diff --git a/brain/src/block.cpp b/brain/src/block.cpp
index 149e399..4286d32 100644
--- a/brain/src/block.cpp
+++ b/brain/src/block.cpp
@@ -112,6 +112,7 @@ void block::process(const sample &pcm, sample &fft, sample &mfcc, float &freq) {
 
   // calculate fft
   std::vector<std::complex<double> > mfspec;
+  mfspec.reserve(m_block_size);
   for (u32 i=0; i<m_block_size; ++i) {
     mfspec.push_back(std::complex<double>(m_fftw->m_spectrum[i][0],
 					  m_fftw->m_spectrum[i][1]));
diff --git a/brain/src/block_stream.cpp b/brain/src/block_stream.cpp
index ec554b6..2c69e77 100644
--- a/brain/src/block_stream.cpp
+++ b/brain/src/block_stream.cpp
@@ -79,6 +79,7 @@ void block_stream::init(u32 block_size, u32 overlap, window::type t, bool ditchp
   m_window.set_current_type(t);
 
   m_blocks.clear();
+  m_blocks.reserve(MAX_BLOCKS);
   sample dummy(block_size);
   for (u32 i=0; i<MAX_BLOCKS; i++) {
     m_blocks.push_back(block(0,"dummy",dummy,44100,m_window));