Are Logic's Compressor Types set to Peak or RMS?

[dgc480]

I notice that the Peak / RMS option only works with the Platimum type. None of the other compressor types give you this option, so I'm trying to figure out which mode (Peak or RMS) these other compressors are automatically set to.

 

Thanks,

Dylan

[beej]

It's usualy a factor of the algorithm - for example, you you have an LA2A opto-type algorithm, it's detection circuit and how it responds is part of the algorith - it does what an LA2A does.

 

So it's purely in terms of the algorithm whether it offers such a feature.

[dgc480]

Thanks, but no offense I really don't understand what that means, or how it pertains to my question. I guess what you're saying is its based on the circuity, which may not specify Peak vs. RMS? In that case, I'm just asking if the compressor types other than Platinum (FET, Opto, VCA, etc.) are more similar to the Peak or RMS mode in Platinum.

 

This is important because I'm trying to use two compressors on my vocal track. The first would ideally react to peaks and just tame the transients (similar to a limiter), while the second would react to RMS to thicken the track. Therefore, I need to know if logic's compressor types are set to peak or RMS. I could just use a limiter for the first compressor, but I like having more parameters / versatility. I suppose I could also use the Platinum compressor twice, first set to peak and second set to RMS. But really I just want to know about the other compressor types for future use, and I'm confused why there aren't any answers to be found.

 

Thanks,

 

Dylan

[beej]

Thanks, but no offense I really don't understand what that means, or how it pertains to my question. I guess what you're saying is its based on the circuity, which may not specify Peak vs. RMS?

 

Yes - those algorithms in the compressor are based on real hardware units, or ideals of those. And each compressor type has it's own characteristics. Some use peak-type detection circuitry. Some have a much smoother characteristic. Some are more complex than that!

 

In that case, I'm just asking if the compressor types other than Platinum (FET, Opto, VCA, etc.) are more similar to the Peak or RMS mode in Platinum.

 

It varies for each algorithm, and I don't know the details of how it's implemented in each algorithm. The best way is to learn the compressor types by how they sound and behave on various sources.

 

This is important because I'm trying to use two compressors on my vocal track. The first would ideally react to peaks and just tame the transients (similar to a limiter), while the second would react to RMS to thicken the track. Therefore, I need to know if logic's compressor types are set to peak or RMS.

 

Well, the type of detection used doesn't really determine this - it's how you set the threshold, ratio, attack and release settings that determine this. Changing the detection type (or switching algorithms" just give different behaviours. Peak-type designs *can* be a little more aggressive than RMS-type, which is why people sometimes go to those for drums, but there are no rules and the end results should always be judged *by your ears* and not what settings someone tells you you should use.

 

What you describe is purely a function of the settings I list above - if you just want to tame the transients, use a fairly high threshold, and a quick attack, with a ratio set to taste. To thicken the track, you use a much lower threshold, and usually a shallower ratio and slow attack and release. The exact behaviour will change by changing the algorithm (and/or peak/RMS) but the principles remain the same - it's true for every compressor.

 

Every compressor can just limit peaks, or thicken a whole track, and these two setups are the fairly fundamental ways of using a compressor - and that has nothing to do with peak/rms behaviour, really. All that determines is how the compressor grabs when yout settings tell it to do something - rms probably has a faster, more aggressive character, but if you have relatively modest compression settings, that doesn't mean your vocal is going to sound horrendously overprocessed or anything.

 

Does that help?

 

There is a post knocking around that roughly lists what the compressor models are, and their general behaviour (VCO, Opto etc) that a search should turn up.

[shivermetimbers]

This may not be the post Beej was referring to, but the info applies. http://www.barryrudolph.com/mix/comp.html

 

And do not forget to spend some time with the Multipressor.

 

 

You may want to look into a mic preamp/processor which will help lessen your need to compress as much.

[rone2him]

This, also, may be helpful:

 

http://www.soundonsound.com/sos/jun11/articles/logic-tech-0611.htm

[beej]

Good links, both of those.

 

And you'll notice, when each of those articles are talking about the various compressor types, no mention anywhere of "peak" or "rms" sidechain detection. It's just not really relevant, for the reasons already mentioned.

 

What the OP is talking about is the difference between setting up a peak limiting type compression, versus a slight thickening compression, and this is entirely down to how you set the controls, and is not related to this peak/rms thing. That is really just part of the character of how a particular compression algorithm sounds given your settings and the source.

 

Ears first.

[dgc480]

Beej,

 

Thanks for your reply, that explains things really well. However, I think you may have made a typo here:

 

"rms probably has a faster, more aggressive character". I assume you meant to say "peak" instead of "rms".

 

Also, this is really great:

 

"if you just want to tame the transients, use a fairly high threshold, and a quick attack, with a ratio set to taste. To thicken the track, you use a much lower threshold, and usually a shallower ratio and slow attack and release".

 

.....but you didn't mention how to set the release time for taming transients. Would you recommend fast or slow? I was thinking fast, like a limiter, but this might cause some pumping. I will play around with all of these parameters and listen, but i'd like to have a good starting point.

 

To everyone else. Thanks for the links! I haven't had time to read them yet, but I will.

 

Thanks,

 

Dylan

[beej]

"rms probably has a faster, more aggressive character". I assume you meant to say "peak" instead of "rms".

 

Sorry, yes, my bad.

 

.....but you didn't mention how to set the release time for taming transients. Would you recommend fast or slow? I was thinking fast, like a limiter, but this might cause some pumping. I will play around with all of these parameters and listen, but i'd like to have a good starting point.

 

The release time is very important, but there are no rules. Different algorithms have different release characteristics. For example, some will initially release really quickly but get slower the longer the release goes on for. Some have automatic release times that are dependent on the source material. Some have aggressive release curves, others quite gentle ones. This all goes into the overall character of the compressor used - and you start to get an idea why there are so many and why they all sound different, even when set to similar settings.

 

If you just want to pull down transients, then you want a fast-ish release generally - let's say you have a part in your song where a loud kick drum hits, together with a sustaining pad sound, and you have a compressor on the mix.

 

With a slow release, the kick hit will cause the compressor to bring the volume down. With a slow release, the volume may take, say, half a second or a second to come back up, long after the kick has ended - causing a dip in volume of the pad sound - this is pumping.

 

In this case, you'd want to set the release so the compressor is hitting the release phase as the kick finishes - and how long this will be depends upon the kick sound, and the release characteristics of the compressor.

 

Too fast a release though, and you might get distortion as the compressor lets go of the peak before it's finished and starts reshaping the waveform.

 

It's *all* very much source dependent - you need to tweak, and get used to the behaviour and hearing the effect - it takes a little time, but once you get it and know what you are listening for it's fairly straightforward...