You may get similar results from an expander depending on how you set the effects. I think of it like this for basic/normal compression and expanding - if I want to add punch, raise the soft parts, or level things out, then I use a compressor. If I want to make the quiet parts quieter, like to suppress some noise, then I use expansion or a gate. I think of normal expansion like a gate that doesn’t fully close.

Now to add to this, you can use a transient shaper on the drums and enhance or even avoid compression, depending on the sound you’re working with and the results you want.

[kritikon]

It's all about make-up gain. Without that, a compressor just reduces level. So the OP's example does reduce the kick body, effectively emphasizing the transient. When you apply make-up gain the body becomes louder compared to the transient and it sounds punchier.

Most people use compressors most of the time for making things sound louder/reducing dynamics which is done with make-up gain - It's probably the most important parameter on a comp for the masses. Without it they wouldn't touch compressors with a bargepole (unless they have autogain)...

[sir-haver]

Thanks for your answers everyone that all makes sense

[gjunk]

Keep in mind typically compression begins when the signal exceeds the threshold so even the transient is slightly compressed. It just takes longer to reach the ratio you set with a slow attack time so it may seem like the transient wasn’t compressed

[sir-haver]

Keep in mind typically compression begins when the signal exceeds the threshold so even the transient is slightly compressed. It just takes longer to reach the ratio you set with a slow attack time so it may seem like the transient wasn’t compressed

You mean that the attack is like an envelope rather than on/off? Interesting I didn't know that
Thanks

[legendCNCD]

I suggest watching this one, even though it tells you about the best transparent ITB compressor, but there is also good generic knowledge about compression:
https://www.youtube.com/watch?v=1Tx6SRCwWug

[gjunk]

Keep in mind typically compression begins when the signal exceeds the threshold so even the transient is slightly compressed. It just takes longer to reach the ratio you set with a slow attack time so it may seem like the transient wasn’t compressed

You mean that the attack is like an envelope rather than on/off? Interesting I didn't know that
Thanks

Sort of definitely a better representation than the “on switch” of a compressor

Check out the video someone posted above I’ve seen it before it’s pretty good

[gjunk]

I just found this audio compression visualizer. Helpful for trying to understand how the dynamics change given different compressor settings

https://codepen.io/animalsnacks/full/VRweeb