Phase Modulator vs Shruti Bot

PHASE MODULATOR Phase modulation perturbs the running phase of a carrier oscillator with a modulating signal. Sweeping the phase back and forth generates a series of sidebands above and below the carrier, spaced by the modulator frequency, whose number and strength grow with the Index. This is the same technique behind classic FM synthesis: small index values add a little harmonic shimmer; large values produce dense, clangorous, often inharmonic spectra. The carrier you hear is always an internal oscillator. What changes between modes is where its phase modulation comes from. ------ CONTROLS: CAR FREQ Frequency of the carrier oscillator, 20 Hz to 20 kHz. This is the audible tone in both modes. CAR AMP Level of the carrier oscillator before the Output gain. MOD FREQ Frequency of the internal modulator oscillator, 20 Hz to 20 kHz. Active in Osc + Osc only. The carrier-to-modulator frequency ratio sets the harmonic character: integer ratios give harmonic, pitched tones; non-integer ratios give bells and metallic, inharmonic results. In Input + Osc the modulator comes from your audio instead, so this control is inactive. MOD AMP Level of the modulation source before it reaches the phase. Together with Index it sets how far the carrier phase is pushed; think of it as a trim ahead of the Index multiplier. INDEX Modulation index, 0 to 10. The headline control: peak phase deviation in radians equals Index times the modulation signal. At 0 the carrier passes clean; raising it brings in progressively more sidebands and brightness. OUTPUT Makeup gain after the effect, -24 dB to +36 dB. No limiter follows this stage, so watch your meters when boosting. WAVEFORM Carrier oscillator shape: Sine, Saw, Triangle, or Square. Sine is the classic FM voice. The richer shapes already contain harmonics, so phase modulating them produces denser spectra and reacts more aggressively to Index. MOD WAVE Modulator oscillator shape (Osc + Osc mode only): Sine, Saw, Triangle, or Square. Changes the harmonic character of the modulation itself. In Input + Osc mode the modulation comes from your audio, so this picker is inactive. FOLLOW Input + Osc only. With Follow On (the default) the carrier tracks the amplitude of your incoming audio: it speaks only while signal is present and falls silent when the input does, so the plugin behaves like an effect rather than a constant tone. With Follow Off the carrier runs continuously at its set level regardless of input, which suits drones and sustained textures. In Osc + Osc there is no input to follow, so this control is inactive. ----- MODES: OSC + OSC Both carrier and modulator are internal oscillators, set by Car Freq and Mod Freq. Classic two-operator FM with no input required, good for bells, electric pianos, and metallic drones. INPUT + OSC Your track's audio becomes the modulation source, perturbing the phase of the internal carrier oscillator. Note that what you hear is the carrier shaped by your audio, not the audio itself passed through; the input controls the timbre rather than being processed in place. Mod Freq does not apply in this mode. This is the default mode. ------ A NOTE ON ALIASING Phase modulation can scatter energy well above Nyquist, so the effect runs internally at four times the host sample rate and filters on the way back down. At extreme Index settings with the saw or square carrier some residual aliasing can remain; lower the Index or the carrier frequency if you hear gritty, detuned overtones.

Shruti Bot is a shruti box you can actually tune. Ten reeds, laid out the way a real box is — the low Pa and Sa drone pair, the full middle saptak from Sa to Ni, and the upper Sa. Every reed sits at its just-intonation ratio against the tonic, not the tempered approximation, so the drone locks together the way the instrument is supposed to. Pull up the bellows and it breathes. At zero no air moves at all and the box is silent; push it up and the drone gets louder and pumps harder, until the breathing turns into an audible tremolo riding on top of the tone. Pressure opens the timbre as well as the volume, so a stroke sounds like air moving rather than a fader going up. THE REEDS • Ten stops — Pa and Sa below, Sa Re Ga Ma Pa Dha Ni across the middle, Sa above • Just intonation throughout — 3/2, 9/8, 5/4, 4/3, 5/3, 15/8 against the tonic • A tapered tuning peg on every reed, plus or minus 100 cents, turned by hand • Detune two neighbouring reeds and they beat against each other — real acoustic summing, not an effect • A mixer fader per reed, independent of the stops, for balancing what's already sounding THE KEY • Any tonic across all twelve pitch classes, octaves 1 through 6 • A peg for each key, arranged as a keyboard • Every pitch class keeps its own microtonal trim, so you can build a tuning that isn't twelve-tone equal temperament and it stays put • The current note and its offset are always on screen MOVEMENT • Two free-running LFOs on every reed — one for tuning, one for level • They run at their own rates and drift in and out of phase, so the beating keeps reorganising and the drone never quite repeats • Set them slow and the box simply sounds alive THE CHAMBER • A swept resonance that moves like a body cavity rather than a filter sweep • Stereo chorus, the point where the drone opens out of the centre • Tape delay with a real moving head — sliding the time bends the pitch the way tape does, and the repeats darken as they recirculate • Plate-style reverb from a quarter second to six TWO INSTRUMENTS Tap the logo. Shruti Bot 2 replaces the reeds with four analogue oscillators — sine, triangle, saw and pulse — with phase shaping on each, from slow comb sweeps to full PWM. Everything else carries straight over: the same tuning, the same reeds switched on, the same effects. Only the sound source changes. No accounts. No subscriptions. No ads. No network. Nothing leaves your device.