diff --git a/src/audio/audio_task.cpp b/src/audio/audio_task.cpp
index 2309a5e5..390e3d2d 100644
--- a/src/audio/audio_task.cpp
+++ b/src/audio/audio_task.cpp
@@ -40,34 +40,12 @@ void AudioTaskMain(std::unique_ptr<Pipeline> pipeline, IAudioSink* sink) {
   std::optional<StreamInfo::Format> output_format;
 
   std::vector<Pipeline*> elements = pipeline->GetIterationOrder();
-  std::size_t max_inputs =
-      (*std::max_element(elements.begin(), elements.end(),
-                         [](Pipeline const* first, Pipeline const* second) {
-                           return first->NumInputs() < second->NumInputs();
-                         }))
-          ->NumInputs();
-
-  // We need to be able to simultaneously map all of an element's inputs, plus
-  // its output. So preallocate that many ranges.
-  std::vector<MappableRegion<kPipelineBufferSize>> in_regions(max_inputs);
-  MappableRegion<kPipelineBufferSize> out_region;
-  std::for_each(in_regions.begin(), in_regions.end(),
-                [](const auto& region) { assert(region.is_valid); });
-  assert(out_region.is_valid);
-
-  // Each element has exactly one output buffer.
-  std::vector<HimemAlloc<kPipelineBufferSize>> buffers(elements.size());
-  std::vector<StreamInfo> buffer_infos(buffers.size());
-  std::for_each(buffers.begin(), buffers.end(),
-                [](const HimemAlloc<kPipelineBufferSize>& alloc) {
-                  assert(alloc.is_valid);
-                });
 
   while (1) {
     for (int i = 0; i < elements.size(); i++) {
       std::vector<RawStream> raw_in_streams;
-      elements.at(i)->InStreams(&in_regions, &raw_in_streams);
-      RawStream raw_out_stream = elements.at(i)->OutStream(&out_region);
+      elements.at(i)->InStreams(&raw_in_streams);
+      RawStream raw_out_stream = elements.at(i)->OutStream();
 
       // Crop the input and output streams to the ranges that are safe to
       // touch. For the input streams, this is the region that contains
@@ -79,17 +57,12 @@ void AudioTaskMain(std::unique_ptr<Pipeline> pipeline, IAudioSink* sink) {
       OutputStream out_stream(&raw_out_stream);
 
       elements.at(i)->OutputElement()->Process(in_streams, &out_stream);
-
-      std::for_each(in_regions.begin(), in_regions.end(),
-                    [](auto&& r) { r.Unmap(); });
-      out_region.Unmap();
     }
 
-    RawStream raw_sink_stream = elements.front()->OutStream(&out_region);
+    RawStream raw_sink_stream = elements.front()->OutStream();
     InputStream sink_stream(&raw_sink_stream);
 
     if (sink_stream.info().bytes_in_stream == 0) {
-      out_region.Unmap();
       vTaskDelay(pdMS_TO_TICKS(100));
       continue;
     }
@@ -121,8 +94,6 @@ void AudioTaskMain(std::unique_ptr<Pipeline> pipeline, IAudioSink* sink) {
       }
       sink_stream.consume(sent);
     }
-
-    out_region.Unmap();
   }
 }
 
diff --git a/src/audio/include/pipeline.hpp b/src/audio/include/pipeline.hpp
index 7a658a38..1fa7da83 100644
--- a/src/audio/include/pipeline.hpp
+++ b/src/audio/include/pipeline.hpp
@@ -8,7 +8,6 @@
 #include "freertos/portmacro.h"
 
 #include "audio_element.hpp"
-#include "himem.hpp"
 #include "stream_info.hpp"
 
 namespace audio {
@@ -25,10 +24,9 @@ class Pipeline {
 
   auto NumInputs() const -> std::size_t;
 
-  auto InStreams(std::vector<MappableRegion<kPipelineBufferSize>>*,
-                 std::vector<RawStream>*) -> void;
+  auto InStreams(std::vector<RawStream>*) -> void;
 
-  auto OutStream(MappableRegion<kPipelineBufferSize>*) -> RawStream;
+  auto OutStream() -> RawStream;
 
   auto GetIterationOrder() -> std::vector<Pipeline*>;
 
@@ -36,7 +34,7 @@ class Pipeline {
   IAudioElement* root_;
   std::vector<std::unique_ptr<Pipeline>> subtrees_;
 
-  HimemAlloc<kPipelineBufferSize> output_buffer_;
+  std::array<std::byte, kPipelineBufferSize> output_buffer_;
   StreamInfo output_info_;
 };
 
diff --git a/src/audio/pipeline.cpp b/src/audio/pipeline.cpp
index bab2f3ff..270622cf 100644
--- a/src/audio/pipeline.cpp
+++ b/src/audio/pipeline.cpp
@@ -23,18 +23,14 @@ auto Pipeline::NumInputs() const -> std::size_t {
   return subtrees_.size();
 }
 
-auto Pipeline::InStreams(
-    std::vector<MappableRegion<kPipelineBufferSize>>* regions,
-    std::vector<RawStream>* out) -> void {
+auto Pipeline::InStreams(std::vector<RawStream>* out) -> void {
   for (int i = 0; i < subtrees_.size(); i++) {
-    RawStream s = subtrees_[i]->OutStream(&regions->at(i));
-    out->push_back(s);
+    out->push_back(subtrees_[i]->OutStream());
   }
 }
 
-auto Pipeline::OutStream(MappableRegion<kPipelineBufferSize>* region)
-    -> RawStream {
-  return {&output_info_, region->Map(output_buffer_)};
+auto Pipeline::OutStream() -> RawStream {
+  return {&output_info_, output_buffer_};
 }
 
 auto Pipeline::GetIterationOrder() -> std::vector<Pipeline*> {