Patchbays are one of the things that tend to separate a project or home studio from a commercial one. If you feel like you need one and the flexibility it allows, you probably already invested a non-negligible amount of money into your gear and you're moving forward. So.. congrats! Patchbays are awesome and fun to work with.

The convention is that the top row is where the outputs of your gear come out and the bottom row is where you input the signal into them. For example, the outputs of your mic preamps should be plugged into the top back row and the inputs of your digital converter into the bottom back row. Signal flow depends on how your patchbay is normalled. There are three modes:

• full-normal means that the top and bottom rows are connected but that connection can be broken if a cable is plugged into one of the front jacks
• half-normal means that the top and bottom rows are connected but plugging a cable into the bottom row breaks that connection and plugging one into the top row splits the signal (without breaking the connection)
• non-normal means that the top and bottom rows are not connected and require front connections to be used.

The idea is that you can have default routing paths set automatically by using full or half normal modes but also be able to change them with patch cables and use different combinations of gear. Think of the previous example: preamp outputs would automatically go into converter inputs... except when something is plugged into the front !

Another important aspect is with regards to plugging microphones that need phantom power into a patchbay. Some manufacturers/models do allow for that and some don't. Be sure to check if yours does. There are some classic horror stories of those 48V hitting some innocent input when a patch cable is unplugged too eagerly. A good tip is to always be safe and turn phantom power off before unplugging the respective patch cable.

A side chain is essentially a copy of the input signal used to modulate (or control) how a device operates. If a device does not have a side chain send/return option, that means it will either use a copy of the signal itself or that it will do some internal processing (to a copy of the input) in order to achieve whatever sound it's trying to achieve. It's important to note that it's always a copy of the signal, and not the input itself. This means that whatever happens to the side chain signal, it does not apply to the audio being processed.

The most common use of side chain processing is with compressors. Due to how much energy low frequency sources have (like the bass drum on electronic music or a bass guitar in rock), these sources can very easily trigger a compressor even though the rest of the material in the input signal doesn't require compression. On those situations, adding a high pass filter to the side chain signal makes it so the compressor will be less sensitive (or completely ignore, depending on the filter) to low frequencies.

Polar patterns are the shape of the area around a microphone's capsule where it will pick up audio.

There are five main shapes:

cardioid

omnidirectional

supercardioid

figure eight

hypercardioid

Most of the time, the polar pattern comes into play when trying to "aim" a microphone at a particular sound source while trying to avoid another. Most handheld microphones have a cardioid pattern for that reason: we want to pickup someone's voice and reject sound coming from the audience. Another great example is when recording orchestras or in a place with great acoustics, an omnidirectional microphone can be used to record both the music and the reverberation from the room.

There are several miking techniques that also require specific patterns or combinations of patterns. Some really interesting techniques for binaural sound (an attempt to mimic a 3D sound image) and stereo miking take advantage of the different polar patterns and allow us to achieve really amazing results. We'll cover those individually in future posts.