A guitar amp sim and multi-effects app.

Eight amps, one at a time

Glass, Ember, Monolith, Lantern, Basalt, Comet, Forge, and Quartz, from clean to a saturated lead, each with a head of its own. Pick one from the shelf of small heads at the top of the Amp page, or with a MIDI footswitch (program change 1 to 8). Each amp remembers its own knobs, and its Gain blends five captures across the knob, so it changes how hard the amp distorts, not just how loud it is.

Only the amp you hear runs; a switch fades the new one in about a tenth of a second later, without a click. The amps are NAM captures trained from BellyDSP's own amp models, not captures of real amps. Load your own .nam file as a ninth.

A cab with mics you can move

Two close mics and a stereo room mic, each an impulse response with level, pan, polarity, delay, and mute, with automatic phase alignment and low and high cuts. Load a cab pack and drag a close mic across the speaker to morph between positions.

21 public-domain (CC0) cab IRs are built in, from a vintage and a modern 4x12. Load your own .wav IRs too.

Pre FX

• Gate before the amp and after it, linked, listening to the clean guitar signal, with adaptive release and a Learn button
• Compressor, in a studio and a pedal style
• Boost and overdrive, modelled from circuit schematics and oversampled, with several modes each
• EQ: a 9-band graphic or a 5-band parametric

Drag the blocks to reorder them.

Post FX

• EQ and compressor
• Harmonizer: up to four voices in key, reading the pitch from the clean guitar signal
• Multivoicer: up to eight voices for stacks and doubles
• Bloom: bitcrusher, phaser, and flanger in one block, in any order
• Chorus, delay (digital, analog, tape; stereo, ping-pong, dual; ducking), and reverb (room, hall, plate; freeze; shimmer)

Delay and reverb tails ring on when you switch them off. Drag to reorder.

Tuner, tempo, presets, scenes, MIDI

• A tuner with a needle on a ±50 cent scale, four tunings, A4 from 430 to 450 Hz, and a mute
• One tempo, tapped from the panel or a footswitch; delay, chorus, phaser, flanger, and reverb pre-delay can sync to it
• Presets with eight scenes each, undo and redo, A/B compare, and five factory presets
• Right-click any control to MIDI-learn a footswitch or an expression pedal; mappings save with the preset

Match tone

Load a song, pick a section where the lead guitar stands out, and BellyDSP sets the amp, its Gain and tone, a pedal and compressor if they help, the cab, and a fine correction curve to get close to that recording. It can pull the guitar out of a full mix first. Play the part along with the song (with a count-in) and it compares your notes with the recording's one by one, and can use them to clean the rest of the band out of the recording.

Switch between the song, the match, and your current sound before you apply it. Applying is one undo step.

A real-time audio engine

Zero added latency. The one exception is opt-in: the flanger's through-zero setting delays the signal by 5 ms while it's switched on, and says so. The audio thread never allocates memory, frees it, or waits on a lock, and an automated test checks that for every feature. The default rig uses about 6% of the time a 128-sample buffer allows on the developer's Apple silicon Mac, and every block on at its heaviest about 22%. A CPU saver switch on the Output page helps older computers.

It runs at 48 kHz, the rate NAM captures are trained at.