diff --git a/packages/webaudio/clockworker.mjs b/packages/webaudio/clockworker.mjs
index c13f79da..e1ec9005 100644
--- a/packages/webaudio/clockworker.mjs
+++ b/packages/webaudio/clockworker.mjs
@@ -9,14 +9,12 @@ const stringifyFunction = (func) => '(' + func + ')();';
 const urlifyFunction = (func) => URL.createObjectURL(new Blob([stringifyFunction(func)], { type: 'text/javascript' }));
 const createWorker = (func) => new Worker(urlifyFunction(func));
 
-// this class is basically the tale of two clocks
+// this is just a setInterval with a counter, running in a worker
 export class ClockWorker {
   worker;
-  audioContext;
-  interval = 0.2; // query span
-  lastEnd = 0;
-  constructor(audioContext, callback, interval = this.interval) {
-    this.audioContext = audioContext;
+  interval = 0.1; // query span
+  tick = 0;
+  constructor(callback, interval = this.interval) {
     this.interval = interval;
     this.worker = createWorker(() => {
       // we cannot use closures here!
@@ -33,6 +31,7 @@ export class ClockWorker {
         if (!interval) {
           throw new Error('no interval set! call worker.postMessage({interval}) before starting.');
         }
+        postMessage('tick');
         timerID = setInterval(() => postMessage('tick'), interval * 1000);
       };
       self.onmessage = function (e) {
@@ -50,25 +49,23 @@ export class ClockWorker {
     });
     this.worker.postMessage({ interval });
     // const round = (n, d) => Math.round(n * d) / d;
-    const precision = 100;
     this.worker.onmessage = (e) => {
       if (e.data === 'tick') {
-        const begin = this.lastEnd || this.audioContext.currentTime;
-        const end = this.audioContext.currentTime + this.interval; // DONT reference begin here!
-        this.lastEnd = end;
         // callback with query span, using clock #2 (the audio clock)
-        callback(begin, end);
+        callback(this.tick++, this.interval);
       }
     };
   }
   start() {
-    console.log('start...');
-    this.audioContext.resume();
+    // console.log('start...');
     this.worker.postMessage('start');
   }
   stop() {
-    console.log('stop...');
+    // console.log('stop...');
     this.worker.postMessage('stop');
+    this.tick = 0;
+  }
+  setInterval(interval) {
+    this.worker.postMessage({ interval });
   }
 }
-
diff --git a/packages/webaudio/examples/repl.html b/packages/webaudio/examples/repl.html
index 97e945d3..b34d956f 100644
--- a/packages/webaudio/examples/repl.html
+++ b/packages/webaudio/examples/repl.html
@@ -1,9 +1,11 @@
 <div style="position: absolute; top: 0; right: 0; padding: 4px">
   <button id="start" style="margin-bottom: 4px; font-size: 2em">start</button><br />
-  <button id="stop" style="font-size: 2em">stop</button>
+  <button id="stop" style="margin-bottom: 4px; font-size: 2em">stop</button><br />
+  <button id="slower" style="font-size: 2em">-</button>
+  <button id="faster" style="font-size: 2em">+</button>
 </div>
 <textarea
-  style="font-size: 2em; background: #bce865; color: #323230; height: 100%; width: 100%; outline: none; border: 0"
+  style="font-size: 2em; background: #052b49; color: #fff; height: 100%; width: 100%; outline: none; border: 0"
   id="text"
   spellcheck="false"
 >
@@ -11,11 +13,9 @@ Loading...</textarea
 >
 <script type="module">
   document.body.style = 'margin: 0';
-  // import * as strudel from '@strudel.cycles/core';
-  import * as strudel from '../../core/index.mjs';
-  import * as util from '../../core/util.mjs';
+  import * as strudel from '@strudel.cycles/core';
+  import * as util from '@strudel.cycles/core/util.mjs';
   import '@strudel.cycles/core/euclid.mjs';
-  // import { Scheduler, getAudioContext } from 'https://cdn.skypack.dev/@strudel.cycles/webaudio@0.0.4';
   import { Scheduler, getAudioContext } from '../index.mjs';
 
   const { cat, State, TimeSpan } = strudel;
@@ -33,11 +33,12 @@ Loading...</textarea
 .mul(slowcat(1,2))
 .mul(slowcat(1,3/2,4/3,5/3).slow(8))
 .fast(3)
+.freq()
 .velocity(.5)
-.wave(cat('sawtooth','square').fast(2))
-.adsr(0.01,.02,.5,0.1)
-.filter('lowshelf',800,25)
-.out()`;
+.s('sawtooth')
+.cutoff(800)
+.out()
+`;
 
   try {
     const base64 = decodeURIComponent(window.location.href.split('#')[1]);
@@ -61,4 +62,6 @@ Loading...</textarea
 
   document.getElementById('start').addEventListener('click', () => scheduler.start());
   document.getElementById('stop').addEventListener('click', () => scheduler.stop());
+  document.getElementById('slower').addEventListener('click', () => scheduler.setCps(scheduler.cps - 0.1));
+  document.getElementById('faster').addEventListener('click', () => scheduler.setCps(scheduler.cps + 0.1));
 </script>
diff --git a/packages/webaudio/scheduler.mjs b/packages/webaudio/scheduler.mjs
index e4719307..618fec96 100644
--- a/packages/webaudio/scheduler.mjs
+++ b/packages/webaudio/scheduler.mjs
@@ -5,35 +5,43 @@ This program is free software: you can redistribute it and/or modify it under th
 */
 
 import { ClockWorker } from './clockworker.mjs';
-import { State, TimeSpan } from '@strudel.cycles/core';
 
 export class Scheduler {
   worker;
   pattern;
-  constructor({ audioContext, interval = 0.2, onEvent, latency = 0.2 }) {
-    this.worker = new ClockWorker(
-      audioContext,
-      (begin, end) => {
-        this.pattern.query(new State(new TimeSpan(begin + latency, end + latency))).forEach((e) => {
-          if (!e.part.begin.equals(e.whole.begin)) {
-            return;
-          }
-          if (e.context.onTrigger) {
-            // TODO: kill first param, as it's contained in e
-            e.context.onTrigger(e.whole.begin, e, audioContext.currentTime, 1 /* cps */);
-          }
-          if (onEvent) {
-            onEvent?.(e);
-          }
-        });
-      },
-      interval,
-    );
+  phase;
+  audioContext;
+  cps = 1;
+  constructor({ audioContext, interval = 0.1, onEvent, latency = 0.1 }) {
+    this.audioContext = audioContext;
+    this.worker = new ClockWorker((tick, interval) => {
+      const begin = this.phase;
+      const end = this.phase + interval * this.cps;
+      this.phase = end;
+      const haps = this.pattern.queryArc(begin, end);
+      haps.forEach((e) => {
+        if (typeof e.value?.cps === 'number') {
+          this.setCps(e.value?.cps);
+        }
+        if (!e.part.begin.equals(e.whole.begin)) {
+          return;
+        }
+        if (e.context.onTrigger) {
+          const ctxTime = (e.whole.begin - begin) / this.cps + this.audioContext.currentTime + latency;
+          e.context.onTrigger(ctxTime, e, this.audioContext.currentTime, this.cps);
+        }
+        if (onEvent) {
+          onEvent?.(e);
+        }
+      });
+    }, interval);
   }
   start() {
     if (!this.pattern) {
       throw new Error('Scheduler: no pattern set! call .setPattern first.');
     }
+    this.audioContext.resume();
+    this.phase = 0;
     this.worker.start();
   }
   stop() {
@@ -42,4 +50,7 @@ export class Scheduler {
   setPattern(pat) {
     this.pattern = pat;
   }
+  setCps(cps = 1) {
+    this.cps = cps;
+  }
 }
diff --git a/packages/webaudio/webaudio.mjs b/packages/webaudio/webaudio.mjs
index aa6262ed..e177d0fd 100644
--- a/packages/webaudio/webaudio.mjs
+++ b/packages/webaudio/webaudio.mjs
@@ -125,7 +125,8 @@ const splitSN = (s, n) => {
 };
 
 Pattern.prototype.out = function () {
-  return this.onTrigger(async (t, hap, ct) => {
+  return this.onTrigger(async (t, hap, ct, cps) => {
+    const hapDuration = hap.duration / cps;
     try {
       const ac = getAudioContext();
       // calculate correct time (tone.js workaround)
@@ -175,7 +176,7 @@ Pattern.prototype.out = function () {
           freq = fromMidi(n); // + 48);
         }
         // make oscillator
-        const o = getOscillator({ t, s, freq, duration: hap.duration, release });
+        const o = getOscillator({ t, s, freq, duration: hapDuration, release });
         chain.push(o);
         // level down oscillators as they are really loud compared to samples i've tested
         const g = ac.createGain();
@@ -183,7 +184,7 @@ Pattern.prototype.out = function () {
         chain.push(g);
         // TODO: make adsr work with samples without pops
         // envelope
-        const adsr = getADSR(attack, decay, sustain, release, 1, t, t + hap.duration);
+        const adsr = getADSR(attack, decay, sustain, release, 1, t, t + hapDuration);
         chain.push(adsr);
       } else {
         // load sample
@@ -221,7 +222,7 @@ Pattern.prototype.out = function () {
         }
         bufferSource.playbackRate.value = Math.abs(speed) * bufferSource.playbackRate.value;
         // TODO: nudge, unit, cut, loop
-        let duration = soundfont || clip ? hap.duration : bufferSource.buffer.duration;
+        let duration = soundfont || clip ? hapDuration : bufferSource.buffer.duration;
         // let duration = bufferSource.buffer.duration;
         const offset = begin * duration;
         duration = ((end - begin) * duration) / Math.abs(speed);