Difficulty

There are six difficulties. From easiest to hardest, they are: 'entry', 'novice', 'medium', 'advanced', 'ambitious', 'ruthless' You can change them either via the SideBar setting or via shortcuts 'alt + <' and 'alt + >'.

So what changes as I go up the difficulty?

There are a couple things, but the first one we'll gonna talk about is 'snap points'.

Snap points

In essence, 'snap points' are the locations the 'user' filter can be placed on and the locations the random 'altered' filter can end up on, albeit with opposite gain.

Graphical equalizers usually show the frequency spectrum in a logarithmic fashion, because it's quite fitting for how the human ear perceives jumps in frequencies. For instance, our ears can divide up the area between 100 Hz to 1 kHz roughly as finely as the area between 1 kHz to 10 kHz.

Furthermore, a big part of one's ear training journey is about becoming better at honing in on smaller frequency changes. As a consequence, someone new to equalization and ear training might only be able to distinguish very roughly: lows, mids and highs. But as they get better, their ears are (or rather brain is) able to divide up the frequency spectrum more finely.

A "one step" increase in difficulty does just that: it divides up the frequency spectrum into 'snap points' twice as finely. To be accurate, every frequency will have two associated snap points: one in the upper (boost), one in the lower (cut) half. While the jumps between snap points are rather big on lower difficulties, they become quite small once on higher difficulties.

One might notice that even on 'ruthless' difficulty, there's still bit of a jump, e.g. 1652 Hz to 1753 Hz, to 1860 Hz. But we believe that if you ever reach a point in your training at which you can give answers with high accuracy at that level, you've already come as far as you'd ever need to go in ear training. One might even argue that point comes sooner, cause after all, the goal is not to be able to know by ear whether a cut needs to happen at 1650 Hz or at 1660 Hz. No, even just knowing by ear that something is amiss around the 1500 Hz to 1800 Hz range is quite an accomplishment and a huge boost to your equalization skills and productivity. Rather, no matter what skill level you end up at, in practice you'll likely always make the final "fine tuning" of placing an EQ change in an iterative fashion by ear, trying out two or three options, maybe using different Q values, maybe using the A/B feature of your equalizer plugin, all to finalize your decision.

Furthermore, one might be inclined to think that it would be nicer if there were "straight" frequency values, such as 1k, 2k, 4k instead of 1027, 2094, 4025 Hz. The reason for having those latter values is a design decision in EQdrill, which prefers having equidistant space between snap points rather than "straight" frequency values.

In a sense, this goes hand in hand with the previous argument on why there's nothing beyond 'ruthless' difficulty regarding "how finely the frequency spectrum is divided up". But considering that especially in today's day and age of having graphical equalizers readily available, considering that music and real world equalization rarely care about "straight" frequency values and considering the already mentioned objective of being able to (by ear) hone in more finely on frequency values and leaving the "fine tuning" up to "iterative A/B-ing", it seems a valid trade off.

After all, the purpose of EQdrill is equalization / frequency based perception / ear training, not being an equalizer!

Rating falloff

Another thing that changes with increased difficulty is the so called 'rating falloff'. The main idea here is that whenever you give your answer in a given turn, a so called 'rating delta' is being determined based on the theoretical "spot on" solution and your actual given 'user' filter position. The 'rating falloff' indicates how quickly you will receive the worst case 'rating delta' as the 'user' filter position is increasingly further off from the "spot on" solution that balances out the altered filter fully.

The higher the difficulty, the quicker this falloff happens. Therefore, the higher the difficulty, the stricter the rating algorithm is whenever your answer is off. The topic 'rating' will be touched upon in more detail in chapter Heatmap.

Gain and Q defaults

The third and last thing is that 'gain' and 'Q' values are distinct for each difficulty. Initial default values exist for each one (also shown in associated context info), but they can be changed as seen fit.

But the general idea here is that as the difficulty increases, 'gain' becomes lower and 'Q' becomes higher (more narrow).