STEREO2MidSide – Passive M/S Transformer Matrix

Overview

Features

Technical data

Downloads

FAQ

STEREO2MidSide – Passive M/S Transformer Matrix

Overview

With the M/S Matrix from AUDIOWERKZEUG, it is possible to convert stereo signals into centre and side signals using transformers. The centre signal is generated by summing the stereo signals, while the side signal is created by the difference between the stereo signals. The inputs and outputs are fully balanced. Reversing the coding of M/S signals to stereo can be realised using a push switch. If required, it is possible to switch the matrix to earth-free or floating via toggle switches in order to eliminate any hum loops.

Features

Passive M/S transformer matrix in a classic design
for converting stereo to mid and side signals
Reversal of the coding by means of a push switch
Balanced matrix design throughout
Studio transformer with wide bandwidth and symmetry
Harmonic distortion when overdriven
Elliptical filter function for low frequencies
Double magnetic shielding of the transformers
Handmade in Germany

Technical data

Input: 2x XLR/f (socket)
Input impedance: 600Ohm
Output: 2x XLR/m (plug)
Output impedance: 600Ohm
Input level max. 29dBu @ 1kHz // 16dBu @ 50Hz (1% THD)
Frequency range: 30Hz to 30kHz +/- 1.5dB
Distortion factor at 0dBu: 0.0053% @ 1kHz // 0.023% @ 50Hz
Distortion factor at 10dBu: 0.0058% @ 1kHz // 0.034% @ 50Hz
Distortion factor at 15dBu: 0.0065% @ 1kHz // 0.57% @ 50Hz
Dimensions: W/H/D: 100mm/42mm/100mm
Weight: 575g

Downloads

( STEREO2MidSide manual, following soon )

MS-Matrix parts (1)

MS-Matrix parts (2)

STEREO2MidSide isometric inside

STEREO2MidSide front

STEREO2MidSide isometric

FAQ

What is a M/S matrix – Detailed explanation

The M/S matrix (mid-side matrix) is a special circuit used in audio technology to convert conventional left/right stereo signals (L/R) into mid/side signals (M/S) and vice versa. Here, “M” stands for the center channel, which represents the sum of the left and right channels (M = L + R), while “S” stands for the side channel, which represents the difference between the left and right channels (S = L – R). This conversion enables differentiated and precise processing of the stereo recordings at a deeper level. The M/S matrix can be implemented either passively, for example using transformers, or actively using electronic circuits, which offers different advantages in terms of sound quality and signal processing depending on the requirements.

How it works in detail

L/R to M/S
In this mode, the M/S matrix adds the two input signals of the left and right channels to form a single center channel (M). At the same time, the side channel (S) is generated by subtracting the right signal from the left channel. This process allows common components of both channels to be bundled in the center channel, while the differences are recorded in the side channel.

M/S to L/R
Reconversion takes place via an inverse circuit that reconstructs the original left/right channels from the center and side signals. The signals are combined in such a way that the original stereo image is restored exactly.

Applications of the M/S matrix

Stereo recording and playback
M/S matrices are an essential tool in professional audio technology, especially for recording, editing and playback of stereo signals. They enable precise control over the stereo image, thereby improving sound quality and spatiality.

Stereo microphone technology
When miking with M/S technology, one microphone is aimed at the mid-range (M), while a second microphone is aimed to the side (S). This arrangement allows flexible editing of the stereo image as well as excellent mono compatibility.

Signal processing and mixing
M/S matrices offer a wide range of options for the specific manipulation of stereo images. For example, you can change the width of the stereo field, emphasize individual elements or correct disruptive phase problems.

Advantages of the M/S technology – overview

Variable stereo image width
By processing the mid and side components separately, you can flexibly adjust the width of the stereo image – from a narrow mono sound to a wide, spatial sound image.

Mono compatibility
Since the M/S signal essentially consists of the sum of M and S, the signal remains stable and free of cancellation or phase problems even in mono playback.

High flexibility and stability
M/S technology enables more creative possibilities than pure L/R stereo playback. The resulting stereo image is much more stable and phase shifts are avoided, especially in the bass range, which allows a clearer and more precise sound.

Summary

To summarise, the MS matrix is a powerful and versatile tool in professional audio and studio technology. It not only allows you to process stereo signals flexibly and precisely, but also improves the sound quality through stable phase characteristics and excellent mono compatibility. Through the targeted use of this technology, you benefit from optimised control over your stereo material – whether for recording, mixing or mastering.