The patch bay is often a great mystery for engineers just starting off and to any musician who comes into a recording studio for the first time. With so many plugs and wires, it can be a little intimidating and you might ask yourself, "Where do all those patch points go?"
Even in a smaller recording session, there is typically a mess of cables going from one end to the other, all in different colors, cable lengths and multiple connection types. I remember being completely overwhelmed the first time I had to use one, and thinking there is no way I would remember how they work. Yet, over a short period of time, I was able to figure it out and that overwhelming feeling went away. Now, I couldn't imagine life without them.
When you learn to control the power of the patch bay, your life as an engineer will become so much easier, as it will allow you to send signals with ease between all the devices in your studio and open up a whole new world of creativity and workflow.
So what does a patch bay do? In a simple answer, a patch bay is a device that connects all of the gear in your recording studio. If you wanted to create a channel strip without the use of a patch bay, you would have to plug your microphone directly into the rear panel of your preamp using an XLR cable, run out of the preamp with another XLR into a the rear panel of an EQ, run out of the EQ into the rear panel of a compressor and then into the input of your audio interface. That’s such a hassle if you are planning to do that with every mic line. If you’ve ever climbed behind a studio rack or workstation, you know it can be a bit messy back there and having to climb behind the rack for every single connection would take up so much time in the recording session.
Since a recording studio typically consists of multiple rooms, it would be really hard to run individual cables from each isolation booth or live room into the control room. So with the use of a snake or wall mounted input panel, all the mic lines can neatly come into the control room through a single cable and connect directly to the patch bay. You would then hook up all the inputs and outputs of all your outboard gear, as well as the inputs and outputs of your recording interface to the patch bay. Now you can easily go in and out of all the mic lines and outboard gear through the front panel of the patch bay.
A standard patch bay uses TT connections (also referred to as tiny telephone, or bantam cables), which stemmed from the old phone patching system. They look similar to a standard guitar cable, but are much smaller and use a 3-section tip, ring, sleeve connection type to handle balanced signals. TT patch bays are the most common due to the ability to have 48 insert points per row, and consist of two rows in only 1 or 1.5 rack spaces, providing 96 total patch points.
Most TT patch bays use what are called “DB25 cables (or snakes, or looms)” to connect the rear of the patch bay to the rest of the equipment in the studio. The DB25 is a multi pin connector with 25 pins and each one carries 8 channels of balanced audio. They are available in various lengths from very short 1.5’ all the way to 50’ or more and can be bought stock off of the shelf with XLR, TRS or another DB25 connector to adapt to any equipment type.
Patch bays also have a convenient feature called “normalling” which allows you to layout it so that certain common connections do not need to be patched for each session, or you can even split the signal into two for routing to various destinations. I’ll first explain the “full normal” setup, which means there is an internal connection inside the patch bay that connects the top row of jacks to the bottom row of jacks. Usually the top row of jacks are outputs on a patch bays and the bottom row are inputs. You can configure the “normal” configuration differently for each pair of top and bottom jacks. In a “full normal” configuration, the audio signal is flowing from the output (top jack) to the input (bottom jack) by default, without any patch cable plugged into either jack. That flow is then broken if a patch cable is inserted into either the top or bottom jack.
Another possibility is a “half normal” configuration. A half normal configuration works the same as its normal counterpart, but the only difference is that the signal flow is not broken if you patch a cable into the output (top jack) but is broken if you patch into the input (bottom jack). This allows you to “mult” or split the signal into two, since the signal will continue to flow from the top patch point to the bottom patchpoint and you can tap the signal off of the top patchpoint to route it to yet another second location. This can be useful for setting up parallel compression, splitting the signal to both record and take a direct cue send, and all sorts of other creative uses.
Finally, you can configure two patch points to be “non-normalled” and this simply means that no signal flows from top to bottom points by default. For any signal to be routed, a patch cable must be used. You would use this configuration on a patch bay to bring up the inputs and outputs of your outboard gear, since if you had them normalled or half-normalled they would be constantly feeding back into itself, which is not good for the gear!
If you do not have an analog console as part of your setup, or if you have instead a control surface such as an Avid S3 or Avid S6, then a patch bay is still a necessity for routing signals in various places in the studio. If you work in a hybrid manner, using analog outboard gear via hardware inserts, then all that routing must be achieved on the patch bay as well. Another common use of the patch bay is to create an insert between the outputs of digital to analog convertors and the inputs of a summing mixer. That allows you to route and insert compressors and EQ’s into your mix.
If you are using an analog console in your setup, the patch bay is a must to properly send signals from one place to another. On a large format recording console, you have the ability to use an Insert on the channel, which is commonly used to add processing such as a compressor or EQ. On the patch bay, you will typically have a row dedicated to insert sends and a row dedicated to insert returns per every channel on your desk. To add an insert on a channel of your console, you would send out of the insert patch point on your patch bay to the input of an external dynamic processor on the bay. You would then send out of the dynamic processor back into the insert return of the channel. Now to engage the dynamics on your console's channel, you press the “Insert” button and now have the ability to bypass the insert as you choose rather than it always being in the audio path.
If your console has auxiliary sends or bus outputs, the outputs would also be dedicated to a row on the patch bay. A common use for auxiliary sends is to send a copy of the signal to an external effects unit such as a reverb or delay. To set this up, you would patch from the auxiliary output on the patch bay to the input of the effects processor. You would then send the outputs of the effects unit on the bay back to one or two channels on your console. Now you can use the aux send dial on your console to send any desired amount to the effects unit, and listen to the return on your desk, which you can then utilize the desk EQ, as well as the inserts mentioned before.
Some of the most popular TT/DB25 patch bays are the Audio Accessories Shorti Quick Switch, Bittree, Switchcraft 9625 and Redco. You’ll also need some DB25 cables, both Vintage King brand cables and Mogami are excellent choices. For TT cable options, those by Redco/Mogami or Mogami are excellent choices.
Even with everything I’ve gone over in this blog, there is still much more that a patch bay can do. It can sometimes take a beginning engineer a year or so to fully understand all the functionality of a patch bay and feel comfortable using one. Even for the home studio user, I recommend integrating a patch bay into your setup. It will help increase productivity as your studio grows, allow you the flexibility to try new channel strip configurations and also prepare you to handle a patch bay in a larger commercial facility if you decide to take a client or your project there.
If you have any questions regarding the integration of a patch bay into your studio setup, contact a Vintage King Audio Consultant via email or by phone at 866.644.0160. At Vintage King, we offer full turn-key patch bay configuration and layout services, as well as on-site installation if so desired.