Virtual Studio Technoloy (VST) is a software interface for the development/integration of VST Instruments and Effects (FX) with a VST host, most typically a Digital Audio Workstation (DAW) such as Cakewalk MC6T and Sonar. The Development Kit is specified by Steinberg GmbH, a German software and equipment company (well recognised for it's Cubase DAW).

VST was first released in 1996 with ehancements specified in VST2 (1999) and VST3 (2008).

VSTs are packaged as a single '.dll' file (dynamic link library)

VSTs along with DX(i)s (Direct X instruments and FX) are collectively and commonly called plug-ins.

With the advent of 64bit computing, so has come the respective variants of VST.

MC6T is only 32bit and will only play 32bit VSTs.

32bit mode Sonar does not play 64bit plug-ins - so just leave the 32bit Sonar VST Scan Path pointing to 32bit plugins. But it'll just ignore the 64bit plugs if they are in the same path.

64bit mode Sonar can play both 32bit and 64bit plug-ins. 64bit natively, 32bit via Sonar's included BitBridge technology to 'bridge' the incompatibilities. 64bit plugins will take precedence over 32bit plugins if they have the same name.

for included/distributed plug-Ins.

VST locations for Steam ditributions of Cakewalk DAWs (MC6T, Sonar X3, Studio, Producer) go to:

VST2:

VST3: (these are a standard/typical location for all Developer VST3s)

My advice when installing product with VST components is to always consider, ahead of time, your VST strategy/location. Installers will typically prompt for VST location (32bit and 64bit) and what variants you want.

Strategy - Do you want VST2 (x32 ?, x64 ?), VST3 (x32 ?, x64 ?).

I suggest you maintain your own common path(s) for VST2s where possible, and with the exception of perhaps 'drive\:', retain the default paths for VST3s. Common paths mean fewer locations having to be defined to your DAW (via VST Scan Paths or PlugIn Manager).

Potential Defaults
It appears not all Developers have adhered to a firm standard for VST2 or perhaps misunderstood / not clear (?). There appears to be a move to rectify that with VST3. Typically, however, they default VST2s to:

a. Definition from Windows Registry entry (if it exists):
(these are not set as default in Windows 8 (at least mine)).

b. Developer/Product specific:

c. Steinberg's Public location:

Steinberg's own 'factory' location is (third parties shouldn't use this area):

Perhaps they'd be more logically laid alongside their VST3 counterparts(?) as per later Steinberg releases:

Once installed, Cakewalk DAWs maintain an Inventory, compiled at Scan time, on a per VST basis. The information is, in turn, held within the Windows Registry.

Self Defined
The general concencus is split your 32bit and 64bit base directories:
e.g.:

Some people like to include the Developer and/or add a layer for Reverb, EQ, Compressors, etc
e.g.:

MeldaProduction e.g, use categories: Delay, Distortion, Dynamics, EQ, Filter, Modulation, Pitch Control, Stereo, Tools.

Mine are actually all under the one to 'top'
e.g.:
(Note: But because e.g. Rapture install only asks for the base directory and deploys 'Rapture' beneath, I had to employ a 'hack' (rename / separate installs) to split it out to 32 and 64).

MC6T should obviously only scan 32bit paths.

Some VSTs are only 32bit yet many people have chosen to move forward and only maintain 64bit Plugins. Against that, you'd be foregoing the likes of Cakewalk Sound Center (only 32bit) which you may like and may have invested in Expansion Packs.

Of course, you can start Sonar in 32bit mode. However, I'd typically start 64bit mode and do a one-time add (Edit > Preferences > File - VST Settings) of the 32bit VST path. The in-built BitBridge feature will allow most of the 32bit plugs to work in Sonar 64bit mode. This is easiest seen in Browser>Plugins>Instruments - where 32bit plugs are 'green' and 64bit plugs are 'blue'. If it finds a double up 64bit will take precedence.

Scan Path denotes the 'top' of the tree. Any .dll beneath will be scanned and added if possible. If not, then in most cases it'll handle it, ignore and move on.

I suggest you DO NOT perform scans of entire/large disks - there is an instance in the forum of someone getting into a pickle as autoscan lauched on DAW startup - for whatever reason the system hung resulting in Support assistance being required.

• Where are the VST2 plug-ins stored on Windows?[www.steinberg.net] - Steinberg
  
  
• VST Configuration[www.cakewalk.com] - Cakewalk
  
  
• Virtual Studio Technology[en.wikipedia.org] - Wikipedia
  
  
• Steinberg[en.wikipedia.org]- Wikipedia
  
  
• Sonar 64bit[www.cakewalk.com] - Cakewalk
  
  
• VST on Windows[www.xlnaudio.com] - XLN
  
  
• KVR Forum Notes:
  - 1. Detecting VST plugins path (x32/x64)[www.kvraudio.com]
  - 2. VST path from registry[www.kvraudio.com]