Thursday, December 13, 2012

The One Click Trick - Using Inserts as Direct Outs

It comes up every now and then that someone needs a way to take individual tracks of audio from a mixer into a recorder but there aren't enough outputs to do it and the console doesn't have direct outputs. There's a little trick you can use, in a number of ways, to get the job done.

If the console has insert jacks you're in luck. An insert jack uses a TRS (tip, ring, sleeve) connector to send audio out for processing and receive it back on the same jack. With a Y cable the audio path uses the tip to go to one TS plug that feeds signal into a piece of outboard gear and the other TS returns signal on the ring. They share the ground. 
By inserting a TS plug into the insert jack just to the first click. That takes the send signal and effectively makes it a direct out. If you have Y cables on hand you can use those, the send branch is your direct out and you can just ignore the return. Some consoles have send on the ring and return on the tip. Older British desks especially. So make sure you check into this first. In a lot of cases though you've just taken a direct out without interrupting the signal in the channel.

Sometimes it's worth it to make up special cables to insure a better connection, especially if it's for frequent use. A cable with a TRS connector at the mixer end and a TS connector for the recording device at the other made from shielded instrument cable is desired. At the mixer end, solder a jumper from the tip to the ring of the TRS connector. This allows the jack to be fully inserted which is more secure and will not interrupt the audio through the channel. The TS jack on the other end functions as a split.  This is the way to go if your desk uses the old British convention as well. Here's a simple diagram:

Mixer End                                                                                    Recorder End
T_________________White Wire_______________________T
R___|
S_________________Black Wire_______________________S

The last thing to remember is that inserts are most commonly located immediately after the mic pre. While larger consoles or ones intended for recording will often have an option to have direct outs be either pre or post fader, on a smaller console there's just one place to get the gain right and not as much opportunity for fine tuning. At home or in the studio this isn't as much of a problem as when you try this out on a gig. The FOH guy may or may not want to cooperate with you on gain structure as his job is to make the show sound good, not keep your clip lights off.

One final thing to mention and this is a pet peeve of mine. Lots of people who start to build their own cables will use black for the signal and white for the ground/shield. While this is correct if you're wiring a house (In North America anyway) audio wiring generally follows the convention for low voltage systems. In those systems the ground is black and signal wires are the rest of the colors. This makes it a lot easier to keep track of things when some of your cables are black/red and some are black/white. Only when you run into the odd red/white cable do you need to make a choice and stick to it. It's important to stick to the system because when you're making quick repairs in the field, especially at a live event, reversing the polarity will have an effect on the signal, sometimes a pretty big one.

That's all for now Brethren of the Knob and Fader. Keep those questions rolling in. We'll be starting up with new podcasts again this week!

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