Blind-Testing Your Plugins with Diffonic

The bias that skews your decisions

You add a plugin and the sound seems better. But is it really better, or just louder? Most processing (compression, saturation, an EQ boosting a few bands) raises the level slightly. And our ears almost always read "louder" as "better".

• A 1 dB difference is enough to sway your judgement.
• What you see (the interface, the brand, the price) influences what you think you hear.
• You hear what you expect: if you know B is the expensive plugin, B often seems better.

What Diffonic does

Diffonic removes these biases in two steps:

1. It automatically matches the level of A and B in LUFS: the volume difference disappears.
2. It hides the label with blind test mode: six steps, A and B swapped after each answer, then an accuracy score.

The score works simply: if you really hear a difference, you'll pick the right version almost every time. If you're guessing, you'll be right about half the time.

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The protocol step by step

1. Prepare A and B: the same source with and without the process (or with two different plugins).
2. Choose a short, representative passage of 5 to 15 seconds.
3. Listen first in normal A/B mode, at matched volume, to spot the difference.
4. Start the blind test and answer without overthinking.
5. Read the score: a result close to chance means the difference isn't audible to you, on that passage, in those conditions.
6. Repeat the test another day or on another passage if the decision matters.

Three concrete examples

Comparing two compressors

Set both to get the same gain reduction on a vocal, then run the test. What seemed like a big difference often shrinks to a nuance once levels are matched. If you still recognise it, you know the choice really matters.

Validating an EQ move

Compare the track with and without your EQ. A 2 dB cut that seemed essential can turn out to be inaudible in the context of the mix. Conversely, if you hear it every time, keep it.

Choosing a reverb

Compare two reverb settings or two plugins on the full mix rather than soloed: it's in the mix that the difference counts.

In your workflow

• When mixing: check every important process at matched volume before keeping it.
• When mastering: compare the master with the mix, and your master with a commercial reference.
• Before buying: test a plugin's trial version against what you already own.

With the other Toool plugins

• Reverbia: compare two reverb families, or two CHARACTER positions.
• Anodyn: check the effect of CHARACTER or SMOOTH at matched level.
• Anadrive: saturation raises perceived loudness, which makes it the ideal case for a blind test.

Training your ears

Blind tests are also excellent training. Start with obvious differences (3 dB of EQ, heavy compression), then gradually make them smaller. You'll learn where your ears stop telling them apart, and gain confidence in your decisions.

In short

Match the volume, hide the label, count the right answers: with Diffonic you finally know whether a process really improves the sound. To go further, see our article on the psychology of listening and our comparison of the best A/B comparison plugins of 2027.

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