Patch Bays. What’s The Deal?

The answer to this is the inevitable:

It depends.

It depends on the kind of set up you have, whether you have a DAW with lots of plugins, whether you have a lot of outboard gear, whether you use more than one instrument or have a console with lots of inputs.

Put simply, it likely depends on how lazy you are. You see, a patch bay can make your life so much easier, you will honestly ask yourself six months down the line “How did I ever manage without one?”

Front view of a patch bay with connectors inserted into some of the bays

A patch bay, yesterday

So, what exactly are they and how do they work?

Well, first of all, their functionality can be understood via the same reductionist realisation which one applies to a multi channel mixing console. A patch bay’s use can be explained by focussing on just one set of patch connectors and on how they can be configured.

Imagine a patch bay but instead of a 24 way bay, just imagine a 1 way patch bay. It has two connectors on the front, one above the other, and two connectors on the back, one above the other.

The simplest way to wire a patch bay is to imagine it as nothing more than a way to bring a connection which is usually out of reach to somewhere easy to reach. Let’s say you have a CD player, for example, and you don’t want to have to pull it out every time you want to connect it to an amp or some other device. We’ll keep things mono for the ease of illustration.

The player will obviously have an output. Using the right lead, likely a1/4″ jack to phono, the output from the back of the CD player can be connected to the top connector on the back of the patch bay. Now, every time you want to either listen to the CD player or record something from it, you have a socket with the output from the player right there, no more pulling the player out to plug stuff into it.

Now, let’s say we have an input on our computer, for example, where we might usually plug our instruments. Well, we would use the bottom connector in the same way, to allow easy access to the input on the computer without having to rummage around behind the desk. We take the input on our computer or audio interface and again, simply extend it to the bottom connector on the back of the patch bay.

Great! We now have an output from our CD player within easy reach and likewise the input to our computer or interface.

Another added bonus is that patch bays are typically either cheaper or less hassle to replace if a socket wears out through use. This is actually a big deal as a large console or audio interface will be both pricey and a major headache to replace or repair.

Now, even if this was all a patch bay could do, we’ve solved some pretty serious problems.

But wait! There’s more!

Most patch bays are switchable between three modes. These three modes are through, half normal, and normal.

We’ll stick to our current simplified model of a single CD player output and a single computer input to illustrate the difference between these modes.


Through mode is the simplest operation, in fact the operation we left our patch bay in. Connections on the back of the patch bay are simply connected directly through the patch bay to the corresponding connectors on the front. This is the simplest configuration and is the easiest to understand. The patch bay acts as a collective extension for our input and output connectors. Plugging a cable into the front of the patch bay connects directly to whatever is plugged into the corresponding connector on the back of the patch bay.

Half Normal

This is where things get interesting and useful. A patch bay configured as half normal works the same way as a patch bay configured as through but with one important difference:

If nothing is connected to the front of the patch bay, the two sockets are internally connected together. Remember, this is still the very simple patch bay we connected the CD player and computer to. In this case, if there were no cables inserted into the sockets on the front of the patch bay, the signal from the CD player will be automatically sent to our computer. This can be handy in a number of cases but then what is the point of having the patch bay there if we just wanted to connect the CD player to our computer?

Well, this is the clever bit. If we wanted to record a guitar part on our computer, our half normal configured patch bay lets us simply plug the guitar into the bottom connector. The guitar then cuts off the CD player without us having to do anything else. Connecting anything to the bottom connector cuts off the top connector and sends our newly connected instrument to the rear socket, breaking this internal connection.

Half normal means something a bit weirder, though. If we now remove our guitar from the bottom socket, that is our input, the internal connection is remade and the CD output is once again internally routed to our computer via the rear connector. The weird part is if we were now to connect something to the CD player output, the top socket. Let’s say we want to take the output from the CD player to an amp. Simple, we take a connector and plug it into the top socket, plug the other end into an amp and Bam! We can listen to our CD player through the amp.

The weird bit is that, when we plug something into the top socket, the internal connection to the bottom socket is not broken. Instead, the output from the CD player is now split, one half of the signal being delivered to the amp we just plugged in and one half still being sent to the computer.

This is why half normal is called half normal, because only one of the two connectors completely breaks the internal connection between the top socket and the bottom socket.

Full normal

Well, now that I’ve explained half normal, you can probably guess what full normal means. If anything is plugged into the top or the bottom connector, the internal connection is cut. The signal is not split. Plugging anything into the CD player’s output on the front panel will now break the internal connection and no signal will be split to the computer.

Why the different modes?

Sometimes, you want a patch bay to just be a disparate collection of inputs and outputs with no real structure or pattern. You’ve got loads of bits of gear and you just want to be able to plug stuff in without moving things around. Through mode is what you want here. There are no default or normal connections between any two bits of gear, it’s just an easy to access collection of sockets.

Sometimes, you will have two pieces of gear which you will normally want connecting together, like a sound module you use very often which you normally want connected to two channels on your console or audio interface. You would then connect your stereo module outs to two top sockets on the back of the patch bay and your two console or interface ins underneath the module sockets, also on the rear of the patch bay. Set these to half normal and now, with no cables plugged in to the front of the patch bay, your module will be connected to your interface but leaving the bottom connector free to take a guitar or other instrument as and when you might need, all just by plugging it in. And if you wanted to listen to the module to monitor it independently of your computer, you could connect an amp to the top socket on the front and still record the module at the same time.

Full normal does the same thing as half normal but it never splits a signal. Anything plugged into a full normal socket will break the internal connection completely.

Now, expand that idea across 24 socket pairs and you can begin to understand just how useful a patch bay can be.

Just be prepared to invest in lots of cables to set the patch bay up in the first place.

Of course, that’s what cable snakes are all about!


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