Mastering 101: Signal flow & metering

Signal flow and metering are essential components of mastering that help set your master up for success.

This post is the second article in our introductory guide to mastering. If you’ve missed an entry, click on any topic below to catch up:

  1. What is mastering?
  2. Signal flow & metering
  3. EQ
  4. Compression
  5. Limiting
  6. Preparation

1. Signal flow

We’re just going to dive straight in and show you what we think is a good starting point for a digital mastering path in your DAW.

Source → EQ → Compressor (2dB GR) → Clipper → Limiter (3dB GR)  

Source: This is your stereo track that you’d like to master (alternately it could be stems, but stem mastering is a whole different ball game).

EQ: Your EQ can be placed here or not – you make the call. Some people place an EQ both before and after the compressor, as the compressor tends to color a signal (we’ll talk about this more in a future entry). But note, there is no gain reduction happening here.

Compressor: Remember, mastering is about subtle touches – you should avoid anything more than 2dB of compression at this stage. You want to feel the compression rather than hear it.

Clipper: Using a clipper is a process that distorts your mix. Yes, you read it right, distorts. The sad truth these days is, to reach commercial loudness, you need to distort your mix (we’ll revisit this later in the guide).

Limiter: Similar to the compressor, any gain reduction of more than 3 dB will sound unnatural. Although some may choose to produce a “pumping” effect for creative purposes, it’s generally recommended to keep gain reduction to a minimum. The trick to do that lies between the clipper and the limiter.

This signal flow may not make any sense to some of you, but it’ll soon become clearer as we go through this mastering guide.

The takeaway here is that to make something louder, you need to reduce the dynamic range. That said, the more dynamic range a mix has, the louder it’ll be on streaming (check this article out if you’re interested in learning more on this).

2. Metering

In mastering, we usually use VU meters that give us RMS (Root Mean Square) readings of our master. In essence, VU meters give us a good indication of the average levels of our master. A good inexpensive meter to get is PSP’s Triple Meter.

meter

A few things to note about VU Meters:

1. 0 VU is relative: The digital value of 0 VU is defined using the meter calibration control. The reason for this is to allow scaling for different target levels.

metering
2. Target Levels: In the mastering world, there are general reference points to reach target levels. For PSP Triple Meter, you can adjust these values by clicking PSP VU 3 and surfacing the ‘back’ of the meter.

  • Classical 0 VU = -18 dBFS
  • Jazz 0 VU = -9 dBFS
  • Pop 0 VU = -8 dBFS
  • Aggressive pop / hip hop = -7 dBFS

Some additional notes:

  • If you’re only touching the 0 VU mark occasionally, you have a dynamic master.
  • If you’re going over 0 VU and into the red occasionally, you have a louder but less dynamic master.
  • If you’re slamming the red, you have a compressed master with less dynamic range.

3. Creating a mastering template

Now that you know about signal flow and metering, it’s easy to create a mastering template in your DAW. Set up a master track with the plugins in this order:
1. EQ
2. Compressor
3. Clipper
4. Limiter
5. VU meter (with your target level set according to genre)

That’s it for this entry – next, let’s cover EQ basics.


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February 8, 2016

Reuben Raman Product Marketing Manager at Splice