diff --git a/lib/cepstrum.py b/lib/cepstrum.py
index daaf1c7..1e00dac 100644
--- a/lib/cepstrum.py
+++ b/lib/cepstrum.py
@@ -1,4 +1,5 @@
 import numpy as np
+from .util import pad2
 
 # fast cepstrum and inverted fast cepstrum
 fcs  = lambda s: np.fft.ifft(np.log(np.fft.fft(s)))
@@ -32,8 +33,11 @@ def fold(r):
         rw = np.hstack((r[0], rf, np.zeros(n-nt-1)))
     return rw
 
-def minphase(s, os=True):
+def minphase(s, pad=True, os=False):
     # via https://ccrma.stanford.edu/~jos/fp/Matlab_listing_mps_m.html
+    # TODO: actual oversampling
+    if pad:
+        s = pad2(s)
     if os:
         s = np.hstack((s, np.zeros(len(s))))
     cepstrum = np.fft.ifft(np.log(clipdb(np.fft.fft(s), -100)))
diff --git a/lib/util.py b/lib/util.py
index 34d40a5..2c71c80 100644
--- a/lib/util.py
+++ b/lib/util.py
@@ -14,6 +14,9 @@ tau = 2*np.pi
 unwarp = lambda w: np.tan(w/2)
 warp = lambda w: np.arctan(w)*2
 
+ceil2 = lambda x: np.power(2, np.ceil(np.log2(x)))
+pad2 = lambda x: np.hstack((x, np.zeros(ceil2(len(x)) - len(x))))
+
 rfft = lambda src, size: np.fft.rfft(src, size*2)
 magnitude = lambda src, size: 10*np.log10(np.abs(rfft(src, size))**2)[0:size]
 
diff --git a/lib/wav.py b/lib/wav.py
index 880c1bb..e6414f2 100644
--- a/lib/wav.py
+++ b/lib/wav.py
@@ -1,5 +1,5 @@
 import numpy as np
-from . import lament
+from .util import lament, count_channels
 
 # TODO: don't use wavfile, it breaks on perfectly good files
 import scipy.io.wavfile as wav
@@ -30,3 +30,9 @@ def wav_read(fn):
         bits = s.dtype.itemsize*8
         s = np.asfarray(s)/2**(bits - 1)
     return s, srate
+
+def wav_write(fn, s, srate, dtype='h'):
+    if dtype in ('b', 'h', 'i', 'l') and np.max(np.abs(s)) > 1:
+        lament('wav_write(): WARNING; clipping')
+    with ewave.open(fn, 'w', srate, dtype, count_channels(s)) as f:
+        f.write(s)