D8 Skills #71 | Practising Headphone Mixes

Starting this Thursday, we will be assessed on our ability to use the patch bay. There will be two tasks for us to do in the assessment, and one of them is setting up two specific headphone mixes. Today, I went into the studio to practice.

I set everything up quickly, however, when I plugged in my headphones at the end to test whether I'd done it correctly, it wasn't right.

The Task:

1. Headphone mix #1 to include all instruments but no vocal
2. Headphone mix #2 to include all instruments including vocal
3. Add 'plate' effect reverb using Lexicon MPX1 effects unit to vocals in headphone mix #2

The problem was that I could hear the vocal in headphone mix #1. I went through the setup over and over again and I was sure I'd done it correctly. I resorted to asking my lecturer what he thought the problem was.

He pointed out this mix knob between AUX and MAIN on the headphone amp. I originally had it in the middle which explains why I could still hear the vocal in headphone mix #1, however, when we turned it to AUX, nothing could be heard at all.

Now, this issue took over 20 minutes of experimenting and reading manuals to sort out. In the end, my lecturer found out that the headphone amp was expecting an unbalanced stereo signal, and we were feeding it a balanced mono signal. He went to get a cable that he had previously made himself which takes a balanced mono signal and turns it into an unbalanced stereo signal by sending the negative signal to ground and duplicating the positive signal to create a dual-mono signal which that headphone amp can recognise as stereo. This sorted out the issue completely, and all was sorted out.

Things I learned:

1. The pan between AUX and MAIN needs to be set to AUX when setting up headphone mixes.
2. The headphone amp expects to receive an unbalanced stereo signal, and you can't feed it a balanced mono signal because everything gets cancelled out. You need a special cable to make it work.