diff --git a/delay/buffer.hpp b/delay/buffer.hpp
index 24416c0..200fb73 100644
--- a/delay/buffer.hpp
+++ b/delay/buffer.hpp
@@ -31,6 +31,7 @@
 #include <stdint.h>
 #include <sys/types.h>
 #include <dsp_types.hpp>
+#include <iostream>
 
 namespace dsp {
 
@@ -41,7 +42,7 @@ class Buffer
 	uint m_mask;
 	size_t m_capacity;
 	vector<T> m_buffer;
-
+	
 	public:
 	Buffer(size_t capacity)
 	: m_index(0)
@@ -75,13 +76,13 @@ class Buffer
 	}
 
 	T & operator[](int offset)
-	{
-		return m_buffer[(m_index + (uint)offset) & m_mask];
+	{	
+		return at(offset);
 	}
 
 	const T & operator[](int offset) const
 	{
-		return m_buffer[(m_index + (uint)offset) & m_mask];
+		return at(offset);
 	}
 
 	Buffer & operator ++() 
@@ -112,7 +113,43 @@ class Buffer
 		return *this;
 	}
 
+	typedef std::vector<T>::iterator iterator;
+	typedef std::vector<T>::const_iterator const_iterator;
+	iterator begin()
+	{
+		return m_buffer.begin();
+	}
+
+	iterator end()
+	{
+		return m_buffer.end();
+	}
+
+	const_iterator begin() const
+	{
+		return m_buffer.begin();
+	}
+
+	const_iterator end() const
+	{
+		return m_buffer.end();
+	}
+
+protected:
+	virtual T & at(int offset)
+	{
+		int i = (m_index + (uint)offset) & m_mask;
+		return m_buffer[i];
+	}
+
+	virtual const T & at(int offset) const
+	{
+		return at(offset);
+	}
+
+
 };
 }
 
+
 #endif // DSP_BUFFER_H
diff --git a/delay/buffer_multi.hpp b/delay/buffer_multi.hpp
index 3363caa..3383b30 100644
--- a/delay/buffer_multi.hpp
+++ b/delay/buffer_multi.hpp
@@ -31,18 +31,17 @@
 namespace dsp {
 
 template <typename T>
-class BufferMulti
+class BufferMulti : public Buffer<T>
 {
-	Buffer<T> m_buffer;
-	size_t m_capacity;
 	size_t m_numChannels;
+	size_t m_capacity;
 
 	public:
-	BufferMulti(size_t capacity, size_t numChannels)
-	: m_capacity(capacity)
+	BufferMulti(size_t numChannels, size_t capacity)
+	: Buffer<T>(capacity*numChannels)
 	, m_numChannels(numChannels)
+	, m_capacity(capacity)
 	{
-		m_buffer.resize(capacity*numChannels);
 	}
 
 	size_t capacity()
@@ -55,11 +54,19 @@ class BufferMulti
 		return m_numChannels;
 	}
 
-	void reset()
+    using Buffer<T>::at;
+	T & at(uint channel, int offset)
 	{
-		m_buffer.reset();
+		return at(int(m_capacity*channel + offset));
 	}
 
+	const T & at(uint channel, int offset) const
+	{
+		return at(channel, offset);
+	}
+
+protected:
+
 };
 }
 
diff --git a/delay/buffer_view.hpp b/delay/buffer_view.hpp
index 13839ac..0d002e3 100644
--- a/delay/buffer_view.hpp
+++ b/delay/buffer_view.hpp
@@ -59,6 +59,28 @@ class BufferView
 		return m_buffer.size();
 	}
 
+	typedef std::vector<T>::iterator iterator;
+	typedef std::vector<T>::const_iterator const_iterator;
+	iterator begin()
+	{
+		return m_buffer.begin();
+	}
+
+	iterator end()
+	{
+		return m_buffer.end();
+	}
+
+	const_iterator begin() const
+	{
+		return m_buffer.begin();
+	}
+
+	const_iterator end() const
+	{
+		return m_buffer.end();
+	}
+
 };
 }
 
diff --git a/delay/tests/Makefile b/delay/tests/Makefile
index 171f6c5..a63d90d 100644
--- a/delay/tests/Makefile
+++ b/delay/tests/Makefile
@@ -5,7 +5,7 @@ CC=clang
 CCC=clang++
 CXX=clang++
 
-NAME := test_dsp_buffer
+NAME := test_main
 CONFIG ?= debug
 TARGET ?= $(NAME)
 
@@ -13,7 +13,7 @@ CXXFLAGS += -std=c++20
 
 INCLUDES += -I $(realpath .) -I $(realpath ../../)
 
-CXX_SRCS := test_buffer.cpp 
+CXX_SRCS := test_main.cpp test_buffer.cpp test_buffer_multi.cpp 
 
 LIBS := -lstdc++
 
diff --git a/delay/tests/test_buffer.cpp b/delay/tests/test_buffer.cpp
index 20a42f6..3e35271 100644
--- a/delay/tests/test_buffer.cpp
+++ b/delay/tests/test_buffer.cpp
@@ -7,10 +7,10 @@
 template<typename T>
 void print(dsp::BufferView<T> &v, size_t size)
 {
-//	for(const auto&i : v)
-//	{
-//		std::cout << i << std::endl;
-//	}
+	for(const auto&i : v)
+	{
+		std::cout << i << std::endl;
+	}
 	std::cout << "----------------------------------------------" << std::endl;
 	for (int i=0; i < size; i++)
 	{
@@ -19,8 +19,17 @@ void print(dsp::BufferView<T> &v, size_t size)
 
 }
 
-int main()
+static void info()
 {
+	std::cout << "----------------------------------------------" << std::endl;
+	std::cout << "Start test_buffer()" << std::endl;
+	std::cout << "----------------------------------------------" << std::endl;
+}
+
+int test_buffer()
+{
+	info();
+
 	dsp::Buffer<int> buffer(10);
 	printf("Buffer capacity = %zu\n", buffer.capacity());
 	for (int i=0; i < 10; i++)
@@ -44,5 +53,10 @@ int main()
 	v2[2] = 77;
 	print(v2,10);
 
+	for(const auto&i : buffer)
+	{
+		std::cout << i+100 << std::endl;
+	}
+
 	return 0;
 }
\ No newline at end of file
diff --git a/delay/tests/test_buffer_multi.cpp b/delay/tests/test_buffer_multi.cpp
new file mode 100644
index 0000000..dbe0b61
--- /dev/null
+++ b/delay/tests/test_buffer_multi.cpp
@@ -0,0 +1,44 @@
+#include <delay/buffer_multi.hpp>
+#include <cstdio>
+
+#include <iostream>
+
+static void info()
+{
+	std::cout << "----------------------------------------------" << std::endl;
+	std::cout << "Start test_buffer_multi()" << std::endl;
+	std::cout << "----------------------------------------------" << std::endl;
+}
+
+int test_buffer_multi()
+{
+	info();
+	dsp::BufferMulti<int>buffer(5, 20);
+	printf("Buffer capacity = %zu\n", buffer.capacity());
+
+	for (int i=0; i < 10; i++)
+	{
+		for (int c=0; c < 5; c++)
+		{
+			buffer.at(c, 0) = i+1;
+		}
+		buffer += 1;
+
+	}
+
+	buffer.reset();
+	for (int i=0; i < 10; i++)
+	{
+		for (int c=0; c < 5; c++)
+		{
+			int v = buffer.at(c, i);
+			printf("c=%d: i=%d: v=%d\n", c, i, v);
+		}
+	}
+
+	for(const auto&i : buffer)
+	{
+	}
+
+	return 0;
+}
\ No newline at end of file
diff --git a/delay/tests/test_main.cpp b/delay/tests/test_main.cpp
new file mode 100644
index 0000000..36dd5b7
--- /dev/null
+++ b/delay/tests/test_main.cpp
@@ -0,0 +1,10 @@
+extern void test_buffer();
+extern void test_buffer_multi();
+
+int main()
+{
+	test_buffer();
+	test_buffer_multi();
+
+	return 0;
+}
\ No newline at end of file