The GROT knob is the big one at the top of the panel, and it's the control most people end up using most. Where DAMAGE breaks the speaker mechanically, GROT shows you what a working speaker does when it's driven far beyond what it was designed for: the low mids compress and bark, the whole thing gets denser, and eventually it screams.
What it does
The 55 Hz – 2 kHz band is pulled out and put under increasing pressure. Three things happen to it together as the knob rises.
Compression. The threshold drops from −6 dB down to −30 dB and the ratio climbs to 8:1, so the low mids are squeezed harder and earlier the further you go. Up to 12 dB of makeup gain keeps the band from collapsing under it.
Saturation. The compressed band is driven through an asymmetric saturator, with the drive rising steeply across the knob's travel.
Bark. A resonance sweeps downward from 1.1 kHz toward 420 Hz and rises by up to 10 dB as you turn it up. This is the vocal, shouting quality the control is named for, and it's what makes GROT read as effort rather than as fuzz.
The low mids bite early by design, so you'll hear real strain well below the halfway mark.
Why it doesn't sound like a low-pass filter
Compressing and saturating a 55 Hz – 2 kHz band costs you top end. Left alone, the knob would behave like a slowly closing 1 kHz filter.
To stop that, an active high shelf at 1.3 kHz ramps in as you turn up, reaching about +13 dB at the 60% mark. Above 60% it eases back to around +4 dB, because by then the chainsaw layer is supplying its own brightness.
The practical consequence: GROT gets denser and angrier as you turn it up, but not darker.
Above 50: the chainsaw
Past the halfway point a second, parallel layer ramps in: a dense, smooth, presence-boosted saturation in the manner of an HM-2 pedal, with a +7 dB lift around 3.2 kHz and a lid at 10 kHz to keep it from turning harsh.
This is a genuine change of character, not just more of the same. Below 50 the knob is strain and bark. Above 50 it's strain and bark plus a bright, fizzy, mid-forward buzz on top. The top quarter of the range is extreme by design, and the drive keeps extending well past what the numbers on the knob suggest.
The travel, summarised
| Position | Character |
|---|---|
| 0–20 | Thickening. The low mids firm up and gain a little weight |
| 20–50 | Real strain. Compression bites, the bark rises, the band gets dense |
| 50–75 | The chainsaw arrives. Bright, fizzy, forward, obviously distorted |
| 75–100 | Full scream. Drive extends far past nominal maximum |
What it does to everything else
GROT feeds DAMAGE. A speaker under strain also fails faster, so turning this knob up advances the effective damage, up to about 18% of DAMAGE's travel at full GROT. If the slap or the terminal failure arrives earlier than the DAMAGE readout suggests, this is why.
MODE matters here too. GROTBOX is modelled as the smallest enclosure and responds most aggressively to GROT, while BOOMBOX is mid-sized and DIRECT is neutral. The same knob position is half again as strained through GROTBOX as through DIRECT, with BOOMBOX between the two.
Because GROT both compresses and applies makeup gain, it raises average level as well as changing tone. The internal level match catches most of it, but if you're A/B-ing settings, trust the VU meter's damage reading rather than your impression of loudness.
