please forgive my ignorance and feel free to simply point to where I can find the information.

a colleague brought in a Sennheiser MKH 418S, I have not used it neither have I done M/S recording before.

My question is:

Even though it is a M/S mic, it is possible to record in a recorder that does not have internal M/S enconding or decoding and then decode the signal in post? I'm assuming this would not work because the information on each channel is not correct, but thought I'd check in!

if that doesn't work, I guess pluging it into a recorder that supports M/S recording such the Zoom F4 would result in the correct recording, then once I bring the file into my DAW I'd need to use a plugin for M/S decoding, is that correct?



p.s: I use Logic Audio Pro X and Pro tools 11!

2 Answers 2


M-S is just a different approach to building a stereo image. There is no magic here. It is two fixed analog audio captures, one which covers the center and one which covers the sides. The left and right sides of the figure 8 side pickup actually pick up sound from both sides, but with phasing. When you duplicate the channel and invert phase and pan, the cancellation produced between the tracks creates the left and right image correctly.

The trick with your Sennheiser MKH 418S is that it uses a single 5 pin XLR connector to provide both audio channels. You will need to break this out to a center and side feed that you can capture as two separate mono channels (via cable adapters) and then combine them in post using the pan and invert phase on the side channel. (or using built in M-S processing in your DAW)

  • Thanks AJ Henderson, super helpful. I do have a breakout splitter cable from the 5 pin to 2 mono channels. are there any specific plugins that you would recommend to decode the Mid-Side signal on the same track? Thanks again! Oct 3, 2017 at 20:09
  • @davidmesiha there is no "decoding". It's an analog thing. You simply duplicate the track, pan one left and one right and do a 180 degree phase shift on one of them. If there happens to be an M-S mode, it will do it automatically for you and might add some other adjustments, but it's nothing particularly fancy. This article on B&H's website is the reference I used when writing the answer and explains it pretty well in more detail.
    – AJ Henderson
    Oct 3, 2017 at 20:20


I found as well that there are in fact some free plugins that allow control over the Mid and Side channels directly and independently. Most of those plugins are free. Voxengo has one and Zoom also released one, although I can't get the AU version of the zoom one to work! The VST version on OSX works great and the Voxengo works great.

These plugins are excellent in the case where you would use a M/S microphone such as the KHM 418s to record into a stereo track. The resulting stereo interleaved file can simply be imported into a stereo track, then you insert the decoder plugin. using the plugin you can dial in precisely the sound you want controlling the relative volume of the Mid Vs Side channel (in effect controlling the perceived stereo width).

Following this technique means you don't have to go through the process of duplicating tracks and reversing the phase on one of them, so you effectively get the same results quicker on a single track vs 3 tracks!

hope this is helpful to someone.

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