Logic Pro X 10.1 Compressor

One of the best feature introduced with the latest update of Logic Pro X 10.1 is the new GUI for the built-in compressor plug-in. With this new interface is much easier to access the different emulations of circuit type that were a «hidden secret» for many users in the previous versions.

Compressors’ Circuit Types

Some hardware compressor had become standards not just because of their ability to compress audio but also for the tonal quality and the side-effects added to the signal. With the advent of DAWs and software plug-ins developers had to emulate this effects, especially with the compressors.

These are the main classes of circuit types used to build hardware compressor:

Before the introduction of Logic Pro X 10.1 we just had a small dropdown menu to choose the circuit type. Many users ignored it and kept using the Platinum which was (and still is) the default choice. This circuit is built by Logic’s developers and although it is very powerful, it doesn’t have any sound quality nor emulates any renowned compressor. If you’re one of that kind of users, please keep reading.

Logic Pro built-in compressor
The circuit type dropdown menu in Logic’s compressor.

The other circuit types were in fact emulations but nobody could name exactly all of them (try a quick search on google to find the guesses), until now. With the new GUI, developers helped us a lot: we can name exactly every emulation thanks to the colours of the panel and the design of the knobs. Now you’re probably asking yourself: “Why is this so important”? Because there are many books, articles and tutorials about which compressor is best for vocals, guitars, drums and any other source. If you learn which circuit type you’re using, you’ll become a better engineer by using Logic’s built-in compressor (and you’ll save a lot of money on third-party plugins).

Platinum Digital

Circuit Type: Platinum Digital

As said before, this circuit is Logic’s own design and it’s the default setting when we load a compressor in our channel strip. It can be very helpful in some situation because of its transparent sound.

Studio VCA

Logic Pro X Studio VCA Compressor

 

This circuit type has been introduced with this latest update so it is completely new. The Studio VCA is an emulation of the Focusrite Red 3 Dual Compressor and Limiter (you can find the user manual here). As the name implies, the original hardware version can be used as a stereo or dual mono compressor and has its own limiter module which can ben enabled separately. The controls are: ratio (1.5:1, 2:1, 3:1, 5:1, 7:1 or 10:1), threshold (the original range is between -24dB to +12dB), attack (fast to slow), release (from 0.1 to 4 seconds) and make-up gain.

Logic Pro X allow us to user different values for all this controls but I strongly suggest you to stick with the original values: anything is easier to use when you have less choices.

Studio FET

Logic Pro X Studio FET Compressor

 

The Studio FET circuit type emulates the Universal Audio 1176 which is still available on the market in its hardware version. The controllers available on the original compressor are: inputoutput, attack (from 20 to 800 microseconds), release (from 50 to 1100 milliseconds), ratio (4:1, 8:1, 12:1 or 20:1).

Unfortunately on Logic’s version of this compressor is not possibile to emulate the “All-Button” mode (all the ratio buttons pressed simultaneously) which many engineers love for its pumping sound.

Classic VCA

Logic Pro X - Classic VCA Compressor

 

The Classic VCA duplicates the discontinued DBX 160 compressor/limiter (the original user manual can be downloaded here). The controls on the original hardware are: threshold (from 10mV to 3 volts), ratio (from 1:1 to 120:1) and output gain (from -20dB to +20dB). Since the attack and release parameters are not available on the hardware, those knobs aren’t available on the plugin either.

Vintage VCA

Logic Pro X - Vintage VCA Compressor

 

The Vintage VCA is the emulation of the SSL G Bus compressor which can still be found on SSL’s desks as well as in other formats such as 500 module or native plugin. The original controls are: threshold (between -20dB and +20dB), ratio (2:1, 4:1 or 20:1), attack (from 0.1 to 30 ms), release (from 0.1 to 1.2 seconds or AUTO) and make-up gain.

Vintage FET

Logic Pro X - Vintage FET Compressor

 

Vintage FET is the emulation of the UREI 1176 Silver Face. Which had different components compared to the Universal Audio 1176 but the same controls. As above, we can’t access the “all-button” mode in Logic’s version.

Vintage Opto

Logic Pro X - Opto Compressor

 

Last but not least the Vintage Opto which is the copy of the Teletronix LA2A, a must-have compressor for any engineer. The original hardware version of this compressor has only two control knobs: gain and peak reduction. As you can read on the user manual, the attack is very fast and the release time is approximately 0.06 seconds for 50% release, 0.5 to 5 seconds for complete release depending upon the amount of previous reduction. The peak reduction knob controls both the threshold and the amount of compression.

  • Sven

    I am using the Platinum Digital model on a vocal speech track. I always had the impression I understand the principle how compressors work but I’d like to give you this example where I am totally confused how the LPX compressor works the way I see it on the graph or output level:
    Ratio=30:1, Threshold=-30dB, Attack=0, Make Up=0. Speech is around -20dB with one peak at -8.7dB. Normally the compressor should reduce everything to an output level between -30dB and -29dB, right? It should compress the range -30..0 to -30..-29 because of ratio 30:1. In practice there is no audible difference anymore with ratios of 3:1 or higher. How can this be? Compressors work on peak db, not rms, right?

    • Hi Sven, in Logic Pro X’s compressor you can switch between peak and rms by clicking on the “side chain” button on the right. This function is available only on Platinum Digital because the other circuit types follows the hardware models. Also note that, by default, Platinum Digital works in rms so this is probably why you couldn’t hear the right effect on your vocal tracks. Try to switch it to peak and let me know if you need further help.

    • Sven

      I knew it was something obvious like that… thank you! Switching to Peak now works as expected.