Racks within a Rack. Working with multiple racks and the chain selector function.
The Audio Effect, Instrument and MIDI racks are one of my favourite features in Ableton Live. They are extremely useful both in the studio and on the stage in a live performance context. 
If you haven’t used Lives’ racks before, in essence they allow us to chain multiple devices together to create complex signal processing chains or layered multitimbral instrument’s. 
They can also be used to house multiple different instrument or effect chains, that we can then select between on the fly. 
This feature is particularly useful for live performance, as it allows us to have say 10 different drum kits available on a single MIDI track. Helping us to reduce our track count and prevent our session from becoming overly cluttered. 
To get started, we begin with a blank rack. If you want to create a multi-effect style device this should be an Audio Effect Rack, otherwise for a rack that contains numerous different instrument’s choose an Instrument Rack. See the GIF below for a quick guide to setting this up.

A powerful modular synthesiser/effects system for Ableton Live. For those who dream of virtual wires... 
OSCiLLOT is a modular Max for Live instrument and audio effect, developed by the brilliant Berlin based Max For Cats (Ableton Live/Max Guru's Christian Kleine and Nico Starke). While they have released a number of highly useful, unique Max for Live devices, and continue to do so. OSCiLLOT is there flagship device and a very deep offering, which has been constantly expanded since it was first released in early 2015.

 The OSCiLLOT pack contains 4 Max for Live devices; The Instrument, the effects device, an Audio Receiver and a MIDI Receiver. There are now well over 100 modules including, oscillators, filters, modulators,sequencers, modifiers, effects and utilities.

​A number of these have been created by third party developers, such as Surreal Machines makers of the    amazing Dub Machines Max for Live devices.

OSCiLLOT is a polyphonic instrument, with up to 6 voices and includes Macro's in the style of Lives' Racks, which can be easily mapped to any parameter, of any OSCiLLOT  module. It can even send and receive CV (Control Voltage) signals, so it can be easily integrated with external hardware, as long as your audio interface offers a DC coupled output/input. The best thing is it sounds great and is very fun to program. And since the SDK (Software Development Kit) has been released publicly, anyone with Max for Live coding chops can make and freely distribute their own modules. ​

The full OSCiLLOT pack retails for $99 and is available directly from the Ableton store.
You can also download a demo version (OSCiLLOT Lite), which has less modules than the full version and some limitations, but is a great introduction for those who are not sure about taking the plunge. 

For those who have taken the plunge or you just want some more information, there are some useful links and resources below:

OSCiLLOT Forum (Max for Cats)
OSCiLLOT SDK
​Max for Cats Youtube - Tutorial and introduction video's

Finally don't forget to check out the included help documentation, accessed through Live's help view under packs, once you have installed OSCiLLOT. It is detailed and well written. Once you are patching together modules within OSCiLLOT, there is a very useful INFO view which can be activated and brings up a great overview for each model as you click on them. See the example below. 

Happy patching !

Side-chain Compression in Ableton Live 
When Ableton updated Live to version 9, they made some great changes to the standard Compressor device, which included altering the various compression algorithms. While this update device is mostly superior to the the previous Live 8 compressor, there are some situations where the old device excels. Most notably for clean side-chain compression. Thankfully we can easily access the Live 8 compressor in Live 9, and we still get the benefits of the new interface. In fact I have the Live 8 compressor saved as my default, knowing that I only need to click the 'Upgrade' button to change to the Live 9 one.

I find the FF1 model type, which stands for feed-forward, to be the best for side-chain compression tasks. It is very clean, even at extreme settings, while the Live 9 compression models click very easily.
I also find the FB model, which stands for feed-back, to be very useful on drums as an alternative to The Glue (Or even in conjunction with The Glue).  

Live 8 Compressor Preset

You can open the Live 8 compressor in Live 9, by dragging the device preset file above into any session. To save the Live 8 compressor as your default, just right click on the Device Title Bar to access the context menu, and select 'Save as Default Preset'. Alternatively you can save it as a preset if you would prefer to leave the Live 9 compressor set as your default.

Excellent Free Plugins for Producers
I love to impose creative limitations on my music making process, so as part of that approach, I mostly try to limit the number of third party plugins I use, but these ones are just too good to pass up.

TDR - Tokyo Dawn Records

They offer a great EQ plugin, compressor and dynamic EQ/multiband device. all of which are free, nice to use and sound great. You can also upgrade to more feature rich versions at a very reasonable price. I have been using their Slick EQ plugin for a while now and I really like the subtle character the different saturations options impart.  Kotelnikov their awesome feedback compressor, is also one of my favourites, for its super smooth, transparent yet musical compression. I like using it on my Drum group, with gentle settings in combination with The Glue. 

Well worth checking out.