diff --git a/crates/tek_core/src/time.rs b/crates/tek_core/src/time.rs
index ea567dd5..ae1c98f1 100644
--- a/crates/tek_core/src/time.rs
+++ b/crates/tek_core/src/time.rs
@@ -27,10 +27,18 @@ pub trait SampleRate<U: TimeUnit> {
     #[inline] fn usec_per_sample (&self) -> U where U: TimeFloat {
         U::from(1_000_000f64 / self.sr().into())
     }
+    /// Return the duration of a sample in microseconds (floating)
+    #[inline] fn sample_per_usec (&self) -> U where U: TimeFloat {
+        U::from(self.sr().into() / 1_000_000f64)
+    }
     /// Convert a number of samples to microseconds (floating)
     #[inline] fn samples_to_usec (&self, samples: U) -> U where U: TimeFloat {
         samples * self.usec_per_sample()
     }
+    /// Convert a number of microseconds to samples (floating)
+    #[inline] fn usecs_to_sample (&self, usecs: U) -> U where U: TimeFloat, Self: SampleRate<U> {
+        usecs * self.sample_per_usec()
+    }
 }
 
 /// Trait for struct that defines a tempo in beats per minute
@@ -79,11 +87,11 @@ pub trait PulsesPerQuaver<U: TimeUnit> {
     fn ppq (&self) -> U;
     /// Set the PPQ
     fn set_ppq (&self, ppq: U);
-    /// Return number of pulses to which a number of microseconds corresponds (BPM-dependent)
-    #[inline] fn usecs_to_pulse (&self, usec: U) -> U
+    /// Return duration of a pulse in microseconds (BPM-dependent)
+    #[inline] fn pulse_per_usec (&self) -> U
         where U: TimeFloat, Self: BeatsPerMinute<U>
     {
-        usec / self.usec_per_pulse()
+        self.ppq() / self.usec_per_beat()
     }
     /// Return duration of a pulse in microseconds (BPM-dependent)
     #[inline] fn usec_per_pulse (&self) -> U
@@ -91,6 +99,18 @@ pub trait PulsesPerQuaver<U: TimeUnit> {
     {
         self.usec_per_beat() / self.ppq()
     }
+    /// Return number of pulses to which a number of microseconds corresponds (BPM-dependent)
+    #[inline] fn usecs_to_pulse (&self, usec: U) -> U
+        where U: TimeFloat, Self: BeatsPerMinute<U>
+    {
+        usec / self.pulse_per_usec()
+    }
+    /// Convert a number of pulses to a sample number (SR- and BPM-dependent)
+    #[inline] fn pulses_to_usec (&self, pulse: U) -> U
+        where U: TimeFloat, Self: SampleRate<U> + BeatsPerMinute<U>
+    {
+        pulse / self.usec_per_pulse()
+    }
     /// Return number of pulses in a second (BPM-dependent)
     #[inline] fn pulses_per_second (&self) -> U
         where U: TimeFloat, Self: BeatsPerMinute<U>
@@ -236,6 +256,29 @@ impl PulsePosition<usize> for Instant {
     #[inline] fn pulse (&self) -> usize { self.pulse.load(Ordering::Relaxed) as usize }
     #[inline] fn set_pulse (&self, usec: usize) { self.pulse.store(usec as f64, Ordering::Relaxed); }
 }
+impl Instant {
+    pub fn from_usec (timebase: &Timebase, usec: usize) -> Self {
+        Self {
+            usec:   usec.into(),
+            sample: (timebase.usecs_to_sample(usec as f64) as usize).into(),
+            pulse:  timebase.usecs_to_pulse(usec as f64).into()
+        }
+    }
+    pub fn from_sample (timebase: &Timebase, sample: usize) -> Self {
+        Self {
+            sample: sample.into(),
+            usec:   (timebase.samples_to_usec(sample as f64) as usize).into(),
+            pulse:  timebase.samples_to_pulse(sample as f64).into()
+        }
+    }
+    pub fn from_pulse (timebase: &Timebase, pulse: f64) -> Self {
+        Self {
+            pulse:  pulse.into(),
+            sample: (timebase.pulses_to_sample(pulse) as usize).into(),
+            usec:   (timebase.pulses_to_usec(pulse) as usize).into()
+        }
+    }
+}
 
 /// (pulses, name)
 pub const NOTE_DURATIONS: [(usize, &str);26] = [