diff --git a/mxdx/_mxdx.py b/mxdx/_mxdx.py
index 09010de..6b5e62f 100644
--- a/mxdx/_mxdx.py
+++ b/mxdx/_mxdx.py
@@ -8,6 +8,7 @@
 import glob
 import re
 import time
+from multiprocessing.synchronize import SEM_VALUE_MAX
 
 from ._io import IO, MuxFile
 from ._constants import (INTERLEAVE, R1ONLY, R2ONLY, SEQUENTIAL,
@@ -138,7 +139,7 @@ def start(self):
         """Start the Multiplexing."""
         ctx = mp.get_context('spawn')
         self.buffered_queue = BufferedQueue(ctx)
-        self.msg_queue = ctx.Queue()
+        self.msg_queue = ctx.Queue(maxsize=16)
 
         reader = ctx.Process(target=self.read)
         writer = ctx.Process(target=self.write)
@@ -176,11 +177,10 @@ class BufferedQueue:
     To adjust for this, we're increasing the amount of data which an
     individual queue item can hold.
     """
-
-    BUFSIZE = 1024
+    BUFSIZE = 128
 
     def __init__(self, ctx):
-        self._queue = ctx.Queue()
+        self._queue = ctx.Queue(maxsize=min(32767, SEM_VALUE_MAX))
         self._buf = None
         self._init_buf()
 
@@ -242,7 +242,7 @@ def start(self):
         """Start the Demultiplexing."""
         ctx = mp.get_context('spawn')
         self.buffered_queue = BufferedQueue(ctx)
-        self.msg_queue = ctx.Queue()
+        self.msg_queue = ctx.Queue(maxsize=16)
 
         reader = ctx.Process(target=self.read)
         writer = ctx.Process(target=self.write)